1
|
Jana M, Blasco D, Sundholm D, Rath H. Organometallic copper(II) complex of meso- meso N-methyl N-confused pyrrole-bridged doubly N-methyl N-confused hexaphyrin. Org Biomol Chem 2024; 22:4461-4465. [PMID: 38766981 DOI: 10.1039/d4ob00691g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Synthesis, spectroscopic and theoretical characterization of a hitherto unknown meso-meso N-confused N-methylpyrrole-bridged doubly N-confused hexaphyrin (molecule 5) and its organometallic copper(II) complex (molecule 6) are reported herein. The absence of Q-type bands in the UV-Vis spectrum and the high chemical shifts of the inner proton signals of 5 suggest its globally non-aromaticity. The spectroscopic evidence of non-aromaticity for 5 and the paramagnetic nature of 6, are fully supported by density functional theory (DFT) calculations of the UV-Vis spectra, electron paramagnetic resonance (EPR) g-tensor parameters, and the magnetically induced current density strengths obtained with the gauge-including magnetically induced currents (GIMIC) method.
Collapse
Affiliation(s)
- Manik Jana
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A/2B Raja S.C Mullick Road, Jadavpur, Kolkata, West Bengal 700 032, India.
| | - Daniel Blasco
- Departamento de Química, Instituto de Investigación en Química (IQUR), Universidad de La Rioja, Madre de Dios 53, 26006, Logroño, Spain
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, P. O. Box 55 (A. I. Virtasen aukio 1), FIN-00014, Helsinki, Finland.
| | - Harapriya Rath
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A/2B Raja S.C Mullick Road, Jadavpur, Kolkata, West Bengal 700 032, India.
| |
Collapse
|
2
|
Badri Z, Nourigheimasi F, Foroutan-Nejad C. Tetraquinolines; four linked quinoline units or porphyrinoids. Org Biomol Chem 2024; 22:2284-2291. [PMID: 38407320 DOI: 10.1039/d3ob01616a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Tetraquinolines (TEQs) have been recently synthesized and proposed to be a new member of the porphyrinoid family with highly distorted, nonplanar, geometries. In this contribution by studying several molecules, closely related to TEQs, we have suggested that the origin of the nonplanarity of TEQs and their counterparts is a combination of steric strain and the propensity of the molecules to avoid antiaromaticity. The tendency of TEQs to coordinate with doubly charged metal ions can be interpreted in terms of their transition from potential antiaromaticity to nonaromaticity. Even metal-coordinated TEQs do not sustain diatropic ring currents. Although full planarization is not possible because of steric strain, doubly oxidized TEQs and their counterparts sustain moderate global diatropic ring currents and partially planarize. The nature of current density in the molecules is studied in the light of Steiner-Fowler selection rules.
Collapse
Affiliation(s)
- Zahra Badri
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| | - Farnoush Nourigheimasi
- Department of Chemistry, State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - Cina Foroutan-Nejad
- Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
| |
Collapse
|
3
|
Saha HK, Mallick D, Das S. Dibenzoheterole-Fused s-Indacenes. J Org Chem 2023; 88:16248-16258. [PMID: 37943573 DOI: 10.1021/acs.joc.3c01719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Heterole (pyrrole, thiophene, furan, thiophene-S,S-dioxide)-fused s-indacenes are known for their enhanced paratropic ring-current strength. However, the outcome of the antiaromatic properties for dibenzoheterole-fused s-indacene antiaromatics remained underexplored. Carbazole-, dibenzothiophene-, dibenzofuran-, and dibenzo[b,d]thiophene-5,5-dioxide-fused s-indacenes 1-4, respectively, were synthesized and characterized by experimental (NMR, single-crystal, UV-vis, CV) and computational (DFT) approaches to study the ground-state antiaromatic properties. Sulfone-containing 4 showed the weakest paratropic ring-current strength for the s-indacene unit, while 1-3 showed a relatively greater paratropicity for the s-indacene unit, as evidenced by the changes in 1H NMR chemical shifts of s-indacene protons. Such observation was explained by the electron-withdrawing effect of the sulfone group and loss of 4n + 2 aromaticity of the heterole unit for 4 reducing its s-indacene paratropicity strength as the nonaromaticity of the heterole unit reduces the π-bond character at the dibenzo[b,d]thiophene-5,5-dioxide/s-indacene fusion site to avoid antiaromatic s-indacene ring formation. The modulation of the paratropic ring-current strength of s-indacene for 1-4 was further supported by the NICS(1)zz and ring-current (ACID) calculations.
Collapse
Affiliation(s)
- Hemonta Kumar Saha
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Dibyendu Mallick
- Department of Chemistry, Presidency University, Kolkata 700073, West Bengal, India
| | - Soumyajit Das
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
El Bakouri O, Szczepanik DW, Jorner K, Ayub R, Bultinck P, Solà M, Ottosson H. Three-Dimensional Fully π-Conjugated Macrocycles: When 3D-Aromatic and When 2D-Aromatic-in-3D? J Am Chem Soc 2022; 144:8560-8575. [PMID: 35523019 PMCID: PMC9121391 DOI: 10.1021/jacs.1c13478] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
![]()
Several fully π-conjugated
macrocycles with puckered or cage-type
structures were recently found to exhibit aromatic character according
to both experiments and computations. We examine their electronic
structures and put them in relation to 3D-aromatic molecules (e.g., closo-boranes) and to 2D-aromatic
polycyclic aromatic hydrocarbons. Using qualitative theory combined
with quantum chemical calculations, we find that the macrocycles explored
hitherto should be described as 2D-aromatic with three-dimensional
molecular structures (abbr. 2D-aromatic-in-3D) and not as truly 3D-aromatic.
3D-aromatic molecules have highly symmetric structures (or nearly
so), leading to (at least) triply degenerate molecular orbitals, and
for tetrahedral or octahedral molecules, an aromatic closed-shell
electronic structure with 6n + 2 electrons. Conversely,
2D-aromatic-in-3D structures exhibit aromaticity that results from
the fulfillment of Hückel’s 4n + 2
rule for each macrocyclic path, yet their π-electron counts
are coincidentally 6n + 2 numbers for macrocycles
with three tethers of equal lengths. It is notable that 2D-aromatic-in-3D
macrocyclic cages can be aromatic with tethers of different lengths, i.e., with π-electron counts different from 6n + 2, and they are related to naphthalene. Finally, we
identify tetrahedral and cubic π-conjugated molecules that fulfill
the 6n + 2 rule and exhibit significant electron
delocalization. Yet, their properties resemble those of analogous
compounds with electron counts that differ from 6n + 2. Thus, despite the fact that these molecules show substantial
π-electron delocalization, they cannot be classified as true
3D-aromatics.
Collapse
Affiliation(s)
- Ouissam El Bakouri
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden.,Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain
| | - Dariusz W Szczepanik
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain.,K. Guminski Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, Kraków 30-387, Poland
| | - Kjell Jorner
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
| | - Rabia Ayub
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
| | - Patrick Bultinck
- Department of Chemistry, Ghent University, Krijgslaan 281 S3, Gent 9000, Belgium
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, C/ Maria Aurèlia Capmany 6, Girona, Catalonia 17003, Spain
| | - Henrik Ottosson
- Department of Chemistry - Ångström Laboratory, Uppsala University, Box 523, Uppsala 751 20, Sweden
| |
Collapse
|
6
|
Gao H, Wu F, Zhao Y, Zhi X, Sun Y, Shen Z. Highly Stable Neutral Corrole Radical: Amphoteric Aromatic-Antiaromatic Switching and Efficient Photothermal Conversion. J Am Chem Soc 2022; 144:3458-3467. [PMID: 35170957 DOI: 10.1021/jacs.1c11716] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The preparation of novel stable radical systems that survive and may be manipulated under harsh conditions is essential for their practical applications, such as energy storage and conversion materials. Here, we present a facile synthesis of an electrically neutral benzo-fused nickel corrole radical that shows remarkable photo- and thermal stability. The carbon-based organic radical character was confirmed using electron spin resonance and spin population analyses. This radical may be reversibly converted to its aromatic or antiaromatic ion via a one-electron redox process, as indicated by nuclear magnetic resonance chemical shifts and theoretical calculations. Notably, the antiaromatic state is stable, showing intense ring currents with complex pathways. The spectroscopic characteristics and calculated molecular orbitals of the corrole radical exhibit a combination of aromatic and antiaromatic features. On the basis of the aromatic light-harvesting property and antiaromatic emission-free character, the corrole radical exhibits highly robust, efficient photothermal energy conversion in water after encapsulation within nanoparticles, with the unpaired spin simultaneously retained. These results provide a fundamental understanding of the relationship between the (anti)aromaticity and photophysical properties of a porphyrinoid radical and a promising platform for the design of radical-based functional materials.
Collapse
Affiliation(s)
- Hu Gao
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Fan Wu
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yue Zhao
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xu Zhi
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yufen Sun
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Zhen Shen
- State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| |
Collapse
|
7
|
Sundholm D, Dimitrova M, Berger RJF. Current density and molecular magnetic properties. Chem Commun (Camb) 2021; 57:12362-12378. [PMID: 34726205 DOI: 10.1039/d1cc03350f] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We give an overview of the molecular response to an external magnetic field perturbing quantum mechanical systems. We present state-of-the-art methods for calculating magnetically-induced current-density susceptibilities. We discuss the essence and properties of current-density susceptibilities and how molecular magnetic properties can be calculated from them. We also review the theory of spin-current densities, how relativity affects current densities and magnetic properties. An overview of the magnetic ring-current criterion for aromaticity is given, which has implications on theoretical and experimental research. The recently reported theory of antiaromaticity and how molecular symmetry affects the magnetic response are discussed and applied to closed-shell paramagnetic molecules. The topology of magnetically induced current densities and its consequences for molecular magnetic properties are also presented with twisted and toroidal molecules as examples.
Collapse
Affiliation(s)
- Dage Sundholm
- Department of Chemistry, Faculty of Science, FI-00014 University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, Finland.
| | - Maria Dimitrova
- Department of Chemistry, Faculty of Science, FI-00014 University of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, Finland. .,Chemistry of Materials, Paris-Lodron University of Salzburg, Jakob-Haringerstr. 2A, A-5020 Salzburg, Austria
| | - Raphael J F Berger
- Chemistry of Materials, Paris-Lodron University of Salzburg, Jakob-Haringerstr. 2A, A-5020 Salzburg, Austria
| |
Collapse
|
8
|
Abstract
Baird's rule predicts that molecules with 4n π electrons should be aromatic in the triplet state, but the realization of simple ring systems with such an electronic ground state has been stymied by these molecules' tendency to distort into structures bearing a large singlet-triplet gap. Here, we show that the elusive benzene diradical dianion can be stabilized through creation of a binucleating ligand that enforces a tightly constrained inverse sandwich structure and direct magnetic exchange coupling. Specifically, we report the compounds [K(18-crown-6)(THF)2]2[M2(BzN6-Mes)] (M = Y, Gd; BzN6-Mes = 1,3,5-tris[2',6'-(N-mesityl)dimethanamino-4'-tert-butylphenyl]benzene), which feature a trigonal ligand that binds one trivalent metal ion on each face of a central benzene dianion. Antiferromagnetic exchange in the Gd3+ compound preferentially stabilizes the triplet state such that it becomes the molecular ground state. Single-crystal X-ray diffraction data and nucleus-independent chemical shift calculations support aromaticity, in agreement with Baird's rule.
Collapse
|
9
|
Lehtola S, Dimitrova M, Fliegl H, Sundholm D. Benchmarking Magnetizabilities with Recent Density Functionals. J Chem Theory Comput 2021; 17:1457-1468. [PMID: 33599491 PMCID: PMC8023670 DOI: 10.1021/acs.jctc.0c01190] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Indexed: 12/21/2022]
Abstract
We have assessed the accuracy of the magnetic properties of a set of 51 density functional approximations, including both recently published and already established functionals. The accuracy assessment considers a series of 27 small molecules and is based on comparing the predicted magnetizabilities to literature reference values calculated using coupled-cluster theory with full singles and doubles and perturbative triples [CCSD(T)] employing large basis sets. The most accurate magnetizabilities, defined as the smallest mean absolute error, are obtained with the BHandHLYP functional. Three of the six studied Berkeley functionals and the three range-separated Florida functionals also yield accurate magnetizabilities. Also, some older functionals like CAM-B3LYP, KT1, BHLYP (BHandH), B3LYP, and PBE0 perform rather well. In contrast, unsatisfactory performance is generally obtained with Minnesota functionals, which are therefore not recommended for calculations of magnetically induced current density susceptibilities and related magnetic properties such as magnetizabilities and nuclear magnetic shieldings. We also demonstrate that magnetizabilities can be calculated by numerical integration of magnetizability density; we have implemented this approach as a new feature in the gauge-including magnetically induced current (GIMIC) method. Magnetizabilities can be calculated from magnetically induced current density susceptibilities within this approach even when analytical approaches for magnetizabilities as the second derivative of the energy have not been implemented. The magnetizability density can also be visualized, providing additional information that is not otherwise easily accessible on the spatial origin of magnetizabilities.
Collapse
Affiliation(s)
- Susi Lehtola
- Department
of Chemistry, University of Helsinki, P.O. Box 55, A.I. Virtanens plats
1, FI-00014 University
of Helsinki, Finland
- Molecular
Sciences Software Institute, Blacksburg, Virginia 24061, United States
| | - Maria Dimitrova
- Department
of Chemistry, University of Helsinki, P.O. Box 55, A.I. Virtanens plats
1, FI-00014 University
of Helsinki, Finland
| | - Heike Fliegl
- Institute
of Nanotechnology, KIT, Hermann-von-Helmholtz Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Dage Sundholm
- Department
of Chemistry, University of Helsinki, P.O. Box 55, A.I. Virtanens plats
1, FI-00014 University
of Helsinki, Finland
| |
Collapse
|
10
|
Patra SG, Mondal T. Interplay of Hückel and Möbius Aromaticity in Metal-Metal Quintuple Bonded Complexes of Cr, Mo, and W with Amidinate Ligand: Ab initio DFT and Multireference Analysis*. Chemphyschem 2021; 22:298-311. [PMID: 33252161 DOI: 10.1002/cphc.202000923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 11/29/2020] [Indexed: 11/10/2022]
Abstract
The aromaticity of metal-metal quintuple bonded complexes of the type M2 L2 (M=Cr, Mo, and W; L=amidinate) are studied employing gauge including magnetically induced ring current (GIMIC) analysis and electron density of delocalized bonds (EDDB). It is found that the complexes possess two types of aromaticity: i) Hückel aromaticity through delocalization of ligand π electrons with metal-metal δ-bond-forming 6 conjugated electrons (4π and 2δ) ring; ii) Craig-Möbius aromaticity through delocalization of π electrons of both the ligands with metal d-orbitals in Craig type orientation forming 10π electrons ring with a double twist. Extended transition state natural orbital chemical valence (ETS-NOCV) and canonical molecular orbital natural chemical shielding (CMO-NCS) analysis confirm the Craig-Möbius type arrangement of the orbitals. Furthermore, the unprecedented Hückel and Möbius type aromaticity is confirmed from the plot of the current pathways using 3D line integral convolution (3D-LIC) plots. The metal-metal bond order also increases down the group as justified from the complete active space self-consistent field (CASSCF) analysis. Due to an increase in the π and δ electron conjugation, both the Hückel and Möbius aromaticity increase down the group.
Collapse
Affiliation(s)
- Shanti G Patra
- Department of Chemical Sciences, Ariel University, Ariel, 40700, Israel
| | - Totan Mondal
- Department of Organic Chemistry and the, Lise Meitner-Minerva Centre for Computational Quantum Chemistry, The Hebrew University, Jerusalem, 91904, Israel
| |
Collapse
|
11
|
Ayub R, El Bakouri O, Smith JR, Jorner K, Ottosson H. Triplet State Baird Aromaticity in Macrocycles: Scope, Limitations, and Complications. J Phys Chem A 2021; 125:570-584. [PMID: 33427474 PMCID: PMC7884009 DOI: 10.1021/acs.jpca.0c08926] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/18/2020] [Indexed: 02/06/2023]
Abstract
The aromaticity of cyclic 4nπ-electron molecules in their first ππ* triplet state (T1), labeled Baird aromaticity, has gained growing attention in the past decade. Here we explore computationally the limitations of T1 state Baird aromaticity in macrocyclic compounds, [n]CM's, which are cyclic oligomers of four different monocycles (M = p-phenylene (PP), 2,5-linked furan (FU), 1,4-linked cyclohexa-1,3-diene (CHD), and 1,4-linked cyclopentadiene (CPD)). We strive for conclusions that are general for various DFT functionals, although for macrocycles with up to 20 π-electrons in their main conjugation paths we find that for their T1 states single-point energies at both canonical UCCSD(T) and approximative DLPNO-UCCSD(T) levels are lowest when based on UB3LYP over UM06-2X and UCAM-B3LYP geometries. This finding is in contrast to what has earlier been observed for the electronic ground state of expanded porphyrins. Yet, irrespective of functional, macrocycles with 2,5-linked furans ([n]CFU's) retain Baird aromaticity until larger n than those composed of the other three monocycles. Also, when based on geometric, electronic and energetic aspects of aromaticity, a 3[n]CFU with a specific n is more strongly Baird-aromatic than the analogous 3[n]CPP while the magnetic indices tell the opposite. To construct large T1 state Baird-aromatic [n]CM's, the design should be such that the T1 state Baird aromaticity of the macrocyclic perimeter dominates over a situation with local closed-shell Hückel aromaticity of one or a few monocycles and semilocalized triplet diradical character. Monomers with lower Hückel aromaticity in S0 than benzene (e.g., furan) that do not impose steric congestion are preferred. Structural confinement imposed by, e.g., methylene bridges is also an approach to larger Baird-aromatic macrocycles. Finally, by using the Zilberg-Haas description of T1 state aromaticity, we reveal the analogy to the Hückel aromaticity of the corresponding closed-shell dications yet observe stronger Hückel aromaticity in the macrocyclic dications than Baird aromaticity in the T1 states of the neutral macrocycles.
Collapse
Affiliation(s)
- Rabia Ayub
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden
| | - Ouissam El Bakouri
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden
| | - Joshua R. Smith
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden
- Department
of Chemistry, Humboldt State University, One Harpst Street, Arcata, California 95521, United States
| | - Kjell Jorner
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden
| | - Henrik Ottosson
- Department
of Chemistry - Ångström Laboratory, Uppsala University, Box 523, SE-751 20, Uppsala, Sweden
| |
Collapse
|
12
|
Escayola S, Poater A, Muñoz-Castro A, Solà M. An unprecedented π-electronic circuit involving an odd number of carbon atoms in a grossly warped non-planar nanographene. Chem Commun (Camb) 2021; 57:3087-3090. [DOI: 10.1039/d1cc00593f] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The formation of π-aromatic circuits along a grossly warped nanographene, C80H30, containing five- and seven-membered rings inserted into a six-membered mesh, reveals global π-circuits at the edge of the backbone.
Collapse
Affiliation(s)
- Sílvia Escayola
- Institute of Computational Chemistry and Catalysis and Department of Chemistry
- University of Girona
- 17003 Girona
- Spain
- Donostia International Physics Center (DIPC)
| | - Albert Poater
- Institute of Computational Chemistry and Catalysis and Department of Chemistry
- University of Girona
- 17003 Girona
- Spain
| | - Alvaro Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares
- Facultad de Ingeniería
- Universidad Autónoma de Chile
- El Llano Subercaseaux 2801
- Chile
| | - Miquel Solà
- Institute of Computational Chemistry and Catalysis and Department of Chemistry
- University of Girona
- 17003 Girona
- Spain
| |
Collapse
|
13
|
Baryshnikov GV, Valiev RR, Nasibullin RT, Sundholm D, Kurten T, Ågren H. Aromaticity of Even-Number Cyclo[ n]carbons ( n = 6-100). J Phys Chem A 2020; 124:10849-10855. [PMID: 33301674 PMCID: PMC7770816 DOI: 10.1021/acs.jpca.0c09692] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The
recently synthesized cyclo[18]carbon molecule has been characterized
in a number of studies by calculating electronic, spectroscopic, and
mechanical properties. However, cyclo[18]carbon is only one member
of the class of cyclo[n]carbons—standalone
carbon allotrope representatives. Many of the larger members of this
class of molecules have not been thoroughly investigated. In this
work, we calculate the magnetically induced current density of cyclo[n]carbons in order to elucidate how electron delocalization
and aromatic properties change with the size of the molecular ring
(n), where n is an even number between
6 and 100. We find that the Hückel rules for aromaticity (4k + 2) and antiaromaticity (4k) become
degenerate for large Cn rings (n > 50), which can be understood as a transition from
a
delocalized electronic structure to a nonaromatic structure with localized
current density fluxes in the triple bonds. Actually, the calculations
suggest that cyclo[n]carbons with n > 50 are nonaromatic cyclic polyalkynes. The influence of the
amount
of nonlocal exchange and the asymptotic behavior of the exchange–correlation
potential of the employed density functionals on the strength of the
magnetically induced ring current and the aromatic character of the
large cyclo[n]carbons is also discussed.
Collapse
Affiliation(s)
- Glib V Baryshnikov
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala SE-751 20, Sweden.,Department of Chemistry and Nanomaterials Science, Bohdan Khmelnytsky National University, Cherkasy 18031, Ukraine
| | - Rashid R Valiev
- Research School of Chemistry & Applied Biomedical Sciences, National Research Tomsk Polytechnic University, Tomsk 634050, Russia.,Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FIN-00014, Finland
| | | | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FIN-00014, Finland
| | - Theo Kurten
- Department of Chemistry, Faculty of Science, University of Helsinki, Helsinki FIN-00014, Finland
| | - Hans Ågren
- Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala SE-751 20, Sweden.,College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, Henan, P. R. China
| |
Collapse
|
14
|
Ni Y, Gopalakrishna TY, Phan H, Kim T, Herng TS, Han Y, Tao T, Ding J, Kim D, Wu J. 3D global aromaticity in a fully conjugated diradicaloid cage at different oxidation states. Nat Chem 2020; 12:242-248. [PMID: 31959959 DOI: 10.1038/s41557-019-0399-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 11/22/2019] [Indexed: 12/17/2022]
Abstract
Aromaticity is a vital concept that governs the electronic properties of π-conjugated organic molecules and has long been restricted to 2D systems. The aromaticity in 3D π-conjugated molecules has been rarely studied. Here we report a fully conjugated diradicaloid molecular cage and its global aromaticity at different oxidation states. The neutral compound has an open-shell singlet ground state with a dominant 38π monocyclic conjugation pathway and follows the [4n + 2] Hückel aromaticity rule; the dication has a triplet ground state with a dominant 36π monocyclic conjugation pathway and satisfies [4n] Baird aromaticity; the tetracation is an open-shell singlet with 52 π-electrons that are delocalized along the 3D rigid framework, showing 3D global antiaromaticity; and the hexacation possesses D3 symmetry with 50 globally delocalized π-electrons, showing [6n + 2] 3D global aromaticity. Different types of aromaticity were therefore accessed in one molecular cage platform, depending on the symmetry, number of π-electrons and spin state.
Collapse
Affiliation(s)
- Yong Ni
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | | | - Hoa Phan
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Taeyeon Kim
- Department of Chemistry, Yonsei University, Seoul, Republic of Korea
| | - Tun Seng Herng
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Yi Han
- Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Tao Tao
- School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, China
| | - Jun Ding
- Department of Materials Science and Engineering, National University of Singapore, Singapore, Singapore
| | - Dongho Kim
- Department of Chemistry, Yonsei University, Seoul, Republic of Korea
| | - Jishan Wu
- Department of Chemistry, National University of Singapore, Singapore, Singapore.
| |
Collapse
|
15
|
Valiev RR, Valiulina LI, Fliegl H, Sundholm D. The effect of anion complexation on the aromatic properties of aromatic and antiaromatic porphyrinoids. NEW J CHEM 2020. [DOI: 10.1039/d0nj04470a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The effect of anion complexation on magnetically induced current densities and excitation energies of antiaromatic molecular rings has been investigated by calculations on expanded antiaromatic porphyrinoids including orangarin, rosarin, amethyrin and on a theoretically predicted strongly antiaromatic hydrocarbon ring.
Collapse
Affiliation(s)
- Rashid R. Valiev
- Department of Chemistry
- Faculty of Science
- University of Helsinki
- Helsinki FIN-00014
- Finland
| | | | - Heike Fliegl
- Karlsruhe Institute of Technology (KIT)
- Institute of Nanotechnology
- Eggenstein-Leopoldshafen
- Germany
| | - Dage Sundholm
- Department of Chemistry
- Faculty of Science
- University of Helsinki
- Helsinki FIN-00014
- Finland
| |
Collapse
|
16
|
Guberman-Pfeffer MJ, Lalisse RF, Hewage N, Brückner C, Gascón JA. Origins of the Electronic Modulations of Bacterio- and Isobacteriodilactone Regioisomers. J Phys Chem A 2019; 123:7470-7485. [PMID: 31361130 DOI: 10.1021/acs.jpca.9b05656] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Advances in the utilization of porphyrinoids for photomedicine, catalysis, and artificial photosynthesis require a fundamental understanding of the relationships between their molecular connectivity and resulting electronic structures. Herein, we analyze how the replacement of two pyrrolic Cβ═Cβ bonds of a porphyrin by two lactone (O═C-O) moieties modulates the ground-state thermodynamic stability and electronic structure of the resulting five possible pyrrole-modified porphyrin isomers. We made these determinations based on density functional theory (DFT) and time-dependent DFT computations of the optical spectra of all regioisomers. We also analyzed the computed magnetically induced currents of their aromatic π-systems. All regioisomers adopt the tautomeric state that maximizes aromaticity, whether or not transannular steric strains are incurred. In all isomers, the O═Cβ-Oβ bonds were found to support a macrocycle diatropic ring current. We attributed this to the delocalization of nonbonding electrons from the ring oxa- and oxo-atoms into the macrocycle. As a consequence of this delocalization, the dilactone regioisomers are as-or even more-aromatic than their hydroporphyrin congeners. The electronic structures follow different trends for the bacteriochlorin- and isobacteriochlorin-type isomers. The presence of either oxo- or oxa-oxygens conjugated with the macrocyclic π-system was found to be the minimal structural requirement for the regioisomers to exhibit distinct electronic properties. Our computational methods and mechanistic insights provide a basis for the systematic exploration of the physicochemical properties of porphyrinoids as a function of the number, relative orientation, and degree of macrocycle-π-conjugation of β-substituents, in general, and for dilactone-based porphyrinic chromophores, in particular.
Collapse
Affiliation(s)
- Matthew J Guberman-Pfeffer
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| | - Remy F Lalisse
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| | - Nisansala Hewage
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| | - Christian Brückner
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| | - José A Gascón
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| |
Collapse
|
17
|
Valiev RR, Hasan G, Salo VT, Kubečka J, Kurten T. Intersystem Crossings Drive Atmospheric Gas-Phase Dimer Formation. J Phys Chem A 2019; 123:6596-6604. [DOI: 10.1021/acs.jpca.9b02559] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Rashid R. Valiev
- Department of Chemistry, University of Helsinki, P.O. Box 55, (A.I. Virtanens Plats 1), Helsinki FIN-00014, Finland
- Tomsk State University, 36, Lenin Avenue, 634050 Tomsk, Russia
| | - Galib Hasan
- Department of Chemistry, University of Helsinki, P.O. Box 55, (A.I. Virtanens Plats 1), Helsinki FIN-00014, Finland
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki 00014, Finland
| | - Vili-Taneli Salo
- Department of Chemistry, University of Helsinki, P.O. Box 55, (A.I. Virtanens Plats 1), Helsinki FIN-00014, Finland
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki 00014, Finland
| | - Jakub Kubečka
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki 00014, Finland
| | - Theo Kurten
- Department of Chemistry, University of Helsinki, P.O. Box 55, (A.I. Virtanens Plats 1), Helsinki FIN-00014, Finland
- Institute for Atmospheric and Earth System Research, University of Helsinki, Helsinki 00014, Finland
| |
Collapse
|
18
|
Fathi-Rasekh M, Rohde GT, Hart MD, Nakakita T, Zatsikha YV, Valiev RR, Barybin MV, Nemykin VN. Positional Isomers of Isocyanoazulenes as Axial Ligands Coordinated to Ruthenium(II) Tetraphenylporphyrin: Fine-Tuning Redox and Optical Profiles. Inorg Chem 2019; 58:9316-9325. [PMID: 31240923 DOI: 10.1021/acs.inorgchem.9b01030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Two isomeric ruthenium(II)/5,10,15,20-tetraphenylporphyrin complexes featuring axially coordinated redox-active, low-optical gap 2- or 6-isocyanoazulene ligands have been isolated and characterized by NMR, UV-vis, and magnetic circular dichroism (MCD) spectroscopic methods, high-resolution mass spectrometry, and single-crystal X-ray crystallography. The UV-vis and MCD spectra support the presence of the low-energy, azulene-centered transitions in the Q band region of the porphyrin chromophore. The first coordination sphere in new L2RuTPP complexes reflects compressed tetragonal geometry. The redox properties of the new compounds were assessed by electrochemical and spectroelectrochemical means and correlated with the electronic structures predicted by density functional theory and CASSCF calculations. Both experimental and theoretical data are consistent with the first two reduction processes involving the axial azulenic ligands, whereas the oxidation profile (in the direction of increasing potential) is exerted by the ruthenium ion, the porphyrin core, and the axial azulenic moieties.
Collapse
Affiliation(s)
- Mahtab Fathi-Rasekh
- Department of Chemistry and Biochemistry , University of Minnesota Duluth , 1039 University Drive , Duluth , Minnesota 55812 , United States
| | | | - Mason D Hart
- Department of Chemistry , University of Kansas , 1567 Irving Hill Road , Lawrence , Kansas 66045 , United States
| | - Toshinori Nakakita
- Department of Chemistry , University of Kansas , 1567 Irving Hill Road , Lawrence , Kansas 66045 , United States
| | - Yuriy V Zatsikha
- Department of Chemistry , University of Manitoba , 144 Dysart Road , Winnipeg , MB R3T 2N2 , Canada
| | - Rashid R Valiev
- Tomsk State University , 36, Lenin Avenue , 634050 Tomsk , Russia.,University of Helsinki , P.O. Box 55, FIN-00014 Helsinki , Finland
| | - Mikhail V Barybin
- Department of Chemistry , University of Kansas , 1567 Irving Hill Road , Lawrence , Kansas 66045 , United States
| | - Victor N Nemykin
- Department of Chemistry and Biochemistry , University of Minnesota Duluth , 1039 University Drive , Duluth , Minnesota 55812 , United States.,Department of Chemistry , University of Manitoba , 144 Dysart Road , Winnipeg , MB R3T 2N2 , Canada
| |
Collapse
|
19
|
Peeks MD, Gong JQ, McLoughlin K, Kobatake T, Haver R, Herz LM, Anderson HL. Aromaticity and Antiaromaticity in the Excited States of Porphyrin Nanorings. J Phys Chem Lett 2019; 10:2017-2022. [PMID: 30951313 PMCID: PMC6488184 DOI: 10.1021/acs.jpclett.9b00623] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 04/05/2019] [Indexed: 06/01/2023]
Abstract
Aromaticity can be a useful concept for predicting the behavior of excited states. Here we show that π-conjugated porphyrin nanorings exhibit size-dependent excited-state global aromaticity and antiaromaticity for rings containing up to eight porphyrin subunits, although they have no significant global aromaticity in their neutral singlet ground states. Applying Baird's rule, even rings ([4 n] π-electrons) are aromatic in their lowest excited states, whereas the lowest excited states of odd rings ([4 n + 2] π-electrons) are antiaromatic. These predictions are borne out by density functional theory (DFT) studies of the nucleus-independent chemical shift (NICS) in the T1 triplet state of each ring, which reveal the critical importance of the triplet delocalization to the emergence of excited-state aromaticity. The singlet excited states (S1) are explored by measurements of the radiative rate and fluorescence peak wavelength, revealing a subtle odd-even alternation as a function of ring size, consistent with symmetry breaking in antiaromatic excited states.
Collapse
Affiliation(s)
- Martin D. Peeks
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Juliane Q. Gong
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
| | - Kirstie McLoughlin
- Department
of Zoology, University of Oxford, Oxford OX1 3SZ, United Kingdom
| | - Takayuki Kobatake
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Renée Haver
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Laura M. Herz
- Department
of Physics, Clarendon Laboratory, University
of Oxford, Parks Road, Oxford OX1
3PU, United Kingdom
| | - Harry L. Anderson
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| |
Collapse
|
20
|
Valiev RR, Drozdova AK, Petunin PV, Postnikov PS, Trusova ME, Cherepanov VN, Sundholm D. The aromaticity of verdazyl radicals and their closed-shell charged species. NEW J CHEM 2018. [DOI: 10.1039/c8nj04341h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The aromaticity of fourteen 3-oxo-verdazyl (1–8) and Kuhn verdazyl (9–14) radicals with different substituents has been investigated computationally using the gauge-including magnetically induced current-density (GIMIC) method.
Collapse
Affiliation(s)
- Rashid R. Valiev
- Tomsk State University
- Tomsk
- Russian Federation
- Department of Chemistry
- University of Helsinki
| | | | - Pavel V. Petunin
- Tomsk Polytechnic University
- Tomsk 634050
- Russian Federation
- Siberian State Medical University
- Tomsk 634050
| | - Pavel S. Postnikov
- Tomsk Polytechnic University
- Tomsk 634050
- Russian Federation
- Department of Solid State Engineering, University of Chemistry and Technology
- Prague
| | | | | | - Dage Sundholm
- Department of Chemistry
- University of Helsinki
- Helsinki FIN-00014
- Finland
| |
Collapse
|