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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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2
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Leyva-Parra L, Casademont-Reig I, Pino-Rios R, Ruiz L, Alonso M, Tiznado W. New Perspectives on Delocalization Pathways in Aromatic Molecular Chameleons. Chemphyschem 2024; 25:e202400271. [PMID: 38530286 DOI: 10.1002/cphc.202400271] [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: 03/15/2024] [Accepted: 03/25/2024] [Indexed: 03/27/2024]
Abstract
This study comprehensively analyzes the magnetically induced current density of polycyclic compounds labeled as "aromatic chameleons" since they can arrange their π-electrons to exhibit aromaticity in both the ground and the lowest triplet state. These compounds comprise benzenoid moieties fused to a central skeleton with 4n π-electrons and traditional magnetic descriptors are biased due to the superposition of local magnetic responses. In the S0 state, our analysis reveals that the molecular constituent fragments preserve their (anti)aromatic features in agreement with two types of resonant structures: one associated with aromatic benzenoids and the other with a central antiaromatic ring. Regarding the T1 state, a global and diatropic ring current is revealed. Our aromaticity study is complemented with advanced electronic and geometric descriptors to consider different aspects of aromaticity, particularly important in the evaluation of excited state aromaticity. Remarkably, these descriptors consistently align with the general features on the main delocalization pathways in polycyclic hydrocarbons consisting of fused 4n π-electron rings. Moreover, our study demonstrates an inverse correlation between the singlet-triplet energy difference and the antiaromatic character of the central ring in S0.
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Affiliation(s)
- Luis Leyva-Parra
- Facultad de Ingeniería y Arquitectura, Universidad Central de Chile (UCEN), Santa Isabel 1186, 8370146, Santiago, Chile
- Centro de Química Teórica & Computacional (CQT&C), Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. República 275, 8370146, Santiago, Chile
| | - Irene Casademont-Reig
- Department of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | - Ricardo Pino-Rios
- Centro de Investigación Medicina de Altura, Universidad Arturo Prat, Iquique, 1100000, Chile
- Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Casilla 121, Iquique, 1100000, Chile
| | - Lina Ruiz
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, 8910060, Chile
| | - Mercedes Alonso
- Department of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050, Brussels, Belgium
| | - William Tiznado
- Centro de Química Teórica & Computacional (CQT&C), Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. República 275, 8370146, Santiago, Chile
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3
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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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4
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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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5
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Zhao M, Xu S, He C, Zhou Y. Synthesis, Structures and Photophysical Properties of Asymmetric Fulvene-[b]-fused BODIPYs. Chemistry 2024; 30:e202303930. [PMID: 38117253 DOI: 10.1002/chem.202303930] [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: 11/26/2023] [Revised: 12/18/2023] [Accepted: 12/18/2023] [Indexed: 12/21/2023]
Abstract
Herein, we developed a one-pot procedure to synthesize novel fulvene-[b]-fused BODIPYs from α-(2-alkynylphenyl)-pyrrole and acylpyrrole, using 5-exo cyclization as the key transformation. Compared to benzene-[b]-fused BODIPYs, although they have similar chemical compositions, their structures and properties significantly differ from each other, which can be attributed to the less aromaticity of the fulvene linker than benzene. Notably, fulvene-[b]-fused BODIPY 1 b exhibits helical-twisted core skeleton, intensified red-shifted absorption, and peak fluorescence. In addition, the pathway of this one-pot reaction and the mechanism of POCl3 mediated 5-exo cyclization have been proposed by a combining experimental and computational study.
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Affiliation(s)
- Mengna Zhao
- College of Life Science, China Jiliang University, Hangzhou, Zhejiang, China
| | - Shaoyu Xu
- College of Life Science, China Jiliang University, Hangzhou, Zhejiang, China
| | - Chun He
- Apeloa Pharmaceutical Co., Ltd Dongyang, Zhejiang, China
| | - Yifeng Zhou
- College of Life Science, China Jiliang University, Hangzhou, Zhejiang, China
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6
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Jalife S, Tsybizova A, Gershoni-Poranne R, Wu JI. Modulating Paratropicity in Heteroarene-Fused Expanded Pentalenes. Org Lett 2024; 26:1293-1298. [PMID: 38307038 DOI: 10.1021/acs.orglett.4c00188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2024]
Abstract
Pentalenes are formally eight-π-electron antiaromatic, but π-expanded pentalenes can display varying levels of paratropicity depending on the choice of annelated (hetero)arenes and the geometry of π-expansion (i.e., linear vs bent topologies) around the [4n] core. Here, we explain the effects of annelation on the paratropicity of π-expanded pentalenes by relating the electronic structure of pentalenes to a pair of conjoined pentafulvenes.
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Affiliation(s)
- Said Jalife
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Alexandra Tsybizova
- Laboratory for Organic Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, Zurich 8092, Switzerland
| | - Renana Gershoni-Poranne
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Technion City, Haifa 32000, Israel
| | - Judy I Wu
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
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7
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Wieczorkiewicz PA, Zborowski KK, Krygowski TM, Szatylowicz H. Substituent Effect versus Aromaticity─A Curious Case of Fulvene Derivatives. J Org Chem 2023; 88:14775-14780. [PMID: 37773323 PMCID: PMC10594647 DOI: 10.1021/acs.joc.3c01539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Indexed: 10/01/2023]
Abstract
A computational study on amino- and nitro-substituted penta- and heptafulvenes reveals the interplay between the aromaticity and the substituent effect (SE). Ring substitution alone has little influence on the aromaticity, but in combination with an exo substituent of opposite properties, it substantially enhances the cyclic π-electron delocalization. Despite the SE being stronger for β substitution, only γ substitution leads to higher aromaticity. An explanation is provided by the electron density of delocalized bonds (EDDB) method, which proves to be a valuable tool in analyzing both cyclic delocalization and the SE.
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Affiliation(s)
- Pawel A. Wieczorkiewicz
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Krzysztof K. Zborowski
- Faculty
of Chemistry, Jagiellonian University in
Kraków, Gronostajowa
2, Kraków 30-387, Poland
| | - Tadeusz M. Krygowski
- Department
of Chemistry, University of Warsaw, Pasteura 1, Warsaw 02-093, Poland
| | - Halina Szatylowicz
- Faculty
of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
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8
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Kim J, Oh J, Osuka A, Kim D. Porphyrinoids, a unique platform for exploring excited-state aromaticity. Chem Soc Rev 2021; 51:268-292. [PMID: 34879124 DOI: 10.1039/d1cs00742d] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recently, Baird (anti)aromaticity has been referred to as a description of excited-state (anti)aromaticity. With the term of Baird's rule, recent studies have intensively verified that the Hückel aromatic [4n + 2]π (or antiaromatic [4n]π) molecules in the ground state are reversed to give Baird aromatic [4n]π (or Baird antiaromatic [4n + 2]π) molecules in the excited states. Since the Hückel (anti)aromaticity has great influence on the molecular properties and reaction mechanisms, the Baird (anti)aromaticity has been expected to act as a dominant factor in governing excited-state properties and processes, which has attracted intensive scientific investigations for the verification of the concept of reversed aromaticity in the excited states. In this scientific endeavor, porphyrinoids have recently played leading roles in the demonstration of the aromaticity reversal in the excited states and its conceptual development. The distinct structural and electronic nature of porphyhrinoids depending on their (anti)aromaticity allow the direct observation of excited-state aromaticity reversal, Baird's rule. The explicit experimental demonstration with porphyrinoids has contributed greatly to its conceptual development and application in novel functional organic materials. Based on the significant role of porphyrinoids in the field of excited-state aromaticity, this review provides an overview of the experimental verification of the reversal concept of excited-state aromaticity by porphyrinoids and the recent progress on its conceptual application in novel functional molecules.
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Affiliation(s)
- Jinseok Kim
- Department of Chemistry, Yonsei University, Seoul 03722, Korea.
| | - Juwon Oh
- Department of Chemistry, Soonchunhyang University, Asan-si 31538, Korea.
| | - Atsuhiro Osuka
- Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Dongho Kim
- Department of Chemistry, Yonsei University, Seoul 03722, Korea.
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9
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Ueta K, Kim J, Ooi S, Oh J, Shin J, Nakai A, Lim M, Tanaka T, Kim D, Osuka A. meso-Oxoisocorroles: Tunable Antiaromaticity by Metalation and Coordination of Lewis Acids as Well as Aromaticity Reversal in the Triplet Excited State. J Am Chem Soc 2021; 143:7958-7967. [DOI: 10.1021/jacs.1c00476] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Kento Ueta
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Jinseok Kim
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Shota Ooi
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Juwon Oh
- Department of Chemistry, Soonchunhyang University, Asan-si 31538, Korea
| | - Juhyang Shin
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 46241, Korea
| | - Akito Nakai
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Manho Lim
- Department of Chemistry and Chemistry Institute for Functional Materials, Pusan National University, Busan 46241, Korea
| | - Takayuki Tanaka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Dongho Kim
- Spectroscopy Laboratory for Functional π-Electronic Systems and Department of Chemistry, Yonsei University, Seoul 03722, Korea
| | - Atsuhiro Osuka
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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10
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Markert G, Paenurk E, Gershoni-Poranne R. Prediction of Spin Density, Baird-Antiaromaticity, and Singlet-Triplet Energy Gap in Triplet-State Polybenzenoid Systems from Simple Structural Motifs. Chemistry 2021; 27:6923-6935. [PMID: 33438296 DOI: 10.1002/chem.202005248] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/08/2021] [Indexed: 12/15/2022]
Abstract
Triplet-state aromaticity has been recently proposed as a strategy for designing functional organic electronic compounds, many of which are polycyclic aromatic systems. However, in many cases, the aromatic nature of the triplet state cannot be easily predicted. Moreover, it is often unclear how specific structural manipulations affect the electronic properties of the excited-state compounds. Herein, the relationship between the structure of polybenzenoid hydrocarbons (PBHs) and their spin-density distribution and aromatic character in the first triplet excited state is studied. Although a direct link is not immediately visible, classifying the PBHs according to their annulation sequence reveals regularities. Based on these, a set of guidelines is defined to qualitatively predict the location of spin and paratropicity and the singlet-triplet energy gap in larger PBHs, using only their smaller tri- and tetracyclic components, and subsequently tested on larger systems.
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Affiliation(s)
- Greta Markert
- Laboratorium für Organische Chemie, ETH, 8093, Zurich, Switzerland
| | - Eno Paenurk
- Laboratorium für Organische Chemie, ETH, 8093, Zurich, Switzerland
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11
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Wang L, Lin L, Yang J, Wu Y, Wang H, Zhu J, Yao J, Fu H. Singlet Fission in a Pyrrole-Fused Cross-Conjugated Skeleton with Adaptive Aromaticity. J Am Chem Soc 2020; 142:10235-10239. [PMID: 32437140 DOI: 10.1021/jacs.0c00089] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Singlet fission (SF) materials hold the potential to increase the power conversion efficiency of solar cells by reducing the thermalization of high-energy excited states. The major hurdle in realizing this potential is the limited scope of SF-active materials with high fission efficiency, suitable energy levels, and sufficient chemical stability. Herein, using theoretical calculation and time-resolved spectroscopy, we developed a highly stable SF material based on dipyrrolonaphthyridinedione (DPND), a pyrrole-fused cross-conjugated skeleton with a distinctive adaptive aromaticity (dual aromaticity) character. The embedded pyrrole ring with 4n+2 π-electron features aromaticity in the ground state, while the dipole resonance of the amide bonds promotes a 4n π-electron Baird's aromaticity in the triplet state. Such an adaptive aromaticity renders the molecule efficient for the SF process [E(S1) ≥ 2E(T1)] without compromising its stability. Up to 173% triplet yield, strong blue-green light absorption, and suitable triplet energy of 1.2 eV, as well as excellent stability, make DPND a promising SF sensitizer toward practical applications.
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Affiliation(s)
- Long Wang
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Lu Lin
- 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
| | - Jingjing Yang
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Yishi Wu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, China
| | - Hua Wang
- Key Laboratory of Interface Science and Engineering in Advanced Materials, Ministry of Education, Taiyuan University of Technology, Taiyuan 030024, China
| | - Jun Zhu
- 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
| | - Jiannian Yao
- Institute of Molecular Plus, School of Chemical Engineering and Technology, Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Hongbing Fu
- Beijing Key Laboratory for Optical Materials and Photonic Devices, Department of Chemistry, Capital Normal University, Beijing 100048, China.,Institute of Molecular Plus, School of Chemical Engineering and Technology, Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
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12
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El Bakouri O, Smith JR, Ottosson H. Strategies for Design of Potential Singlet Fission Chromophores Utilizing a Combination of Ground-State and Excited-State Aromaticity Rules. J Am Chem Soc 2020; 142:5602-5617. [PMID: 32107921 PMCID: PMC7307911 DOI: 10.1021/jacs.9b12435] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Indexed: 12/15/2022]
Abstract
Singlet exciton fission photovoltaic technology requires chromophores with their lowest excited states arranged so that 2E(T1) < E(S1) and E(S1) < E(T2). Herein, qualitative theory and quantum chemical calculations are used to develop explicit strategies on how to use Baird's 4n rule on excited-state aromaticity, combined with Hückel's 4n + 2 rule for ground-state aromaticity, to tailor new potential chromophores for singlet fission. We first analyze the E(T1), E(S1), and E(T2) of benzene and cyclobutadiene (CBD) as excited-state antiaromatic and aromatic archetypes, respectively, and reveal that CBD fulfills the criteria on the state ordering for a singlet fission chromophore. We then look at fulvenes, a class of compounds that can be tuned by choice of substituents from Baird-antiaromatic to Baird-aromatic in T1 and S1 and from Hückel-aromatic to Hückel-antiaromatic in S0. The T1 and S1 states of most substituted fulvenes (159 of 225) are described by singly excited HOMO → LUMO configurations, providing a rational for the simultaneous tuning of E(T1) and E(S1) along an approximate (anti)aromaticity coordinate. Key to the tunability is the exchange integral (KH,L), which ideally is constant throughout the compound class, providing a constant ΔE(S1 - T1). This leads us to a geometric model for the identification of singlet fission chromophores, and we explore what factors limit the model. Candidates with calculated E(T1) values of ∼1 eV or higher are identified among benzannelated 4nπ-electron compound classes and siloles. In brief, it is clarified how the joint utilization of Baird's 4n and Hückel's 4n + 2 rules, together with substituent effects (electronic and steric) and benzannelation, can be used to tailor new chromophores with potential use in singlet fission photovoltaics.
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Affiliation(s)
- Ouissam El Bakouri
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Joshua R. Smith
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
- Department
of Chemistry, Humboldt State University, One Harpst Street, Arcata, California 95521, United States
| | - Henrik Ottosson
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
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13
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Abstract
Density functional theory calculations have been performed to explore the substituent effect on benzene's structure and aromaticity upon excitation to the first triplet excited state (T1). Discussion is based on spin density analysis, HOMA (harmonic oscillator model of aromaticity), NICS (nucleus-independent chemical shift), ACID (anisotropy of the induced current density), and monohydrogenation free energies and shows that a large span of aromatic properties, from highly antiaromatic to strongly aromatic, could be achieved by varying the substituent. This opens up a possibility of controlling benzene's physicochemical behavior in its excited state, while molecular motion, predicted for several derivatives, could be of interest for the development of photomechanical materials.
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Affiliation(s)
- Marija Baranac-Stojanović
- Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, P.O. Box 158, Belgrade 11000, Serbia
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14
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Wu J, Rouf AM, Huang Y, Zhuang D, Zhu J. Theoretical study on the stability and aromaticity in silapentafulvenes towards triplet ground state species. Phys Chem Chem Phys 2020; 22:4668-4676. [PMID: 32057041 DOI: 10.1039/c9cp06506g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Pentafulvenes are dipolar hydrocarbons since they shift their π-electrons to achieve Hückel aromaticity and thus the electron donating groups at the exocyclic position can enhance their aromaticity. Silapentafulvenes are analogues of pentafulvene formed by the replacement of the carbon atoms at the exocyclic C[double bond, length as m-dash]C double bond with a silicon atom in pentafulvene. It remains unclear how the aromaticity of 5-silapentafulvenes and 6-silapentafulvenes can be changed due to the polarization of the C[double bond, length as m-dash]Si double bond. Here we perform density functional theory calculations and reveal the increased aromatic character in 6-silapentafulvenes and the reduced aromaticity of 5-silapentafulvenes in the ground state. In addition, the origin of the relative thermodynamic stability of the silapentafulvene isomers can be attributed to the bond dissociation energy (BDE) of the exocyclic bond. More interestingly, some triplet ground state 5-silapentafulvene species are predicted by introducing amino groups on the ring, which is supported by the coupled cluster calculations. Our findings could be useful for experimentalists to realize silaaromatics.
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Affiliation(s)
- Jiashun Wu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China.
| | - Alvi Muhammad Rouf
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China.
| | - Yuanyuan Huang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China.
| | - Danling Zhuang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China.
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian, China.
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15
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Shen T, Chen D, Lin L, Zhu J. Dual Aromaticity in Both the T0 and S1 States: Osmapyridinium with Phosphonium Substituents. J Am Chem Soc 2019; 141:5720-5727. [DOI: 10.1021/jacs.8b11564] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Ting Shen
- 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
| | - Dandan 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
| | - Lu Lin
- 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
- 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
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