1
|
George G, Stasyuk AJ, Solà M. Prediction of the ground state for indenofluorene-type systems with Clar's π-sextet model. Chem Sci 2024; 15:13676-13687. [PMID: 39211490 PMCID: PMC11351611 DOI: 10.1039/d4sc03465a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Accepted: 07/23/2024] [Indexed: 09/04/2024] Open
Abstract
This study introduces the Ground State Stability (GSS) rule that allows predicting the nature of the ground state of indenofluorene (IF)-type systems from the simple counting of the Clar's π-sextets in the closed- and open-shell configurations. The IF-type system exhibits a triplet ground state when acquiring double or more the number of Clar's π-sextets in the open-shell form relative to the closed-shell form; otherwise, it assumes an open-shell singlet ground state. Performed state-of-the-art DFT calculations and analysis of aromaticity for the systems of interest validate the effectiveness of the proposed rule. We demonstrate that aromaticity plays the most crucial role in determining the ground electronic state for such polycyclic hydrocarbons. The simplicity of the GSS rule makes it a robust strategy for identifying promising systems in the development of indenofluorene-type materials.
Collapse
Affiliation(s)
- Gibu George
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona C/Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
| | - Anton J Stasyuk
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona C/Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
- Faculty of Chemistry, University of Warsaw Pasteura 1 02-093 Warsaw Poland
- Departament de Farmàcia i Tecnologia Farmacèutica, i Fisicoquímica, Facultat de Farmàcia i Ciències de l'Alimentació, Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona (UB) Av. Joan XXIII 27-31 Barcelona Spain
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona C/Maria Aurèlia Capmany 69 17003 Girona Catalonia Spain
| |
Collapse
|
2
|
Monaco G, Summa FF, Zanasi R, Lazzeretti P. Electronic Current Density Induced by Uniform Magnetic Fields in Clarenes. Chemistry 2024; 30:e202401167. [PMID: 38656896 DOI: 10.1002/chem.202401167] [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: 03/25/2024] [Revised: 04/19/2024] [Accepted: 04/22/2024] [Indexed: 04/26/2024]
Abstract
Some planar and non-planar clarenes have been studied using maps of magnetically induced quantum-mechanical current density and tools from differential topology to assess their magnetic response in connection with recent results by Du and Wang. Bond current strengths have been computed to estimate quantitative measures. Isosurfaces of the divergence of induced Lorentz force density have been shown to provide useful additional criteria, especially in the case of non-planar clarenes.
Collapse
Affiliation(s)
- Guglielmo Monaco
- Department of Chemistry and Biology "A. Zambelli", University of Salerno, via Giovanni Paolo II, 132, Fisciano, 84084, SA, Italy
| | - Francesco F Summa
- Department of Chemistry and Biology "A. Zambelli", University of Salerno, via Giovanni Paolo II, 132, Fisciano, 84084, SA, Italy
| | - Riccardo Zanasi
- Department of Chemistry and Biology "A. Zambelli", University of Salerno, via Giovanni Paolo II, 132, Fisciano, 84084, SA, Italy
| | - Paolo Lazzeretti
- Department of Chemistry and Biology "A. Zambelli", University of Salerno, via Giovanni Paolo II, 132, Fisciano, 84084, SA, Italy
| |
Collapse
|
3
|
Kleinpeter E, Koch A. Identification and quantification of local antiaromaticity in polycyclic aromatic hydrocarbons (PAHs) based on the magnetic criterion. Org Biomol Chem 2024; 22:3035-3044. [PMID: 38534070 DOI: 10.1039/d4ob00114a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
The spatial magnetic properties, through-space NMR shieldings (TSNMRSs, actually the ring current effect in 1H NMR spectroscopy), of a selection of entirely antiaromatic and aromatic polycyclic conjugated hydrocarbons (PCHs), and aromatic PCHs with antiaromatic components, have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept and visualized as iso-chemical-shielding surfaces (ICSSs) of various sizes and directions. Using both in-plane and above/below-plane ICSS data, polycyclic aromatic hydrocarbons can be readily distinguished from polycyclic antiaromatic ones, even when antiaromatic components are present in the polycyclic aromatic hydrocarbons (PAHs). These antiaromatic zones can also be attributed to internal components of the in-plane deshielding belt present in aromatic compounds and possible partial antiaromatic ring current effects in the same place. This makes it possible to unequivocally confirm correctly assigned or adjust incorrectly assigned antiaromaticity of individual rings in the same molecule.
Collapse
Affiliation(s)
- Erich Kleinpeter
- Universität Potsdam, Institut für Chemie, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam (Golm), Germany.
| | - Andreas Koch
- Universität Potsdam, Institut für Chemie, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam (Golm), Germany.
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
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.
| |
Collapse
|
6
|
Merkel K, Greiner J, Ortmann F. Understanding the electronic pi-system of 2D covalent organic frameworks with Wannier functions. Sci Rep 2023; 13:1685. [PMID: 36717636 PMCID: PMC9886956 DOI: 10.1038/s41598-023-28285-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 01/16/2023] [Indexed: 01/31/2023] Open
Abstract
We investigate a family of hexagonal 2D covalent organic frameworks (COFs) with phenyl and biphenyl spacer units and different chemical linker species. Chemical trends are elucidated and attributed to microscopic properties of the [Formula: see text]-electron-system spanned by atomic [Formula: see text]-orbitals. We systematically investigate the electronic structure, delocalization of electronic states, effects of disorder, bond torsion, and doping, and correlate these with variable [Formula: see text]-conjugation and nucleus-independent chemical shift (NICS) aromaticity. Molecular orbitals are obtained from maximally localized Wannier functions that have [Formula: see text]- and [Formula: see text]-character, forming distinct [Formula: see text]- and [Formula: see text]-bands for all valence states. The Wannier-orbital description goes beyond simple tight-binding models and enables a detailed understanding of the electronic topology, effective electronic coupling and delocalization. It is shown that a meaningful comparison between COFs with different chemical elements can only be made by examining the entire [Formula: see text]-electron system, while a comparison of individual bands (e.g., bands near the Fermi energy) can be a insufficient to derive general design rules for linker and spacer monomer selection. We further identify delocalized states that are spread across tens or hundreds of pores of the 2D COFs and analyze their robustness against structural and energetic disorders like out-of-plane rotations of molecular fragments, different strength of energetic disorder and energetic shifts due to chemical doping.
Collapse
Affiliation(s)
- Konrad Merkel
- grid.6936.a0000000123222966TUM School of Natural Sciences, Technical University of Munich, Munich, Germany
| | - Johannes Greiner
- grid.6936.a0000000123222966TUM School of Natural Sciences, Technical University of Munich, Munich, Germany
| | - Frank Ortmann
- grid.6936.a0000000123222966TUM School of Natural Sciences, Technical University of Munich, Munich, Germany
| |
Collapse
|
7
|
Abstract
A novel class of stable monoareno-pentalenes is introduced that have an olefinic proton on each five-membered ring of the pentalene subunit. Their synthesis was accomplished via a regioselective carbopalladation cascade reaction between ortho-arylacetyleno gem-dibromoolefins and TIPS-acetylene. These molecules could be experimental probes of magnetic (anti)aromaticity effects.
Collapse
Affiliation(s)
- Péter
J. Mayer
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, Research Centre for
Natural Sciences, Magyar tudósok krt 2., Budapest, 1117, Hungary,Institute
of Chemistry, University of Szeged, Rerrich tér 1., Szeged, 6720, Hungary
| | - Gábor London
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, Research Centre for
Natural Sciences, Magyar tudósok krt 2., Budapest, 1117, Hungary,E-mail:
| |
Collapse
|
8
|
Stanger A. Singlet Fission and Aromaticity. J Phys Chem A 2022; 126:8049-8057. [DOI: 10.1021/acs.jpca.2c04146] [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)
- Amnon Stanger
- Schulich Department of Chemistry, Technion, Haifa 3200003, Israel
| |
Collapse
|
9
|
Landi A, Summa FF, Zanasi R, Monaco G. On the JAP Method for the Indirect Determination of Delocalized Currents from Experimental Chemical Shifts. Chemphyschem 2022; 23:e202200411. [PMID: 35811448 PMCID: PMC9796333 DOI: 10.1002/cphc.202200411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/02/2022] [Indexed: 01/01/2023]
Abstract
The JAP model (after Jirásek, Anderson, and Peeks) to retrieve global current strengths from experimental 1 H chemical shifts has been tested with DFT computations. Both global and local tropicities are correctly predicted in most cases and the quantitative agreement is overall fair. An extension of the model is found to give improvement in an exemplary critical case, where the global delocalized current is negligible and the current density map is dominated by local currents.
Collapse
Affiliation(s)
- Alessandro Landi
- Department of Chemistry and Biology “A. Zambelli”Università di SalernoVia G. Paolo II, 132Fisciano84084 SAItaly
| | - Francesco F. Summa
- Department of Chemistry and Biology “A. Zambelli”Università di SalernoVia G. Paolo II, 132Fisciano84084 SAItaly
| | - Riccardo Zanasi
- Department of Chemistry and Biology “A. Zambelli”Università di SalernoVia G. Paolo II, 132Fisciano84084 SAItaly
| | - Guglielmo Monaco
- Department of Chemistry and Biology “A. Zambelli”Università di SalernoVia G. Paolo II, 132Fisciano84084 SAItaly
| |
Collapse
|
10
|
Abstract
Aromaticity, a very important term in organic chemistry, has never been defined unambiguously. Various ways to describe it come from different phenomena that have been experimentally observed. The most important examples related to some theoretical concepts are presented here.
Collapse
|
11
|
Gazdag T, Mayer PJ, Kalapos PP, Holczbauer T, El Bakouri O, London G. Unsymmetrical Thienopentalenes: Synthesis, Optoelectronic Properties, and (Anti)aromaticity Analysis. ACS OMEGA 2022; 7:8336-8349. [PMID: 35309486 PMCID: PMC8928497 DOI: 10.1021/acsomega.1c05618] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
The synthesis and properties of a series of unsymmetrical thienopentalenes are explored, including both monoareno and diareno derivatives. For the synthesis of monoareno pentalenes, a carbopalladation cascade reaction between alkynes and gem-dibromoolefins was applied. Diareno pentalene derivatives were accessed via gold-catalyzed cyclization of diynes. Thiophene was fused to pentalene in two different geometries via its 2,3 and 3,4 bonds. 2,3-Fusion resulted in increased antiaromaticity of the pentalene unit compared to the 3,4-fusion both in the monoareno and diareno framework. Monothienopentalenes that contained the destabilizing 2,3-fusion could not be isolated. For diareno derivatives, the aromatic character of the different aryl groups fused to the pentalene was not independent. Destabilizing fusion on one side resulted in alleviated aromaticity on the other side and vice versa. The synthesized molecules were characterized experimentally by 1H NMR and UV-vis spectroscopies, cyclic voltammetry, and X-ray crystallography, and their aromatic character was assessed using magnetic (NICS and ACID) and electronic indices (MCI and FLU).
Collapse
Affiliation(s)
- Tamás Gazdag
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, Research Centre for
Natural Sciences, Magyar tudósok krt. 2., Budapest 1117, Hungary
- Hevesy
György PhD School of Chemistry, Eötvös
Loránd University, Pázmány Péter sétány 1/a, Budapest 1117, Hungary
| | - Péter J. Mayer
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, Research Centre for
Natural Sciences, Magyar tudósok krt. 2., Budapest 1117, Hungary
- Institute
of Chemistry, University of Szeged, Rerrich tér 1, Szeged 6720, Hungary
| | - Péter Pál Kalapos
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, Research Centre for
Natural Sciences, Magyar tudósok krt. 2., Budapest 1117, Hungary
| | - Tamás Holczbauer
- Centre
for Structural Science and Institute of Organic Chemistry, Research Centre for Natural Sciences, Magyar tudósok körútja
2 Budapest 1117, Hungary
| | - Ouissam El Bakouri
- Institut
de Química Computacional i Catàlisi (IQCC) and Departament
de Química, Universitat de Girona, C/Maria Aurèlia Capmany 6, Girona 17003, Catalonia, Spain
| | - Gábor London
- MTA
TTK Lendület Functional Organic Materials Research Group, Institute
of Organic Chemistry, Research Centre for
Natural Sciences, Magyar tudósok krt. 2., Budapest 1117, Hungary
| |
Collapse
|
12
|
Paenurk E, Gershoni-Poranne R. Simple and efficient visualization of aromaticity: bond currents calculated from NICS values. Phys Chem Chem Phys 2022; 24:8631-8644. [PMID: 35132428 DOI: 10.1039/d1cp05757j] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Aromaticity is a fundamental concept in chemistry, underpinning the properties and reactivity of many organic compounds and materials. The ability to easily and accurately discern aromatic behavior is key to leveraging it as a design element, yet most aromaticity metrics struggle to combine accurate quantitative evaluation, intuitive interpretability, and user-friendliness. We introduce a new method, NICS2BC, which uses simple and inexpensive NICS calculations to generate information-rich and easily-interpreted bond-current graphs. We test the quantitative and qualitative characterizations afforded by NICS2BC for a selection of molecules of varying structural and electronic complexity, to demonstrate its accuracy and ease of analysis. Moreover, we show that NICS2BC successfully identifies ring-current patterns in molecules known to be difficult cases to interpret with NICS and enables deeper understanding of local aromaticity trends, demonstrating that our method adds additional insight.
Collapse
Affiliation(s)
- Eno Paenurk
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland
| | - Renana Gershoni-Poranne
- Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland.,Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa 32000, Israel.
| |
Collapse
|
13
|
Stanger A. The Aromatic Character of Diindeno[2,1- b:2',1'- h]biphenylene. Org Lett 2022; 24:1243-1246. [PMID: 35089721 DOI: 10.1021/acs.orglett.2c00104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The tropicity of the title system was studied using NICS(1.7)π,zz-XY-scans and current density analysis, showing a global diatropic loop and local dia- and paratropic loops. This aromaticity picture is very different from the one proposed based on NICS(1) and HOMA ( Org. Lett. 2021, 23, 8794-8798). It is predicted that 1 should be suitable for singlet fission applications. It is concluded that local aromatic indices should not be used for the full analysis of multiring conjugated systems.
Collapse
Affiliation(s)
- Amnon Stanger
- Schulich Department of Chemistry, Technion, Haifa 3200003, Israel
| |
Collapse
|
14
|
Abstract
The ascertainment of magnetic aromaticity is not necessarily straightforward, especially for large and bent systems, such as the cycloporphyrin nanorings recently synthesized by the group of Anderson. Six of these cycloporphyrin nanorings were studied here computationally. Indirect methods, based on nuclear shielding and magnetizabilities, and direct methods, based on standard quantum mechanics, were both used effectively to determine their magnetically induced current strength, which mostly confirmed Anderson’s classification. However, in the case of hexanions, and in particular for cyclohexaporphyrin hexacations, a significant cancellation of delocalized diatropic and paratropic flow occurred, showing that the resultant faint aromatic character was a result of competing aromatic and antiaromatic contributions, as also evidenced by the ipsocentric method. A warning is renewed on the use of isotropic shielding to determine the tropicity of the magnetically induced current.
Collapse
|
15
|
Rimmele M, Nogala W, Seif-Eddine M, Roessler MM, Heeney M, Plasser F, Glöcklhofer F. Functional group introduction and aromatic unit variation in a set of π-conjugated macrocycles: revealing the central role of local and global aromaticity. Org Chem Front 2021; 8:4730-4745. [PMID: 34484800 PMCID: PMC8382046 DOI: 10.1039/d1qo00901j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/17/2021] [Indexed: 12/18/2022]
Abstract
π-Conjugated macrocycles are molecules with unique properties that are increasingly exploited for applications and the question of whether they can sustain global aromatic or antiaromatic ring currents is particularly intriguing. However, there are only a small number of experimental studies that investigate how the properties of π-conjugated macrocycles evolve with systematic structural changes. Here, we present such a systematic experimental study of a set of [2.2.2.2]cyclophanetetraenes, all with formally Hückel antiaromatic ground states, and combine it with an in-depth computational analysis. The study reveals the central role of local and global aromaticity for rationalizing the observed optoelectronic properties, ranging from extremely large Stokes shifts of up to 1.6 eV to reversible fourfold reduction, a highly useful feature for charge storage/accumulation applications. A recently developed method for the visualization of chemical shielding tensors (VIST) is applied to provide unique insight into local and global ring currents occurring in different planes along the macrocycle. Conformational changes as a result of the structural variations can further explain some of the observations. The study contributes to the development of structure-property relationships and molecular design guidelines and will help to understand, rationalize, and predict the properties of other π-conjugated macrocycles. It will also assist in the design of macrocycle-based supramolecular elements with defined properties.
Collapse
Affiliation(s)
- Martina Rimmele
- Department of Chemistry, Imperial College London London W12 0BZ UK .,Centre for Processable Electronics, Imperial College London London W12 0BZ UK
| | - Wojciech Nogala
- Institute of Physical Chemistry, Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | | | - Maxie M Roessler
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | - Martin Heeney
- Department of Chemistry, Imperial College London London W12 0BZ UK .,Centre for Processable Electronics, Imperial College London London W12 0BZ UK
| | - Felix Plasser
- Department of Chemistry, Loughborough University Loughborough LE11 3TU UK
| | - Florian Glöcklhofer
- Department of Chemistry, Imperial College London London W12 0BZ UK .,Centre for Processable Electronics, Imperial College London London W12 0BZ UK
| |
Collapse
|
16
|
Plasser F, Glöcklhofer F. Visualisation of Chemical Shielding Tensors (VIST) to Elucidate Aromaticity and Antiaromaticity. European J Org Chem 2021; 2021:2529-2539. [PMID: 34248413 PMCID: PMC8251739 DOI: 10.1002/ejoc.202100352] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/01/2021] [Indexed: 01/25/2023]
Abstract
Aromaticity is a central concept in chemistry, pervading areas from biochemistry to materials science. Recently, chemists also started to exploit intricate phenomena such as the interplay of local and global (anti)aromaticity or aromaticity in non-planar systems and three dimensions. These phenomena pose new challenges in terms of our fundamental understanding and the practical visualisation of aromaticity. To overcome these challenges, a method for the visualisation of chemical shielding tensors (VIST) is developed here that allows for a 3D visualisation with quantitative information about the local variations and anisotropy of the chemical shielding. After exemplifying the method in different planar hydrocarbons, we study two non-planar macrocycles to show the unique benefits of the VIST method for molecules with competing π-conjugated systems and conclude with a norcorrole dimer showing clear evidence of through-space aromaticity. We believe that the VIST method will be a highly valuable addition to the computational toolbox.
Collapse
Affiliation(s)
- Felix Plasser
- Department of ChemistryLoughborough UniversityLoughboroughLE11 3TUUnited Kingdom
| | - Florian Glöcklhofer
- Department of Chemistry andCentre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUnited Kingdom
| |
Collapse
|
17
|
Rottschäfer D, Neumann B, Stammler H, Sergeieva T, Andrada DM, Ghadwal RS. Isolation of a 16π-Electrons 1,4-Diphosphinine-1,4-diide with a Planar C 4 P 2 Ring. Chemistry 2021; 27:3055-3064. [PMID: 33080114 PMCID: PMC7898681 DOI: 10.1002/chem.202003617] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/05/2020] [Indexed: 02/02/2023]
Abstract
Herein, we report the first 1,4-diphosphinine-1,4-diide compound [(ADCPh )P]2 (5-Ph) (ADCPh =PhC{(NDipp)C}2 ; Dipp=2,6-iPr2 C6 H3 ) derived from an anionic dicarbene (ADCPh ) as a red crystalline solid. Compound 5-Ph containing a 16π-electron planar fused-tricyclic ring system was obtained by the 4e reduction of [(ADCPh )PCl2 ]2 (4-Ph) with Mg (or KC8 ) in a quantitative yield. Experimental and computational results imply that the central 8π-electrons C4 P2 ring of 5-Ph, which is fused between two 6π-electrons C3 N2 aromatic rings, is antiaromatic. Thus, each of the phosphorus atoms of 5-Ph has two electron-lone-pairs, one in a p-type orbital is in conjugation with the C=C bonds of the C4 P2 ring, while the second resides in a σ-symmetric orbital. This can be shown with the gold complex [(ADCPh )P(AuCl)2 ]2 (6-Ph) obtained by reacting 5-Ph with (Me2 S)AuCl. A mixture of 5-Ph and 4-Ph undergoes comproportionation in the presence of MgCl2 to form the intermediate oxidation state compound [(ADCAr )P]2 (MgCl4 ) (7-Ph), which is an aromatic species.
Collapse
Affiliation(s)
- Dennis Rottschäfer
- Molecular Inorganic Chemistry and CatalysisInorganic and Structural ChemistryCenter for Molecular MaterialsFaculty of ChemistryUniversität BielefeldUniversitätsstrasse 2533615BielefeldGermany
| | - Beate Neumann
- Molecular Inorganic Chemistry and CatalysisInorganic and Structural ChemistryCenter for Molecular MaterialsFaculty of ChemistryUniversität BielefeldUniversitätsstrasse 2533615BielefeldGermany
| | - Hans‐Georg Stammler
- Molecular Inorganic Chemistry and CatalysisInorganic and Structural ChemistryCenter for Molecular MaterialsFaculty of ChemistryUniversität BielefeldUniversitätsstrasse 2533615BielefeldGermany
| | - Tetiana Sergeieva
- Inorganic and Computational Chemistry GroupAllgemeine und Anorganische ChemieUniversität des SaarlandesCampus C4.166123SaarbrückenGermany
| | - Diego M. Andrada
- Inorganic and Computational Chemistry GroupAllgemeine und Anorganische ChemieUniversität des SaarlandesCampus C4.166123SaarbrückenGermany
| | - Rajendra S. Ghadwal
- Molecular Inorganic Chemistry and CatalysisInorganic and Structural ChemistryCenter for Molecular MaterialsFaculty of ChemistryUniversität BielefeldUniversitätsstrasse 2533615BielefeldGermany
| |
Collapse
|
18
|
Paenurk E, Feusi S, Gershoni-Poranne R. Predicting bond-currents in polybenzenoid hydrocarbons with an additivity scheme. J Chem Phys 2021; 154:024110. [DOI: 10.1063/5.0038292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Eno Paenurk
- Laboratorium für Organische Chemie, ETH Zurich, Switzerland
| | - Stefan Feusi
- Laboratorium für Organische Chemie, ETH Zurich, Switzerland
| | | |
Collapse
|
19
|
Cui Y, Xia D. Recent Advances of Polycyclic Aromatic Compounds Containing Four-Membered Rings. CHINESE J ORG CHEM 2021. [DOI: 10.6023/cjoc202008036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
20
|
Monaco G, Summa FF, Zanasi R. Program Package for the Calculation of Origin-Independent Electron Current Density and Derived Magnetic Properties in Molecular Systems. J Chem Inf Model 2020; 61:270-283. [PMID: 33347314 DOI: 10.1021/acs.jcim.0c01136] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present SYSMOIC, a program package for the calculation of the origin-independent current density induced at first order by an external magnetic field in planar and nonplanar molecular systems. Origin independence is obtained adopting the continuous transformation of the origin of the current density method, implemented at both density functional theory (DFT) and Hartree-Fock (HF) levels. Expansion coefficients for perturbed and unperturbed molecular orbitals, over basis sets containing up to m-type Gaussian functions, can be calculated by the package itself or obtained from a Gaussian calculation. A number of different functionalities presented so far in the literature that are connected to the induced current, such as current density maps for any orientation of the inducing magnetic field, net bond current strengths, stagnation graphs, magnetic shielding densities, vorticities, and anisotropies, are now made available all together in a single multiplatform package installation.
Collapse
Affiliation(s)
- Guglielmo Monaco
- Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno, via Giovanni Paolo II 132, Fisciano 84084 SA, Italy
| | - Francesco F Summa
- Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno, via Giovanni Paolo II 132, Fisciano 84084 SA, Italy
| | - Riccardo Zanasi
- Dipartimento di Chimica e Biologia "A. Zambelli", Università degli Studi di Salerno, via Giovanni Paolo II 132, Fisciano 84084 SA, Italy
| |
Collapse
|
21
|
Molenda R, Boldt S, Villinger A, Ehlers P, Langer P. Synthesis of 2-Azapyrenes and Their Photophysical and Electrochemical Properties. J Org Chem 2020; 85:12823-12842. [PMID: 32885654 DOI: 10.1021/acs.joc.0c01622] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of 5,7,9-substituted 2-azapyrenes were synthesized for the first time. The synthesis relies on Brønsted acid promoted benzannulation of alkyne precursors prepared by palladium-catalyzed cross-coupling reactions. The synthetic strategy is efficient and the scope covers a variety of functional groups. The electrochemical behavior and photophysical properties of the products were investigated by UV-vis and fluorescence spectroscopy, cyclic voltammetry, and DFT calculations.
Collapse
Affiliation(s)
- Ricardo Molenda
- Universität Rostock, Institut für Chemie, A.-Einstein-Strasse 3a, 18059 Rostock, Germany
| | - Sebastian Boldt
- Universität Rostock, Institut für Chemie, A.-Einstein-Strasse 3a, 18059 Rostock, Germany
| | - Alexander Villinger
- Universität Rostock, Institut für Chemie, A.-Einstein-Strasse 3a, 18059 Rostock, Germany
| | - Peter Ehlers
- Universität Rostock, Institut für Chemie, A.-Einstein-Strasse 3a, 18059 Rostock, Germany.,Leibniz Institut für Katalyse an der Universität Rostock, A.-Einstein-Strasse 29a, 18059 Rostock, Germany
| | - Peter Langer
- Universität Rostock, Institut für Chemie, A.-Einstein-Strasse 3a, 18059 Rostock, Germany.,Leibniz Institut für Katalyse an der Universität Rostock, A.-Einstein-Strasse 29a, 18059 Rostock, Germany
| |
Collapse
|
22
|
Monaco G, Scott ELT, Zanasi R. Reversal of Clar's Aromatic-Sextet Rule in Ultrashort Single-End-Capped [5,5] Carbon Nanotubes. ChemistryOpen 2020; 9:616-622. [PMID: 32489766 PMCID: PMC7253069 DOI: 10.1002/open.202000091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/06/2020] [Indexed: 12/18/2022] Open
Abstract
The three-fold HOMO-LUMO gap oscillation, typical of finite length armchair carbon nanotubes (CNT), has a major effect on the magnetic response of ultrashort, single-end-capped [5,5] carbon nanotubes to a perturbing magnetic field parallel to the main symmetry axis. For the CNT's containing 40, 70, and 100 carbon atoms, for which 100 % of the C=C double bonds can be grouped into aromatic-sextets, i. e., fully or complete Clar networks, large paratropic (antiaromatic) global circulations around the cylindrical axis are predicted at the DFT level of calculation. Local and semi-global diatropic (aromatic) currents of strengths not larger than that of the benzene molecule are determined for a perpendicular perturbing magnetic field. CNTs of intermediate lengths do not display this enhanced antiaromatic response. The paratropic current flow clearly shows that these complete Clar networks can be viewed as stacked cycloparaphenylene belts, each providing a double 4 n annulene circuit as a consequence of the quinoidal resonance structure that results from their closure. Paradoxically, the fully aromatic Clar structure itself is responsible for the enhanced global antiaromaticity.
Collapse
Affiliation(s)
- Guglielmo Monaco
- Dipartimento di Chimica e Biologia “A. Zambelli”Università degli studi di Salernovia Giovanni Paolo II 132Fisciano84084SAItaly
| | | | - Riccardo Zanasi
- Dipartimento di Chimica e Biologia “A. Zambelli”Università degli studi di Salernovia Giovanni Paolo II 132Fisciano84084SAItaly
| |
Collapse
|
23
|
Affiliation(s)
- Amnon Stanger
- Schulich faculty of Chemistry Technion-Israel Institute of Technology; 32000 Haifa Israel
| |
Collapse
|
24
|
Benkyi I, Staszewska-Krajewska O, Gryko DT, Jaszuński M, Stanger A, Sundholm D. Interplay of Aromaticity and Antiaromaticity in N-Doped Nanographenes. J Phys Chem A 2020; 124:695-703. [PMID: 31917567 DOI: 10.1021/acs.jpca.9b11315] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The aromaticity of three nonplanar, fully conjugated aza-nanographenes built around a pyrrolo[3,2-b]pyrrole core is assessed through the application of two different computational procedures-GIMIC and NICS. We examine the calculated magnetically induced current densities (GIMIC) and nucleus-independent chemical shifts (NICS). The structural differences between these three apparently similar molecules lead to significantly different aromatic properties. GIMIC analysis indicates that the peripheral diatropic ring current of 3.9 nA/T for the studied bowl-shaped diaza-nanographene is the strongest, followed by the double [6]helicene which lacks seven-membered rings, and is practically nonexistent for the double [5]helicene possessing seven-membered rings. The biggest difference however is that in the two not-fully-fused molecules, the central pyrrole rings possess a significant diatropic current of about 4.1 nA/T, whereas there is no such current in the diaza-nanographene. Moreover, the antiaromaticity of the seven-membered rings is increasing while moving from double [5]helicene to diaza-nanographene (from -2.4 to -6.0 nA/T). The induced currents derived from NICSπ,zz-XY-scan analysis for all of the studied systems are in qualitative agreement with the GIMIC results. Subtle differences may originate from σ-electron currents in GIMIC or inaccuracy of NICSπ,zz values due to the nonplanarity of the systems, but the general picture is similar.
Collapse
Affiliation(s)
- Isaac Benkyi
- Department of Chemistry , University of Helsinki , P.O. Box 55, A.I. Virtanens Plats 1 , FIN-00014 Helsinki , Finland
| | - Olga Staszewska-Krajewska
- Institute of Organic Chemistry , Polish Academy of Sciences , Kasprzaka 44-52 , 01-224 Warsaw , Poland
| | - Daniel T Gryko
- Institute of Organic Chemistry , Polish Academy of Sciences , Kasprzaka 44-52 , 01-224 Warsaw , Poland
| | - Michał Jaszuński
- Institute of Organic Chemistry , Polish Academy of Sciences , Kasprzaka 44-52 , 01-224 Warsaw , Poland
| | - Amnon Stanger
- Schulich Department of Chemistry Technion , 3200008 Haifa , Israel
| | - Dage Sundholm
- Department of Chemistry , University of Helsinki , P.O. Box 55, A.I. Virtanens Plats 1 , FIN-00014 Helsinki , Finland
| |
Collapse
|