1
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Fan H, Tang J, Lei C, Hu W, Yang H, Xiao C, Cheng G. Construction of Nitrogen-Rich Energetic Isomers Containing Multiple Hydrogen Bond Networks. Org Lett 2024; 26:8045-8050. [PMID: 39291907 DOI: 10.1021/acs.orglett.4c02867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
Nitrogen-rich energetic materials have been the focus of a few studies on their isomers. Novel nitrogen-rich energetic compounds TZ, DTZ, and NTZ were synthesized through simple steps. The hydrogen bond networks significantly enhanced their properties (TZ, Td = 290 °C and Dv = 8370 m s-1; DTZ, Td = 282 °C and Dv = 8392 m s-1; and NTZ, Td = 272 °C and Dv = 8762 m s-1), which are superior to their isomers. This realized a balance between the energy and stability of polycyclic tetrazoles, providing insights for high-performance energetic materials.
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Affiliation(s)
- Hanghong Fan
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, Jiangsu 210094, People's Republic of China
| | - Jie Tang
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, Jiangsu 210094, People's Republic of China
| | - Caijin Lei
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, Jiangsu 210094, People's Republic of China
| | - Wei Hu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, Jiangsu 210094, People's Republic of China
| | - Hongwei Yang
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, Jiangsu 210094, People's Republic of China
| | - Chuan Xiao
- China Northern Industries Group Company, Limited (Norinco Group), Beijing 100089, People's Republic of China
| | - Guangbin Cheng
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing, Jiangsu 210094, People's Republic of China
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2
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Zhang D, Guo L, Yuan Q, Shen K, Li D, Cheng L. Three-Supercenter Two-Electron Bonds in C 16H 10: Two-Dimensional Analogue of Halogen-Bridge Bonding. J Phys Chem A 2024; 128:8137-8143. [PMID: 39284747 DOI: 10.1021/acs.jpca.4c04877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2024]
Abstract
Three-center two-electron bridging bonding plays a vital role in rationalizing structures and stabilities of certain molecules. Herein, the π electron rule of pyrene (C16H10) was unraveled based on a newly proposed two-dimensional (2D) superatomic-molecule theory, where the superatomic sextet rule was regarded as a π electron counting target. C16H10 can be taken as a ◊N2◊F2 superatomic molecule, where ◊N and ◊F denote 2D superatoms bearing 3π and 5π electrons, respectively. Interestingly, it represents the first 2D superatomic halogen-bridge molecule, which realizes π electronic shell-closure via two three-supercenter two-electron bridging bonds. Additionally, a N-doped nanoporous graphene with a wide band gap (1.22 eV) was designed based on C16H10, which can be considered as a periodic aggregate of 2D superatomic wires composed of 2π-◊C and bridging ◊F superatoms. This work enriches the 2D superatomic-molecule chemistry and provides a practicable bottom-up assemble approach to obtain 2D functional materials with tunable band gaps.
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Affiliation(s)
- Dandan Zhang
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Lijiao Guo
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Qinqin Yuan
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Kaidong Shen
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Dan Li
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Longjiu Cheng
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
- Key Laboratory of Structure and Functional Regulation of Hybrid Materials, Ministry of Education, Anhui University, Hefei 230601, P. R. China
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3
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Li D, Gui Z, Ling M, Guo L, Wang Z, Yuan Q, Cheng L. Modulating the bandgap of Cr-intercalated bilayer graphene via combining the 18-electron rule and the 2D superatomic-molecule theory. NANOSCALE 2024; 16:17433-17441. [PMID: 39219367 DOI: 10.1039/d4nr02440k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Bandgap engineering of graphene is of great significance for its potential applications in electronic devices. Herein, we used a sandwich compound Cr(C6H6)2 as the building block to construct Cr-intercalated bilayer graphene (BLG), namely a C12Cr monolayer. Chemical bonding analysis reveals that strong d-π interaction ensures π electrons of the graphene layers and d orbitals of the Cr atoms localized in C6CrC6 units to achieve the favored 18-electron rule, thus leading to a bandgap of 0.24 eV. Subsequently, a C48Cr monolayer with lower proportion of Cr is further designed using Cr(C54H18)2 as building units, where a newly developed two-dimensional (2D) superatomic-molecule theory is introduced to rationalize its electronic structure. The C48Cr monolayer not only satisfies the 18-electron rule, but also localizes extra π electrons to form two layers of 2D superatomic crystals composed of 2D superatoms (◊O and ◊N), resulting in a wider bandgap of 0.74 eV. This work opens an effective avenue to modulate the bandgap of BLG via combining the 18-electron rule and the 2D superatomic-molecule theory.
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Affiliation(s)
- Dan Li
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Zaijun Gui
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Mengxuan Ling
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Lijiao Guo
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Zhifang Wang
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Qinqin Yuan
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
| | - Longjiu Cheng
- Department of Chemistry, Anhui University, Hefei, 230601, P. R. China.
- Key Laboratory of Structure and Functional Regulation of Hybrid Materials (Anhui University), Ministry of Education, Hefei, 230601, P. R. China
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4
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Amiri O, Bazgir A. Anionic aza 8π-electrocyclization as an unprecedented pathway versus 7- endo-dig: DFT study on the mechanism of base-catalyzed benzofuroazepine synthesis via cyclization of (2-alkynylbenzyl)oxy nitriles. Phys Chem Chem Phys 2024; 26:24431-24437. [PMID: 39258867 DOI: 10.1039/d4cp02458c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2024]
Abstract
DFT calculations are used to disclose the mechanism of Brønsted base-mediated cyclization of (2-alkynylbenzyl)oxy nitriles for the synthesis of benzofuroazepines. In 2015, the synthesis of substituted benzofuroazepines was reported by Zeni et al. via a stepwise mechanism known as 7-endo-dig. However, DFT calculations revealed that the anionic aza 8π-electrocyclization is more favorable than the proposed 7-endo-dig mechanism.
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Affiliation(s)
- Omid Amiri
- Department of Organic Chemistry, Shahid Beheshti University, Tehran 1983969411, Iran.
| | - Ayoob Bazgir
- Department of Organic Chemistry, Shahid Beheshti University, Tehran 1983969411, Iran.
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5
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Joshi G, Jemmis ED. The Quest for Stable Borozene Core in Main-Group Capped Inverse Sandwich Complexes, [(HE) 2B 6H 6] 2- (E=B, Al, Ga, In, and Tl). Chemistry 2024; 30:e202402410. [PMID: 39034295 DOI: 10.1002/chem.202402410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2024] [Revised: 07/15/2024] [Accepted: 07/16/2024] [Indexed: 07/23/2024]
Abstract
The ubiquitous chemistry of benzene led us to explore ways to stabilise analogous borozene, by capping them with appropriate groups. The mismatch in overlap of ring-cap fragment molecular orbitals in [(HB)2B6H6]2- is overcome by replacing the two BH caps with higher congeners of boron. We calculated the relative energies of all the polyhedral structural candidates for [(HE)2B6H6]2- (E=Al-Tl) and found hexagonal bipyramid (HBP) to be more stable with Al-H caps. A global minimum search also gives HBP as the most stable structure for [Al2B6H8]2-. The capped B6H6 ring in [(HAl)2B6H6]2- has aromaticity comparable to that of benzene.
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Affiliation(s)
- Gaurav Joshi
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Eluvathingal D Jemmis
- Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
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6
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Zhang ZF, So CW, Su MD. Four-membered heterocyclic molecules featuring boron and heavy group 14 elements that exhibit both σ-aromatic and π-aromatic properties: a new synthetic target. Dalton Trans 2024; 53:14866-14874. [PMID: 39189107 DOI: 10.1039/d4dt02002b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
In this study, we present a series of theoretically designed B2G14G14' molecules, featuring four-membered-ring heterocycles containing boron and heavy group 14 elements (G14 and G14' = Si, Ge, Sn, and Pb). Through the use of density functional theory (DFT), natural bond orbital (NBO) analysis, quantum theory of atoms in molecules (QTAIM), and electron localization function (ELF), our studies demonstrate a strong π single bond between the bridgehead G14 and G14' atoms, with minimal participation from a very weak G14-G14' σ bond. Additionally, the nucleus independent chemical shift (NICS), anisotropy of current-induced density (ACID), and adaptive natural density partitioning (AdNDP) analyses definitively establish the presence of both σ-aromaticity and π-aromaticity in these inorganic four-membered heterocyclic neutral molecules.
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Affiliation(s)
- Zheng-Feng Zhang
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan
| | - Cheuk-Wai So
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, 637371, Singapore.
| | - Ming-Der Su
- Department of Applied Chemistry, National Chiayi University, Chiayi 60004, Taiwan
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
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7
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Yu Q, Chen YC, Guo Z, Li T, Liu Z, Yi W, Staples RJ, Shreeve JM. Energetic derivatives substituted with trinitrophenyl: improving the sensitivity of explosives. Dalton Trans 2024. [PMID: 39240192 DOI: 10.1039/d4dt02070g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2024]
Abstract
The incorporation of trinitrophenyl-modified 1,3,4-oxadiazole fragments is commonly observed in high-energy molecules with heat-resistant properties. This study explores the strategy of developing heat-resistant energetic materials by incorporating trinitrophenyl and an azo group into 1,3,4-oxadiazole, which involved the synthesis and characterization of (E)-1,2-bis(5-(2,4,6-trinitrophenyl)-1,3,4-oxadiazol-2-yl)diazene (2), N-(5-(2,4,6-trinitrophenyl)-1,3,4-oxadiazol-2-yl)nitramide (3), and the energetic salts of 3. Characterization techniques employed included 1H and 13C NMR, IR and elemental analysis. Additionally, the structures of 2 and 3 were validated using single crystal X-ray analysis. To further understand the physical and chemical characteristics of these novel energetic compounds, various calculations and measurements were performed. Compound 2 exhibits excellent thermostability (Td = 294 °C), which is comparable to that of traditional heat-resistant explosive HNS (Td = 318 °C). But 2 is insensitive towards impact (>40 J) and friction (>360 N), surpassing HNS (5 J, 240 N), suggesting that compound 2 deserves further investigation as a potential heat-resistant explosive.
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Affiliation(s)
- Qiong Yu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Yu-Cong Chen
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Zihao Guo
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Tao Li
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Zunqi Liu
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Wenbin Yi
- School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Richard J Staples
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Jean'ne M Shreeve
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, USA
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8
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Zhang Z, Zhu H, Gu J, Shi H, Hirose T, Jiang L, Zhu Y, Zhong D, Wang J. Nonplanar Nanographene with a Large Conjugated π-Surface. J Am Chem Soc 2024; 146:24681-24688. [PMID: 39166837 DOI: 10.1021/jacs.4c09167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Conjugated π-surfaces are ubiquitous in molecules and materials. However, large π-surfaces up to a few nanometers in size are difficult to construct in an atomically precise manner. They tend to aggregate because of strong π-π interactions, resulting in notorious problems for both purification and spectroscopic investigations. Here, by contrast, we report the design, synthesis, and full characterizations of a nonplanar nanographene 1, which has a large, precise, and nonstacked π-surface. It is soluble in common organic solvents and allows for thorough investigations. The structure of 1, comprising 85 fused rings with an extended π-surface of 3 nm in size, is unambiguously confirmed by single-crystal X-ray diffraction. Unusual electronic structures, record-high near-infrared absorption, pronounced magnetic shielding, and ultrastrong heteromolecular van der Waals complexations are demonstrated, enabling us to establish a clear structure-property relationship, which has been elusive for decades. These results have broad implications for studying and understanding various phenomena and processes relevant to both discrete and interacting π-surfaces.
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Affiliation(s)
- Zongchi Zhang
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Han Zhu
- School of Physics, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jiajian Gu
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Haonan Shi
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Takashi Hirose
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Long Jiang
- Instrumental Analysis and Research Center, Sun Yat-Sen University, Guangzhou 510275, China
| | - Yanpeng Zhu
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
| | - Dingyong Zhong
- School of Physics, Sun Yat-Sen University, Guangzhou 510275, China
| | - Jiaobing Wang
- School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, China
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9
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Kleinpeter E, Koch A. 1H and 13C NMR spectra of infinitene and the ring current effect of the aromatic molecule. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024; 62:686-693. [PMID: 38782584 DOI: 10.1002/mrc.5467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 05/08/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024]
Abstract
The spatial magnetic properties (through-space NMR shieldings-TSNMRSs-actually the ring current effect in 1H NMR spectroscopy) of the recently synthesized infinitene (the helically twisted [12]circulene) have been calculated using the GIAO perturbation method employing the nucleus-independent chemical shift (NICS) concept and visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction. Both 1H and 13C chemical shifts of infinitene and the aromaticity of this esthetically very appealing molecule have been studied subject to the ring current effect thus obtained. This spatial magnetic response property of TSNMRSs dominates the different magnitude of 1H and 13C chemical shifts, especially in the cross-over section of infinitene, which is unequivocally classified as an aromatic molecule based on the deshielding belt of its ring current effect. Differences in aromaticity of infinitene compared with isolated benzene can also be qualified and quantified on the magnetic criterion.
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Affiliation(s)
- Erich Kleinpeter
- Institut für Chemie, Universität Potsdam, Potsdam (Golm), Germany
| | - Andreas Koch
- Institut für Chemie, Universität Potsdam, Potsdam (Golm), Germany
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10
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Valiulina LI, Cherepanov VN, Khoroshkin K. Insight into magnetically induced ring currents and photophysics of six-porphyrin nanorings. Phys Chem Chem Phys 2024; 26:22337-22345. [PMID: 39157944 DOI: 10.1039/d4cp02547d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2024]
Abstract
The series of nanorings based on Zn-porphyrins and tetraoxa-isophlorins in different oxidation states (Q = 0, 2+, 4+, 6+) have been studied studied computationally at density functional theory level (DFT) using BHandHLYP functional combined with def2-SVP basis sets. Magnetically induced ring currents of nanorings have been calculated using the GIMIC method and the Ampère-Maxwell integration scheme. Ring current calculations show that neutral nanorings sustain equal diatropic and paratropic currents of 8 nA T-1, resulting in zero net ring current strengths. The charged nanorings sustain strong ring currents with tropicity depending on the oxidation state Q. Among the considered nanorings, the nanoring composed of 6 isophlorins c-Iso66+ is the most aromatic with a ring current of IGIMIC = 81.6 nA T-1. The structure c-P62+ with a ring current of IGIMIC = 54.9 nA T-1 can be considered as the most aromatic among the synthesized porphyrin nanorings. Spin-orbit coupling matrix elements, oscillator strengths, and excitation energies calculated at the CAM-B3LYP/def2-SVP level of theory were used to estimate rate constants for radiative and nonradiative processes. The algorithm based on X-H approximation were used to calculate the internal conversion rates (kIC). The main channel for the deactivation of the excitation energy in the studied nanorings is the process of internal conversion. The deactivation of excited energy occurs due to the vibrations of certain groups of C-H bonds in the nanorings. The nanoring c-Iso6 has magnetically allowed low-lying transitions that contributes significantly to the paratropic ring current, resulting in strong local antiaromaticity in the tetraoxa-isophlorin units.
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Affiliation(s)
- Lenara I Valiulina
- Department of Optics and Spectroscopy, Tomsk State University, Tomsk, 634050, Russia.
| | - Victor N Cherepanov
- Department of Optics and Spectroscopy, Tomsk State University, Tomsk, 634050, Russia.
| | - Kirill Khoroshkin
- Department of Optics and Spectroscopy, Tomsk State University, Tomsk, 634050, Russia.
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11
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Ren P, Chen L, Sun C, Hua X, Luo N, Fan B, Chen P, Shao X, Zhang HL, Liu Z. Linear Non-benzenoid Isomer of Acene Fusing Chrysene with Azulene Units. J Phys Chem Lett 2024; 15:8410-8419. [PMID: 39116005 DOI: 10.1021/acs.jpclett.4c01917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Non-benzenoid polycyclic aromatic hydrocarbons (PAHs) have received considerable attention owing to their distinctive optical and electrical properties. Nevertheless, the synthesis and optoelectronic application of non-benzenoid PAHs remain challenging. Herein, we present a facile synthesis of linear non-benzenoid PAH with an armchair edge, diACh, by fusing chrysene with two azulene units. We systematically investigated the optical and electrical properties, which were also compared to its isomers, including benzenoid and non-benzenoid zigzag edge isomers. diACh exhibits global aromaticity, good planarity, and suitable highest occupied molecular orbital/lowest unoccupied molecular orbital energy levels. The protonation of diACh in solution successively forms a stable tropylium cation and dication. Moreover, the neutral, cationic, and dicationic states of diACh can be transformed with remarkable reversibility during the protonation-deprotonation process, as confirmed by ultraviolet-visible absorptions, fluorescence spectra, 1H nuclear magnetic resonance, and theoretical calculations. Additionally, we fabricate p-type organic field-effect transistor (OFET) devices based on diACh with hole mobility up to 0.026 cm2 V-1 s-1, and we further develop OFET-based acid vapor sensors with good sensitivity, recyclability, and selectivity. These findings underscore the unique properties of linear non-benzenoid PAHs with an armchair edge engendered by the fusion of azulene with the acene backbone, showcasing prospective applications in organic optoelectronics.
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Affiliation(s)
- Peng Ren
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China
| | - Liangliang Chen
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, People's Republic of China
| | - Chunlin Sun
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China
| | - Xinqiang Hua
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China
| | - Nan Luo
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China
| | - Baojin Fan
- College of Chemistry and Chemical Engineering Institute of Polymers and Energy Chemistry, Nanchang University, Nanchang, Jiangxi 330031, People's Republic of China
| | - Pinyu Chen
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China
| | - Xiangfeng Shao
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China
| | - Hao-Li Zhang
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China
| | - Zitong Liu
- State Key Laboratory of Applied Organic Chemistry, Key Laboratory of Special Function Materials and Structure Design, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, People's Republic of China
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12
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Ferreras KN, Harville T, Del Angel Cruz D, Gordon MS. Analysis of bonding motifs in unusual molecules II: infinitene. Phys Chem Chem Phys 2024; 26:21407-21418. [PMID: 39081231 DOI: 10.1039/d4cp01802h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
The bonding structures of infinitene, the Chemical and Engineering News 2021 Molecule of the Year, is studied by means of oriented quasi-atomic orbitals (QUAOs) to assess the degree of aromaticity within the molecule. It is found that the angularity introduced into infinitene when it takes on the helical shape of the infinity symbol has a profound effect on bond order, delocalization of bonding interactions, and the aromatic character of the system. In kekulene, a planar isomer of infinitene, the bonding analysis shows fluctuations of pocketed delocalization of bonding interactions in π-sextets associated with Clar's rule. Conversely, much smaller fluctuations are observed between the adjacent rings of infinitene. The observations drawn from the quasi-atomic bonding analysis support the idea that there is aromatic character across the entire infinitene molecule, not just localized around individual rings as in kekulene.
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Affiliation(s)
- Katherine N Ferreras
- Department of Chemistry and Ames National Laboratory, Iowa State University, Ames, Iowa, 50011, USA.
| | - Taylor Harville
- Department of Chemistry and Ames National Laboratory, Iowa State University, Ames, Iowa, 50011, USA.
| | - Daniel Del Angel Cruz
- Department of Chemistry and Ames National Laboratory, Iowa State University, Ames, Iowa, 50011, USA.
| | - Mark S Gordon
- Department of Chemistry and Ames National Laboratory, Iowa State University, Ames, Iowa, 50011, USA.
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13
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Borah B, Sharma R, Sharma PK, Barman AK. Novel 2-mercaptobenzothiazole and 2-mercaptobenzimidazole-derived Ag 16 and Ag 18 nanoclusters: synthesis and optical properties. NANOSCALE 2024; 16:14844-14852. [PMID: 39034676 DOI: 10.1039/d4nr01606h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Silver and gold nanoclusters are promising nanomaterials for various applications such as sensing, catalysis, and bioimaging. However, their synthetic control and repeatability, and determination of their structures are highly complicated. Only a handful of crystal structures of silver nanoclusters (AgNCs) have been reported, while structures of a few others have been reported with the help of mass spectrometry. We synthesized two AgNCs, viz., Ag-MBTNC (Ag16 cluster) and Ag-MBINC (Ag18 cluster) respectively stabilized by 2-mercaptobenzothiazole (2-MBT) and 2-mercaptobenzimidazole (2-MBI) with excellent repeatability; determined their composition and plausible structures using XPS, TGA and MALDI-TOF mass spectrometry; and compared their optical properties. Interestingly, Ag-MBTNC is fluorescent while Ag-MBINC is not, although these are synthesized using stabilizing ligands that have difference in only one atom. The structural features of the clusters are found to be similar but they have contrasting optical behaviours due to the effect of one S atom (in 2-MBT) in place of one N atom (in 2-MBI).
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Affiliation(s)
- Bedanta Borah
- Department of Chemistry, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
| | - Rohan Sharma
- Department of Chemistry, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
| | - Pankaz K Sharma
- Department of Chemistry, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
| | - Apurba Kr Barman
- Department of Chemistry, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
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14
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Adusei EBA, Casetti VT, Goldsmith CD, Caswell M, Alinj D, Park J, Zeller M, Rusakov AA, Kinney ZJ. Bent naphthodithiophenes: synthesis and characterization of isomeric fluorophores. RSC Adv 2024; 14:25120-25129. [PMID: 39139244 PMCID: PMC11318266 DOI: 10.1039/d4ra04850d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Accepted: 07/26/2024] [Indexed: 08/15/2024] Open
Abstract
Thiophene-containing heteroarenes are one of the most well-known classes of π-conjugated building blocks for photoactive molecules. Isomeric naphthodithiophenes (NDTs) are at the forefront of this research area due to their straightforward synthesis and derivatization. Notably, NDT geometries that are bent - such as naphtho[2,1-b:3,4-b']dithiophene (α-NDT) and naphtho[1,2-b:4,3-b']dithiophene (β-NDT) - are seldom employed as photoactive small molecules. This report investigates how remote substituents impact the photophysical properties of isomeric α- and β-NDTs. The orientation of the thiophene units plays a critical role in the emission: in the α(OHex)R2 series conjugation from the end-caps to the NDT core is apparent, while in the β(Oi-Pent)R2 series minimal change is observed unless strong electron acceptors, such as β(Oi-Pent)(PhCF3)2, are employed. This push-pull acceptor-donor-acceptor (A-D-A) fluorophore exhibits positive fluorosolvatochromism that correlates with increasing solvent polarity parameter, E T(30). In total, these results highlight how remote substituents are able to modulate the emission of isomeric bent NDTs.
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Affiliation(s)
- Emmanuel B A Adusei
- Department of Chemistry, Oakland University Rochester Michigan USA +1-248-370-2347
| | - Vincent T Casetti
- Department of Chemistry, Oakland University Rochester Michigan USA +1-248-370-2347
| | - Calvin D Goldsmith
- Department of Chemistry, Oakland University Rochester Michigan USA +1-248-370-2347
| | - Madison Caswell
- Department of Chemistry, Oakland University Rochester Michigan USA +1-248-370-2347
| | - Drecila Alinj
- Department of Chemistry, Oakland University Rochester Michigan USA +1-248-370-2347
| | - Jimin Park
- Department of Chemistry, Oakland University Rochester Michigan USA +1-248-370-2347
| | - Matthias Zeller
- Department of Chemistry, Purdue University West Lafayette Indiana USA
| | - Alexander A Rusakov
- Department of Chemistry, Oakland University Rochester Michigan USA +1-248-370-2347
| | - Zacharias J Kinney
- Department of Chemistry, Oakland University Rochester Michigan USA +1-248-370-2347
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15
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Song Y, Zhu J. Spin population determines whether antiaromaticity can increase or decrease radical stability. Phys Chem Chem Phys 2024; 26:21213-21221. [PMID: 39073087 DOI: 10.1039/d4cp01031k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Aromaticity, as a classical and fundamental concept in chemistry, can enhance thermodynamic stability. In sharp contrast, a previous study showed that antiaromaticity rather than aromaticity can enhance the radical stability of α-methyl heterocyclic compounds. Here, we demonstrate a similar antiaromaticity-promoted radical stability when the methyl group is replaced by five-membered (alkyl)(amino)cyclics (AACs). More interestingly, when an AAC is fused with an antiaromatic ring, the radical stability could be either reduced or enhanced, depending on the spin population. Specifically, when the spin density is populated on an incoming antiaromatic 1,4-dihydro-1,4-diborinine moiety, the radical stability is enhanced whereas when the spin density is maintained on the original five-membered ring, the radical stability is reduced. Our findings highlight the importance of spin density in tuning the radical stability, inviting experimental chemists' verification.
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Affiliation(s)
- Yanlin Song
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People's Republic of China
| | - Jun Zhu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, 518172, People's Republic of China.
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16
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Wang Q, Wang Y, Zhao Y, Li Y, Jiang W, Bai W. Aza-metallacycles with a heptavalent Re (d 0) center. Dalton Trans 2024; 53:12872-12875. [PMID: 39051780 DOI: 10.1039/d4dt02082k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
The oxidation state of the metal center is important for a conjugated metallacycle. Although high valent d0-metallacycles of main groups and early transition metals have been reported, such examples of late transition metals are limited. The reactions of ReOCl3(PPh3)2 with 2-ethynyl anilines produced alkenyl amino Re(V) complexes, which can be further oxidized to Re(VII) aza-metallacycles. The conjugated rhenacycle is nonaromatic, however, with close to zero NICS values and localized currents observed by AICD and GIMIC studies.
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Affiliation(s)
- Qianhang Wang
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, P.R. China.
| | - Yarong Wang
- School of Chemical Engineering, Ocean and Life Sciences, Dalian University of Technology, Panjin 124221, P.R. China.
| | - Yue Zhao
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, P.R. China.
| | - Yang Li
- School of Chemical Engineering, Ocean and Life Sciences, Dalian University of Technology, Panjin 124221, P.R. China.
| | - Wenfeng Jiang
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, P.R. China.
| | - Wei Bai
- School of Chemistry, Dalian University of Technology, Dalian, Liaoning 116024, P.R. China.
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17
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Arathi PK, Suresh CH. Direct Estimation of Aromatization Energy from 1H NMR and UV-Vis Absorption Data of Homodesmotic Molecules. J Org Chem 2024; 89:10485-10497. [PMID: 39042814 DOI: 10.1021/acs.joc.4c00668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
This study delves into the ring-opening reaction of two distinct diaryl-ring-pyran systems, referred to as drnp1 and drnp2, where the term 'ring' encompasses aromatic, nonaromatic, or antiaromatic motifs. These systems transform into the corresponding cis-ortho quinonoid systems, denoted as c-drnq1 and c-drnq2. Homodesmotic pairs (drnp1, drnp2) and (c-drnq1, c-drnq2) are categorized as (aromatic, nonaromatic), (aromatic, partially aromatic), (antiaromatic, nonaromatic), and (nonaromatic, nonaromatic), with their energy difference representing aromatization energy (Earoma). Using reliable density functional theory, Earoma is assessed for various aromatic and antiaromatic ring motifs, including borderline cases and nonaromatic structures. For example, benzene exhibits an Earoma of 23.4 kcal/mol, indicating 3.9 kcal/mol aromatic stabilization per CC bond, while cyclobutadiene shows -29.9 kcal/mol, indicating a 7.5 kcal/mol destabilization of the CC bond. This approach extends to evaluating global and local aromatic stabilization effects in polycyclic hydrocarbons, nonbenzenoid systems, and heterocyclic compounds. Additionally, variation in 1H NMR chemical shift (δavg) correlates with Earoma, suggesting that a -1.0 ppm shift corresponds to 24.2 kcal/mol aromatization energy. UV-vis absorption maxima difference (Δλavg) correlates linearly with Earoma, enabling direct assessment of aromatization energy from UV-vis spectra using suitable homodesmotic pairs. This comprehensive approach enhances our understanding of structural, energetic, and spectroscopic aspects of aromatic and antiaromatic systems.
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Affiliation(s)
- Puthiyavalappil K Arathi
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Cherumuttathu H Suresh
- Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Thiruvananthapuram 695019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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18
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Pooja, Yadav S, Pawar R. Chemistry of Cyclo[18]Carbon (C 18): A Review. CHEM REC 2024; 24:e202400055. [PMID: 38994665 DOI: 10.1002/tcr.202400055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 05/27/2024] [Indexed: 07/13/2024]
Abstract
Carbon-based allotropes are propelling a technological revolution in communication, sensing, and computing, concurrently challenging fundamental theories of the previous century. Nevertheless, the demand for advanced carbon-based materials remains substantial. The crux lies in the efficient and reliable engineering of novel carbon allotrope. Although C18 has undergone theoretical and experimental investigation for an extended period, its preparation and direct observation in the condensed phase occurred only recently through STM/AFM techniques. The distinctive cyclic ring structure and the dual 18-center π delocalization character introduce various uncommon properties to C18, rendering it a subject worthy of in-depth exploration. In this context, this review delves into past developments contributing to the state-of-the-art understanding of C18 and provides insights into how future endeavours can expedite practical applications. Encompassing a broad spectrum, this review comprehensively investigates almost all facets of C18, including geometric characteristics, electron delocalization, bonding nature, aromaticity, reactivity, electronic excitation, UV/Vis spectrum, intermolecular interaction, response to external fields, electron affinity, ionization, and other molecular properties. Moreover, the review also outlines representative strategies for the direct synthesis and characterization of C18 using atom manipulation techniques. Following this, C18-based complexes are summarized, and potential applications in catalysis, electrochemical devices, optoelectronics, and sensing are discussed.
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Affiliation(s)
- Pooja
- Laboratory of Advanced Computation and Theory for Materials and Chemistry (LACTMC), Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana, 506004, India
| | - Sarita Yadav
- Laboratory of Advanced Computation and Theory for Materials and Chemistry (LACTMC), Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana, 506004, India
| | - Ravinder Pawar
- Laboratory of Advanced Computation and Theory for Materials and Chemistry (LACTMC), Department of Chemistry, National Institute of Technology Warangal (NITW), Warangal, Telangana, 506004, India
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19
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Chen S, Imran S, Zhao Y, Zhu J. Probing the Limit of the Number of Saturated Atoms for Achieving Hyperconjugative Aromaticity. Inorg Chem 2024; 63:14162-14170. [PMID: 39014904 DOI: 10.1021/acs.inorgchem.4c02050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2024]
Abstract
Aromaticity is a fundamental concept in organic chemistry. Hyperconjugative aromaticity, also known as hyperconjugation-induced aromaticity, has evolved from its origin from main group substituents to transition metal analogues, establishing itself as an important category of aromaticity. Additionally, aromatic compounds comprising two sp3-carbon atoms have recently been reported both experimentally and computationally. However, what is the maximum number of sp3-hybridized atoms needed to maintain hyperconjugative aromaticity? Here, we report that hyperconjugative aromaticity can be achieved in hexa-substituted indoliums and octa-substituted pyrroliums, possessing three-five sp3-hybridized carbon/nitrogen atoms by means of density functional theory (DFT) calculations. The aromaticity was confirmed by using various aromaticity indices, i.e., NICS, MCI, and EDDB. Notably, the strong electron-donating ability and aurophilicity of Au(I) substituents play a pivotal role in maintaining the aromaticity and structural integrity. In addition, increasing the number of hyperconjugative centers will decrease the aromaticity in these five-membered rings. Our findings highlight the significance of transition metal substituents in hyperconjugative aromaticity and offer a novel approach for designing aromatic organometallics.
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Affiliation(s)
- Shuwen Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Sajid Imran
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Yu Zhao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Jun Zhu
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
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20
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Ganoe B, Shee J. On the notion of strong correlation in electronic structure theory. Faraday Discuss 2024. [PMID: 39072670 DOI: 10.1039/d4fd00066h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Strong correlation has been said to have many faces, and appears to have many synonyms of questionable suitability. In this work we aim not to define the term once and for all, but to highlight one possibility that is both rigorously defined and physically transparent, and remains so in reference to molecules and quantum lattice models. We survey both molecular examples - hydrogen systems (Hn, n = 2, 4, 6), Be2, H-He-H, and benzene - and the half-filled Hubbard model over a range of correlation regimes. Various quantities are examined including the extent of spin symmetry breaking in correlated single-reference wave functions, energetic ratios inspired by the Hubbard model and the Virial theorem, and metrics derived from the one- and two-electron reduced density matrices (RDMs). The trace and the square norm of the cumulant of the two-electron reduced density matrix capture what may well be defined as strong correlation. Accordingly, strong correlation is understood as a statistical dependence between two electrons, and is distinct from the concepts of "correlation energy" and more general than entanglement quantities that require a partitioning of a quantum system into distinguishable subspaces. This work enables us to build a bridge between a rigorous and quantifiable regime of strong electron correlation and more familiar chemical concepts such as anti-aromaticity in the context of Baird's rule.
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Affiliation(s)
- Brad Ganoe
- Department of Chemistry, Rice University, Houston, TX, 77005, USA.
| | - James Shee
- Department of Chemistry, Rice University, Houston, TX, 77005, USA.
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21
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Sokolova AD, Platonov DN, Belyy AY, Salikov RF, Erokhin KS, Tomilov YV. The Antiaromatic Nucleophilic Substitution Reaction (S NAAr) in Cycloheptatrienyl-Anion Containing Zwitterions with a Möbius-Aromatic Intermediate. Org Lett 2024; 26:5877-5882. [PMID: 38958743 DOI: 10.1021/acs.orglett.4c01446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
Antiaromatic nucleophilic substitution reactions in cycloheptatrienide pyridinium and phosphonium zwitterions with initial formation of a cycloheptatetraene intermediate are explored. The mechanism was supported by quantum chemical calculations, first-order reaction kinetics, and high-resolution mass spectrometry. The pyridinium zwitterion exhibited weak antiaromaticity, whereas the intermediate displayed Möbius aromaticity, as evidenced by nuclear independent chemical shift values and the shape of its HOMO. This study represents the eighth confirmed instance of a Möbius-aromatic organic species in its ground state.
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Affiliation(s)
- Alena D Sokolova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Dmitry N Platonov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Alexander Yu Belyy
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Rinat F Salikov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Kirill S Erokhin
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
| | - Yury V Tomilov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., 119991 Moscow, Russian Federation
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22
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Salikov RF, Belyy AY, Ilyushchenko MK, Platonov DN, Sokolova AD, Tomilov YV. Antiaromaticity of Cycloheptatrienyl Anions: Structure, Acidity, and Magnetic Properties. Chemistry 2024; 30:e202401041. [PMID: 38785416 DOI: 10.1002/chem.202401041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 05/25/2024]
Abstract
Investigations of the nature and degree of antiaromaticity of cycloheptatrienyl anion derivatives using both experimental and computational tools are presented. The ground state of cycloheptatrienyl anion in the gas phase is triplet, planar and Baird-aromatic. In DMSO, it assumes a singlet distorted allylic form with a paratropic ring current. The other derivatives in both phases assume either allylic or diallylic conformations depending on the substituent pattern. A combination of experimental and computational methods was used to determine the pKa values of 16 derivatives in DMSO, which ranged from 36 to -10.7. We revealed that the stronger stabilization of the anionic system, which correlates with acidity, does not necessarily imply a lower degree of antiaromaticity in terms of magnetic properties. Conversely, the substitution pattern first affects the geometry of the ring through the bulkiness of the substituents and their better conjugation with a more distorted system. Consequently, the distortion reduces the cyclic conjugation in the π-system and thereby decreases the paratropic current in a magnetic field, which manifests itself as a decrease in the NICS. The triplet-state geometries and magnetic properties are nearly independent on the substitution pattern, which is typical for simple aromatic systems.
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Affiliation(s)
- Rinat F Salikov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., Moscow, 119991, Russian Federation
- Department of Chemistry, Higher School of Economics National Research University, Moscow, 101000, Russian Federation
| | - Alexander Y Belyy
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., Moscow, 119991, Russian Federation
| | - Matvey K Ilyushchenko
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., Moscow, 119991, Russian Federation
| | - Dmitry N Platonov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., Moscow, 119991, Russian Federation
| | - Alena D Sokolova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., Moscow, 119991, Russian Federation
| | - Yury V Tomilov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky prosp., Moscow, 119991, Russian Federation
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23
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Blackner JJ, Schneider OM, Wong WO, Hall DG. Removing Neighboring Ring Influence in Monocyclic B-OH Diazaborines: Properties and Reactivity as Phenolic Bioisosteres with Dynamic Hydroxy Exchange. J Am Chem Soc 2024; 146:19499-19508. [PMID: 38959009 DOI: 10.1021/jacs.4c06360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2024]
Abstract
The design of small molecules with unique geometric profiles or molecular connectivity represents an intriguing yet neglected challenge in modern organic synthesis. This challenge is compounded when emphasis is placed on the preparation of new chemotypes that have distinct and practical functions. To expand the structural diversity of boron-containing heterocycles, we report herein the preparation of novel monocyclic hemiboronic acids, diazaborines. These compounds have enabled the study of a pseudoaromatic boranol-containing (B-OH) ring free of influence from an appended aromatic system. Synthetic and spectroscopic studies have provided insight into the aromatic character, Lewis acidic nature, chemical reactivity, and unique ability of the exocyclic B-OH unit to participate in hydroxy exchange, suggesting their use in organocatalysis and as reversible covalent inhibitors. Moreover, density functional theory and nucleus-independent chemical shift calculations reveal that the aromatic character of the boroheterocyclic ring is increased significantly in comparison to known bicyclic benzodiazaborines (naphthoid congeners), consequently leading to attenuated Lewis acidity. Direct structural comparison to a well-established biaryl isostere, 2-phenylphenol, through X-ray crystallographic analysis reveals that N-aryl derivatives are strikingly similar in size and conformation, with attenuated logP values underscoring the value of the polar BNN unit. Their potential application as low-molecular-weight scaffolds in drug discovery is demonstrated through orthogonal diversification and preliminary antifungal evaluation (Candida albicans), which unveiled analogs with low micromolar inhibitory concentration.
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Affiliation(s)
- Jake J Blackner
- Department of Chemistry, University of Alberta, Centennial Centre for Interdisciplinary Science, Edmonton, Alberta T6G 2G2, Canada
| | - Olivia M Schneider
- Department of Chemistry, University of Alberta, Centennial Centre for Interdisciplinary Science, Edmonton, Alberta T6G 2G2, Canada
| | - Warren O Wong
- Department of Chemistry, University of Alberta, Centennial Centre for Interdisciplinary Science, Edmonton, Alberta T6G 2G2, Canada
| | - Dennis G Hall
- Department of Chemistry, University of Alberta, Centennial Centre for Interdisciplinary Science, Edmonton, Alberta T6G 2G2, Canada
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24
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Qu C, Gong X, Sun Y, Gao H, Cai F, Zhao Y, Wu F, Shen Z. Synergistic meso-β regulation of porphyrins: squeezing the band gap into the near-infrared I/II region. Chem Sci 2024; 15:10491-10498. [PMID: 38994426 PMCID: PMC11234831 DOI: 10.1039/d4sc01806k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 06/01/2024] [Indexed: 07/13/2024] Open
Abstract
The development of novel near-infrared (NIR) materials with extremely small energy gaps and high stability is highly desirable in bioimaging and phototherapy. Here we report an effective strategy for narrowing the energy gaps of porphyrins by synergistic regulation of meso/β substituents. The novel NIR absorbing/emitting meso-alkynyl naphthoporphyrins (Zn-TNP and Pt-TNP) are synthesized via the retro-Diels-Alder reaction. X-ray crystallography analysis confirms the highly distorted structures of the complexes. Both compounds exhibit intense Q bands around 800 nm, while Zn-TNP shows deep NIR fluorescence at 847 nm. Pt-TNP displays NIR-II room temperature phosphorescence peaking at 1106 nm with an extremely large Stokes shift of 314 nm, which are the longest wavelengths observed among the reported platinum porphyrinoids. Furthermore, Pt-TNP shows remarkable photostability and a notable capacity for synchronous singlet oxygen and heat generation under NIR light irradiation, demonstrating potential in combined photodynamic/photothermal therapy. A theoretical analysis reveals the progressive lifting of the HOMO by the β-fused benzene ring, the decrease of the LUMO upon meso-alkynyl substitution, and energy-releasing pathways varying with metal ions. This dual regulation approach demonstrates great promise in designing innovative multifunctional NIR porphyrin materials.
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Affiliation(s)
- Chulin Qu
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Xinxin Gong
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Yufen Sun
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Hu Gao
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Fangjian Cai
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Yue Zhao
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
| | - Fan Wu
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
- School of Chemistry and Materials Science, Nanjing Normal University Nanjing 210023 China
| | - Zhen Shen
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University Nanjing 210023 China
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25
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Jiang Q, Tang H, Peng Y, Hu Z, Zeng W. Helical polycyclic hydrocarbons with open-shell singlet ground states and ambipolar redox behaviors. Chem Sci 2024; 15:10519-10528. [PMID: 38994409 PMCID: PMC11234857 DOI: 10.1039/d4sc02116a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Accepted: 05/28/2024] [Indexed: 07/13/2024] Open
Abstract
Organic π-conjugated polycyclic hydrocarbons (PHs) with an open-shell diradical character are attracting increasing interest due to their promising applications in organic electronics and spintronics. However, most of the open-shell PHs synthesized thus far are based on planar π-conjugated molecules. Herein, we report the synthesis and characterization of two new quinodimethane-embedded expanded helicenes H1 and H2. The helical structures of both molecules were revealed using X-ray crystallographic analysis. It was elucidated in detailed experimental and theoretical studies that they possess an open-shell singlet biradical structure in the ground state and show a small energy gap and amphoteric redox behavior. Both compounds can also be easily oxidized or reduced into relatively stable charged species. The dianions of H1 and H2 exhibit similar electronic structures to the respective isoelectronic structures of their all-benzenoid helical analogues according to NMR measurements and theoretical calculations. Moreover, the structures of the dication and dianion of H2 were identified by X-ray crystallographic analysis, revealing the effect of electron transfer on their backbones and aromaticity. This study thus opens up new avenues for both helical polycyclic π-systems and diradicaloids.
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Affiliation(s)
- Qing Jiang
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering Yongzhou 425100 China
| | - Hui Tang
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering Yongzhou 425100 China
| | - Yuchen Peng
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering Yongzhou 425100 China
| | - Zhenni Hu
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering Yongzhou 425100 China
| | - Wangdong Zeng
- School of Materials Science and Engineering, Hunan University of Science and Technology Xiangtan 411201 China
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26
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Zhang F, Sasmal HS, Rana D, Glorius F. Switchable and Chemoselective Arene Hydrogenation for Efficient Late Stage Applications. J Am Chem Soc 2024; 146:18682-18688. [PMID: 38934861 DOI: 10.1021/jacs.4c05883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
The incorporation of three-dimensional structures into drug molecules has demonstrated significant improvements in clinical success. Late-stage saturation of drug molecules provides a direct pathway for this transformation. However, achieving selective and controllable reduction of aromatic rings remains challenging, particularly when multiple aromatic rings coexist. Herein, we present the switchable and chemoselective hydrogenation of benzene and pyridine rings. The utility of the protocol has been comprehensively investigated in diversified substrates with the assistance of a fragment-screening technique. This approach provides convenient access to a diverse array of cyclohexane and piperidine compounds, prevalent in various bioactive molecules and drugs. Furthermore, it discloses promising avenues for applications in the late-stage switchable saturation of drugs, facilitating an increase in the fraction of sp3-carbons which holds the potential to enhance the medicinal properties of drugs.
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Affiliation(s)
- Fuhao Zhang
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Himadri Sekhar Sasmal
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Debanjan Rana
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Frank Glorius
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 36, 48149 Münster, Germany
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27
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Karmakar P, Finnegan TJ, Rostam DC, Taneja S, Uçar S, Hansen AL, Moore CE, Hadad CM, Pratumyot K, Parquette JR, Badjić JD. Molecular bowls for inclusion complexation of toxic anticancer drug methotrexate. Chem Sci 2024; 15:10155-10163. [PMID: 38966368 PMCID: PMC11220613 DOI: 10.1039/d3sc05627a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Accepted: 05/13/2024] [Indexed: 07/06/2024] Open
Abstract
We describe the preparation and study of novel cavitands, molecular bowls 16+ and 26+, as good binders of the anticancer drug methotrexate (MTX). Molecular bowls are comprised of a curved tribenzotriquinacene (TBTQ) core conjugated to three macrocyclic pyridinium units at the top. The cavitands are easily accessible via two synthetic steps from hexabromo-tribenzotriquinacene in 25% yield. As amphiphilic molecules, bowls 16+ and 26+ self-associate in water by the nucleation-to-aggregation pathway (NMR). The bowls are preorganized, having a semi-rigid framework comprising a fixed bottom with a wobbling pyridinium rim (VT NMR and MD). Further studies, both experimental (NMR) and computational (DFT and MCMM), suggested that a folded MTX occupies the cavity of bowls wherein it forms π-π, C-H-π, and ion pairing intermolecular contacts but also undergoes desolvation to give stable binary complexes (μM) in water. Moreover, a computational protocol is introduced to identify docking pose(s) of MTX inside molecular bowls from NMR shielding data. Both molecular bowls have shown in vitro biocompatibility with liver and kidney cell lines (MTS assay). As bowl 26+ is the strongest binder of MTX reported to date, we envision it as an excellent candidate for further studies on the way toward developing an antidote capable of removing MTX from overdosed cancer patients.
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Affiliation(s)
- Pratik Karmakar
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
- Supramolecular Chemistry Research Unit, Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi 126 Pracha Uthit Road, Bang Mod, Thung Khru Bangkok 10140 Thailand
| | - Tyler J Finnegan
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
| | - Darian C Rostam
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
| | - Sagarika Taneja
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
| | - Sefa Uçar
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
- Atatürk University, Faculty of Science, Department of Chemistry Erzurum 25240 Turkey
| | - Alexandar L Hansen
- Campus Chemical Instrumentation Center, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
| | - Curtis E Moore
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
| | - Christopher M Hadad
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
| | - Kornkanya Pratumyot
- Supramolecular Chemistry Research Unit, Department of Chemistry, Faculty of Science, King Mongkut's University of Technology Thonburi 126 Pracha Uthit Road, Bang Mod, Thung Khru Bangkok 10140 Thailand
| | - Jon R Parquette
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
| | - Jovica D Badjić
- Department of Chemistry and Biochemistry, The Ohio State University 100 West 18th Avenue Columbus Ohio 43210 USA
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28
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Uhlenbruck BJH, Josephitis CM, de Lescure L, Paton RS, McNally A. A deconstruction-reconstruction strategy for pyrimidine diversification. Nature 2024; 631:87-93. [PMID: 38697196 PMCID: PMC11421208 DOI: 10.1038/s41586-024-07474-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/26/2024] [Indexed: 05/04/2024]
Abstract
Structure-activity relationship (SAR) studies are fundamental to drug and agrochemical development, yet only a few synthetic strategies apply to the nitrogen heteroaromatics frequently encountered in small molecule candidates1-3. Here we present an alternative approach in which we convert pyrimidine-containing compounds into various other nitrogen heteroaromatics. Transforming pyrimidines into their corresponding N-arylpyrimidinium salts enables cleavage into a three-carbon iminoenamine building block, used for various heterocycle-forming reactions. This deconstruction-reconstruction sequence diversifies the initial pyrimidine core and enables access to various heterocycles, such as azoles4. In effect, this approach allows heterocycle formation on complex molecules, resulting in analogues that would be challenging to obtain by other methods. We anticipate that this deconstruction-reconstruction strategy will extend to other heterocycle classes.
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Affiliation(s)
| | | | - Louis de Lescure
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA
| | - Robert S Paton
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA.
| | - Andrew McNally
- Department of Chemistry, Colorado State University, Fort Collins, CO, USA.
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29
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Badri Z, Foroutan-Nejad C. On the aromaticity of actinide compounds. Nat Rev Chem 2024; 8:551-560. [PMID: 38907002 DOI: 10.1038/s41570-024-00617-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2024] [Indexed: 06/23/2024]
Abstract
The chemistry of actinides has flourished since the late 2010s with the synthesis of new actinide complexes and clusters. On the theoretical side, a range of tools is available for the characterization of these heavy element-containing compounds, but discrepancies in the assessment of aromaticity using different tools have led to controversies. In this Perspective, we examine the origin of controversies relating to the aromaticity of metallic compounds, with a focus on actinides. The aromaticity of actinides is important, not because these molecules are numerous or have a special role in catalysis or reactivity, but because this topic pushes theories of aromaticity to their limits. Owing to its reference independence, the magnetic criterion of aromaticity has been the most popular choice for the characterization of the aromaticity of metallic compounds, including actinide compounds. Through examination of several case studies, we show why this criterion might be misleading for metallic species and explain how findings relating to actinide compounds could reshape theories of aromaticity, not just for actinides but perhaps also for well-known hydrocarbons.
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Affiliation(s)
- Zahra Badri
- Institute of Organic Chemistry, Polish Academy of Sciences, Warsaw, Poland
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30
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Takahashi S, Kazama Y, Nakata N, Baceiredo A, Hashizume D, Saffon-Merceron N, Branchadell V, Kato T. Silyliumylidene Ion Stabilized by Two σ-Donating Ni(0)- and Pd(0)-Fragments. Chemistry 2024; 30:e202400054. [PMID: 38779843 DOI: 10.1002/chem.202400054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Indexed: 05/25/2024]
Abstract
A silyliumylidene ion 2 stabilized by two σ-donating Ni(0)- and Pd(0)-fragments was successfully synthesized. Due to the σ-donation of M→Si interactions, 2 presents a pyramidalized cationic silicon center with a localized lone pair. The additional coordination of basic Pd(0) fragment to the mono-Ni(0)-stabilized silyliumylidene 1 results in a higher HOMO level and an unchanged HOMO-LUMO gap and thus, 2 remains highly reactive. Interestingly, the coordination mode at the Si center is closely related to the nature of M-ligands. Indeed, the donor/donor-stabilized silyliumylidene ion 2 has been transformed into a donor/acceptor-stabilized ion 13, featuring a trigonal planar Si center with a vacant orbital, just via a ligand exchange reaction from PCy3/NHC toward PMe3.
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Affiliation(s)
- Shintaro Takahashi
- Laboratoire Hétérochimie Fondamentale et Appliquée (UMR 5069), Université de Toulouse, CNRS, 118 route de Narbonne, F-31062, Toulouse, France
| | - Yugo Kazama
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Norio Nakata
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570, Japan
| | - Antoine Baceiredo
- Laboratoire Hétérochimie Fondamentale et Appliquée (UMR 5069), Université de Toulouse, CNRS, 118 route de Narbonne, F-31062, Toulouse, France
| | - Daisuke Hashizume
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Nathalie Saffon-Merceron
- Institut de Chimie de Toulouse, UAR 2599), UPS, CNRS, ICT UAR2599 118 route de Narbonne, F-31062, Toulouse, France
| | - Vicenç Branchadell
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
| | - Tsuyoshi Kato
- Laboratoire Hétérochimie Fondamentale et Appliquée (UMR 5069), Université de Toulouse, CNRS, 118 route de Narbonne, F-31062, Toulouse, France
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31
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Venkataramanan NS, Suvitha A, Sahara R. Unveiling the Intermolecular Interactions between Drug 5-Fluorouracil and Watson-Crick/Hoogsteen Base Pairs: A Computational Analysis. ACS OMEGA 2024; 9:24831-24844. [PMID: 38882136 PMCID: PMC11170692 DOI: 10.1021/acsomega.4c01545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2024] [Revised: 05/09/2024] [Accepted: 05/14/2024] [Indexed: 06/18/2024]
Abstract
The adsorption of 5-fluorouracil (5FU) on Watson-Crick (WC) base pairs and Hoogsteen (HT) base pairs has been studied using the dispersion-corrected density functional theory (DFT). The adsorption, binding energy, and thermochemistry for the drug 5FU on the WC and HT base pairs were determined. The most stable geometries were near planar geometry, and 5FU has a higher preference for WC than HT base pairs. The adsorption energies of 5FU on nucleobase pairs are consistently higher than pristine nucleobase pairs, indicating that nucleobase pair cleavage is less likely during the adsorption of the 5FU drug. The enthalpy change for the formation of 5FU-DNA base pairs is higher than that for the formation of 5FU-nucleobases and is enthalpy-driven. The E gap of AT base pairs is higher, suggesting that their chemical reactivity toward further reaction would be less than that of GC base pairs. The electron density difference (EDD) analysis shows a significant decrease in electron density in aromatic regions on the purine bases (adenine/guanine) compared to the pyrimidine bases. The MESP diagram of the stable 5FU-nucleobase pair complexes shows a directional interaction, with the positive regions in a molecule interacting with the negative region of other molecules. The atoms in molecule analysis show that the ρ(r) values of C=O···H-N are higher than those of N···H/N-H···O. The N···H intermolecular bonds between the base pair/drug and nucleobases are weak, closed shell interactions and are electrostatic in nature. The noncovalent interaction analysis shows that several new spikes are engendered along with an increase in their strength, which indicates that the H-bonding interactions are stronger and play a dominant role in stabilizing the complexes. Energy decomposition analysis shows that the drug-nucleobase pair complex has a marginal increase in the electrostatic contributions compared to nucleobase pair complexes.
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Affiliation(s)
| | | | - Ryoji Sahara
- Research Center for Structural Materials, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305-0047, Japan
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32
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Proos Vedin N, Escayola S, Radenković S, Solà M, Ottosson H. The n,π* States of Heteroaromatics: When are They the Lowest Excited States and in What Way Can They Be Aromatic or Antiaromatic? J Phys Chem A 2024; 128:4493-4506. [PMID: 38787346 PMCID: PMC11163469 DOI: 10.1021/acs.jpca.4c02580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 05/10/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024]
Abstract
Heteroaromatic molecules are found in areas ranging from biochemistry to photovoltaics. We analyze the n,π* excited states of 6π-electron heteroaromatics with in-plane lone pairs (nσ, herein n) and use qualitative theory and quantum chemical computations, starting at Mandado's 2n + 1 rule for aromaticity of separate spins. After excitation of an electron from n to π*, a (4n + 2)π-electron species has 2n + 2 πα-electrons and 2n + 1 πβ-electrons (or vice versa) and becomes πα-antiaromatic and πβ-aromatic. Yet, the antiaromatic πα- and aromatic πβ-components seldom cancel, leading to residuals with aromatic or antiaromatic character. We explore vertically excited triplet n,π* states (3n,π*), which are most readily analyzed, but also singlet n,π* states (1n,π*), and explain which compounds have n,π* states with aromatic residuals as their lowest excited states (e.g., pyrazine and the phenyl anion). If the πβ-electron population becomes more (less) uniformly distributed upon excitation, the system will have an (anti)aromatic residual. Among isomers, the one that has the most aromatic residual in 3n,π* is often of the lowest energy in this state. Five-membered ring heteroaromatics with one or two N, O, and/or S atoms never have n,π* states as their first excited states (T1 and S1), while this is nearly always the case for six-membered ring heteroaromatics with electropositive heteroatoms and/or highly symmetric (D2h) diheteroaromatics. For the complete compound set, there is a modest correlation between the (anti)aromatic character of the n,π* state and the energy gap between the lowest n,π* and π,π* states (R2 = 0.42), while it is stronger for monosubstituted pyrazines (R2 = 0.84).
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Affiliation(s)
- Nathalie Proos Vedin
- Department
of Chemistry—Ångström Laboratory, Uppsala University, 751 20 Uppsala, Sweden
| | - Sílvia Escayola
- Institut
de Quìmica Computacional i Catàlisi and Departament
de Química, Universitat de Girona, C/Maria Aurèlia Capmany,
69, 17003 Girona, Catalonia, Spain
- Donostia
International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain
| | - Slavko Radenković
- Faculty
of Science, University of Kragujevac, P.O. Box 60, 34000 Kragujevac, Serbia
| | - Miquel Solà
- Institut
de Quìmica Computacional i Catàlisi and Departament
de Química, Universitat de Girona, C/Maria Aurèlia Capmany,
69, 17003 Girona, Catalonia, Spain
| | - Henrik Ottosson
- Department
of Chemistry—Ångström Laboratory, Uppsala University, 751 20 Uppsala, Sweden
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33
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Eshagh Saatlo R, Oczlon J, Wunsch JF, Rudolph M, Rominger F, Oeser T, Shiri F, Ariafard A, Hashmi ASK. Gold(I)-Catalyzed Intramolecular 7-endo-dig Cyclization of Triene-Yne Systems: New Access towards Azulenothiophenes. Angew Chem Int Ed Engl 2024; 63:e202402481. [PMID: 38529673 DOI: 10.1002/anie.202402481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 03/27/2024]
Abstract
We report the direct synthesis of new azulene derivatives through gold-catalyzed cyclization reactions. A five-membered ring as backbone in the applied triene-yne substrates turned out to be crucial to induce the 7-endo-dig cyclization mode necessary to trigger azulene formation. The obtained targets are of high interest due to their potential applications in different fields, like organic materials, medicine or cosmetics. UV/Vis spectra and cyclic voltammetry were measured, based on these the electronic properties were determined. Short two or three step sequences towards the applied starting materials make this approach synthetically highly attractive.
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Affiliation(s)
- Rebeka Eshagh Saatlo
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Julian Oczlon
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Jonas F Wunsch
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Matthias Rudolph
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Thomas Oeser
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Farshad Shiri
- Department of Chemistry, Islamic Azad University, Central Tehran Branch, Poonak, Tehran, Iran
| | - Alireza Ariafard
- Department of Chemistry, Islamic Azad University, Central Tehran Branch, Poonak, Tehran, Iran
- Research School of Chemistry, Australian National University, Building 137, Sullivans Creek Road, Canberra, ACT 2601, Australia
| | - A Stephen K Hashmi
- Organisch-Chemisches Institut, Heidelberg University, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
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34
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Kenouche S, Bachir N, Bouchal W, Martínez-Araya JI. Aromaticity of six-membered nitro energetic compounds through molecular electrostatic potential, magnetic, electronic delocalization and reactivity-based indices. J Mol Graph Model 2024; 129:108728. [PMID: 38412811 DOI: 10.1016/j.jmgm.2024.108728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/06/2024] [Accepted: 02/13/2024] [Indexed: 02/29/2024]
Abstract
The electron density depletion associated with π-hole at the ring center typical of energetic compounds was clearly revealed by the molecular electrostatic potential (ESP). In addition, the spatial arrangement of NO2 groups appears to affect the ESP value in the ring center, and therefore sensitivity to detonation. Indeed, for monocyclic nitrobenzene compounds with the same number of NO2 groups, the ESP value in the ring center decreases as the NO2 groups are more closely spaced. As expected, the central rings become less aromatic as NO2 groups are added. The MCI, PDI, PLR, NICSzz(1), FLU indices are all strongly correlated with the ESP values observed in the ring center of the set of nitrobenzenes. Aromaticity indices based on electron delocalization criteria appear to be very sensitive to small variations in aromaticity. Among magnetic-based indices, only NICSzz(1) is capable to predict small changes in aromaticity. The PLR index derived from conceptual DFT is quite relevant for predicting small variations in aromaticity. According to our results, the most suitable aromaticity index is not based on a single criterion, and that selecting it is more subtle. Therefore, it is important to combine information from several criteria to obtain a more complete description of the aromaticity of the studied compounds.
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Affiliation(s)
- Samir Kenouche
- Group of Modeling of Chemical Systems using Quantum Calculations, Applied Chemistry Laboratory (LCA). University M. Khider of Biskra, 07000 Biskra, Algeria
| | - Nassima Bachir
- Group of Modeling of Chemical Systems using Quantum Calculations, Applied Chemistry Laboratory (LCA). University M. Khider of Biskra, 07000 Biskra, Algeria
| | - Wissam Bouchal
- Molecular Chemistry and Environment Laboratory, University of Mohammed Khider of Biskra, BP 145 RP, Biskra 07000, Algeria
| | - Jorge I Martínez-Araya
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello (UNAB), Av. República 275, 8370146 Santiago, Chile; Centro de Química Teórica y Computacional (CQT&C). Facultad de Ciencias Exactas, Santiago, Chile.
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35
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Guo L, Zhang D, Shen K, Yuan Q, Li D, Cheng L. Aromatic Rules of C 22H 122+/2•/2-: Flexibility in Electronic Structures of 2D Superatomic Molecules. J Phys Chem Lett 2024; 15:5754-5760. [PMID: 38776121 DOI: 10.1021/acs.jpclett.4c01109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2024]
Abstract
Triangulene (C22H122•), a nonclassic non-Kekulé polycyclic aromatic hydrocarbon, is identified to be aromatic by structural and magnetic criteria. However, its aromatic origin remains confusing. Herein, the aromatic rules of C22H122• and its two charged counterparts C22H122+/2- were investigated on the basis of a recently developed two-dimensional (2D) superatomic-molecule theory. [C22H12]2+/2•/2- exhibit obvious local aromatic characters and can be regarded as [◊N3◊O3]+, [◊N3◊O3]-, and ◊N3◊F3 superatomic molecules, respectively, where ◊N, ◊O, and ◊F denote 2D superatoms bearing 3π, 4π, and 5π electrons. [C22H12]2+/2- realize electronic shell closure via superatomic lone pairs and covalent bonds, mimicking simple molecules, whereas the α-π and β-π electrons in C22H122• follow the superatomic bonding patterns of C22H122- and C22H122+, respectively. Furthermore, based on the local character in 2D superatomic molecules, a doped nanoporous graphene, namely, C9N12B monolayer, was predicted. The material possesses excellent dynamical and thermodynamical stability, as well as a wide band gap of 2.77 eV, positioning it as a promising 2D material for future electronic applications.
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Affiliation(s)
- Lijiao Guo
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Dandan Zhang
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Kaidong Shen
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Qinqin Yuan
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Dan Li
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
| | - Longjiu Cheng
- Department of Chemistry, Anhui University, Hefei 230601, P. R. China
- Key Laboratory of Structure and Functional Regulation of Hybrid Materials, (Anhui University), Ministry of Education, Hefei 230601, P. R. China
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36
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Yang J, Xu X, Lin Z, Xie Z. Metallaaromaticity involving a d 0 early transition metal centre: synthesis, structure, and aromaticity of tantallapyridinazirine complexes. Chem Sci 2024; 15:7943-7948. [PMID: 38817586 PMCID: PMC11134392 DOI: 10.1039/d4sc02629b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Accepted: 05/03/2024] [Indexed: 06/01/2024] Open
Abstract
Though late transition metal aromatic metallabenzenes and related heteroatom-containing analogues have been well studied, the corresponding aromatic early transition metal complexes remain elusive. Herein, we demonstrate the synthesis of aromatic, planar, and delocalised organotantallapyridinium complexes via a simple one-pot process by sequential treatment of tantalum methyl complex [η5:σ-Me2C(C5H4)(C2B10H10)]TaMe3 with alkynes and isocyanide. Single-crystal X-ray analyses, NMR spectroscopic data and DFT calculations suggest that they are aromatic tantallapyridinium complexes, a class of long-sought-after molecules. This work would shed some light on the preparation of metallaaromatics involving early transition metals.
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Affiliation(s)
- Jingting Yang
- Department of Chemistry, State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin New Territories Hong Kong China
| | - Xin Xu
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong China
| | - Zuowei Xie
- Department of Chemistry, State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong Shatin New Territories Hong Kong China
- Shenzhen Grubbs Institute, Department of Chemistry, Southern University of Science and Technology Shenzhen 518055 China
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37
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Li J, Li K, Wu L, Wang H. Synthesis and Characterization of an All-Germanium Analogue of Cyclobutane-1,3-diyl. J Am Chem Soc 2024; 146:14386-14390. [PMID: 38747544 DOI: 10.1021/jacs.3c13727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
A tetragermacyclobutane-1,3-diyl was prepared and structurally characterized via the reduction of chlorogermylene-coordinated germylgermylene with potassium graphite, which represents the first all-germanium analogue of cyclobutane-1,3-diyl. Single-crystal X-ray analysis of the tetragermacyclobutane-1,3-diyl disclosed that it adopts a planar-cis structure, which is different from those reported all-silicon cyclobutane-1,3-diyls. DFT calculations revealed that both the bulky substituents on the germanium atoms and the tethering of the amido groups are important for the planar cis-configuration of 5.
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Affiliation(s)
- Jiazhong Li
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, P. R. China
| | - Kai Li
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interfaces Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Linlin Wu
- Hunan Provincial Key Laboratory of Micro & Nano Materials Interfaces Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, P. R. China
| | - Hao Wang
- School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, P. R. China
- State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, P. R. China
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38
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Radenković S, Đorđević S, Nikolendžić M. Effect of Benzo-Annelation on Triplet State Energies in Polycyclic Conjugated Hydrocarbons. Chemistry 2024; 30:e202400361. [PMID: 38488676 DOI: 10.1002/chem.202400361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Indexed: 04/09/2024]
Abstract
In a series of earlier studies, the effect of benzo-annelation was found to be a useful tool for tuning the aromaticity in polycyclic conjugated compounds to desired level. In this work we studied the (anti)aromaticity of benzo-annelated derivatives of three conjugated hydrocarbons (anthracene, fluoranthene and biphenylene) in their lowest lying singlet (S0) and triplet (T1) states by means of the energy effect (ef), harmonic oscillator model of aromaticity (HOMA), multicentre delocalization indices (MCI), magnetically induced current densities (MICDs) and nucleus independent chemical shifts (NICS). We showed that benzo-annelation is a topology-based effect which can be used to modify the T1 state excitation energies (E(T1)). A quantitative model was established being able to accurately predict the E(T1) based only on the numbers of angularly, linearly and geminally annelated benzene rings. In addition, it was demonstrated that the E(T1) can be directly related to the (anti)aromatic character of the central ring in the studied molecules in their S0 state.
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Affiliation(s)
- Slavko Radenković
- University of Kragujevac, Faculty of Science, P.O. Box 60, Kragujevac, 34000, Serbia
| | - Slađana Đorđević
- University of Kragujevac, Faculty of Science, P.O. Box 60, Kragujevac, 34000, Serbia
| | - Marijana Nikolendžić
- University of Kragujevac, Faculty of Science, P.O. Box 60, Kragujevac, 34000, Serbia
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Dunkel P, Bogdán D, Deme R, Zimber Á, Ballayová V, Csizmadia E, Kontra B, Kalydi E, Bényei A, Mátyus P, Mucsi Z. C(sp 3)-H cyclizations of 2-(2-vinyl)phenoxy- tert-anilines. RSC Adv 2024; 14:16784-16800. [PMID: 38784409 PMCID: PMC11112676 DOI: 10.1039/d3ra08974f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 04/29/2024] [Indexed: 05/25/2024] Open
Abstract
1,5-hydride transfer-triggered cyclization reactions offering a robust method for C(sp3)-C(sp3) coupling and the synthesis of e.g. tetrahydroquinolines have been thoroughly investigated in the literature. Catalysts allowing milder reaction conditions or the development of enantioselective processes were important recent contributions to the field, as well as the studies on subtrates with oxygen or sulfur heteroatoms (besides the originally described nitrogen heterocycles). In a series of studies, we focused on expanded, higher order H-transfers/cyclizations by positioning the interacting substituents on distanced rings. Cyclizations of appropriately functionalized biaryl and fused bicyclic systems led to 7-9 membered rings. In the frame of this research, we set out to study the feasibility of the cyclization and the factors affecting it by in silico methods. The conclusions drawn from computational studies were complemented by cyclization screens on 2-(2-vinyl)phenoxy-tert-anilines and their CH2-expanded analogues, the results of which are presented here. Besides isolating the expected oxazonine products in several cases, we also observed a unique dimer formation, leading to an interesting 5-6-5 ring system.
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Affiliation(s)
- Petra Dunkel
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
| | - Dóra Bogdán
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
| | - Ruth Deme
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
| | - Ádám Zimber
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
| | - Veronika Ballayová
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
- Department of Chemical Drugs, Masaryk University Palackého 1946/1 612 00 Brno Czech Republic
| | - Eszter Csizmadia
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
| | - Bence Kontra
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
- Department of Biological Chemistry, Brain Vision Center Liliom utca 43-45 H-1094 Budapest Hungary
| | - Eszter Kalydi
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
| | - Attila Bényei
- Institute of Physical Chemistry, University of Debrecen Egyetem tér 1 H-4010 Debrecen Hungary
| | - Péter Mátyus
- Department of Organic Chemistry, Semmelweis University Hőgyes Endre utca 7 H-1092 Budapest Hungary
- University of Veterinary Medicine István utca 2 H-1078 Budapest Hungary
| | - Zoltán Mucsi
- Department of Biological Chemistry, Brain Vision Center Liliom utca 43-45 H-1094 Budapest Hungary
- Department of Chemistry, Femtonics Ltd Tűzoltó utca 59 H-1094 Budapest Hungary
- Institute of Chemistry, University of Miskolc Egyetem út 1 H-3515 Miskolc Hungary
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40
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Cador A, Kahlal S, Richards GJ, Halet JF, Hill JP. Protic Processes in an Extended Pyrazinacene: The Case of Dihydrotetradecaazaheptacene. Molecules 2024; 29:2407. [PMID: 38792268 PMCID: PMC11124472 DOI: 10.3390/molecules29102407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 05/14/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024] Open
Abstract
Pyrazinacenes are linearly fused heteroaromatic rings, with N atoms replacing all apical CH moieties. Component rings may exist in a reduced state, having NH groups instead of N, causing cross-conjugation. These compounds have interesting optical and electronic properties, including strong fluorescence in the near-infrared region and photocatalytic properties, leading to diverse possible applications in bio-imaging and organic synthesis, as well as obvious molecular electronic uses. In this study, we investigated the behavior of seven-ring pyrazinacene 2,3,11,12-tetraphenyl-7,16-dihydro-1,4,5,6,7,8,9,12,13,14,15,16,17,18-tetradecaazaheptacene (Ph4H2N14HEPT), with an emphasis on protic processes, including oxidation, tautomerism, deprotonation, and protonation, and the species resulting from those processes. We used computational methods to optimize the structures of the different species and generate/compare molecular orbital structures. The aromaticity of the species generated by the different processes was assessed using the nucleus-independent chemical shifts, and trends in the values were associated with the different transformations of the pyrazinacene core. The computational data were compared with experimental data obtained from synthetic samples of the molecule tBu8Ph4H2N14HEPT.
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Affiliation(s)
- Aël Cador
- French Alternative Energies and Atomic Energy Commission, CEA Saclay, DRF/IRAMIS/NIMBE/LSDRM, F-91191 Gif-sur-Yvette, France;
- Ecole Nationale Supérieure de Chimie de Rennes (ENSCR), CNRS, Institut des Sciences Chimiques de Rennes (ISCR), University of Rennes, UMR 6226, 11 Allée de Beaulieu, F-35708 Rennes, France;
| | - Samia Kahlal
- Ecole Nationale Supérieure de Chimie de Rennes (ENSCR), CNRS, Institut des Sciences Chimiques de Rennes (ISCR), University of Rennes, UMR 6226, 11 Allée de Beaulieu, F-35708 Rennes, France;
| | - Gary J. Richards
- Department of Applied Chemistry, Graduate School of Engineering and Science, Shibaura Institute of Technology, Fukasaku 307, Minuma-ku, Saitama-shi 337-8570, Saitama, Japan;
| | - Jean-François Halet
- Ecole Nationale Supérieure de Chimie de Rennes (ENSCR), CNRS, Institut des Sciences Chimiques de Rennes (ISCR), University of Rennes, UMR 6226, 11 Allée de Beaulieu, F-35708 Rennes, France;
- CNRS–Saint-Gobain–NIMS, IRL 3629, Laboratory for Innovative Key Materials and Structures (LINK), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Ibaraki, Japan
| | - Jonathan P. Hill
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, Namiki 1-1, Tsukuba 305-0044, Ibaraki, Japan
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41
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Franquesa-Viñas P, Ribas-Ariño J, Santiago R, Deumal M. Enhancing Intramolecular Ferromagnetic Coupling in Tetrathiafulvalene-Nitronyl Nitroxide-Based Compounds through Spin Polarization Mechanism. Chemistry 2024; 30:e202400166. [PMID: 38530333 DOI: 10.1002/chem.202400166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/01/2024] [Accepted: 03/11/2024] [Indexed: 03/27/2024]
Abstract
Spin-polarized donor radicals based on tetrathiafulvalene (TTF) derivatives and nitronyl nitroxide (NN) radicals in which one-electron oxidation involves the HOMO instead of the SOMO are well known for exhibiting magnetoresistance. In particular, BTBN consists of one dibromo-TTF and one NN radical, which are linked by a phenyl coupler group. One of the key factors driving magnetoresistance is the presence of intramolecular ferromagnetic (FM) coupling between the oxidized π-donor (TTF+⋅, D unit) and NN (R unit). Here, a theoretical study is carried out to assess suitable candidates with enhanced FM coupling with respect BTBN, which is thus used as a reference. The study is conducted via in silico chemical modification of the substituents of the BTBN basic functional units (D and R radicals, C coupler) to benefit from the spin polarization mechanism to boost the intramolecular FM coupling, aiming to distort the BTBN radical arrangement within the molecular crystal as little as possible, in the event the material can be synthesized. NICSiso(1) and Wiberg's Bond Order are analyzed to further assist in identifying promising potential candidates, since the decrease in aromaticity is expected to enhance the diradical character and give rise to a larger magnetic coupling value. The most favorable diradical building block to replace the BTBN moiety results from using a hydroxyl-ethylene (-(H)C=C(OH)-) as a coupler preserving BTBN original radicals, namely, NN and TTF+⋅ units. This study aims at illustrating the feasibility of improving the intramolecular FM interaction between radical moieties, which is fully realized, as a first step towards the synthesis of new materials with (possibly) enhanced magnetoresistance properties.
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Affiliation(s)
- Pau Franquesa-Viñas
- Departament de Ciència de Materials i Química Física & IQTCUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona
| | - Jordi Ribas-Ariño
- Departament de Ciència de Materials i Química Física & IQTCUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona
| | - Raul Santiago
- Departament de Ciència de Materials i Química Física & IQTCUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona
| | - Mercè Deumal
- Departament de Ciència de Materials i Química Física & IQTCUB, Facultat de Química, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona
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42
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Filatov M, Mironov V, Kraka E. Unraveling the effect of aromaticity for the dynamics of excited states of single benzene fluorophores. J Comput Chem 2024; 45:1033-1045. [PMID: 38216513 DOI: 10.1002/jcc.27304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/23/2023] [Accepted: 12/23/2023] [Indexed: 01/14/2024]
Abstract
The photophysical properties of a series of recently synthesized single benzene fluorophores were investigated using ensemble density functional theory calculations. The energetic stability of the ground and excited state species were counterposed against the aromaticity index derived from local vibrational modes. It was found that the large Stokes shift of the fluorophores (up to ca. 5800 cm - 1 ) originates from the effect of electron donating and electron withdrawing substituents rather than π -delocalization and related (anti-)aromaticity. On the basis of nonadiabatic molecular dynamics simulations, the absence of fluorescence from one of the regioisomers was explained by the occurrence of easily accessible S 1 /S 0 conical intersections below the vertical excitation energy level. It is demonstrated in the manuscript that the analysis of local mode force constants and the related aromaticity index represent a useful tool for the characterization of π -delocalization effects in π -conjugated compounds.
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Affiliation(s)
- Michael Filatov
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan, Republic of Korea
- Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, Dallas, Texas, USA
| | | | - Elfi Kraka
- Computational and Theoretical Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, Dallas, Texas, USA
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43
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Wang K, You X, Miao X, Yi Y, Peng S, Wu D, Chen X, Xu J, Sfeir MY, Xia J. Activated Singlet Fission Dictated by Anti-Kasha Property in a Rylene Imide Dye. J Am Chem Soc 2024; 146:13326-13335. [PMID: 38693621 DOI: 10.1021/jacs.4c01732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
A key challenge in the search of new materials capable of singlet fission (SF) arises from the primary energy conservation criterion, i.e., the energy of the triplet exciton has to be half that of the singlet (E(S1) ≥ 2E(T1)), which excludes most photostable organic materials from consideration and confines the design strategy to materials with low energy triplet states. One potential way to overcome this energy requirement and improve the triplet energy is to enable a SF channel from higher energy ("hot") excitonic states (Sn) in a process called activated SF. Herein, we demonstrate that efficient activated SF is achieved in a rylene imide-based derivative acenaphth[l, 2-a]acenaphthylene diimide (AADI). This process is enabled by an increase in the energy gap to greater than 1.0 eV between the S3 and S1 states due to the incorporation of an antiaromatic pentalene unit, which leads to the emergence of anti-Kasha properties in the isolated molecule. Transient spectroscopy studies show that AADI undergoes ultrafast SF from higher singlet excited states in thin film, with excitation wavelength-dependent SF yields. The SF yield of ∼200% is observed upon higher energy excitation, and long-lived free triplets persist on the μs time scale suggesting that AADI can be used in SF-enhanced devices. Our results suggest that enlarging the Sn-S1 energy gap is an effective way to turn on the activated SF channel and shed light on the development of novel, stable SF materials with high triplet energies.
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Affiliation(s)
- Kangwei Wang
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan 430070, China
| | - Xiaoxiao You
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan 430070, China
| | - Xiaodan Miao
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy Sciences, Beijing 100049, China
| | - Yuanping Yi
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy Sciences, Beijing 100049, China
| | - Shaoqian Peng
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan 430070, China
| | - Di Wu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan 430070, China
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, China
| | - Xingyu Chen
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan 430070, China
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, China
| | - Jingwen Xu
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan 430070, China
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, China
| | - Matthew Y Sfeir
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York 10016, United States
- Department of Physics, Graduate Center, City University of New York, New York 10031, United States
| | - Jianlong Xia
- State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Center of Smart Materials and Devices, Wuhan University of Technology, Wuhan 430070, China
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, China
- International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China
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44
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Preethalayam P, Roldao JC, Castet F, Casanova D, Radenković S, Ottosson H. 3,4-Dimethylenecyclobutene: A Building Block for Design of Macrocycles with Excited State Aromatic Low-Lying High-Spin States. Chemistry 2024; 30:e202303549. [PMID: 38433097 DOI: 10.1002/chem.202303549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/25/2024] [Accepted: 02/29/2024] [Indexed: 03/05/2024]
Abstract
3,4-Dimethylenecyclobutene (DMCB) is an unusual isomer of benzene. Motivated by recent synthetic progress to substituted derivatives of this scaffold, we carried out a theoretical and computational analysis with a particular focus on the extent of (anti)aromatic character in the lowest excited states of different multiplicities. We found that the parent DMCB is non-aromatic in its singlet ground state (S0), lowest triplet state (T1), and lowest singlet excited state (S1), while it is aromatic in its lowest quintet state (Q1) as this state is represented by a triplet multiplicity cyclobutadiene (CBD) ring and two uncoupled same-spin methylene radicals. Interestingly, the Q1 state, despite having four unpaired electrons, is placed merely 4.8 eV above S0, and there is a corresponding singlet tetraradical 0.16 eV above. The DMCB is potentially a highly useful structural motif for the design of larger molecular entities with interesting optoelectronic properties. Here, we designed macrocycles composed of fused DMCB units, and according to our computations, two of these have low-lying nonet states (i. e., octaradical states) at energies merely 2.40 and 0.37 eV above their S0 states as a result of local Hückel- and Baird-aromatic character of individual 6π- and 4π-electron monocycles.
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Affiliation(s)
| | - Juan Carlos Roldao
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
- Donostia International Physics Center (DIPC), 20018, Donostia, Euskadi, Spain
- University of Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33405 Cedex, Talence, France
| | - Frédéric Castet
- University of Bordeaux, CNRS, Bordeaux INP, ISM, UMR 5255, F-33405 Cedex, Talence, France
| | - David Casanova
- Donostia International Physics Center (DIPC), 20018, Donostia, Euskadi, Spain
- IKERBASQUE - Basque Foundation for Science, 48009, Bilbao, Euskadi, Spain
| | - Slavko Radenković
- University of Kragujevac, Faculty of Science, P. O. Box 60, 34000, Kragujevac, Serbia
| | - Henrik Ottosson
- Department of Chemistry - Ångström Laboratory, Uppsala University, Uppsala, Sweden
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45
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Cañadas P, Díaz J, López R, Menéndez MI, Pérez J, Riera L. Elucidation of the Pyridine Ring-Opening Mechanism of 2,2'-Bipyridine or 1,10-Phenanthroline Ligands at Re(I) Carbonyl Complexes. Inorg Chem 2024; 63:8593-8603. [PMID: 38640477 DOI: 10.1021/acs.inorgchem.3c04434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Abstract
The cleavage of the C-N bonds of aromatic heterocycles, such as pyridines or quinolines, is a crucial step in the hydrodenitrogenation (HDN) industrial processes of fuels in order to minimize the emission of nitrogen oxides into the atmosphere. Due to the harsh conditions under which these reactions take place (high temperature and H2 pressure), the mechanism by which they occur is only partially understood, and any study at the molecular level that reveals new mechanistic possibilities in this area is of great interest. Herein, we unravel the pyridine ring-opening mechanism of 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen) ligands coordinated to the cis-{Re(CO)2(N-RIm)(PMe3)} (N-RIm= N-alkylimidazole) fragment under mild conditions. Computational calculations show that deprotonation of the pyridine ring, once dearomatized, is crucial to induce ring contraction, triggering extrusion of the nitrogen atom from the ring and cleavage of the C-N bond. It is noteworthy that different products (regioisomers) are obtained depending on whether the ligand used is bipy or phen due to the additional rigidity and stability conferred by the central ring of the phen ligand, an issue also addressed and clarified computationally. Strong support for the proposed mechanism is provided by the characterization and isolation, including three single-crystal X-ray diffraction structures, of several of the proposed reaction intermediates.
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Affiliation(s)
- Purificación Cañadas
- Departamento de Química Orgánica e Inorgánica, Universidad de Oviedo, Julián Clavería, 8, Oviedo 33006, Spain
| | - Jesús Díaz
- Departamento de Química Orgánica e Inorgánica, Universidad de Extremadura, Avda. de la Universidad s/n, Cáceres 33071, Spain
| | - Ramón López
- Departamento de Química Física y Analítica, Universidad de Oviedo, Julián Clavería, 8, Oviedo 33006, Spain
| | - M Isabel Menéndez
- Departamento de Química Física y Analítica, Universidad de Oviedo, Julián Clavería, 8, Oviedo 33006, Spain
| | - Julio Pérez
- Departamento de Química Orgánica e Inorgánica, Universidad de Oviedo, Julián Clavería, 8, Oviedo 33006, Spain
- Centro de Investigación en Nanomateriales y Nanotecnología (CINN), Consejo Superior de Investigaciones Científicas (CSIC). Avda. de la Vega, 4-6, El Entrego 33940, Spain
| | - Lucía Riera
- Centro de Investigación en Nanomateriales y Nanotecnología (CINN), Consejo Superior de Investigaciones Científicas (CSIC). Avda. de la Vega, 4-6, El Entrego 33940, Spain
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46
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Swain CK, Scheiner S. Comparison of Various Theoretical Measures of Aromaticity within Monosubstituted Benzene. Molecules 2024; 29:2260. [PMID: 38792120 PMCID: PMC11123954 DOI: 10.3390/molecules29102260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
The effects of monosubstitution on the aromaticity of benzene are assessed using a number of different quantitative schemes. The ability of the mobile π-electrons to respond to an external magnetic field is evaluated using several variants of the NICS scheme which calculate the shielding of points along the axis perpendicular to the molecule. Another class of measures is related to the drive toward the uniformity of C-C bond lengths and strengths. Several energetic quantities are devised to approximate an aromatic stabilization energy and the tendency of the molecule to maintain planarity. There is a lack of consistency in that the various measures of aromaticity lead to differing conclusions as to the effects of substituents on the aromaticity of the ring.
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Affiliation(s)
| | - Steve Scheiner
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
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47
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Xia Z, Wang W, Zhang G. Formation of Nitrogen-Doped Positively Curved Molecules by π-Extension. Org Lett 2024; 26:3901-3905. [PMID: 38666661 DOI: 10.1021/acs.orglett.4c01087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2024]
Abstract
Two nitrogen-doped positively curved aromatic molecules bearing doubly fused pentagonal rings were synthesized and characterized. Crystallographic analysis confirms the formation of a bowl-shaped structure, which is induced by the fusion of adjacent pentagons to the rigid aromatic planes. Both compounds demonstrate good photoluminescence. These electron-rich bowl-shaped molecules can associate with C60 to form complexes in 2:1 ratio in toluene with different association constants depending on the molecular dimension of the hosts.
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Affiliation(s)
- Zhen Xia
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, P. R. China
| | - Weifan Wang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, P. R. China
| | - Gang Zhang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, P. R. China
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48
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Sheng W, Rajeshkumar T, Zhao Y, Maron L, Zhu C. Electronic Delocalization and σ-Aromaticity in Heterometallic Cluster with Multiple Thorium-Palladium Bonds. J Am Chem Soc 2024; 146:12790-12798. [PMID: 38684067 DOI: 10.1021/jacs.4c03058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Research on metal-metal bonds involving f-block actinides, such as thorium, lags far behind the well-studied metal-metal bonds of d-block transition metals. The complexes with Th-TM bonds are extremely rare; all previously identified examples have only a single Th-TM bond with the Th center at an invariably +IV oxidation state. Herein, we report a series of Th2Pdn (n = 2, 3, and 6) clusters (complexes 3, 4, and 7) with multiple Th(III)-Pd bonds. Theoretical studies reveal that the Th2Pdn unit allows electronic delocalization and σ aromaticity, leading to unexpected closed-shell singlet structures for these Th(III) species. This electronic delocalization is evident in the highest occupied molecular orbital of Th(III) complexes and facilitates a 2e reduction of alkyne by complex 7, resulting in the formation of 8. Complexes 7 and 8 are distinctive in featuring a Th2Pd6 core with six and eight Th-Pd bonds, respectively, making them the largest known d-f heterometallic clusters exhibiting metal-metal bonding.
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Affiliation(s)
- Weiming Sheng
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Thayalan Rajeshkumar
- LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Yue Zhao
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Laurent Maron
- LPCNO, CNRS & INSA, Université Paul Sabatier, 135 Avenue de Rangueil, 31077 Toulouse, France
| | - Congqing Zhu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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49
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Cai L, Xu B, Cheng J, Cong F, Riedel S, Wang X. N 2 cleavage by silylene and formation of H 2Si(μ-N) 2SiH 2. Nat Commun 2024; 15:3848. [PMID: 38719794 PMCID: PMC11078988 DOI: 10.1038/s41467-024-48064-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 04/19/2024] [Indexed: 05/12/2024] Open
Abstract
Fixation and functionalisation of N2 by main-group elements has remained scarce. Herein, we report a fixation and cleavage of the N ≡ N triple bond achieved in a dinitrogen (N2) matrix by the reaction of hydrogen and laser-ablated silicon atoms. The four-membered heterocycle H2Si(μ-N)2SiH2, the H2SiNN(H2) and HNSiNH complexes are characterized by infrared spectroscopy in conjunction with quantum-chemical calculations. The synergistic interaction of the two SiH2 moieties with N2 results in the formation of final product H2Si(μ-N)2SiH2, and theoretical calculations reveal the donation of electron density of Si to π* antibonding orbitals and the removal of electron density from the π bonding orbitals of N2, leading to cleave the non-polar and strong NN triple bond.
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Affiliation(s)
- Liyan Cai
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai, 200092, China
| | - Bing Xu
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai, 200092, China.
| | - Juanjuan Cheng
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai, 200092, China
| | - Fei Cong
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai, 200092, China
| | - Sebastian Riedel
- Institut für Chemie und Biochemie - Anorganische Chemie, Freie Universität Berlin, Fabeckstrasse 34-36, D-14195, Berlin, Germany.
| | - Xuefeng Wang
- School of Chemical Science and Engineering, Shanghai Key Lab of Chemical Assessment and Sustainability, Tongji University, Shanghai, 200092, China.
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Zubkov MO, Dilman AD. Radical reactions enabled by polyfluoroaryl fragments: photocatalysis and beyond. Chem Soc Rev 2024; 53:4741-4785. [PMID: 38536104 DOI: 10.1039/d3cs00889d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Polyfluoroarenes have been known for a long time, but they are most often used as fluorinated building blocks for the synthesis of aromatic compounds. At the same time, due to peculiar fluorine effect, they have unique properties that provide applications in various fields ranging from synthesis to materials science. This review summarizes advances in the radical chemistry of polyfluoroarenes, which have become possible mainly with the advent of photocatalysis. Transformations of the fluorinated ring via the C-F bond activation, as well as use of fluoroaryl fragments as activating groups and hydrogen atom transfer agents are discussed. The ability of fluoroarenes to serve as catalysts is also considred.
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Affiliation(s)
- Mikhail O Zubkov
- N. D. Zelinsky Institute of Organic Chemistry, Leninsky prosp. 47, 119991 Moscow, Russian Federation.
| | - Alexander D Dilman
- N. D. Zelinsky Institute of Organic Chemistry, Leninsky prosp. 47, 119991 Moscow, Russian Federation.
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