1
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Orozco-Ic M, Soriano-Agueda L, Sundholm D, Matito E, Merino G. Core-electron contributions to the magnetic response of molecules with heavy elements and their significance in aromaticity assessments. Chem Sci 2024; 15:12906-12921. [PMID: 39148783 PMCID: PMC11323299 DOI: 10.1039/d4sc02269f] [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: 04/05/2024] [Accepted: 07/07/2024] [Indexed: 08/17/2024] Open
Abstract
This study delves into the magnetic response of core electrons and their influence on the global magnetic response of planar and three-dimensional systems containing heavy elements, employing the removing valence electron (RVE) approximation. We also explore electronic aromaticity indices to understand the potential role of core electrons on electron delocalization in the absence of an external perturbation. The study reveals that core electrons significantly contribute to the overall magnetic response, especially to the magnetic shielding, affecting the interpretation of aromaticity. In contrast, the calculation of the electronic aromaticity indices suggests a negligible participation of the core electrons on electron delocalization. Despite their widespread use, the study emphasizes caution in labeling systems as strongly aromatic based solely on shielding function computations. It is noteworthy to emphasize the limitations associated with each aromaticity criterion; particularly in the context of magnetic shielding function calculations, the core-electron effect contamination is undeniable. Hence, the integration of various criteria becomes imperative for attaining a comprehensive understanding of magnetic responses within complex systems.
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Affiliation(s)
- Mesías Orozco-Ic
- Donostia International Physics Center (DIPC) 20018 Donostia Euskadi Spain
| | | | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki P.O. Box 55, A. I. Virtasen aukio 1 FIN-00014 Helsinki Finland
| | - Eduard Matito
- Donostia International Physics Center (DIPC) 20018 Donostia Euskadi Spain
| | - Gabriel Merino
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex 97310 Mérida Yuc. Mexico
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2
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Xing JF, Tan YZ, Zhu J. Probing σ-Aromaticity-Driven Ring Contraction of Metallabenzocyclobutadiene to Metallabenzocyclopropene. Inorg Chem 2024; 63:13903-13910. [PMID: 39014892 DOI: 10.1021/acs.inorgchem.4c01118] [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
Ring contraction of metallacyclobutadiene to metallacyclopropene is rare because of the increasing strain from a four-membered ring to a three-membered one. Here we demonstrate a new series of reactions of metallabenzocyclobutadiene to metallabenzocyclopropene via density functional theory calculations. The results suggest that these reactions are thermodynamically favorable ranging from -17.4 to -29.4 kcal mol-1, and a low reaction barrier (10.3 kcal mol-1) is achieved when the metal center is Ru and the ligands are one cyanide and one chloride. Further analysis suggests that a strengthened binding energy helps stabilize the transition state in the protonation process. The aromaticity during the reaction was investigated using the electron density of delocalized bonds (EDDB), isomerization stabilization energy, and isodesmic reactions. The EDDB shows that the π-conjugation is disrupted in the intermediate, and then σ-aromaticity is generated and dominant in the products. Our findings could be helpful for experimentalists in developing novel ring contraction reactions driven by aromaticity.
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Affiliation(s)
- Jiang-Feng Xing
- 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
| | - Yuan-Zhi Tan
- 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, Guangdong 518172, People's Republic of China
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3
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Cui LJ, Liu XB, Zhang HY, Yan B, Orozco-Ic M, Pan S, Cui ZH. In nTl 4-nH + ( n = 0∼4): Tetracoordinate Hydrogen in a Planar Fashion? Inorg Chem 2024; 63:13938-13947. [PMID: 38996364 DOI: 10.1021/acs.inorgchem.4c01224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
The recent report of planar tetracoordinate hydrogen (ptH) in In4H+ is very intriguing in planar hypercoordinate chemistry. Our high-level CCSD(T) calculations revealed that the proposed D4h-symmetric ptH In4H+ is a first-order saddle point with an imaginary frequency in the out-of-plane mode of the hydrogen atom. In fact, at the CCSD(T)/aug-cc-pV5Z/aug-cc-pV5Z-PP level, the C4v isomer, with the H atom located 0.70 Å above the In4 plane, is 0.5 kcal/mol more stable than the D4h isomer. However, given the small perturbation from planarity and essentially barrierless C4v ↔ D4h ↔ C4v transition, the vibrationally averaged structure can still be considered as a planar. Extending our exploration to the InnTl4-nH+ (n = 0-3) systems, we found all these ptH structures, except for In2Tl2H+, to be the putative global minimum. The single σ-delocalized interaction between the central hydrogen atom and InnTl4-n ligand rings proves pivotal in establishing planarity and aromaticity and conferring substantial stability upon these rule-breaking ptH species.
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Affiliation(s)
- Li-Juan Cui
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Xin-Bo Liu
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Hui-Yu Zhang
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Bing Yan
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Mesías Orozco-Ic
- Donostia International Physics Center (DIPC), Donostia, Euskadi 20018, Spain
| | - Sudip Pan
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
| | - Zhong-Hua Cui
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, China
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), Jilin University, Changchun 130023, China
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4
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Zhang YH, Wang HQ, Li HF, Zeng JK, Zheng H, Mei XJ, Zhang JM, Jiang KL, Zhang B, Wu WH. Probing the Structural and Electronic Properties of the Anionic and Neutral Tellurium-Doped Boron Clusters TeB nq ( n = 3-16, q = 0, -1). J Phys Chem A 2024; 128:5459-5472. [PMID: 38973649 DOI: 10.1021/acs.jpca.4c00907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/09/2024]
Abstract
In this study, we employ density functional theory along with the artificial bee colony algorithm for cluster global optimization to explore the low-lying structures of TeBnq (n = 3-16, q = 0, -1). The primary focus is on reporting the structural properties of these clusters. The results reveal a consistent doping pattern of the tellurium atom onto the in-plane edges of planar or quasi-planar boron clusters in the most energetically stable isomers. Additionally, we simulate the photoelectron spectra of the cluster anions. Through relative stability analysis, we identify three clusters with magic numbers -TeB7-, TeB10, and TeB12. The aromaticity of these clusters is elucidated using adaptive natural density partitioning (AdNDP) and magnetic properties analysis. Notably, TeB7- exhibits a perfect σ-π doubly aromatic structure, while TeB12 demonstrates strong island aromaticity. These findings significantly contribute to our understanding of the structural and electronic properties of these clusters.
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Affiliation(s)
- Yong-Hang Zhang
- College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Huai-Qian Wang
- College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China
- College of Engineering, Huaqiao University, Quanzhou 362021, China
| | - Hui-Fang Li
- College of Engineering, Huaqiao University, Quanzhou 362021, China
| | - Jin-Kun Zeng
- College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Hao Zheng
- College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Xun-Jie Mei
- College of Engineering, Huaqiao University, Quanzhou 362021, China
| | - Jia-Ming Zhang
- College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Kai-Le Jiang
- College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Bo Zhang
- College of Information Science and Engineering, Huaqiao University, Xiamen 361021, China
| | - Wen-Hai Wu
- College of Engineering, Huaqiao University, Quanzhou 362021, China
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5
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Lin X, Lu X, Tang S, Wu W, Mo Y. Multiconfigurational actinide nitrides assisted by double Möbius aromaticity. Chem Sci 2024; 15:8216-8226. [PMID: 38817572 PMCID: PMC11134321 DOI: 10.1039/d4sc01549e] [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: 03/05/2024] [Accepted: 04/25/2024] [Indexed: 06/01/2024] Open
Abstract
Understanding the bonding nature between actinides and main-group elements remains a key challenge in actinide chemistry due to the involvement of f orbitals. Herein, we propose a unique "aromaticity-assisted multiconfiguration" (AAM) model to elucidate the bonding nature in actinide nitrides (An2N2, An = Ac, Th, Pa, U). Each planar four-membered An2N2 with equivalent An-N bonds possesses four delocalized π electrons and four delocalized σ electrons, forming a new family of double Möbius aromaticity that contributes to the molecular stability. The unprecedented aromaticity further supports actinide nitrides to exhibit multiconfigurational characters, where the unpaired electrons (2, 4 or 6 in naked Th2N2, Pa2N2 or U2N2, respectively) either are spin-free and localized on metal centres or form metal-ligand bonds. High-level multiconfigurational computations confirm an open-shell singlet ground state for actinide nitrides, with small energy gaps to high spin states. This is consistent with the antiferromagnetic nature observed experimentally in uranium nitrides. The novel AAM bonding model can be authenticated in both experimentally identified compounds containing a U2N2 motif and other theoretically modelled An2N2 clusters and is thus expected to be a general chemical bonding pattern between actinides and main-group elements.
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Affiliation(s)
- Xuhui Lin
- School of Physics, Central South University Changsha Hunan 410083 China
| | - Xiaoli Lu
- School of Chemistry, Southwest Jiaotong University Chengdu Sichuan 610031 China
| | - Shenghui Tang
- School of Chemistry, Southwest Jiaotong University Chengdu Sichuan 610031 China
| | - Wei Wu
- The State Key Laboratory of Physical Chemistry of Solid Surfaces, iChEM, Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry and College of Chemistry and Chemical Engineering, Xiamen University Xiamen Fujian 361005 China
| | - Yirong Mo
- Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro Greensboro NC 27401 USA
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6
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Li Q, Liu QY, Zhao YX, He SG. Conversion of Methane at Room Temperature Mediated by the Ta-Ta σ-Bond. JACS AU 2024; 4:1824-1832. [PMID: 38818048 PMCID: PMC11134373 DOI: 10.1021/jacsau.4c00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 06/01/2024]
Abstract
Metal-metal bonds constitute an important type of reactive centers for chemical transformation; however, the availability of active metal-metal bonds being capable of converting methane under mild conditions, the holy grail in catalysis, remains a serious challenge. Herein, benefiting from the systematic investigation of 36 metal clusters of tantalum by using mass spectrometric experiments complemented with quantum chemical calculations, the dehydrogenation of methane at room temperature was successfully achieved by 18 cluster species featuring σ-bonding electrons localized in single naked Ta-Ta centers. In sharp contrast, the other 18 remaining clusters, either without naked Ta-Ta σ-bond or with σ-bonding electrons delocalized over multiple Ta-Ta centers only exhibit molecular CH4-adsorption reactivity or inertness. Mechanistic studies revealed that changing cluster geometric configurations and tuning the number of simple inorganic ligands (e.g., oxygen) could flexibly manipulate the presence or absence of such a reactive Ta-Ta σ-bond. The discovery of Ta-Ta σ-type bond being able to exhibit outstanding activity toward methane conversion not only overturns the traditional recognition that only the metal-metal π- or δ-bonds of early transition metals could participate in bond activation but also opens up a new access to design of promising metal catalysts with dual-atom as reactive sites for chemical transformations.
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Affiliation(s)
- Qian Li
- State
Key Laboratory for Structural Chemistry of Unstable and Stable Species,
Institute of Chemistry, Chinese Academy
of Sciences, Beijing 100190, PR China
- University
of Chinese Academy of Sciences, Beijing 100049, PR China
- Beijing
National Laboratory for Molecular Sciences and CAS Research/Education
Centre of Excellence in Molecular Sciences, Beijing 100190, PR China
| | - Qing-Yu Liu
- State
Key Laboratory for Structural Chemistry of Unstable and Stable Species,
Institute of Chemistry, Chinese Academy
of Sciences, Beijing 100190, PR China
- Beijing
National Laboratory for Molecular Sciences and CAS Research/Education
Centre of Excellence in Molecular Sciences, Beijing 100190, PR China
| | - Yan-Xia Zhao
- State
Key Laboratory for Structural Chemistry of Unstable and Stable Species,
Institute of Chemistry, Chinese Academy
of Sciences, Beijing 100190, PR China
- Beijing
National Laboratory for Molecular Sciences and CAS Research/Education
Centre of Excellence in Molecular Sciences, Beijing 100190, PR China
| | - Sheng-Gui He
- State
Key Laboratory for Structural Chemistry of Unstable and Stable Species,
Institute of Chemistry, Chinese Academy
of Sciences, Beijing 100190, PR China
- University
of Chinese Academy of Sciences, Beijing 100049, PR China
- Beijing
National Laboratory for Molecular Sciences and CAS Research/Education
Centre of Excellence in Molecular Sciences, Beijing 100190, PR China
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7
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Chen J, Huang L, Wu L, Zhang Y, Zhang R, Li Y, Zhao Y, Wang L, Feng D, Kira M, Lin Z, Li Z. Isolable Tetragold(0) Clusters with Polarity-Tunable exo-Au-Au Bond via Intramolecular σ-Aromatization. Angew Chem Int Ed Engl 2023; 62:e202311230. [PMID: 37596803 DOI: 10.1002/anie.202311230] [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: 08/03/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/20/2023]
Abstract
Intramolecular π-aromatization is a trait of many organic compounds that enhances the stability of their structures and polarizes related C-C π bonds. In contrast, rare study is focused on this phenomenon in metal clusters. Many existing homometallic clusters exhibit aromaticity, often characterized by nonpolar metal-metal bonds and a high degree of symmetry. However, synthesizing low-symmetric homometallic clusters with high-polar metal-metal bonds is challenging due to their limited thermodynamic stability. Herein, we report a facile strategy for the synthesis of [Au(μ2 -ER2 )]3 -AuPMe3 (E=Ge, Sn; R2 =1,1,4,4-tetrakis(trimethylsilyl)butane-1,4-diyl) clusters and reveal a novel stabilization mode, intramolecular σ-aromatization. Our electronic structure analyses show that these low-symmetric clusters possess a ten-electron σ-aromatic system, which is achieved via intramolecular σ-aromatization. Moreover, the strength of σ-aromaticity gives rise to a polarity-tunable exo-Au-Au bond.
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Affiliation(s)
- Jiaxin Chen
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
- Department of Chemistry, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Lu Huang
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Lifang Wu
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Yichi Zhang
- Department of Chemistry, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Rong Zhang
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Yinhuan Li
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Yunqing Zhao
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Liliang Wang
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Dewei Feng
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Mitsuo Kira
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Zhifang Li
- College of Material Chemistry and Chemical Engineering, Key Laboratory of Organosilicon Chemistry and Material Technology, Ministry of Education, Key Laboratory of Organosilicon Material Technology of Zhejiang Province, Hangzhou Normal University, Hangzhou, China
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8
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Wang MH, Kalita AJ, Orozco-Ic M, Yan GR, Chen C, Yan B, Castillo-Toraya G, Tiznado W, Guha AK, Pan S, Merino G, Cui ZH. Planar pentacoordinate s-block metals. Chem Sci 2023; 14:8785-8791. [PMID: 37621437 PMCID: PMC10445469 DOI: 10.1039/d2sc05939h] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 07/14/2023] [Indexed: 08/26/2023] Open
Abstract
The presence of a delocalized π-bond is often considered an essential criterion for achieving planar hypercoordination. Herein, we show that σ-delocalization could be sufficient to make the planar configuration the most stable isomer in a series of planar pentacoordinate s-block metals. High-level ab initio computations reveal that the global minimum of a series of interalkali and interalkali-alkaline earth clusters (LiNa5, Li5Mg+, Na5Mg+, K5Ca+, CaRb5+, Rb5Sr+, and SrCs5+) adopts a singlet D5h structure with a planar pentacoordinate lithium or alkaline earth metal (AE = Mg, Ca, Sr). These clusters are unusual combinations to stabilize a planar pentacoordinate atom, as all their constituents are electropositive. Despite the absence of π-electrons, Hückel's rule is fulfilled by the six σ-electrons. Furthermore, the systems exhibit a diatropic ring current in response to an external magnetic field and a strong magnetic shielding, so they might be classified as σ-aromatic. Therefore, multicenter σ-bonds and the resulting σ-delocalization stabilize these clusters, even though they lack π-aromaticity.
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Affiliation(s)
- Meng-Hui Wang
- Institute of Atomic and Molecular Physics, Jilin University Changchun 130023 China
| | - Amlan J Kalita
- Advanced Computational Chemistry Centre, Department of Chemistry, Cotton University Panbazar Guwahati Assam 781001 India
| | - Mesías Orozco-Ic
- Donostia International Physics Center (DIPC) 20018 Donostia Euskadi Spain
| | - Gai-Ru Yan
- Institute of Atomic and Molecular Physics, Jilin University Changchun 130023 China
| | - Chen Chen
- Institute of Atomic and Molecular Physics, Jilin University Changchun 130023 China
| | - Bing Yan
- Institute of Atomic and Molecular Physics, Jilin University Changchun 130023 China
| | - Gabriela Castillo-Toraya
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex 97310 Mérida Yucatan Mexico
| | - William Tiznado
- Centro de Química Teórica & Computacional (CQT&C), Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello Avenida República 275 Santiago Chile
| | - Ankur K Guha
- Advanced Computational Chemistry Centre, Department of Chemistry, Cotton University Panbazar Guwahati Assam 781001 India
| | - Sudip Pan
- Institute of Atomic and Molecular Physics, Jilin University Changchun 130023 China
| | - Gabriel Merino
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex 97310 Mérida Yucatan Mexico
| | - Zhong-Hua Cui
- Institute of Atomic and Molecular Physics, Jilin University Changchun 130023 China
- Key Laboratory of Physics and Technology for Advanced Batteries (Ministry of Education), Jilin University Changchun 130023 China
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9
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Lingas R, Charistos ND, Muñoz-Castro A. Charge delocalization and aromaticity of doubly reduced double-walled carbon nanohoops. Phys Chem Chem Phys 2023. [PMID: 37448229 DOI: 10.1039/d3cp01994b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/15/2023]
Abstract
Cycloparaphenylenes (CPPs) exhibit selective host capabilities, featuring the ability to incorporate smaller CPPs to form double-walled host-guest complexes. Moreover, CPPs can also be stabilized by global aromaticity under twofold oxidation or reduction, involving electronic conjugation along with the overall structural backbone. Herein we explore the structural modifications, bonding, electron delocalization and magnetic properties of doubly reduced double-walled CPP complexes with DFT methods, in the isolated and aggregate [n + 5]CPP⊃[n]CPP2- (n = 5-8) species. Our results show that the hosts undergo structural, bonding and delocalization deformations towards quinoidal configurations and exhibit global long-ranged shielding cones similar to global aromatic free dianionic CPPs, accounting for charge delocalization on the outer nanohoops, whereas the guests preserve local aromatic benzenoid configurations, resulting in global and local aromatic circuits within the host-guest aggregate. This observation suggests that in multi-layered related species electronic delocalization will be retained at the outer structural surface. The aromaticity of the hosts is manifested in the strong upfield shifts of the guests 1H-NMR signals. Hence, CPP complexes can be extended to doubly reduced species stabilized by global host aromaticity expanding our understanding of doubled-walled nanotubes at the nanoscale regime.
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Affiliation(s)
- Rafael Lingas
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54 124, Greece.
| | - Nickolas D Charistos
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Aristotle University of Thessaloniki, Thessaloniki, 54 124, Greece.
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
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10
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Lingas R, Charistos ND, Muñoz-Castro A. Local and global aromaticity under rotation: analysis of two- and three-dimensional representative carbon nanostructures. Phys Chem Chem Phys 2023; 25:14285-14293. [PMID: 37183443 DOI: 10.1039/d3cp00569k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Nanoscaled 2D and 3D carbon structures with closed curved π-surfaces are of relevance in the development of desirable building units for materials science. Such species are able to sustain local and global aromatic circuits involving isolated regions or the overall structural backbone, respectively. Here we account for local and global aromaticity under rotation of representative two- and three-dimensional species involving para-connected and fused edge-sharing phenyl rings ([8]CPP, [10]CPP, CNB), and C60 fullerene at different charge states. Our results denote that nanoscaled 2D global aromatics mimic the behaviour of the most prototypical aromatic 6π-circuit, given by benzene, where the shielding cone properties vary along the rotation motion. In contrast, 3D spherical aromatics remain almost invariant under rotation, given the distinctive characteristics of such species, differing from 2D global aromatics. Dissection of orbital contributions reveals that π-orbitals are determinants for shifting from non-aromatic to spherical aromatic species. Under rotation, the variation of the anisotropic effect inherent to such nanoscaled structures is accounted for, which is relevant to rationalize variation in NMR signal shifts upon the formation of host-guest aggregates.
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Affiliation(s)
- Rafael Lingas
- Aristotle University of Thessaloniki, Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Thessaloniki, 54 124, Greece.
| | - Nickolas D Charistos
- Aristotle University of Thessaloniki, Department of Chemistry, Laboratory of Quantum and Computational Chemistry, Thessaloniki, 54 124, Greece.
| | - Alvaro Muñoz-Castro
- Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Bellavista 7, Santiago, 8420524, Chile.
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11
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Orozco-Ic M, Sundholm D. Magnetic response properties of carbon nano-onions. Phys Chem Chem Phys 2022; 24:22487-22496. [PMID: 36106772 DOI: 10.1039/d2cp02718f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The magnetic response of a number of double- and triple-layer carbon nano-onions (CNOs) is analyzed by calculating the magnetically induced current density and the induced magnetic field using the pseudo-π model. Qualitatively the same magnetic response was obtained in calculations at the all-electron level. The calculations show that the CNOs exhibit strong net diatropic (paratropic) ring currents when the external magnetic field points perpendicularly to one of the six-membered (five-membered) rings. They are deshielded inside and shielded outside the CNO; the latter dominates for larger CNOs. The magnetic response originates from a combination of spherical paratropic current densities on the inside of each carbon layer and diatropic current densities on the outside of them. The quantitative differences in the aromaticity of the CNOs as compared to single fullerenes are discussed in terms of ring-current strengths. The magnetic response of some of the CNOs is approximately the sum of the magnetic response of the individual layers, whereas deviations are significant for CNOs containing C80. For the largest CNOs, the deviation from the sum of the fullerene contributions is larger, especially when the external magnetic field is perpendicular to a six-membered ring.
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Affiliation(s)
- Mesías Orozco-Ic
- Department of Chemistry, Faculty of Science, University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland.
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland.
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Wang ZL, Chen TT, Chen WJ, Li WL, Zhao J, Jiang XL, Li J, Wang LS, Hu HS. The smallest 4f-metalla-aromatic molecule of cyclo-PrB 2− with Pr–B multiple bonds. Chem Sci 2022; 13:10082-10094. [PMID: 36128247 PMCID: PMC9430590 DOI: 10.1039/d2sc02852b] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 07/18/2022] [Indexed: 11/25/2022] Open
Abstract
The concept of metalla-aromaticity proposed by Thorn–Hoffmann (Nouv. J. Chim. 1979, 3, 39) has been expanded to organometallic molecules of transition metals that have more than one independent electron-delocalized system. Lanthanides, with highly contracted 4f atomic orbitals, are rarely found in multiply aromatic systems. Here we report the discovery of a doubly aromatic triatomic lanthanide-boron molecule PrB2− based on a joint photoelectron spectroscopy and quantum chemical investigation. Global minimum structural searches reveal that PrB2− has a C2v triangular structure with a paramagnetic triplet 3B2 electronic ground state, which can be viewed as featuring a trivalent Pr(III,f2) and B24−. Chemical bonding analyses show that this cyclo-PrB2− species is the smallest 4f-metalla-aromatic system exhibiting σ and π double aromaticity and multiple Pr–B bonding characters. It also sheds light on the formation of the rare B24− tetraanion by the high-lying 5d orbitals of the 4f-elements, completing the isoelectronic B24−, C22−, N2, and O22+ series. We report the smallest 4f-metalla-aromatic molecule of PrB2− exhibiting σ and π double aromaticity and multiple Pr–B bond characters.![]()
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Affiliation(s)
- Zhen-Ling Wang
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084, China
| | - Teng-Teng Chen
- Department of Chemistry, Brown University, Providence 02912, Rhode Island, USA
| | - Wei-Jia Chen
- Department of Chemistry, Brown University, Providence 02912, Rhode Island, USA
| | - Wan-Lu Li
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084, China
| | - Jing Zhao
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084, China
| | - Xue-Lian Jiang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jun Li
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence 02912, Rhode Island, USA
| | - Han-Shi Hu
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084, China
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Arias-Olivares D, Páez-Hernández D. The spin–orbit effects on platinabenzene: a ring current and electron delocalization approach. NEW J CHEM 2022. [DOI: 10.1039/d2nj03317h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aromaticity of platinabenzene was studied using the electronic structure and magnetic descriptors with relativistic corrections. It presents aromatic character following the Hückel's rule, negative NICS values, and diatropic current densities.
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