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Chen S, Zhu J. Probing the Hyperconjugative Aromaticity of Cyclopentadiene and Pyrroliums Containing Group 7 Transition Metal Substituents. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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
| | - 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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2
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El Bakouri O, Szczepanik DW, Jorner K, Ayub R, Bultinck P, Solà M, Ottosson H. Three-Dimensional Fully π-Conjugated Macrocycles: When 3D-Aromatic and When 2D-Aromatic-in-3D? J Am Chem Soc 2022; 144:8560-8575. [PMID: 35523019 PMCID: PMC9121391 DOI: 10.1021/jacs.1c13478] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
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Several fully π-conjugated
macrocycles with puckered or cage-type
structures were recently found to exhibit aromatic character according
to both experiments and computations. We examine their electronic
structures and put them in relation to 3D-aromatic molecules (e.g., closo-boranes) and to 2D-aromatic
polycyclic aromatic hydrocarbons. Using qualitative theory combined
with quantum chemical calculations, we find that the macrocycles explored
hitherto should be described as 2D-aromatic with three-dimensional
molecular structures (abbr. 2D-aromatic-in-3D) and not as truly 3D-aromatic.
3D-aromatic molecules have highly symmetric structures (or nearly
so), leading to (at least) triply degenerate molecular orbitals, and
for tetrahedral or octahedral molecules, an aromatic closed-shell
electronic structure with 6n + 2 electrons. Conversely,
2D-aromatic-in-3D structures exhibit aromaticity that results from
the fulfillment of Hückel’s 4n + 2
rule for each macrocyclic path, yet their π-electron counts
are coincidentally 6n + 2 numbers for macrocycles
with three tethers of equal lengths. It is notable that 2D-aromatic-in-3D
macrocyclic cages can be aromatic with tethers of different lengths, i.e., with π-electron counts different from 6n + 2, and they are related to naphthalene. Finally, we
identify tetrahedral and cubic π-conjugated molecules that fulfill
the 6n + 2 rule and exhibit significant electron
delocalization. Yet, their properties resemble those of analogous
compounds with electron counts that differ from 6n + 2. Thus, despite the fact that these molecules show substantial
π-electron delocalization, they cannot be classified as true
3D-aromatics.
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Affiliation(s)
- Ouissam El Bakouri
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden.,Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain
| | - Dariusz W Szczepanik
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain.,K. Guminski Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, Kraków 30-387, Poland
| | - Kjell Jorner
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
| | - Rabia Ayub
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
| | - Patrick Bultinck
- Department of Chemistry, Ghent University, Krijgslaan 281 S3, Gent 9000, Belgium
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain
| | - Henrik Ottosson
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
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3
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Lin L, Zhu Q, Rouf AM, Zhu J. Probing the Aromaticity and Stability of Metallatricycles by DFT Calculations: Toward Clar Structure in Organometallic Chemistry. Organometallics 2020. [DOI: 10.1021/acs.organomet.9b00653] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lu Lin
- 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
| | - Qin Zhu
- 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
| | - Alvi Muhammad Rouf
- 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
- 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
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4
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Orozco‐Ic M, Barroso J, Charistos ND, Muñoz‐Castro A, Merino G. Consequences of Curvature on Induced Magnetic Field: The Case of Helicenes. Chemistry 2019; 26:326-330. [DOI: 10.1002/chem.201904390] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Mesías Orozco‐Ic
- Departamento de Física Aplicada Centro de Investigación y, de Estudios Avanzados, Unidad Mérida Mérida Yucatán México
| | - Jorge Barroso
- Departamento de Física Aplicada Centro de Investigación y, de Estudios Avanzados, Unidad Mérida Mérida Yucatán México
| | - Nickolas D. Charistos
- Department of Chemistry, Laboratory of Quantum and Computational Chemistry Aristotle University of Thessaloniki Thessaloniki 54 124 Greece
| | - Alvaro Muñoz‐Castro
- Laboratorio de Química Inorgánica y Materiales Moleculares Facultad de Ingeniería Universidad Autónoma de Chile Santiago Chile
| | - Gabriel Merino
- Departamento de Física Aplicada Centro de Investigación y, de Estudios Avanzados, Unidad Mérida Mérida Yucatán México
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Xie Q, Zhao Y, Chen D, Zhu J. Probing Reaction Mechanism of [1,5]‐Migration in Pyrrolium and Pyrrole Derivatives: Activation of a Stronger Bond in Electropositive Groups Becomes Easier. Chem Asian J 2019; 14:2604-2610. [DOI: 10.1002/asia.201900440] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/12/2019] [Indexed: 12/25/2022]
Affiliation(s)
- Qiong Xie
- 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, ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P.R. 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, ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P.R. 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, ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P.R. 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, ChemistryCollege of Chemistry and Chemical EngineeringXiamen University Xiamen 361005 P.R. China
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Chu Z, He G, Cheng X, Deng Z, Chen J. Synthesis and Characterization of Cyclopropaosmanaphthalenes Containing a Fused σ-Aromatic Metallacyclopropene Unit. Angew Chem Int Ed Engl 2019; 58:9174-9178. [PMID: 31056849 DOI: 10.1002/anie.201904815] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Indexed: 12/21/2022]
Abstract
Metalla-aromatics are important complexes that show unique properties owing to their highly conjugated systems, which show Hückel or Möbius aromaticity. Recently, several metalla-aromatics showing spiro-aromaticity or σ-aromaticity have been reported. Herein, we report the isolation of the first cyclopropametallanaphthalenes, in which the metallacyclopropene ring shows σ-aromaticity and weak hyperconjugative aromaticity. The reaction of OsCl2 (PPh3 )3 with o-ethynylphenyl alkynes in the presence of PPh3 followed by protonation with HCl yielded the first cyclopropametallanaphthalenes. The reaction mechanism and the aromaticity were also investigated by density functional theory studies.
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Affiliation(s)
- Zhenwei Chu
- Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen, 361005, P. R. China
| | - Guomei He
- Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen, 361005, P. R. China
| | - Xiaoli Cheng
- Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen, 361005, P. R. China
| | - Zhirong Deng
- Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen, 361005, P. R. China
| | - Jiangxi Chen
- Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen, 361005, P. R. China
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Chen D, Xie Q, Zhu J. Unconventional Aromaticity in Organometallics: The Power of Transition Metals. Acc Chem Res 2019; 52:1449-1460. [PMID: 31062968 DOI: 10.1021/acs.accounts.9b00092] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Aromaticity, one of the most fundamental concepts in chemistry, has attracted considerable attention from both theoreticians and experimentalists. Much effort on aromaticity in organometallics has been devoted to metallabenzene and derivatives. In comparison, aromaticity in other organometallics is less developed. This Account describes how our group has performed quantum chemical calculations to examine aromaticity in recently synthesized novel organometallic complexes. By collaborations with experimentalists, we have extended several aromaticity concepts into organometallics to highlight the power of transition metals. In general, the transition metal could participate in delocalization either out of rings or in the rings. We examined the former by probing the possibility of transition metal substituents in hyperconjugative aromaticity, where the metal is out of the rings. Calculations on tetraaurated heteroaryl complexes reveal that incorporation of the aurated substituents at the nitrogen atom can convert nonaromaticity in the parent indolium into aromaticity in the aurated one due to hyperconjugation, thus extending the concept of hyperconjugative aromaticity to heterocycles with transition metal substituents. More importantly, further analysis indicates that the aurated substituents can perform better than traditional main-group substituents. Recently, we also probed the strongest aromatic cyclopentadiene and pyrrolium rings by hyperconjugation of transition metal substituents. Moreover, theoretical calculations suggest that one electropositive substituent is able to induce aromaticity; whereas one electronegative substituent prompts nonaromaticity rather than antiaromaticity. We also probed the possibility of Craig-type Möbius aromaticity in organometallic chemistry, where the position of the transition metals is in the rings. According to the electron count and topology, aromaticity can be classified as Hückel-type and Möbius-type. In comparison with numerous Hückel aromatics containing 4 n+2 π-electrons, Möbius aromatics with 4 n π-electrons, especially the Craig-type species, are particularly limited. We first examined aromaticity in osmapentalynes. Theoretical calculations reveal that incorporation of the osmium center not only reduces the ring strain of the parent pentalyne, but also converts Hückel antiaromaticity in the parent pentalyne into Craig-type Möbius aromaticity in metallapentalynes. Further studies show that the transition metal fragments can also make both 16e and 18e osmapentalenes aromatic, indicating that the Craig-type Möbius aromaticity in osmapentalyne is rooted in osmapentalenes. In addition, Möbius aromaticity is also possible in dimetalla[10]annulenes, where the lithium atoms are not spectator cations but play an important role due to their bonding interaction with the diene moieties. We then examined the possibility of σ-aromaticity in an unsaturated ring. Traditional π-aromaticity is used to describe the π-conjugation in fully unsaturated rings; whereas σ-aromaticity may stabilize fully saturated rings with delocalization caused by σ-electron conjugation. We found that the unsaturated three-membered ring in cyclopropaosmapentalene is σ-aromatic. Very recently, we extended σ-aromaticity into in a fully unsaturated ring. The concepts and examples presented here show the importance of interplay and union between experiment and theory in developing novel aromatic systems and, especially, the indispensable role of computational study in rationalization of unconventional aromaticity. All these findings highlight the strong power of transition metals originating from participation of d orbitals in aromaticity, opening an avenue to the design of unique metalla-aromatics.
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Affiliation(s)
- 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, People’s Republic of China
| | - Qiong Xie
- 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, People’s Republic of 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, People’s Republic of China
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8
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Chu Z, He G, Cheng X, Deng Z, Chen J. Synthesis and Characterization of Cyclopropaosmanaphthalenes Containing a Fused σ‐Aromatic Metallacyclopropene Unit. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201904815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Zhenwei Chu
- Department of Materials Science and EngineeringCollege of MaterialsXiamen University Xiamen 361005 P. R. China
| | - Guomei He
- Department of Materials Science and EngineeringCollege of MaterialsXiamen University Xiamen 361005 P. R. China
| | - Xiaoli Cheng
- Department of Materials Science and EngineeringCollege of MaterialsXiamen University Xiamen 361005 P. R. China
| | - Zhirong Deng
- Department of Materials Science and EngineeringCollege of MaterialsXiamen University Xiamen 361005 P. R. China
| | - Jiangxi Chen
- Department of Materials Science and EngineeringCollege of MaterialsXiamen University Xiamen 361005 P. R. China
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