1
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Rabe A, Wang Q, Sundholm D. Unraveling the enigma of Craig-type Möbius-aromatic osmium compounds. Dalton Trans 2024; 53:10938-10946. [PMID: 38888198 DOI: 10.1039/d4dt01110d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Nuclear magnetic resonance (NMR) chemical shifts and the magnetically induced current density (MICD) susceptibility of four osmium containing molecules have been calculated at the density functional theory (DFT) level using three relativistic levels of theory. The calculations were performed at the quasi-relativistic level using an effective core potential (ECP) for Os, at the all-electron scalar exact two-component (X2C) relativistic level, and at the relativistic X2C level including spin-orbit coupling (SO-X2C). In earlier studies, the osmapentalene (1) and the osmapentalynes (2 and 3) were considered Craig-type Möbius aromatic and it was suggested that the analogous osmium compound (4) is Craig-type Möbius antiaromatic. Here, the ring-current strengths were obtained with the gauge including magnetically induced currents (GIMIC) method by integrating the MICD susceptibility passing through planes that intersect chemical bonds and by line integration of the induced magnetic field using Ampère-Maxwell's law. The ring-current calculations suggest that 1, 2 and 3 are weakly aromatic and that 4 is nonaromatic. The accuracy of the MICD susceptibility was assessed by comparing calculated NMR chemical shifts to available experimental data. Visualization of the MICD susceptibility shows that the ring current does not pass from one side of the molecular plane to the other, which means that the MICD susceptibility of the studied molecules does not exhibit any Möbius topology as one would expect for Craig-type Möbius aromatic and for Craig-type Möbius antiaromatic molecules. Thus, molecules 1-3 are not Craig-type Möbius aromatic and molecule 4 is not Craig-type Möbius antiaromatic as previously suggested. Calculations of the 1H NMR and 13C NMR chemical shifts of atoms near the Os atom show the importance of including spin-orbit effects. Overall, our study revisits the understanding of the aromaticity of organometallic molecules containing transition metals.
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Affiliation(s)
- Antonia Rabe
- Department Chemie, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
- Department of Chemistry, Faculty of Science, University of Helsinki, P. O. Box 55 (A. I. Virtasen aukio 1), FIN-00014, Helsinki, Finland.
| | - Qian Wang
- 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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2
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Worth GA, Robb MA. Controlling Electronic Coherences and the Curvature Induced by the Derivative Coupling at a Conical Intersection: A Quantum Ehrenfest (QuEh) Protocol for Reaction Path Following Application to "Channel 3" Benzene Photochemistry. J Phys Chem A 2024. [PMID: 38917388 DOI: 10.1021/acs.jpca.4c02449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
We report a protocol for the implementation of "reaction path following" from a transition state through a conical intersection, including both the path curvature induced by the derivative coupling and the corresponding induced electronic coherences. This protocol focuses on the "central" Gaussian wavepacket (initially unexcited) in the quantum Ehrenfest (QuEh) method. Like the reaction path following, the normal mode corresponding to the imaginary frequency at the transition state is given an initial momentum. The protocol is applied to the "channel 3" radiationless decay of benzene. We also demonstrate that one can enhance the effect of the derivative coupling and the electronic coherence with an IR pulse.
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Affiliation(s)
- Graham A Worth
- Department of Chemistry, University College London, 20, Gordon Street, WC1H 0AJ London, U.K
| | - Michael A Robb
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, 80 Wood Lane, W12 0BZ London, U.K
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3
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Badri Z, Foroutan-Nejad C. On the aromaticity of actinide compounds. Nat Rev Chem 2024:10.1038/s41570-024-00617-y. [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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4
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Artigas A, Carissan Y, Hagebaum-Reignier D, Bock H, Durola F, Coquerel Y. Aromaticity in Semi-Condensed Figure-Eight Molecules. Chemistry 2024; 30:e202401016. [PMID: 38642001 DOI: 10.1002/chem.202401016] [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: 03/12/2024] [Revised: 04/08/2024] [Accepted: 04/19/2024] [Indexed: 04/22/2024]
Abstract
Electron delocalization and aromaticity was comparatively evaluated in recently synthesized figure-eight molecules made of two condensed U-shaped polycyclic aromatic hydrocarbon moieties connected either by two single bonds or by two para-phenylene groups. The selected examples include molecules that incorporate eight-membered and sixteen-membered rings, as well as a doubly [5]helicene-bridged (1,4)cyclophane. We probe whether some electron delocalization could occur through the stereogenic single bonds in these molecules: Is aromaticity purely (semi-)local, or possibly also global in these molecules? It was concluded that the situation can go from a purely (semi-)local character when the dihedral angle at the connecting single bonds is large, such as in biphenyl, to a predominantly (semi-)local character with a minor global contribution when the dihedral angle is small, such as in the para-phenylene connectors of the [5] helicene-bridged cyclophane.
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Affiliation(s)
- Albert Artigas
- Facultat de Ciències, Universitat de Girona, Campus Montilivi, Carrer de Maria Aurèlia Capmany i Farnès 69, 17003, Girona, Catalunya, Spain
| | - Yannick Carissan
- Aix Marseille Univ, CNRS, Centrale Méditerranée, iSm2, Marseille, France
| | | | - Harald Bock
- Centre de Recherche Paul Pascal, CNRS, 115 av. Schweitzer, 33600, Pessac, France
| | - Fabien Durola
- Centre de Recherche Paul Pascal, CNRS, 115 av. Schweitzer, 33600, Pessac, France
| | - Yoann Coquerel
- Aix Marseille Univ, CNRS, Centrale Méditerranée, iSm2, Marseille, France
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5
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Blasco D, Sundholm D. The aromatic nature of auracycles and diauracycles based on calculated ring-current strengths. Dalton Trans 2024; 53:10150-10158. [PMID: 38819195 DOI: 10.1039/d4dt00827h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2024]
Abstract
We have calculated the magnetically induced current density susceptibility for gold-containing organometallic molecular rings using the gauge-including magnetically induced currents (GIMIC) method. The aromatic nature has been determined by calculating the strength of the magnetically induced ring current susceptibility, which is often called ring current. To our knowledge, we show here for the first time that gold-containing organometallic rings may be aromatic or antiaromatic sustaining ring currents in the presence of an external magnetic field. The calculated aromatic character of the rings agrees with the aromatic nature one expects when using Hückel's aromaticity rules. The studied auracycles and diauracycles with 4n electrons in the conjugated orbitals generally sustain a weak paratropic ring current, whereas those having 4n + 2 electrons in the conjugated orbitals sustain a diatropic ring current that is almost as strong as that of benzene. The number of electrons are obtained by assuming that each C, N and Au atom of the ring contribute one electron, and a H atom connected to a N atom in the ring increases the number of electrons by one. An electron-attracting ligand at Au removes one electron from the ring. Formation of a short Au-Au bonding diauracycles reduces the number of electrons in the ring by two.
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Affiliation(s)
- Daniel Blasco
- Departamento de Química, Instituto de Investigación en Química (IQUR), Universidad de La Rioja, Madre de Dios 53, 26006, Logroño, 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.
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6
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Wolf S, Köppe R, Treptow J, Feuerstein W, Wenzel J, Breher F, Roesky PW, Weigend F, Klopper W, Feldmann C. [GeRu 6(CO) 18HI]: A Germanium-Centered Ruthenium Carbonyl Cluster with Aromatic Ring Current. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309043. [PMID: 38509846 DOI: 10.1002/advs.202309043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/15/2024] [Indexed: 03/22/2024]
Abstract
The carbonyl cluster compound [GeRu6(CO)18HI] is unique in regard to its structure and bonding with a GeRu6 cluster core, a planar GeRu4HI unit, extensive multi-center bonding, and an aromatic ring current similar to benzene (9-10 nA T-1). The open-shell cluster core is a Ge-centered five-membered Ru4(Ru2) ring with CO ligands and an additional H and I atom, each bridging two Ru atoms on opposite sides of the cluster core. The compound is prepared at 130 °C in a weakly-coordinating ionic liquid.
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Affiliation(s)
- Silke Wolf
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Ralf Köppe
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Jens Treptow
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Wolfram Feuerstein
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Jonas Wenzel
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Frank Breher
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Peter W Roesky
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
| | - Florian Weigend
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, D-35043, Marburg, Germany
| | - Wim Klopper
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, D-76131, Karlsruhe, Germany
| | - Claus Feldmann
- Institute for Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße 15, D-76131, Karlsruhe, Germany
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7
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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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8
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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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9
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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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10
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Meiszter E, Gazdag T, Mayer PJ, Kunfi A, Holczbauer T, Sulyok-Eiler M, London G. Revisiting Hafner's Azapentalenes: The Chemistry of 1,3-Bis(dimethylamino)-2-azapentalene. J Org Chem 2024; 89:5941-5951. [PMID: 38630009 PMCID: PMC11077492 DOI: 10.1021/acs.joc.3c02564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 03/19/2024] [Accepted: 04/03/2024] [Indexed: 05/04/2024]
Abstract
Stable azaheterocyclic derivatives of pentalene have been reported by the group of Hafner in the 1970s. However, these structures remained of low interest until recently, when they started to be investigated in the context of organic light-emitting diodes' (OLEDs') development. Herein, we revisit the synthesis of stable azapentalene derivative 1,3-bis(dimethylamino)-2-azapentalene and further explore its properties both computationally and experimentally. Beyond the reproduction and optimization of some previously reported transformations, such as formylation and amine substitution, the available scope of reactions was expanded with azo-coupling, selective halogenations, and cross-coupling reactions.
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Affiliation(s)
- Enikő Meiszter
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
- Department
of Organic Chemistry and Technology, Faculty of Chemical Technology
and Biotechnology, Budapest University of
Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Tamás Gazdag
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
- Hevesy
György PhD School of Chemistry, Eötvös
Loránd University, Pázmány Péter Sétány 1/a, 1117 Budapest, Hungary
| | - Péter J. Mayer
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
| | - Attila Kunfi
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
| | - Tamás Holczbauer
- Chemical
Crystallography Research Laboratory and Stereochemistry Research Group,
Institute for Organic Chemistry, HUN-REN
Research Centre for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
| | - Máté Sulyok-Eiler
- Hevesy
György PhD School of Chemistry, Eötvös
Loránd University, Pázmány Péter Sétány 1/a, 1117 Budapest, Hungary
- Laboratory
of Structural Chemistry and Biology, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter
Sétány 1/a, 1117 Budapest, Hungary
| | - Gábor London
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, HUN-REN Research Centre
for Natural Sciences, Magyar tudósok krt. 2, 1117 Budapest, Hungary
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11
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Sieroka N, Lossau T, Neudecker T. Emergent Properties in Chemistry - Relating Molecular Properties to Bulk Behavior. Chemistry 2024; 30:e202303868. [PMID: 38558443 DOI: 10.1002/chem.202303868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Indexed: 04/04/2024]
Abstract
Certain properties of an object only emerge when a sufficient number of those objects are present in a definite arrangement. For example, one or two water molecules cannot said to be in a liquid state, but a drop of water can be. This concept of emergence has been studied extensively, but only occasionally discussed explicitly in the context of chemistry. In this paper, we aim to show the fruitfulness of the concept of emergence for chemical inquiry by considering four case studies of emergent chemical properties, i. e., the liquidity and freezing of water, structural properties of crystals, thermodynamical phase transitions and quantum mechanical phenomena. We show that some of these properties emerge gradually, some at discrete points, and some should be taken to emerge only when the number of constituents tends to infinity. We argue that studying the way in which chemical properties emerge presents a useful avenue for research that promises greater insight into the nature of those properties.
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Affiliation(s)
- Norman Sieroka
- University of Bremen, Institute for Philosophy, Enrique-Schmidt-Straße 7, D-28359, Bremen, Germany
- ETH Zurich, Department of Chemistry and Applied Biosciences, Vladimir-Prelog-Weg, CH-8093, Zurich, Switzerland
| | - Tammo Lossau
- University of Bremen, Institute for Philosophy, Enrique-Schmidt-Straße 7, D-28359, Bremen, Germany
| | - Tim Neudecker
- University of Bremen, Institute for Physical and Theoretical Chemistry, Leobener Straße 6, D-28359, Bremen, Germany
- Bremen Center for Computational Materials Science, Am Fallturm 1, D-28359, Bremen, Germany
- MAPEX Center for Materials and Processes, Bibliothekstraße 1, D-28359, Bremen, Germany
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12
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Scholz AS, Bolte M, Virovets A, Peresypkina E, Lerner HW, Anstöter CS, Wagner M. Tetramerization of BEB-Doped Phenalenyls to Obtain (BE) 8-[16]Annulenes (E = N, O). J Am Chem Soc 2024; 146:12100-12112. [PMID: 38635878 DOI: 10.1021/jacs.4c02163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Two (BE)8-[16]annulenes were prepared and fully characterized by experimental and quantum-chemical means (1, E = N; 2, E = O). The 1,8-naphthalenediyl-bridged diborane(6) 3 served as their common starting material, which was treated with [Al(NH3)6]Cl3 to form 1 (91% yield) or with 1,8-naphthalenediboronic acid anhydride to form 2 (93% yield). As a result, the heteroannulenes 1 and 2 are supported by four aromatic "clamps" and may also be viewed as NH- or O-bridged cyclic tetramers of BNB- or BOB-doped phenalenyls. X-ray crystallography on mono-, di-, and tetraadducts 2·thf, 2·py2, and 2·py4 showed that 2 is an oligotopic Lewis acid (thf/py: tetrahydrofuran/pyridine donor). The applicability of 2 also as a Lewis basic ligand in coordination chemistry was demonstrated by the synthesis of the mononuclear Ag+ complex [Ag(py)2(2·py4)]+ and the dinuclear Pb2+ complex 6. During the assembly of 6, the rearrangement of 2 led to the formation of two (BO)9-macrocycles linked by two BOB-phenalenyls to form a nanometer-sized cage with four negatively charged, tetracoordinated B atoms. Both 1 and 2 show several redox waves in the cathodic regions of the cyclic voltammograms. An in-depth assessment of the consequences of electron injection on the aromaticity of 1 and 2 was achieved by electronic structure calculations. 1 and 2 are proposed to exhibit aromatic switching capabilities in the [16]annulene motif.
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Affiliation(s)
- Alexander S Scholz
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Michael Bolte
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Alexander Virovets
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Eugenia Peresypkina
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Hans-Wolfram Lerner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
| | - Cate S Anstöter
- EaStCHEM School of Chemistry, University of Edinburgh, EH8 9YLEdinburgh,U.K
| | - Matthias Wagner
- Institut für Anorganische und Analytische Chemie, Goethe-Universität Frankfurt am Main, Max-von-Laue-Straße 7, 60438 Frankfurt am Main, Germany
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13
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Escayola S, Jimenez-Izal E, Matito E, Ugalde JM, Grande-Aztatzi R, Mercero JM. Unveiling the quantum secrets of triel metal triangles: a tale of stability, aromaticity, and relativistic effects. Phys Chem Chem Phys 2024; 26:12619-12627. [PMID: 38597590 DOI: 10.1039/d4cp00484a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Low lying electronic states of Al3-, Ga3-, In3-, and Tl3- have been characterized using high level multiconfigurational quasi degenerate perturbation theory on the multiconfigurational self-consistent field. Among these species, the singlet states emerge as the predominant energy minima, displaying remarkable stability. However, within the Tl3- series, our investigation leads to the identification of the high-spin , as the most stable spin state, a result corroborated by previous experimental detection via photoelectron spectroscopy. Similarly, we have also identified the singlet state of In3- as the signal detected previously experimentally. By applying Mandado's rules and an array of aromaticity indicators, it is conclusively demonstrated that both the singlet and quintet states exhibit multiple-fold aromaticity, while the triplets exhibit conflicting aromaticity. Furthermore, this investigation highlights the significant impact of relativistic effects, as they enhance the stability of the state relative to its singlet counterpart. These findings shed new light on the electronic structures and properties of these ions, offering valuable insights into their chemical behavior and potential applications.
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Affiliation(s)
- Sílvia Escayola
- Institute of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, C/M. Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
| | - Elisa Jimenez-Izal
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
- Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), P.K. 1072, 20080 Donostia, Euskadi, Spain
| | - Eduard Matito
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
- IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Euskadi, Spain
| | - Jesus M Ugalde
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
- Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), P.K. 1072, 20080 Donostia, Euskadi, Spain
| | - Rafael Grande-Aztatzi
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
- Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey, Av. Eugenio Garza Sada 2501, 64849 Monterrey, Nuevo León, Mexico
| | - Jose M Mercero
- Donostia International Physics Center (DIPC), 20018 Donostia, Euskadi, Spain.
- Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU), P.K. 1072, 20080 Donostia, Euskadi, Spain
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14
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Yang C, Dong H, Li X, Zhou N, Liu Y, Jin J, Wang Y. The σ+π dual aromaticity of typical bi-tetrazole ring molecule TKX-50. Chemphyschem 2024; 25:e202400005. [PMID: 38259129 DOI: 10.1002/cphc.202400005] [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: 01/02/2024] [Revised: 01/19/2024] [Accepted: 01/23/2024] [Indexed: 01/24/2024]
Abstract
Two complexes of dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50) were employed to evaluate the aromaticity of their tetrazole rings via deep analysis such as the electronic structure, the ZZ component of the natural chemical shielding tensor (NICSZZ) and component orbitals, localized orbital locator purely contributed by σ-orbitals (LOL-σ) and localized orbital locator purely contributed by π-orbitals (LOL-π), the anisotropy of the induced current density (AICD) and the ZZ component of iso-chemical shielding surface (ICSSZZ) of these tetrazole rings thereof. The conclusion shows: that all tetrazole rings and bi-tetrazole rings in complexes have strong σ and a comparable strength π double aromaticity; all these magnetic shields almost symmetrically increase from the central axis to the tetrazole ring atoms; tetrazole rings in complex II show a little stronger dual aromaticity than that in complex I mainly due to the different orientation of the fragment 2 encompassing two hydroxylamine groups resulting in different effects on the contributions of σ orbitals and π orbitals to total aromaticity of tetrazole rings thereof; the difference in aromaticity is fundamentally caused by the atoms O with stronger electron-withdrawing than atom N in fragment 2 interact with bi-tetrazole ring through O in complex I but through N in complex II.
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Affiliation(s)
- Chunhai Yang
- School of Materials Engineering, Changshu Institute of Technology, Suzhou, 215500, China
| | - Huilong Dong
- School of Materials Engineering, Changshu Institute of Technology, Suzhou, 215500, China
| | - Xue Li
- School of Petroleum Engineering, Changzhou University, Changzhou, 213164, China
| | - Ning Zhou
- School of Petroleum Engineering, Changzhou University, Changzhou, 213164, China
| | - Yi Liu
- College of Chemistry and Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, China
| | - Junxun Jin
- School of Materials Engineering, Changshu Institute of Technology, Suzhou, 215500, China
| | - Yinjun Wang
- BGRIMM Explosive & Blasting Technology Co., Ltd., Beijing, 100160, China
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15
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Yang K, Li Z, Huang Y, Zeng Z. bay/ ortho-Octa-substituted Perylene: A Versatile Building Block toward Novel Polycyclic (Hetero)Aromatic Hydrocarbons. Acc Chem Res 2024; 57:763-775. [PMID: 38386871 DOI: 10.1021/acs.accounts.3c00793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
ConspectusPolycyclic (hetero)aromatic hydrocarbons (PAHs) have emerged as a focal point in current interdisciplinary research, spanning the realms of chemistry, physics, and materials science. Possessing distinctive optical, electronic, and magnetic properties, these π-functional materials exhibit significant potential across diverse applications, including molecular electronic devices, organic spintronics, and biomedical functions, among others. Despite the extensive documentation of various PAHs over the decades, the efficient and precise synthesis of π-extended PAHs remains a formidable challenge, hindering their broader application. This challenge is primarily attributed to the intricate and often elusive nature of their synthesis, compounded by issues related to low solubility and unfavored stability.The development of π-building blocks that can be facilely and modularly transformed into diverse π-frameworks constitutes a potent strategy for the creation of novel PAH materials. For instance, based on the classic perylene diimide (PDI) unit, researchers such as Würthner, Wang, and Nuckolls have successfully synthesized a plethora of structurally diverse PAHs, as well as numerous other π-functional materials. However, until now the availability of such versatile building blocks is still severely limited, especially for those simultaneously having a facile preparation process, adequate solubilizing groups, favored material stability, and critically, rich possibilities for structural extension spaces.In this Account, we present an overview of our invention of a highly versatile bay-/ortho-octa-substituted perylene building block, designated as Per-4Br, for the construction of a series of novel PAH scaffolds with tailor-made structures and rich optoelectronic and magnetic properties. First, starting with a brief discussion of current challenges associated with the bottom-up synthesis of π-extended PAHs, we rationalize the key features of Per-4Br that enable facile access to new PAH molecules including its ease of large-scale preparation, favored material stability and solubility, and multiple flexible reaction sites, with a comparison to the PDI motif. Then, we showcase our rational design and sophisticated synthesis of a body of neutral or charged, closed- or open-shell, curved, or planar PAHs via controlled annulative π-extensions in different directions such as peripheral, diagonal, or multiple dimensions of the Per-4Br skeleton. In this part, the fundamental structure-property relationships between molecular conformations, electronic structures, and self-assembly behaviors of these PAHs and their unique physiochemical properties such as unusual open-shell ground states, global aromaticity, state-associated/stimuli-responsive magnetic activity, and charge transport characteristics will be emphatically elaborated. Finally, we offer our perspective on the continued advancement of π-functional materials based on Per-4Br, which, we posit, may stimulate heightened research interest in the versatile structural motifs typified by Per-4Br, consequently catalyzing further progress in the realm of organic π-functional materials.
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Affiliation(s)
- Kun Yang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, China
| | - Zuhao Li
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, China
| | - Yulin Huang
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, China
| | - Zebing Zeng
- State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan 410082, China
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16
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Orozco-Ic M, Soriano-Agueda L, Escayola S, Sundholm D, Merino G, Matito E. Understanding Aromaticity in [5]Helicene-Bridged Cyclophanes: A Comprehensive Study. J Org Chem 2024; 89:2459-2466. [PMID: 38236016 DOI: 10.1021/acs.joc.3c02485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
This study explores the aromaticity of doubly [5]helicene-bridged (1,4)cyclophane and triply [5]helicene-bridged (1,3,5)cyclophane via calculations of the magnetic response and of electronic aromaticity indices. The primary objective is to assess the π-electron delocalization to determine whether they sustain global ring currents associated with π aromaticity. The molecules show local ring currents in the presence of an external magnetic field. The ring currents flow diatropically in the stacked six-membered rings and in the helicene arms. However, these π currents are not interconnected due to the discontinuity of the π delocalization at the C-C single bonds connecting the central six-membered rings to the helicene arms. Electronic indices suggest that the helicene-arm systems have significantly smaller electron delocalization than benzene. The reduction in the delocalization does not compromise their ability to exhibit ring currents in the presence of an external magnetic field. The analysis provides further evidence that the magnetic criteria yield a different degree of aromaticity for the helicene arms than obtained in the calculation of the electronic aromaticity indices. However, both approaches confirm that the studied molecules are not globally aromatic.
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Affiliation(s)
- Mesías Orozco-Ic
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
| | - Luis Soriano-Agueda
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
| | - Sílvia Escayola
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany, 69, Girona, 17003 Catalonia, Spain
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, A. I. Virtasen aukio 1, P.O. Box 55, FIN-00014 Helsinki, Finland
| | - 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., México
| | - Eduard Matito
- Donostia International Physics Center (DIPC), Donostia, 20018 Euskadi, Spain
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17
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Miwa K, Yokota T, Wang Q, Sakurai T, Fliegl H, Sundholm D, Shinokubo H. Metallaantiaromaticity of 10-Platinacorrole Complexes. J Am Chem Soc 2024; 146:1396-1402. [PMID: 38172072 PMCID: PMC10882971 DOI: 10.1021/jacs.3c10250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
The aromaticity of cyclic π-conjugated organometallic compounds is known as metallaaromaticity. π-Conjugated metallacycles, such as metallabenzenes and metallapentalenes, have been investigated in order to understand the involvement of the d electrons from the metal center in the π-conjugated systems of the organic ligands. Here, we report the synthesis of Pd(II) 10-platinacorrole complexes with cyclooctadiene (COD) and norbornadiene (NBD) ligands. While the Pd(II) 10-platinacorrole COD complex adopts a distorted structure without showing appreciable antiaromaticity, the corresponding NBD complex exhibits a distinct antiaromatic character due to its highly planar conformation. Detailed density functional theory (DFT) calculations revealed that two d orbitals are involved in macrocyclic π-conjugation. We furthermore demonstrated that Craig-Möbius antiaromaticity is not present in the studied system. The synthesis of 10-platinacorroles enables a systematic comparison of the antiaromaticity and aromaticity of closely related porphyrin analogues, providing a better understanding of π-conjugation that involves d orbitals.
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Affiliation(s)
- Kazuki Miwa
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering and Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 Aichi, Japan
| | - Tomoya Yokota
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering and Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 Aichi, Japan
| | - Qian Wang
- Department of Chemistry, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Takahiro Sakurai
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering and Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 Aichi, Japan
| | - Heike Fliegl
- FIZ Karlsruhe─Leibniz Institute for Information Infrastructure, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Hiroshi Shinokubo
- Department of Molecular and Macromolecular Chemistry, Graduate School of Engineering and Integrated Research Consortium on Chemical Sciences (IRCCS), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 Aichi, Japan
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18
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Dishi O, Rahav Y, Gidron O. π-Conjugated oligofuran macrocycles. Chem Commun (Camb) 2024; 60:522-529. [PMID: 38109063 DOI: 10.1039/d3cc05225g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
This Feature Article overviews a new class of π-conjugated materials - macrocyclic furans. Starting from their synthesis, we review their unique structural, optical and electronic properties, chemical reactivity, and potential application as synthons. Finally, we discuss the study of oligofuran macrocycles as a model system for exploring the concept of global aromaticity and the size limitation of Hückel's rule in neutral macrocycles.
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Affiliation(s)
- Or Dishi
- The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel.
| | - Yuval Rahav
- The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel.
| | - Ori Gidron
- The Hebrew University of Jerusalem, Edmond J. Safra Campus, 9190401, Jerusalem, Israel.
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19
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Huo Y, Gu X, Li X, Jin P. Group 13 five- and six-membered rings with rare 2π aromaticity. Phys Chem Chem Phys 2023; 26:342-351. [PMID: 38063083 DOI: 10.1039/d3cp04159j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
According to Hückel's rule, cyclic species are aromatic if they have 4n + 2 (n = 0, 1, 2, etc.) π electrons. However, large aromatic rings (atom number > 4) with minimum 2π electrons (i.e., n = 0) are rather rare because of the structural instability stemming from the deficient π electrons compared to the ring size. To date, the largest 2π-aromatic ring is a five-membered Ga5 core reported in a recent experiment. Herein, density functional theory calculations predicted seven inverse-sandwich Na2(MH)5 and half-sandwich Ca(MH)5 or Ca(MH)6 (M = Al, Ga or In) structures. They all have planar central five- or six-membered Al/Ga/In rings, rather negative binding energies and large HOMO-LUMO gaps. Their dianionic metal rings exhibit obvious aromatic characters and appreciable diatropic ring currents due to the good delocalization of 2π electrons donated by the Na/Ca metals. Interestingly, they also have novel collective bonding with the Na/Ca atoms interacting with both the metal ring and surrounding H atoms. These metalloaromatic rings not only greatly enrich the precious family of 2π aromatics, but also increase the maximum ring atom number from five to six, thus paving the way for Hückel-type 2π-aromatic large rings.
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Affiliation(s)
- Yutong Huo
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China.
| | - Xiaojiao Gu
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China.
| | - Xinde Li
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China.
| | - Peng Jin
- School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China.
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20
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Rončević I, Leslie FJ, Rossmannek M, Tavernelli I, Gross L, Anderson HL. Aromaticity Reversal Induced by Vibrations in Cyclo[16]carbon. J Am Chem Soc 2023; 145:26962-26972. [PMID: 38039504 PMCID: PMC10722511 DOI: 10.1021/jacs.3c10207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 10/29/2023] [Accepted: 10/31/2023] [Indexed: 12/03/2023]
Abstract
Aromaticity is typically regarded as an intrinsic property of a molecule, correlated with electron delocalization, stability, and other properties. Small variations in the molecular geometry usually result in small changes in aromaticity, in line with Hammond's postulate. For example, introducing bond-length alternation in benzene and square cyclobutadiene by modulating the geometry along the Kekulé vibration gradually decreases the magnitude of their ring currents, making them less aromatic and less antiaromatic, respectively. A sign change in the ring current, corresponding to a reversal of aromaticity, typically requires a gross perturbation such as electronic excitation, addition or removal of two electrons, or a dramatic change in the molecular geometry. Here, we use multireference calculations to show how movement along the Kekulé vibration, which controls bond-length alternation, induces a sudden reversal in the ring current of cyclo[16]carbon, C16. This reversal occurs when the two orthogonal π systems of C16 sustain opposing currents. These results are rationalized by a Hückel model which includes bond-length alternation, and which is combined with a minimal model accounting for orbital contributions to the ring current. Finally, we successfully describe the electronic structure of C16 with a "divide-and-conquer" approach suitable for execution on a quantum computer.
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Affiliation(s)
- Igor Rončević
- Department
of Chemistry, Oxford University, Chemistry
Research Laboratory, Oxford OX1 3TA, United
Kingdom
| | - Freddie J. Leslie
- Department
of Chemistry, Oxford University, Chemistry
Research Laboratory, Oxford OX1 3TA, United
Kingdom
| | - Max Rossmannek
- IBM
Research Europe − Zurich, Säumerstrasse 4, Rüschlikon 8803, Switzerland
| | - Ivano Tavernelli
- IBM
Research Europe − Zurich, Säumerstrasse 4, Rüschlikon 8803, Switzerland
| | - Leo Gross
- IBM
Research Europe − Zurich, Säumerstrasse 4, Rüschlikon 8803, Switzerland
| | - Harry L. Anderson
- Department
of Chemistry, Oxford University, Chemistry
Research Laboratory, Oxford OX1 3TA, United
Kingdom
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21
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Inostroza D, Leyva-Parra L, Pino-Rios R, Solar-Encinas J, Vásquez-Espinal A, Pan S, Merino G, Yañez O, Tiznado W. Li 6 E 5 Li 6 : Tetrel Sandwich Complexes with 10-π-Electrons. Angew Chem Int Ed Engl 2023:e202317848. [PMID: 38087836 DOI: 10.1002/anie.202317848] [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: 11/22/2023] [Indexed: 12/29/2023]
Abstract
When (4n +2) π-electrons are located in single planar ring, it conventionally qualifies as aromatic. According Hückel's rule, systems possessing ten π-electrons should be aromatic. Herein we report a series of D5h Li6 E5 Li6 sandwich structures, representing the first global minima featuring ten π-electrons E5 10- ring (E=Si-Pb). However, these π-electrons localize as five π-lone-pairs rather than delocalized orbitals. The high symmetry structure achieved is a direct consequence of σ-aromaticity, particularly favored in elements from Si to Pb, resulting in a pronounced diatropic ring current flow that contributes to the enhanced stability of these systems.
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Affiliation(s)
- Diego Inostroza
- Centro de Química Teórica & Computacional (CQT&C), Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andrés Bello, Avenida República 275, 8370146, Santiago de Chile, Chile
- Doctorado en Fisicoquímica Molecular, Facultad de Ciencias Exactas, Universidad Andres Bello, Avenida República 275, 8370146, Santiago, Chile
| | - Luis Leyva-Parra
- Centro de Química Teórica & Computacional (CQT&C), Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andrés Bello, Avenida República 275, 8370146, Santiago de Chile, Chile
- Doctorado en Fisicoquímica Molecular, Facultad de Ciencias Exactas, Universidad Andres Bello, Avenida República 275, 8370146, Santiago, Chile
| | - Ricardo Pino-Rios
- Instituto de Estudios de la Salud, Universidad Arturo Prat, 1100000, Iquique, Chile
- Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Casilla 121, 1100000, Iquique, Chile
| | - José Solar-Encinas
- Centro de Química Teórica & Computacional (CQT&C), Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andrés Bello, Avenida República 275, 8370146, Santiago de Chile, Chile
- Doctorado en Fisicoquímica Molecular, Facultad de Ciencias Exactas, Universidad Andres Bello, Avenida República 275, 8370146, Santiago, Chile
| | - Alejandro Vásquez-Espinal
- Instituto de Estudios de la Salud, Universidad Arturo Prat, 1100000, Iquique, Chile
- Química y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Casilla 121, 1100000, Iquique, Chile
| | - Sudip Pan
- Institute of Atomic and Molecular Physics, Jilin University, 130023, Changchun, China
| | - Gabriel Merino
- Departamento de Fisica Aplicada, Centro de Investigacion y de Estudios Avanzados Merida, Km. 6 Antigua carretera a Progreso Apdo. Postal 73, Cordemex, 97310, Mérida, Yuc., México
| | - Osvaldo Yañez
- Núcleo de Investigación en Data Science, Facultad de Ingeniería y Negocios, Universidad de las Américas, 7500000, Santiago, Chile
| | - William Tiznado
- Centro de Química Teórica & Computacional (CQT&C), Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andrés Bello, Avenida República 275, 8370146, Santiago de Chile, Chile
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22
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Saha HK, Mallick D, Das S. Dibenzoheterole-Fused s-Indacenes. J Org Chem 2023; 88:16248-16258. [PMID: 37943573 DOI: 10.1021/acs.joc.3c01719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Heterole (pyrrole, thiophene, furan, thiophene-S,S-dioxide)-fused s-indacenes are known for their enhanced paratropic ring-current strength. However, the outcome of the antiaromatic properties for dibenzoheterole-fused s-indacene antiaromatics remained underexplored. Carbazole-, dibenzothiophene-, dibenzofuran-, and dibenzo[b,d]thiophene-5,5-dioxide-fused s-indacenes 1-4, respectively, were synthesized and characterized by experimental (NMR, single-crystal, UV-vis, CV) and computational (DFT) approaches to study the ground-state antiaromatic properties. Sulfone-containing 4 showed the weakest paratropic ring-current strength for the s-indacene unit, while 1-3 showed a relatively greater paratropicity for the s-indacene unit, as evidenced by the changes in 1H NMR chemical shifts of s-indacene protons. Such observation was explained by the electron-withdrawing effect of the sulfone group and loss of 4n + 2 aromaticity of the heterole unit for 4 reducing its s-indacene paratropicity strength as the nonaromaticity of the heterole unit reduces the π-bond character at the dibenzo[b,d]thiophene-5,5-dioxide/s-indacene fusion site to avoid antiaromatic s-indacene ring formation. The modulation of the paratropic ring-current strength of s-indacene for 1-4 was further supported by the NICS(1)zz and ring-current (ACID) calculations.
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Affiliation(s)
- Hemonta Kumar Saha
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Dibyendu Mallick
- Department of Chemistry, Presidency University, Kolkata 700073, West Bengal, India
| | - Soumyajit Das
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
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23
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Srivastava AK. Boronyl-Based Polycyclic Superhalogens. J Phys Chem A 2023. [PMID: 38032043 DOI: 10.1021/acs.jpca.3c05583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Superhalogenity refers to the tendency of radicals to have higher electron affinity (EA) than halogens or anions to possess higher vertical detachment energy (VDE) than do halides (3.64 eV). In Srivastava, A. K. J. Phys. Chem. A 2023, 127, 4867-4872, we demonstrated a simple strategy in which some polycyclic hydrocarbons (PHs) can be turned into polycyclic superhalogens (PSs) by substituting CN groups in the place of hydrogens. We also notice that the superhalogenity of cyanide-based PSs is related to their aromaticity. Boronyl (BO) is an isoelectronic and inorganic analog of the cyano (CN) group. Therefore, we consider the substitution of BO in PHs and compare them with CN-based PSs using the density functional theory. In the case of C5H5-, we notice that the B3LYP and CCSD(T) calculated VDEs of resulting C5H5-n(BO)n- anions increase with the increase in the number of BO substituents (n) such that they become superhalogens for n ≥ 3 like C5H5-n(CN)n- anions. However, their aromaticity does not correspond to the superhalogenity, unlike C5H5-n(CN)n-. Similarly, all BO-substituted PHs possess structures similar to their CN analogs. Although their aromaticity is reduced compared to CN-based anions, the VDE of all these BO-based polycyclic anions and the EA of their radicals exceed 5 eV than those of the corresponding CN-based PSs. Therefore, this study proposes a new class of boronyl-based polycyclic superhalogens. These superhalogen anions might attract synthetic chemists and experimentalists for further explorations.
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Affiliation(s)
- Ambrish Kumar Srivastava
- Department of Physics, Deen Dayal Upadhyaya Gorakhpur University, Gorakhpur, Uttar Pradesh 223009, India
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Ao MZ, Ma YY, Mu YW, Li SD. Perfect cubic metallo-borospherenes TM 8B 6 (TM = Ni, Pd, Pt) as superatoms following the 18-electron rule. NANOSCALE ADVANCES 2023; 5:6688-6694. [PMID: 38024293 PMCID: PMC10662020 DOI: 10.1039/d3na00551h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 10/15/2023] [Indexed: 12/01/2023]
Abstract
Transition-metal (TM)-doped metallo-borospherenes exhibit unique structures and bonding in chemistry which have received considerable attention in recent years. Based on extensive global minimum searches and first-principles theory calculations, we predict herein the first and smallest perfect cubic metallo-borospherenes Oh TM8B6 (TM = Ni (1), Pd (2), Pt (3)) and Oh Ni8B6- (1-) which contain eight equivalent TM atoms at the vertexes of a cube and six quasi-planar tetra-coordinate face-capping boron atoms on the surface. Detailed canonical molecular orbital and adaptive natural density partitioning bonding analyses indicate that Oh TM8B6 (1/2/3) as superatoms possess nine completely delocalized 14c-2e bonds following the 18-electron principle (1S21P61D10), rendering spherical aromaticity and extra stability to the complex systems. Furthermore, Ni8B6 (1) can be used as building blocks to form the three-dimensional metallic binary crystal NiB (4) (Pm3̄m) in a bottom-up approach which possesses a typical CsCl-type structure with an octa-coordinate B atom located exactly at the center of the cubic unit cell. The IR, Raman, UV-vis and photoelectron spectra of the concerned clusters are computationally simulated to facilitate their experimental characterization.
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Affiliation(s)
- Mei-Zhen Ao
- Nanocluster Laboratory, Institute of Molecular Science, Shanxi University Taiyuan 030006 P. R. China
- Fenyang College of Shanxi Medical University Fenyang 032200 China
| | | | - Yue-Wen Mu
- Nanocluster Laboratory, Institute of Molecular Science, Shanxi University Taiyuan 030006 P. R. China
| | - Si-Dian Li
- Nanocluster Laboratory, Institute of Molecular Science, Shanxi University Taiyuan 030006 P. R. China
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25
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Bradley D, Hillier BK, Peeks MD. Electronic delocalization in charged macrocycles is associated with global aromaticity. Chem Commun (Camb) 2023; 59:13438-13441. [PMID: 37860973 DOI: 10.1039/d3cc03464j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
When oxidized, cycloparaphenylenes and porphyrin nanorings can exhibit macrocyclic ring currents which have been used to assign these molecules as (anti)aromatic. These assignments have been controversial because the presence of ring currents does not always imply cyclic electronic delocalization, which is essential to the definition of aromaticity. Here, we show that the emergence of macrocyclic ring currents in these molecules is correlated with increased electronic delocalization, supporting assignments of these molecules as (anti)aromatic.
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Affiliation(s)
- David Bradley
- School of Chemistry, UNSW Sydney, NSW 2052, Australia.
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26
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Gaweł P, Foroutan-Nejad C. Carbon rings push limits of chemical theories. Nature 2023; 623:922-924. [PMID: 38030774 DOI: 10.1038/d41586-023-03575-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
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27
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Zhu Q, Chen S, Chen D, Lin L, Xiao K, Zhao L, Solà M, Zhu J. The application of aromaticity and antiaromaticity to reaction mechanisms. FUNDAMENTAL RESEARCH 2023; 3:926-938. [PMID: 38933008 PMCID: PMC11197727 DOI: 10.1016/j.fmre.2023.04.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 03/31/2023] [Accepted: 04/24/2023] [Indexed: 06/28/2024] Open
Abstract
Aromaticity, in general, can promote a given reaction by stabilizing a transition state or a product via a mobility of π electrons in a cyclic structure. Similarly, such a promotion could be also achieved by destabilizing an antiaromatic reactant. However, both aromaticity and transition states cannot be directly measured in experiment. Thus, computational chemistry has been becoming a key tool to understand the aromaticity-driven reaction mechanisms. In this review, we will analyze the relationship between aromaticity and reaction mechanism to highlight the importance of density functional theory calculations and present it according to an approach via either aromatizing a transition state/product or destabilizing a reactant by antiaromaticity. Specifically, we will start with a particularly challenging example of dinitrogen activation followed by other small-molecule activation, C-F bond activation, rearrangement, as well as metathesis reactions. In addition, antiaromaticity-promoted dihydrogen activation, CO2 capture, and oxygen reduction reactions will be also briefly discussed. Finally, caution must be cast as the magnitude of the aromaticity in the transition states is not particularly high in most cases. Thus, a proof of an adequate electron delocalization rather than a complete ring current is recommended to support the relatively weak aromaticity in these transition states.
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Affiliation(s)
- Qin Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- Key Laboratory for Organic Electronics & Information Displays (KLOEID) and Institute of Advanced Materials (IAM), SICAM, Nanjing University of Posts & Telecommunications, Nanjing 210023, China
| | - Shuwen Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), 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), 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), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Kui Xiao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Liang Zhao
- Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China
| | - Miquel Solà
- Institute of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, C/ M. Aurèlia Capmany, 69, 17003 Girona, Catalonia, Spain
| | - Jun Zhu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen 518172, China
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Foroutan-Nejad C. Magnetic Antiaromaticity─Paratropicity─Does Not Necessarily Imply Instability. J Org Chem 2023; 88:14831-14835. [PMID: 37774173 PMCID: PMC10594649 DOI: 10.1021/acs.joc.3c01807] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Indexed: 10/01/2023]
Abstract
Magnetically induced ring currents are a conventional tool for the characterization of aromaticity. Dia- and paratropic currents are thought to be associated with stabilization (aromaticity) and destabilization (antiaromaticity), respectively. In the present work, I have questioned the validity of the paratropic currents as a measure of antiaromaticity among monocyclic hydrocarbons. I have shown that while reduced/oxidized radical ions of hydrocarbons sustain strong paratropic currents, they often gain extra stabilization via cyclic conjugation compared to their acyclic counterparts.
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Affiliation(s)
- Cina Foroutan-Nejad
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
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29
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Sudhakaran KP, Benny A, John AT, Hariharan M. Exploring the influence of graphene on antiaromaticity of pentalene. Phys Chem Chem Phys 2023; 25:26986-26990. [PMID: 37812393 DOI: 10.1039/d3cp02760k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Theoretical investigations on the influence of graphene fragments on the antiaromaticity of pentalene are conducted by employing multiple aromaticity descriptors based on magnetic, geometric and electronic criteria. NICS as a sole descriptor for analysing the antiaromaticity of pentalene on graphene fragments has to be carefully considered while looking through the other aromaticity indicators.
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Affiliation(s)
- Keerthy P Sudhakaran
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala, 695551, India.
| | - Alfy Benny
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA
| | - Athira T John
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala, 695551, India.
| | - Mahesh Hariharan
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Vithura, Thiruvananthapuram, Kerala, 695551, India.
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30
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Esteruelas MA, Leon F, Moreno-Blázquez S, Oliván M, Oñate E. Preparation, Aromaticity, and Bromination of Spiro Iridafurans. Inorg Chem 2023; 62:16810-16824. [PMID: 37782299 DOI: 10.1021/acs.inorgchem.3c02228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Iridium centers of [Ir(μ-Cl)(C8H14)2]2 (1) activate the Cβ(sp2)-H bond of benzylideneacetone to give [Ir(μ-Cl){κ2-C,O-[C(Ph)CHC(Me)O]}2]2 (2), which is the starting point for the preparation of the spiro iridafurans IrCl{κ2-C,O-[C(Ph)CHC(Me)O]}2(PiPr3) (3), [Ir{κ2-C,O-[C(Ph)CHC(Me)O]}2(MeCN)2]BF4 (4), [Ir(μ-OH){κ2-C,O-[C(Ph)CHC(Me)O]}2]2 (5), Ir{κ2-C,O-[C(Ph)CHC(Me)O]}2{κ2-C,N-[C6MeH3-py]} (6), and Ir{κ2-C,O-[C(Ph)CHC(Me)O]}2{κ2-O,O-[acac]} (7). The five-membered rings are orthogonally arranged with the oxygen atoms in trans in an octahedral environment of the iridium atom. Spiro iridafurans are aromatic. The degree of aromaticity and the negative charge of the CH-carbon of the rings depend on ligand trans to the carbon directly attached to the metal. Aromaticity has been experimentally confirmed by bromination of iridafurans with N-bromosuccinimide (NBS). Reactions are sensitive to the degree of aromaticity of the ring and the negative charge of the attacked CH-carbon. Iridafurans can be selectively brominated, when different ligands lie trans to metalated carbons. Bromination of 3 occurs in the ring with the metalated carbon trans to chloride, whereas the bromination of 6 takes place in the ring with the metalated carbon trans to pyridyl. The first gives IrCl{κ2-C,O-[C(Ph)CBrC(Me)O]}{κ2-C,O-[C(Ph)CHC(Me)O]}(PiPr3) (8), which reacts with more NBS to form IrCl{κ2-C,O-[C(Ph)CBrC(Me)O]}2(PiPr3) (9). The second yields Ir{κ2-C,O-[C(Ph)CBrC(Me)O]}{κ2-C,O-[C(Ph)CHC(Me)O]}{κ2-C,N-[C6MeH3-py]} (10). The origin of the selectivity is kinetic, with the rate-determining step of the reaction being the NBS attack. The activation energy depends on the negative charge of the attacked atom; a higher negative charge allows for a lower activation energy. Accordingly, complex 7 undergoes bromination in the acetylacetonate ligand, giving Ir{κ2-C,O-[C(Ph)CHC(Me)O]}2{κ2-O,O-[acacBr]} (11).
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Affiliation(s)
- Miguel A Esteruelas
- Departamento de Química Inorgánica - Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) - Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza - CSIC, 50009 Zaragoza, Spain
| | - Félix Leon
- Departamento de Química Inorgánica - Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) - Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza - CSIC, 50009 Zaragoza, Spain
| | - Sonia Moreno-Blázquez
- Departamento de Química Inorgánica - Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) - Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza - CSIC, 50009 Zaragoza, Spain
| | - Montserrat Oliván
- Departamento de Química Inorgánica - Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) - Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza - CSIC, 50009 Zaragoza, Spain
| | - Enrique Oñate
- Departamento de Química Inorgánica - Instituto de Síntesis Química y Catálisis Homogénea (ISQCH) - Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Zaragoza - CSIC, 50009 Zaragoza, Spain
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31
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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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32
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Mahmood A, Dimitrova M, Sundholm D. Current-Density Calculations on Zn-Porphyrin 40 Nanorings. J Phys Chem A 2023; 127:7452-7459. [PMID: 37665662 PMCID: PMC10510378 DOI: 10.1021/acs.jpca.3c03564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/04/2023] [Indexed: 09/06/2023]
Abstract
Two porphyrinoid nanorings have been studied computationally. They were built by linking 40 Zn-porphyrin units with butadiyne bridges. The molecular structures belonging to the D40h point group were fully optimized with the Turbomole program at the density functional theory (DFT) level using the B3LYP functional and the def2-SVP basis sets. The aromatic character was studied at the DFT level by calculating the magnetically induced current-density (MICD) susceptibility using the GIMIC program. The neutral molecules are globally non-aromatic with aromatic Zn-porphyrin units. Charged nanorings could not be studied because almost degenerate frontier orbitals led to vanishing optical gaps for the cations. Since DFT calculations of the MICD are computationally expensive, we also calculated the MICD using three pseudo-π models. Appropriate pseudo-π models were constructed by removing the outer hydrogen atoms and replacing all carbon and nitrogen atoms with hydrogen atoms. The central Zn atom was either replaced with a beryllium atom or with two inner hydrogen atoms. Calculations with the computationally inexpensive pseudo-π models yielded qualitatively the same magnetic response as obtained in the all-electron calculations.
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Affiliation(s)
- Atif Mahmood
- Department of Chemistry, University
of Helsinki, P.O. Box 55, A. I. Virtasen Aukio 1, FIN-00014 Helsinki, Finland
| | - Maria Dimitrova
- Department of Chemistry, University
of Helsinki, P.O. Box 55, A. I. Virtasen Aukio 1, FIN-00014 Helsinki, Finland
| | - Dage Sundholm
- Department of Chemistry, University
of Helsinki, P.O. Box 55, A. I. Virtasen Aukio 1, FIN-00014 Helsinki, Finland
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33
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Abstract
Complexes with aromaticity in both the lowest singlet state (S0) and the lowest triplet state (T1) (denoted as adaptive aromaticity) are rare because according to Hückel's and Baird's rules, a species could be aromatic in either the S0 or T1 state in most cases. Thus, it is particularly challenging to design species with adaptive aromaticity. Previous reports on adaptive aromaticity were mainly focused on 16e metallapentalenes. Here, we demonstrate that 18e metallapentalenes could possess adaptive aromaticity supported by a set of aromaticity indices when the nitrido and imido ligands are introduced via density functional theory calculations. Further investigation suggests that the metal-carbon bond strength plays an important role in the S0 state aromaticity and the T1 state aromaticity could be attributed to spin electron localization. All these findings could be useful for the development of metallaaromatic chemistry.
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Affiliation(s)
- Qingfu Ye
- 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
| | - Yifei Fang
- 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, China
- 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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Kalita AJ, Gohain N, Bordoloi A, Guha AK. Planar pentacoordinate carbon in a 16-electron neutral CCu 2Be 3H 4 cluster. Phys Chem Chem Phys 2023. [PMID: 37486198 DOI: 10.1039/d3cp00758h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Planar hypercoordination in carbon is a fascinating area, which departs from the usual view of coordination geometry in carbon. Herein, we propose a planar pentacoordinate carbon species in the global minimum of the CCu2Be3H4 cluster. The cluster is a 16-electron species that is thermodynamically and kinetically very stable. Bonding analyses reveal 2π/6σ double aromaticity in the cluster. A low-energy isomerization pathway also reveals that the cluster has a sufficient lifetime for its experimental detection.
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Affiliation(s)
- Amlan J Kalita
- Advanced Computational Chemistry Centre, Department of Chemistry, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
| | - Namrata Gohain
- Advanced Computational Chemistry Centre, Department of Chemistry, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
| | - Abhik Bordoloi
- Advanced Computational Chemistry Centre, Department of Chemistry, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
| | - Ankur K Guha
- Advanced Computational Chemistry Centre, Department of Chemistry, Cotton University, Panbazar, Guwahati, Assam, 781001, India.
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35
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Artigas A, Rigoulet F, Giorgi M, Hagebaum-Reignier D, Carissan Y, Coquerel Y. Overcrowded Triply Fused Carbo[7]helicene. J Am Chem Soc 2023. [PMID: 37428944 DOI: 10.1021/jacs.3c05415] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
This paper presents the synthesis and comprehensive analysis of a highly contorted and doubly negatively curved multihelicene compound, composed of three carbo[7]helicene units fused within a central six-membered ring. The synthesis of this compound involved a [2 + 2 + 2] cycloaddition reaction of 13,14-picyne, employing a Ni(0) catalyst, which exhibited superior performance compared to conventional Pd(0) catalysts. The evaluation of aromaticity in this triple carbo[7]helicene, utilizing magnetic and electronic criteria, led to noteworthy insights challenging the limitations of Clar's model of aromaticity.
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Affiliation(s)
- Albert Artigas
- Aix Marseille Univ, CNRS, Centrale Marseille, ISM2, 13397 Marseille, France
| | - Florian Rigoulet
- Aix Marseille Univ, CNRS, Centrale Marseille, ISM2, 13397 Marseille, France
| | - Michel Giorgi
- Aix Marseille Univ, CNRS, Centrale Marseille, FSCM, 13397 Marseille, France
| | | | - Yannick Carissan
- Aix Marseille Univ, CNRS, Centrale Marseille, ISM2, 13397 Marseille, France
| | - Yoann Coquerel
- Aix Marseille Univ, CNRS, Centrale Marseille, ISM2, 13397 Marseille, France
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36
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Abstract
The field of aromaticity has grown five-fold in the last two decades as revealed by Merino et al. in their Perspective "Aromaticity: Quo Vadis" where they ask where the field is heading (Chem. Sci., 2023, https://doi.org/10.1039/D2SC04998H). Numerous computational tools for aromaticity analysis have been introduced and novel classes of molecules that exhibit aromatic (or antiaromatic) features have been explored experimentally. Hence, the aromaticity concept is broader and possibly fuzzier than ever. Yet, earlier it also triggered vigorous debates after periods when new analysis tools emerged, and it survived. Today's debate reveals that the field is vital and that new knowledge is produced. Yet, as much as we ask where the field is moving, we should ask "Aromaticity: Cui Bono?"; who utilizes the aromaticity concept and who benefits from it? Especially, who benefits from it being overly fuzzy and who does the opposite? It is an exciting debate. We should get out of it with a better understanding of the chemical-bonding phenomenon labelled aromaticity.
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Affiliation(s)
- Henrik Ottosson
- Department of Chemistry - Ångström, Uppsala University Box 523 Uppsala 751 20 Sweden
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37
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Orozco-Ic M, Sundholm D. On the antiaromatic-aromatic-antiaromatic transition of the stacked cyclobutadiene dimer. Phys Chem Chem Phys 2023; 25:12777-12782. [PMID: 37128984 DOI: 10.1039/d3cp01350b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We have studied the changes in the aromatic nature of two cyclobutadiene (C4H4) molecules on decreasing the intermolecular distance and approaching the cubane structure in a face-to-face fashion. The analysis based on the calculations of the magnetically induced current density and the induced magnetic field shows that the aromaticity of the two C4H4 rings changes from a strongly antiaromatic character at long distances to an aromatic transition state of stacked C4H4 rings at intermediate internuclear distances when approaching the antiaromatic state of cubane.
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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.
- 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.
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