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Kenouche S, Bachir N, Bouchal W, Martínez-Araya JI. Aromaticity of six-membered nitro energetic compounds through molecular electrostatic potential, magnetic, electronic delocalization and reactivity-based indices. J Mol Graph Model 2024; 129:108728. [PMID: 38412811 DOI: 10.1016/j.jmgm.2024.108728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/06/2024] [Accepted: 02/13/2024] [Indexed: 02/29/2024]
Abstract
The electron density depletion associated with π-hole at the ring center typical of energetic compounds was clearly revealed by the molecular electrostatic potential (ESP). In addition, the spatial arrangement of NO2 groups appears to affect the ESP value in the ring center, and therefore sensitivity to detonation. Indeed, for monocyclic nitrobenzene compounds with the same number of NO2 groups, the ESP value in the ring center decreases as the NO2 groups are more closely spaced. As expected, the central rings become less aromatic as NO2 groups are added. The MCI, PDI, PLR, NICSzz(1), FLU indices are all strongly correlated with the ESP values observed in the ring center of the set of nitrobenzenes. Aromaticity indices based on electron delocalization criteria appear to be very sensitive to small variations in aromaticity. Among magnetic-based indices, only NICSzz(1) is capable to predict small changes in aromaticity. The PLR index derived from conceptual DFT is quite relevant for predicting small variations in aromaticity. According to our results, the most suitable aromaticity index is not based on a single criterion, and that selecting it is more subtle. Therefore, it is important to combine information from several criteria to obtain a more complete description of the aromaticity of the studied compounds.
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Affiliation(s)
- Samir Kenouche
- Group of Modeling of Chemical Systems using Quantum Calculations, Applied Chemistry Laboratory (LCA). University M. Khider of Biskra, 07000 Biskra, Algeria
| | - Nassima Bachir
- Group of Modeling of Chemical Systems using Quantum Calculations, Applied Chemistry Laboratory (LCA). University M. Khider of Biskra, 07000 Biskra, Algeria
| | - Wissam Bouchal
- Molecular Chemistry and Environment Laboratory, University of Mohammed Khider of Biskra, BP 145 RP, Biskra 07000, Algeria
| | - Jorge I Martínez-Araya
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello (UNAB), Av. República 275, 8370146 Santiago, Chile; Centro de Química Teórica y Computacional (CQT&C). Facultad de Ciencias Exactas, Santiago, Chile.
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2
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Bradley D, Jirásek M, Anderson HL, Peeks MD. Disentangling global and local ring currents. Chem Sci 2023; 14:1762-1768. [PMID: 36819862 PMCID: PMC9930925 DOI: 10.1039/d2sc05923a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 01/13/2023] [Indexed: 01/18/2023] Open
Abstract
Magnetic field-induced ring currents in aromatic and antiaromatic molecules cause characteristic shielding and deshielding effects in the molecules' NMR spectra. However, it is difficult to analyze (anti)aromaticity directly from experimental NMR data if a molecule has multiple ring current pathways. Here we present a method for using the Biot-Savart law to deconvolute the contributions of different ring currents to the experimental NMR spectra of polycyclic compounds. This method accurately quantifies local and global ring current susceptibilities in porphyrin nanorings, as well as in a bicyclic dithienothiophene-bridged [34]octaphyrin. There is excellent agreement between ring current susceptibilities derived from both experimental and computationally-predicted chemical shifts, and with ring currents calculated by the GIMIC method. Our method can be applied to any polycyclic system, with any number of ring currents, provided that appropriate NMR data are available.
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Affiliation(s)
- David Bradley
- School of Chemistry, University of New South Wales Sydney NSW 2052 Australia
| | | | | | - Martin D. Peeks
- School of Chemistry, University of New South WalesSydneyNSW 2052Australia
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3
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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.
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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
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4
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Deng JR, Bradley D, Jirásek M, Anderson HL, Peeks MD. Correspondence on "How Aromatic Are Molecular Nanorings? The Case of a Six-Porphyrin Nanoring". Angew Chem Int Ed Engl 2022; 61:e202201231. [PMID: 35818688 DOI: 10.1002/anie.202201231] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Indexed: 12/20/2022]
Abstract
A recent Research Article in this journal by Matito and co-workers claimed that none of the oxidation states of a butadiyne-linked six-porphyrin nanoring exhibit global aromaticity or antiaromaticity. Here we show that this conclusion is incorrect. Experimental data from NMR spectroscopy for a whole family of nanorings provide strong evidence for global ring currents. The NMR data reveal these ring currents directly, without needing analysis by density functional theory (DFT). Furthermore, DFT calculations reproduce the experimental results when a suitable functional is used.
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Affiliation(s)
- Jie-Ren Deng
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - David Bradley
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
| | - Michael Jirásek
- Laboratory of Organic Chemistry, ETH Zurich, 8093, Zurich, Switzerland
| | - Harry L Anderson
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Martin D Peeks
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
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5
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Deng J, Bradley D, Jirásek M, Anderson HL, Peeks MD. Correspondence on “How Aromatic Are Molecular Nanorings? The Case of a Six‐Porphyrin Nanoring”**. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201231] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jie‐Ren Deng
- Department of Chemistry University of Oxford Oxford OX1 3TA UK
| | - David Bradley
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
| | - Michael Jirásek
- Laboratory of Organic Chemistry ETH Zurich 8093 Zurich Switzerland
| | | | - Martin D. Peeks
- School of Chemistry University of New South Wales Sydney NSW 2052 Australia
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6
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Yan ST, Xu HG, Xu XL, Zheng WJ. Anion photoelectron spectroscopy and theoretical calculations of Cu4On−/0 (n = 1–4): Identification of stable quasi-square structure for Cu4O4−. J Chem Phys 2022; 156:054304. [DOI: 10.1063/5.0078415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Shuai-Ting Yan
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong-Guang Xu
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xi-Ling Xu
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei-Jun Zheng
- Beijing National Laboratory for Molecular Sciences (BNLMS), State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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7
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Berger RJF, Dimitrova M, Nasibullin RT, Valiev RR, Sundholm D. Integration of global ring currents using the Ampère-Maxwell law. Phys Chem Chem Phys 2022; 24:624-628. [PMID: 34913459 DOI: 10.1039/d1cp05061c] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetically induced ring currents are calculated from the magnetic shielding tensor by employing the Ampère-Maxwell law. The feasibility of the method is demonstrated by integrating the zz component of the shielding tensor along the symmetry axis of highly symmetric ring-shaped aromatic, antiaromatic and nonaromatic molecules. The calculated ring-current strengths agree perfectly with the ones obtained by integrating the current-density flux passing through a plane cutting half the molecular ring. The method can be used in combination with all electronic structure codes capable of calculating nuclear magnetic resonance (NMR) shielding tensors in general points in space. We also show that nucleus independent chemical shifts (NICS) along the symmetry axis are related to the spatial derivative of the strength of the global ring-current along the z axis.
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Affiliation(s)
- Raphael J F Berger
- Chemistry of Materials, Paris-Lodron University of Salzburg, Jakob-Haringerstr. 2A, A-5020 Salzburg, Austria.
| | - Maria Dimitrova
- Chemistry of Materials, Paris-Lodron University of Salzburg, Jakob-Haringerstr. 2A, A-5020 Salzburg, Austria. .,Department of Chemistry, Faculty of Science, P.O. Box 55, A. I. Virtasen aukio 1, FI-00014 University of Helsinki, Finland.
| | | | - Rashid R Valiev
- Department of Chemistry, Faculty of Science, P.O. Box 55, A. I. Virtasen aukio 1, FI-00014 University of Helsinki, Finland. .,Tomsk State University, 36 Lenin Avenue, Tomsk 634050, Russia
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, P.O. Box 55, A. I. Virtasen aukio 1, FI-00014 University of Helsinki, Finland.
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8
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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.
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9
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Jirásek M, Anderson HL, Peeks MD. From Macrocycles to Quantum Rings: Does Aromaticity Have a Size Limit? Acc Chem Res 2021; 54:3241-3251. [PMID: 34347441 DOI: 10.1021/acs.accounts.1c00323] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
ConspectusThe ring currents of aromatic and antiaromatic molecules are remarkable emergent phenomena. A ring current is a quantum-mechanical feature of the whole system, and its existence cannot be inferred from the properties of the individual components of the ring. Hückel's rule states that when an aromatic molecule with a circuit of [4n + 2] π electrons is placed in a magnetic field, the field induces a ring current that creates a magnetic field opposing the external field inside the ring. In contrast, antiaromatic rings with 4n π electrons exhibit ring currents in the opposite direction. This rule bears the name of Erich Hückel, and it grew from his molecular orbital theory, but modern formulations of Hückel's rule incorporate contributions from others, particularly William Doering and Ronald Breslow. It is often assumed that aromaticity is restricted to small molecular rings with up to about 22 π electrons. This Account outlines the discovery of global ring currents in large macrocycles with circuits of up to 162 π electrons. The largest aromatic rings yet investigated are cyclic porphyrin oligomers, which exhibit global ring currents after oxidation, reduction or optical excitation but not in the neutral ground state. The global aromaticity in these porphyrin nanorings leads to experimentally measurable aromatic stabilization energies in addition to magnetic effects that can be studied by NMR spectroscopy. Wheel-like templates can be bound inside these nanorings, providing excellent control over the molecular geometry and allowing the magnetic shielding to be probed inside the nanoring. The ring currents in these systems are well-reproduced by density functional theory (DFT), although the choice of DFT functional often turns out to be critical. Here we review recent contributions to this field and present a simple method for determining the ring current susceptibility (in nA/T) in any aromatic or antiaromatic ring from experimental NMR data by classical Biot-Savart calculations. We use this method to quantify the ring currents in a variety of aromatic rings. This survey confirms that Hückel's rule reliably predicts the direction of the ring current, and it reveals that the ring current susceptibility is surprisingly insensitive to the size of the ring. The investigation of aromaticity in even larger molecular rings is interesting because ring currents are also observed when mesoscopic metal rings are placed in a magnetic field at low temperatures. The striking similarity between the ring currents in molecules and mesoscopic metal rings arises because the effects have a common origin: a field-dependent phase shift in the electronic wave function. The main difference is that the magnetic flux through mesoscopic rings is much greater because of their larger areas, so their persistent currents are nonlinear and oscillatory with the applied field, whereas the flux through aromatic molecules is so small that their response is approximately linear in the applied field. We discuss how nonlinearity is expected to emerge in large molecular nanorings at high magnetic fields. The insights from this work are fundamentally important for understanding aromaticity and for bridging the gap between chemistry and mesoscopic physics, potentially leading to new functions in molecular electronics.
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Affiliation(s)
- Michael Jirásek
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
- Laboratory of Organic Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Harry L Anderson
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Martin D Peeks
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
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10
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Fowler PW, Havenith RWA. Periodoannulenes: A Generalized Annulene-within-an-Annulene Paradigm for Combined σ and π Ring Currents. J Phys Chem A 2021; 125:6374-6383. [PMID: 34279938 DOI: 10.1021/acs.jpca.1c03170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Periodoannulene molecules and ions CxIxq in planar geometry offer examples of systems with the potential for outer σ and inner π ring-current double aromaticity, given a sufficient overlap of tangential pσ-orbital manifolds on the large atoms of the outer cycle. Previous theoretical work indicated concentric diatropic currents in the dication C6I62+. Ab initio ipsocentric calculations support an account in terms of frontier-orbital selection rules for current contributions in C6I62+ (and radical C6I6+, implicated in recent experimental work on the oxidation of periodobenzene). A σ/π analogue of the annulene-within-an-annulene model is applied here to periodo systems based on cyclooctatetraene. Model species C8I8q with charges q = 0, +1, +2, +4, -2 and structures constrained to a planar D4h symmetry exhibit maps with all combinations of σ/π con- and counter-rotation, comprising global σ ring currents on the iodine perimeter and central π ring currents on the carbocycle. All can be rationalized by the separate application of the tropicity selection rules to the two subsystems, whether in singlet or triplet states.
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Affiliation(s)
- Patrick W Fowler
- Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K
| | - Remco W A Havenith
- Stratingh Institute for Chemistry and Zernike Institute for Advanced Materials, Rijksuniversiteit Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.,Ghent Quantum Chemistry Group, Department of Chemistry, Ghent University, Krijgslaan 281 (S3), B-9000 Gent, Belgium
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11
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Orozco-Ic M, Dimitrova M, Barroso J, Sundholm D, Merino G. Magnetically Induced Ring-Current Strengths of Planar and Nonplanar Molecules: New Insights from the Pseudo-π Model. J Phys Chem A 2021; 125:5753-5764. [PMID: 34161099 DOI: 10.1021/acs.jpca.1c03555] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The pseudo-π model yields current densities and induced magnetic fields that mimic the π-component, allowing investigations of large molecular structures, whether they are planar or not, at a low computational cost but with high accuracy. Herein the π-contribution to the magnetically induced current densities and induced magnetic fields of large planar molecules and nonplanar molecules (such as [10]cyclophenacene and chiral toroidal nanotubes C2016 and C2196) were computed using the pseudo-π model with the gauge-including magnetically induced currents method. Additionally, we provide a way to determine the π-component of the ring-current strengths, which can be used for assessing the aromatic character of large carbon molecules.
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Affiliation(s)
- Mesías Orozco-Ic
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310, Mérida, Yucatan, México
| | - Maria Dimitrova
- Department of Chemistry, Faculty of Science, University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland
| | - Jorge Barroso
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310, Mérida, Yucatan, México
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, 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, Yucatan, México
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12
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Exploitation of Baird Aromaticity and Clar’s Rule for Tuning the Triplet Energies of Polycyclic Aromatic Hydrocarbons. CHEMISTRY 2021. [DOI: 10.3390/chemistry3020038] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAH) are a prominent substance class with a variety of applications in molecular materials science. Their electronic properties crucially depend on the bond topology in ways that are often highly non-intuitive. Here, we study, using density functional theory, the triplet states of four biphenylene-derived PAHs finding dramatically different triplet excitation energies for closely related isomeric structures. These differences are rationalised using a qualitative description of Clar sextets and Baird quartets, quantified in terms of nucleus independent chemical shifts, and represented graphically through a recently developed method for visualising chemical shielding tensors (VIST). The results are further interpreted in terms of a 2D rigid rotor model of aromaticity and through an analysis of the natural transition orbitals involved in the triplet excited states showing good consistency between the different viewpoints. We believe that this work constitutes an important step in consolidating these varying viewpoints of electronically excited states.
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13
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Tuerhong M, Kerim A. A study on the aromaticity and conjugation pathways of diheterodiazuliporphyrins and their dications. J PHYS ORG CHEM 2021. [DOI: 10.1002/poc.4127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Mireguli Tuerhong
- The College of Chemistry and Chemical Engineering Xinjiang University Urumqi 830046 China
| | - Ablikim Kerim
- The College of Chemistry and Chemical Engineering Xinjiang University Urumqi 830046 China
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14
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Inostroza D, García V, Yañez O, Torres-Vega JJ, Vásquez-Espinal A, Pino-Rios R, Báez-Grez R, Tiznado W. On the NICS limitations to predict local and global current pathways in polycyclic systems. NEW J CHEM 2021. [DOI: 10.1039/d1nj01510a] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here, we analyze the possibility of predicting local and global current densities in a series of bicyclic hydrocarbons with 4n and 4n + 2 π-electrons from the nucleus-independent chemical shifts (NICS) computations.
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Affiliation(s)
- Diego Inostroza
- Computational and Theoretical Chemistry Group
- Departamento de Ciencias Químicas
- Facultad de Ciencias Exactas
- Universidad Andres Bello
- Santiago
| | - Victor García
- Departamento Académico de Fisicoquímica - Facultad de Química e Ingeniería Química
- Universidad Nacional Mayor de San Marcos
- Lima
- Peru
| | - Osvaldo Yañez
- Center of New Drugs for Hypertension (CENDHY)
- Santiago
- Chile
- Department of Pharmaceutical Science and Technology
- School of Chemical and Pharmaceutical Sciences
| | - Juan J. Torres-Vega
- Centro de Investigaciones Tecnológicas
- Biomédicas y Medioambientales
- Callao
- Peru
| | - Alejandro Vásquez-Espinal
- Computational and Theoretical Chemistry Group
- Departamento de Ciencias Químicas
- Facultad de Ciencias Exactas
- Universidad Andres Bello
- Santiago
| | - Ricardo Pino-Rios
- Laboratorio de Química Teórica
- Facultad de Química y Biología. Universidad de Santiago de Chile (USACH)
- Santiago
- Chile
| | - Rodrigo Báez-Grez
- Computational and Theoretical Chemistry Group
- Departamento de Ciencias Químicas
- Facultad de Ciencias Exactas
- Universidad Andres Bello
- Santiago
| | - William Tiznado
- Computational and Theoretical Chemistry Group
- Departamento de Ciencias Químicas
- Facultad de Ciencias Exactas
- Universidad Andres Bello
- Santiago
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15
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Orozco‐Ic M, Barroso J, Islas R, Merino G. Delocalization in Substituted Benzene Dications: A Magnetic Point of View. ChemistryOpen 2020; 9:657-661. [PMID: 32499992 PMCID: PMC7266496 DOI: 10.1002/open.202000105] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 04/21/2020] [Indexed: 11/24/2022] Open
Abstract
In this work, the induced magnetic field is analyzed for a series of substituted benzenes dications with formula C6R62+ (R=I, At, SeH, SeCH3, TeH, TeCH3), presumably exhibiting concentric aromaticity. Previous studies concluded that in the carbon skeleton, just π-electrons are delocalized. However, our results support that both the σ- and π-electrons are delocalized in the carbon skeleton, combined with a σ-delocalization in the external ring. The role of the relativistic effects in these dications is discussed in detail.
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Affiliation(s)
- Mesías Orozco‐Ic
- Departamento de Física AplicadaCentro de Investigación y de Estudios AvanzadosUnidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex97310Mérida, Yuc.México
| | - Jorge Barroso
- Departamento de Física AplicadaCentro de Investigación y de Estudios AvanzadosUnidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex97310Mérida, Yuc.México
| | - Rafael Islas
- Departamento de Ciencias Químicas Facultad de Ciencias ExactasUniversidad Andres BelloAv. República 2758320000SantiagoChile
| | - Gabriel Merino
- Departamento de Física AplicadaCentro de Investigación y de Estudios AvanzadosUnidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex97310Mérida, Yuc.México
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16
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Yu D, Rong C, Lu T, Geerlings P, De Proft F, Alonso M, Liu S. Switching between Hückel and Möbius aromaticity: a density functional theory and information-theoretic approach study. Phys Chem Chem Phys 2020; 22:4715-4730. [PMID: 32057037 DOI: 10.1039/c9cp06120g] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Benziporphyrins are versatile macrocycles exhibiting aromaticity switching behaviors. The existence of both Hückel and Möbius (anti)aromaticity has been reported in these systems, whose validity is respectively governed by the [4n + 2] and [4n] π-electron rule on the macrocyclic pathway. Despite the experimental evidence on the floppiness of benziporphyrins, the switching mechanism between Hückel and Möbius structures is still not clear, as well as the factors influencing the stability of the different π-conjugation topologies. For these reasons, we performed a systematic study on A,D-di-p-benzihexaphyrins(1.1.1.1.1.1) with two redox states corresponding to [28] and [30] π-electron conjugation pathways. Whereas benzi[28]hexaphyrin obeys Möbius aromaticity, benzi[30]hexaphyrin follows Hückel aromaticity. The dynamic interconversion between Möbius and Hückel aromaticity is investigated through the rotation of a phenylene ring, which acts as the topology selector. Further analyses of the energy profiles using energy decomposition and information-theoretic approaches provide new insights into conformational stability, aromaticity and antiaromaticity for these species. Strong and opposite cross correlations between aromaticity indexes and information-theoretic quantities were found for the two macrocyclic systems with opposite global aromaticity and antiaromaticity behaviors. These results indicate that Hückel and Möbius aromaticity and antiaromaticity, though qualitatively different, are closely related and can be interchanged, and information-theoretic quantities provide a novel understanding about their relevance. Our present results should provide in-depth insights to appreciate the nature and origin about Möbius (anti)aromaticity and its close relationship with Hückel (anti)aromaticity.
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Affiliation(s)
- Donghai Yu
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, 410081, China.
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17
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Orozco-Ic M, Celaya CA, Sundholm D. Calculation of magnetic response properties of tetrazines. RSC Adv 2020; 10:18124-18130. [PMID: 35517234 PMCID: PMC9053762 DOI: 10.1039/d0ra01641a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/01/2020] [Indexed: 12/18/2022] Open
Abstract
Magnetic response properties of 1,2,3,5-tetrazine derivatives including the newly synthesized 4,6-diphenyl-1,2,3,5-tetrazine have been studied computationally at the density functional theory (DFT) level. Calculations of magnetically induced current densities and induced magnetic fields show that the unsubstituted 1,2,3,5-tetrazine is almost as aromatic as benzene. Separating the magnetic shielding functions into molecular orbital components provided additional insights into the magnetic response. The aromatic character estimated from magnetically induced current densities and induced magnetic fields shows that NICSπzz(0) values and ring-current strengths yield about the same degree of aromaticity, whereas NICSzz(0) and NICSzz(1) values are contaminated by σ electron contributions. The studied 1,2,3,5-tetrazine derivatives are less aromatic than the unsubstituted one. Calculations of magnetic response properties of 4,6-diphenyl-1,2,3,5-tetrazine showed that it is the least aromatic among the studied molecules according to the ring-current criterion, while 4,6-[1,2,3,5]-ditetrazinyl-1,2,3,5-tetrazine is as aromatic as 4,6-dimethyl-1,2,3,5-tetrazine and slightly less aromatic than the unsubstituted 1,2,3,5-tetrazine. Magnetic response properties of 1,2,3,5-tetrazine derivatives including the newly synthesized 4,6-diphenyl-1,2,3,5-tetrazine have been studied computationally at the density functional theory level.![]()
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Affiliation(s)
- Mesías Orozco-Ic
- Department of Chemistry
- University of Helsinki
- FIN-00014 Helsinki
- Finland
| | - Christian A. Celaya
- Department of Chemistry
- University of Helsinki
- FIN-00014 Helsinki
- Finland
- Departamento de Materiales de Baja Dimensionalidad
| | - Dage Sundholm
- Department of Chemistry
- University of Helsinki
- FIN-00014 Helsinki
- Finland
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18
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Stanger A, Monaco G, Zanasi R. NICS‐
XY
‐Scan Predictions of Local, Semi‐Global, and Global Ring Currents in Annulated Pentalene and s‐Indacene Cores Compared to First‐Principles Current Density Maps. Chemphyschem 2019; 21:65-82. [DOI: 10.1002/cphc.201900952] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/23/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Amnon Stanger
- Schulich faculty of ChemistryTechnion-Israel Institute of Technology Haifa 32000 Israel
| | - Guglielmo Monaco
- 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
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19
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Cherni E, Champagne B, Ayadi S, Liégeois V. Magnetically-induced current density investigation in carbohelicenes and azahelicenes. Phys Chem Chem Phys 2019; 21:14678-14691. [PMID: 31215922 DOI: 10.1039/c9cp02071c] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A computational study of the magnetically-induced current (MIC) density has been carried out for a variety of ortho fused polycyclic aromatic molecules at the density functional theory level with the gauge including magnetically induced current (GIMIC) method. With this method, the aromatic character of each ring in a homologous series of carbohelicenes with an increasing number of fused benzene rings is assessed and compared with other aromaticity criteria such as the Nucleus Independent Chemical Shift [NICS(0), NICSzz(0)] and Bond Length Alternation (BLA) parameters. All criteria indicate that the two outer rings are the most aromatic ones [i.e. higher induced current, more negative NICS(0) and NICSzz(0) values, and smaller BLA values]. For the large helicenes (n > 10), the current drops along the following four rings and then rises again. Additionally, we have proven that this behavior is not due to a difference of the local magnetic field coming from a difference of orientation of the ring with respect to the external magnetic field (oriented along the helical axis). Upon fusing additional benzene rings to form hexa-peri-hexabenzo[7]helicene, some rings (B, D, and F) are a lot less aromatic (even non-aromatic) than the others. The NICS(0) and NICSzz(0) values exaggerate this behavior because they are all positive values, which is a signature of antiaromaticity. Then, when substituting one, three, or four benzene rings with pyrrole ones to form mono-aza-[7]-helicene, tri-aza-[7]-helicene, and tetra-aza-[7]-helicene, remarkable changes in the electronic structures of the helicenes are observed. Indeed, the induced currents are always smaller in the pyrrole rings than in the benzene ones. This has been further investigated using the streamline and the color map representations, which indicate that the diatropic current density passing through the plane cutting the C-N bonds in the pyrrole rings is stronger but is more localized than the current density passing through the plane cutting the C-C bonds in the benzene rings. This gives a positive but smaller total induced current for the pyrrole rings than for the benzene ones. For these systems, the NICS(0) and even more the NICSzz(0) values are not fully reliable to probe the local aromaticity, contrary to the induced current. Indeed, the NICSzz(0) values for the tri-aza-[7]-helicene molecule range from -14.23 to 1.14 ppm, which cannot lead to the same conclusion as the induced current values (10.03 to 12.87 nA T-1).
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Affiliation(s)
- Emna Cherni
- Chemistry Department, Faculty of Sciences of Tunis, University of Tunis El Manar, B.P 248 El Manar II, 2092 Tunis, Tunisia and Laboratory of Materials Molecules and Applications, Preparatory Institute for Scientific and Technical Studies, Carthage University, B.P:51, La Marsa, 2075 Tunis, Tunisia and Laboratory of Theoretical Chemistry, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium.
| | - Benoît Champagne
- Laboratory of Theoretical Chemistry, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium.
| | - Sameh Ayadi
- Laboratory of Materials Molecules and Applications, Preparatory Institute for Scientific and Technical Studies, Carthage University, B.P:51, La Marsa, 2075 Tunis, Tunisia
| | - Vincent Liégeois
- Laboratory of Theoretical Chemistry, Unit of Theoretical and Structural Physical Chemistry, Namur Institute of Structured Matter, University of Namur, Rue de Bruxelles, 61, 5000 Namur, Belgium.
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20
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Orozco-Ic M, Restrepo A, Muñoz-Castro A, Merino G. Molecular Helmholtz coils. J Chem Phys 2019; 151:014102. [DOI: 10.1063/1.5094547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Mesías Orozco-Ic
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310 Mérida, Yuc., Mexico
| | - Albeiro Restrepo
- Instituto de Química, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Antioquia, Colombia
| | - Alvaro Muñoz-Castro
- Laboratorio de Química Inorgánica y Materiales Moleculares, Facultad de Ingeniería, Universidad Autonoma de Chile, Llano Subercaseaux 2801, San Miguel, Santiago, Chile
| | - Gabriel Merino
- Departamento de Física Aplicada, Centro de Investigación y de Estudios Avanzados, Unidad Mérida. Km 6 Antigua Carretera a Progreso. Apdo. Postal 73, Cordemex, 97310 Mérida, Yuc., Mexico
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21
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Lazzeretti P. Frequency-dependent current density tensors as density functions of dynamic polarizabilities. J Chem Phys 2019; 150:184117. [PMID: 31091911 DOI: 10.1063/1.5097578] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Relationships accounting for contributions to the first-order charge density ρ(1) and current density J(1), induced in the electrons of a molecule by a monochromatic plane wave, have been obtained via time-dependent quantum mechanical perturbation theory. Their gauge invariance and invariance in passive translations of the coordinate system have been demonstrated (i) within the (long wavelengths) electric dipole approximation, in which only the electric field contributions to these densities are required, and (ii) within the electric quadrupole approximation, in which nonseparable terms provided by the magnetic field and by the electric field gradient, assumed uniform over the molecular domain, are needed. It is shown that the physical meaning of current density tensors depending on the frequency ω of the monochromatic wave shone on the molecule, and corresponding to derivatives of the current density J(1)(r, ω) with respect to components of the perturbing fields, is that of property density. Therefore, frequency-dependent current density tensors can be interpreted as the integrand function in 3d-space integrals defining dynamic molecular response tensors, e.g., electric dipole, mixed electric dipole-magnetic dipole, and electric dipole-quadrupole polarizabilites. Plots of current density tensors are expected to provide important information on the molecular domains giving dominant contributions to these properties.
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Affiliation(s)
- Paolo Lazzeretti
- Istituto di Struttura Della Materia, Consiglio Nazionale Delle Ricerche, Via Del Fosso Del Cavaliere, 100, 00133 Roma, Italy
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22
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Stanger A. Reexamination of NICS π,zz: Height Dependence, Off-Center Values, and Integration. J Phys Chem A 2019; 123:3922-3927. [PMID: 30964982 DOI: 10.1021/acs.jpca.9b02083] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Applying fine grids of nucleus independent chemical shift (NICS) probes (BQs) at different distances from the molecular plane of aromatic and antiaromatic molecules suggests that, at short distances, NICSπ,zz is maximal (absolute values) off the geometrical center of the systems. In nonsymmetric systems, the center of the induced ring current may be a little off the geometrical center, but the difference is negligible at distances ≥2 Å. At these distances, the change of NICSπ,zz with the distance from the ring follows a power relation. It is shown that the order of diatropicity and paratropicity within a group of molecules depends on the distance from the system (namely, the order of NICS( r)π,zz depends on r). It is thus suggested to use ∫NICSπ,zz as a quantitative measure of aromaticity.
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Affiliation(s)
- Amnon Stanger
- Schulich Department of Chemistry , Technion , Haifa 32000 , Israel
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23
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Đorđević S, Radenković S. Magnetically induced current density in triple-layered beryllium–boron clusters. Phys Chem Chem Phys 2019; 21:7105-7114. [DOI: 10.1039/c9cp00541b] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Magnetically induced current densities reveal the double aromatic character of the examined Be–B clusters.
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Affiliation(s)
- Slađana Đorđević
- Faculty of Science
- University of Kragujevac
- 34000 Kragujevac
- Serbia
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24
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Janda T, Foroutan‐Nejad C. Why is Benzene Unique? Screening Magnetic Properties of C6H6Isomers. Chemphyschem 2018; 19:2357-2363. [DOI: 10.1002/cphc.201800364] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Tomáš Janda
- Department of Chemistry, Faculty of ScienceMasaryk University Kamenice 5, CZ – 62500 Brno Czech Republic
- Institute of Chemistry and Technology of Macromolecular Materials, Faculty of Chemical TechnologyUniversity of Pardubice
| | - Cina Foroutan‐Nejad
- CEITEC – Central European Institute of Technology, Masaryk University Kamenice 5, CZ – 62500 Brno Czech Republic
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25
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Monaco G, Zanasi R. AACID: Anisotropy of the Asymmetric Magnetically Induced Current Density Tensor. J Phys Chem A 2018; 122:4681-4686. [DOI: 10.1021/acs.jpca.8b03663] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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
| | - Riccardo Zanasi
- Dipartimento di Chimica e Biologia “A. Zambelli”, Università degli Studi di Salerno, Via Giovanni Paolo II 132, Fisciano 84084, SA Italy
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26
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Franzke YJ, Sundholm D, Weigend F. Calculations of current densities and aromatic pathways in cyclic porphyrin and isoporphyrin arrays. Phys Chem Chem Phys 2018; 19:12794-12803. [PMID: 28484758 DOI: 10.1039/c7cp00624a] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetically induced current density susceptibilities have been studied for a number of cyclic ethyne- and butadiyne-bridged porphyrin and isoporphyrin arrays. The current density susceptibilities have been calculated using the gauge-including magnetically induced current (GIMIC) method, which is interfaced to the TURBOMOLE quantum chemistry code. Aromatic properties and current pathways have been analyzed and discussed by numerical integration of the current density susceptibilities passing selected chemical bonds yielding current strength susceptibilities. Despite the interrupted π-framework, zinc(ii) isoporphyrin sustains a ring current of ca. 10 nA T-1. Porphyrin and isoporphyrin dimers sustain a significant current strength at the linker, whereas the larger porphyrinoid arrays sustain mainly local ring currents. Isoporphyrin dimers with saturated meso carbons have strong net diatropic ring-current strengths of 20 nA T-1 fulfilling Hückels aromaticity rule. Porphyrin trimers and tetramers exhibit almost no current strength at the linker. The porphyrin moieties maintain their strong net diatropic ring current.
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Affiliation(s)
- Yannick J Franzke
- Department of Chemistry, University of Helsinki, P. O. Box 55, FIN-00014 Helsinki, Finland.
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27
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Stuyver T, Perrin M, Geerlings P, De Proft F, Alonso M. Conductance Switching in Expanded Porphyrins through Aromaticity and Topology Changes. J Am Chem Soc 2018; 140:1313-1326. [DOI: 10.1021/jacs.7b09464] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thijs Stuyver
- Department
of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Mickael Perrin
- Kavli
Institute of Nanoscience, Delft University of Technology, Lorentzweg
1, 2628 CJ Delft, The Netherlands
- Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland
| | - Paul Geerlings
- Department
of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Frank De Proft
- Department
of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - Mercedes Alonso
- Department
of General Chemistry (ALGC), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
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28
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Báez-Grez R, Ruiz L, Pino-Rios R, Tiznado W. Which NICS method is most consistent with ring current analysis? Assessment in simple monocycles. RSC Adv 2018; 8:13446-13453. [PMID: 35542548 PMCID: PMC9079725 DOI: 10.1039/c8ra01263f] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/05/2018] [Indexed: 02/05/2023] Open
Abstract
A linear relationship between NICSzz,π and NICSπ,σ with their current strength counterparts is shown. The comparative analysis was performed in simple and representative monocycles.
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Affiliation(s)
- R. Báez-Grez
- Doctorado en Fisicoquímica Molecular
- Facultad de Ciencias Exactas
- Universidad Andres Bello
- Santiago
- Chile
| | - Lina Ruiz
- Instituto de Ciencias Biomédicas
- Universidad Autónoma de Chile
- Santiago
- Chile
| | - R. Pino-Rios
- Departamento de CienciasQuímicas
- Facultad de Ciencias Exactas Universidad Andres Bello
- Santiago
- Chile
- Laboratorio de Química Teórica
| | - W. Tiznado
- Doctorado en Fisicoquímica Molecular
- Facultad de Ciencias Exactas
- Universidad Andres Bello
- Santiago
- Chile
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29
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Pelloni S, Lazzeretti P. Polygonal current models for polycyclic aromatic hydrocarbons and graphene sheets of various shapes. J Comput Chem 2017; 39:21-34. [DOI: 10.1002/jcc.25076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 09/15/2017] [Accepted: 09/18/2017] [Indexed: 01/11/2023]
Affiliation(s)
- Stefano Pelloni
- ITIS Galileo Galilei, Via Martiri di Cefalonia 14; S. Secondo, Parma 43017 Italy
| | - Paolo Lazzeretti
- Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere 100; Roma 00133 Italy
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30
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Monaco G, Zanasi R. Analysis of the Nucleus-Independent Chemical Shifts of [10]Cyclophenacene: Is It an Aromatic or Antiaromatic Molecule? J Phys Chem Lett 2017; 8:4673-4678. [PMID: 28892392 DOI: 10.1021/acs.jpclett.7b01937] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
[10]Cyclophenacene is an important synthetic target that shows a pair of nucleus-independent chemical shift (NICS) values for the center of mass and six-membered rings typical of an aromatic species. This is found in contrast with the global paratropic current density induced by a magnetic field parallel to the main symmetry axis. This apparent contradiction has been analyzed by studying the tensor character of the magnetic response. It turns out that the molecule displays two characters, one paratropic (antiaromatic) and another one diatropic (aromatic), depending on the orientation of the inducing magnetic field. The paratropic response, which cannot be recognized from the NICS values, is associated with a well-defined destabilization of the belt closure, as witnessed by homodesmotic reactions. A scalar measure of magnetic aromaticity, the field-independent current strength, has been introduced, which allows us to reach the conclusion that [10]cyclophenacene is indeed an aromatic molecule, although it is significantly affected by the paratropic response.
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Affiliation(s)
- Guglielmo Monaco
- Department of Chemistry and Biology "A. Zambelli", University of Salerno , via Giovanni Paolo II 132, Fisciano (SA) 84084, Italy
| | - Riccardo Zanasi
- Department of Chemistry and Biology "A. Zambelli", University of Salerno , via Giovanni Paolo II 132, Fisciano (SA) 84084, Italy
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31
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Kumar C, Fliegl H, Sundholm D. Relation Between Ring Currents and Hydrogenation Enthalpies for Assessing the Degree of Aromaticity. J Phys Chem A 2017; 121:7282-7289. [DOI: 10.1021/acs.jpca.7b07607] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Chandan Kumar
- Hylleraas
Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.
O. Box 1033, N-1315 Blindern, Norway
| | - Heike Fliegl
- Hylleraas
Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.
O. Box 1033, N-1315 Blindern, Norway
| | - Dage Sundholm
- Department
of Chemistry, University of Helsinki, P.O. Box 55, A. I. Virtanens Plats
1, FIN-00014 Helsinki, Finland
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32
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Dimitrova M, Fliegl H, Sundholm D. The influence of heteroatoms on the aromatic character and the current pathways of B2N2-dibenzo[a,e]pentalenes. Phys Chem Chem Phys 2017; 19:20213-20223. [DOI: 10.1039/c7cp02964k] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Four polycyclic molecules have been investigated at the DFT level of theory using magnetically induced current densities calculated with the GIMIC program as an indicator of their (anti)aromaticity.
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Affiliation(s)
- Maria Dimitrova
- University of Helsinki
- Department of Chemistry
- FIN-00014 University of Helsinki
- Finland
| | - Heike Fliegl
- Centre for Theoretical and Computational Chemistry (CTCC)
- Department of Chemistry
- University of Oslo
- 0315 Oslo
- Norway
| | - Dage Sundholm
- University of Helsinki
- Department of Chemistry
- FIN-00014 University of Helsinki
- Finland
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33
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Molina V, Rauhalahti M, Hurtado J, Fliegl H, Sundholm D, Muñoz-Castro A. Aromaticity introduced by antiferromagnetic ligand mediated metal–metal interactions. Insights from the induced magnetic response in [Cu6(dmPz)6(OH)6]. Inorg Chem Front 2017. [DOI: 10.1039/c7qi00023e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ligand-mediated antiferromagnetic coupling induces aromatic-ring behavior.
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Affiliation(s)
- V. Molina
- Grupo de Química Inorgánica y Materiales Moleculares
- Universidad Autonoma de Chile
- Santiago
- Chile
- Liceo Politécnico Ciencia y Tecnología
| | - M. Rauhalahti
- Department of Chemistry
- University of Helsinki
- Finland
| | - J. Hurtado
- Departamento de Química
- Universidad de los Andes
- Bogotá
- Colombia
| | - H. Fliegl
- Centre for Theoretical and Computational Chemistry (CTCC)
- Department of Chemistry
- University of Oslo
- Oslo
- Norway
| | - D. Sundholm
- Department of Chemistry
- University of Helsinki
- Finland
| | - A. Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares
- Universidad Autonoma de Chile
- Santiago
- Chile
- Doctorado en Fisicoquímica Molecular
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34
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Affiliation(s)
- Riccardo Zanasi
- Dipartimento di Chimica e Biologia “Adolfo Zambelli”; Università di Salerno; Via Giovanni Paolo II, 132, Fisciano Salerno 84084 Italy
| | - Paolo Della Porta
- Dipartimento di Chimica e Biologia “Adolfo Zambelli”; Università di Salerno; Via Giovanni Paolo II, 132, Fisciano Salerno 84084 Italy
| | - Guglielmo Monaco
- Dipartimento di Chimica e Biologia “Adolfo Zambelli”; Università di Salerno; Via Giovanni Paolo II, 132, Fisciano Salerno 84084 Italy
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35
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Rakhi R, Suresh CH. A DFT study on dihydropyrazine annulated linear polyacenes: aromaticity, stability and HOMO–LUMO energy modulation. Phys Chem Chem Phys 2016; 18:24631-41. [DOI: 10.1039/c6cp03723b] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Linear polyacene (LPA) mimics containing up to 34 rings have been designed by annulating dihydropyrazine units to LPA cores and they showed enhanced aromatic character than the LPA due to significant mixing of the N-lone pairs with the carbon π-orbitals.
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Affiliation(s)
- Ramachandran Rakhi
- Chemical Sciences and Technology Division
- Academy of Scientific and Innovative Research (AcSIR)
- CSIR–National Institute for Interdisciplinary Science and Technology (CSIR–NIIST)
- Thiruvananthapuram 695019
- India
| | - Cherumuttathu H. Suresh
- Chemical Sciences and Technology Division
- Academy of Scientific and Innovative Research (AcSIR)
- CSIR–National Institute for Interdisciplinary Science and Technology (CSIR–NIIST)
- Thiruvananthapuram 695019
- India
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36
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Abstract
A definition of ring currents in a velocity vector field is proposed according to topological criteria: ring currents are axial vortices confined in, or rotating beyond, a separatrix, i.e., the boundary which marks the limits of the vortex.
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Affiliation(s)
- Paolo Lazzeretti
- Dipartimento di Scienze Chimiche e Geologiche
- Università degli Studi di Modena e Reggio Emilia
- 41125 Modena
- Italy
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37
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Abstract
The π-electron diatropic ring current emerging throughout the trimerization of acetylene to benzene.
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Affiliation(s)
- Guglielmo Monaco
- Department of Chemistry and Biology “A. Zambelli”
- University of Salerno
- 84084 Fisciano
- Italy
| | - Riccardo Zanasi
- Department of Chemistry and Biology “A. Zambelli”
- University of Salerno
- 84084 Fisciano
- Italy
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38
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Sundholm D, Berger RJF, Fliegl H. Analysis of the magnetically induced current density of molecules consisting of annelated aromatic and antiaromatic hydrocarbon rings. Phys Chem Chem Phys 2016; 18:15934-42. [DOI: 10.1039/c6cp01968d] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aromatic pathway of molecules with annelated aromatic and antiaromatic rings has been studied by calculating magnetically induced current densities.
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Affiliation(s)
- Dage Sundholm
- University of Helsinki
- Department of Chemistry
- Finland
| | | | - Heike Fliegl
- Centre for Theoretical and Computational Chemistry (CTCC)
- Department of Chemistry
- University of Oslo
- NO-0315 Oslo
- Norway
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Benkyi I, Fliegl H, Valiev RR, Sundholm D. New insights into aromatic pathways of carbachlorins and carbaporphyrins based on calculations of magnetically induced current densities. Phys Chem Chem Phys 2016; 18:11932-41. [DOI: 10.1039/c5cp06987d] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aromatic pathways of carbaporphyrins and carbachlorins that are based on magnetically induced current density DFT-GIMIC calculations are presented and discussed.
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Affiliation(s)
- Isaac Benkyi
- University of Helsinki
- Department of Chemistry
- FIN-00014 University of Helsinki
- Finland
| | - Heike Fliegl
- Centre for Theoretical and Computational Chemistry (CTCC)
- Department of Chemistry
- University of Oslo
- 0315 Oslo
- Norway
| | - Rashid R. Valiev
- Tomsk Polytechnic University
- Tomsk 634050
- Russian Federation
- Tomsk State University
- Tomsk
| | - Dage Sundholm
- University of Helsinki
- Department of Chemistry
- FIN-00014 University of Helsinki
- Finland
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40
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Woller T, Contreras-García J, Geerlings P, De Proft F, Alonso M. Understanding the molecular switching properties of octaphyrins. Phys Chem Chem Phys 2016; 18:11885-900. [DOI: 10.1039/c5cp07413d] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Triggering Hückel–Möbius topological and aromaticity switches in octaphyrins by protonation and redox reactions.
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Affiliation(s)
- T. Woller
- Eenheid Algemene Chemie (ALGC)
- Vrije Universiteit Brussel (VUB)
- 1050 Brussels
- Belgium
| | - J. Contreras-García
- Sorbonne Universités
- UPMC Univ Paris 06
- UMR 7616
- Laboratoire de Chimie Théorique
- Paris
| | - P. Geerlings
- Eenheid Algemene Chemie (ALGC)
- Vrije Universiteit Brussel (VUB)
- 1050 Brussels
- Belgium
| | - Frank De Proft
- Eenheid Algemene Chemie (ALGC)
- Vrije Universiteit Brussel (VUB)
- 1050 Brussels
- Belgium
| | - M. Alonso
- Eenheid Algemene Chemie (ALGC)
- Vrije Universiteit Brussel (VUB)
- 1050 Brussels
- Belgium
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41
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Du D, Sundholm D, Fliegl H. Evaluating Shielding‐Based Ring‐Current Models by Using the Gauge‐Including Magnetically Induced Current Method. J CHIN CHEM SOC-TAIP 2015. [DOI: 10.1002/jccs.201500027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Dou Du
- University of Helsinki, Department of Chemistry, P.O. Box 55 (A.I. Virtanens plats 1), FIN‐00014 University of Helsinki, Finland
| | - Dage Sundholm
- University of Helsinki, Department of Chemistry, P.O. Box 55 (A.I. Virtanens plats 1), FIN‐00014 University of Helsinki, Finland
| | - Heike Fliegl
- Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, 0315 Oslo, Norway
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Della Porta P, Zanasi R, Monaco G. Hydrogen-hydrogen bonding: the current density perspective. J Comput Chem 2015; 36:707-16. [PMID: 25689556 DOI: 10.1002/jcc.23841] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/20/2014] [Accepted: 12/23/2014] [Indexed: 11/08/2022]
Abstract
Current density plots of closed-shell intermolecular H-H interactions characterized by a bond critical point (BCP) show two vortices separated by a saddle, a pattern which allows for a clear definition of a pair current strength. This H-H current strength turns out to be roughly related to the potential energy density at the BCP and then to the dissociation energy. The same pattern is also recognizable, at least for an azimuthal orientation of a field perpendicular to the H-H line, for the intramolecular interactions previously investigated to propose the H-H bonding. In the case of the H atoms of the bay region of polycyclic aromatic hydrocarbons, the current of the H-H delocalized diatropic vortex gives a quantitative indication of stabilization; however, on rotation of the field and the subsequent onset of a bay-delocalized paratropic vortex (a typical signature of antiaromaticity), the diatropic vortex can be reshaped or it can even disappear, consistently with its smallness, and thus showing the effect of other more relevant interactions.
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Affiliation(s)
- Paolo Della Porta
- Department of Chemistry and Biology, University of Salerno, Via Giovanni Paolo II, 132, Fisciano, 84084 SA, Italy
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Abstract
Ab initio calculations confirm that the design of large paratropic circuits through altanisation fails in altan-[10,5]coronene. This molecule is predicted to be an open-shell singlet biradical, like the cycloacene that it contains.
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Affiliation(s)
- Guglielmo Monaco
- Dip. di Chimica e Biologia “Adolfo Zambelli”
- Università di Salerno
- Fisciano
- Italy
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Pelloni S, Monaco G, Della Porta P, Zanasi R, Lazzeretti P. Delocalized Currents without a Ring of Bonded Atoms: Strong Delocalized Electron Currents Induced by Magnetic Fields in Noncyclic Molecules. J Phys Chem A 2014; 118:3367-75. [DOI: 10.1021/jp502491a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stefano Pelloni
- Dipartimento
di Scienze Chimiche e Geologiche, Universitá degli Studi di Modena, via G. Campi 183, 41100 Modena, Italy
| | - Guglielmo Monaco
- Dipartimento
di Chimica e Biologia, Università degli Studi di Salerno, Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy
| | - Paolo Della Porta
- Dipartimento
di Chimica e Biologia, Università degli Studi di Salerno, Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy
| | - Riccardo Zanasi
- Dipartimento
di Chimica e Biologia, Università degli Studi di Salerno, Via Giovanni Paolo II, 132, Fisciano 84084 SA, Italy
| | - Paolo Lazzeretti
- Dipartimento
di Scienze Chimiche e Geologiche, Universitá degli Studi di Modena, via G. Campi 183, 41100 Modena, Italy
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