51
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Đorđević S, Solà M, Radenković S. Aromaticity of Singlet and Triplet Boron Disk-like Clusters: A Test for Electron Counting Aromaticity Rules. Inorg Chem 2022; 61:10116-10125. [PMID: 35737864 DOI: 10.1021/acs.inorgchem.2c01197] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Boron clusters are polyhedral boron-containing structures that have unique features and properties. The disk-like boron clusters are among the most fascinating boron cluster forms. These clusters have a molecular orbital (MO) distribution similar to the one derived from the simple particle-on-a-disk model. In this model, the MOs come in pairs except for m = 0. Disk-like boron clusters in their singlet ground state are aromatic when they reach a closed-shell structure. One could expect that disk-like aromatic boron clusters in the singlet state, when acquiring or releasing two electrons, may also be aromatic in the lowest-lying triplet state. We use magnetically induced current densities and bond current strengths to analyze the aromatic character of a series of disk-like boron clusters. Our results show that, with the exception of triplet 3B19-, the disk-like boron clusters follow Hückel and Baird's rules if one considers the different MOs grouped by their symmetry. We also found that if the lowest-lying triplet state in disk-like boron clusters is aromatic, this triplet state is the ground state for this species.
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Affiliation(s)
- Slađana Đorđević
- Faculty of Science, University of Kragujevac, P.O. Box 60, Kragujevac 34000, Serbia
| | - Miquel Solà
- Institute of Computational Chemistry and Catalysis and Department of Chemistry, University of Girona, C/M. Aurèlia Capmany, 69, Girona 17003, Catalonia, Spain
| | - Slavko Radenković
- Faculty of Science, University of Kragujevac, P.O. Box 60, Kragujevac 34000, Serbia
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52
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Pemberton MJ, Irons TJP, Helgaker T, Teale AM. Revealing the exotic structure of molecules in strong magnetic fields. J Chem Phys 2022; 156:204113. [DOI: 10.1063/5.0092520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A novel implementation for the calculation of molecular gradients under strong magnetic fields is employed at the current-density functional theory level to optimize the geometries of molecular structures, which change significantly under these conditions. An analog of the ab initio random structure search is utilized to determine the ground-state equilibrium geometries for He n and CH n systems at high magnetic field strengths, revealing the most stable structures to be those in high-spin states with a planar geometry aligned perpendicular to the field. The electron and current densities for these systems have also been investigated to develop an explanation of chemical bonding in the strong field regime, providing an insight into the exotic chemistry present in these extreme environments.
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Affiliation(s)
- Miles J. Pemberton
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Tom J. P. Irons
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Trygve Helgaker
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, Oslo N-0315, Norway
| | - Andrew M. Teale
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
- Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, Oslo N-0315, Norway
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53
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Baryshnikov GV, Valiev RR, Valiulina LI, Kurtsevich AE, Kurtén T, Sundholm D, Pittelkow M, Zhang J, Ågren H. Odd-Number Cyclo[ n]Carbons Sustaining Alternating Aromaticity. J Phys Chem A 2022; 126:2445-2452. [PMID: 35420813 PMCID: PMC9059118 DOI: 10.1021/acs.jpca.1c08507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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Cyclo[n]carbons (n = 5, 7, 9,
..., 29) composed from an odd number of carbon atoms are studied computationally
at density functional theory (DFT) and ab initio complete
active space self-consistent field (CASSCF) levels of theory to get
insight into their electronic structure and aromaticity. DFT calculations
predict a strongly delocalized carbene structure of the cyclo[n]carbons and an aromatic character for all of them. In
contrast, calculations at the CASSCF level yield geometrically bent
and electronically localized carbene structures leading to an alternating
double aromaticity of the odd-number cyclo[n]carbons.
CASSCF calculations yield a singlet electronic ground state for the
studied cyclo[n]carbons except for C25, whereas at the DFT level the energy difference between the lowest
singlet and triplet states depends on the employed functional. The
BHandHLYP functional predicts a triplet ground state of the larger
odd-number cyclo[n]carbons starting from n = 13. Current-density calculations at the BHandHLYP level
using the CASSCF-optimized molecular structures show that there is
a through-space delocalization in the cyclo[n]carbons.
The current density avoids the carbene carbon atom, leading to an
alternating double aromaticity of the odd-number cyclo[n]carbons satisfying the antiaromatic [4k+1] and aromatic [4k+3] rules.
C11, C15, and C19 are aromatic and
can be prioritized in future synthesis. We predict a bond-shift phenomenon
for the triplet state of the cyclo[n]carbons leading
to resonance structures that have different reactivity toward dimerization.
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Affiliation(s)
- Glib V Baryshnikov
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, Henan, P. R. China.,Laboratory of Organic Electronics, Department of Science and Technology, Linköping University, Norrköping SE-60174, Sweden
| | - Rashid R Valiev
- Department of Chemistry, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Lenara I Valiulina
- Department of Optics and Spectroscopy, Tomsk State University, Tomsk 634050, Russia
| | | | - Theo Kurtén
- Department of Chemistry, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Dage Sundholm
- Department of Chemistry, Faculty of Science, University of Helsinki, FIN-00014 Helsinki, Finland
| | - Michael Pittelkow
- Department of Chemistry, University of Copenhagen, Copenhagen Ø DK-2100, Denmark
| | - Jinglai Zhang
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, Henan, P. R. China
| | - Hans Ågren
- College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, Henan, P. R. China.,Department of Physics and Astronomy, Uppsala University, Uppsala SE-75120, Sweden
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54
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Mondal H, Patra SG, Chattaraj PK. Small molecule activation and dehydrogenation of an amine–borane system using frustrated Lewis pairs. Struct Chem 2022. [DOI: 10.1007/s11224-022-01934-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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55
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Merino-García MDR, Soriano-Agueda LA, Guzmán-Hernández JDD, Martínez-Otero D, Landeros Rivera B, Cortés-Guzmán F, Barquera-Lozada JE, Jancik V. Benzene and Borazine, so Different, yet so Similar: Insight from Experimental Charge Density Analysis. Inorg Chem 2022; 61:6785-6798. [PMID: 35472275 DOI: 10.1021/acs.inorgchem.1c03923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although benzene and borazine are isoelectronic and isostructural, they have very different electronic structures, mainly due to the polar nature of the B-N bond. Herein, we present an experimental study of the charge density distribution obtained from the multipole model formalism and Hirshfeld atom refinement (HAR) based on high-resolution X-ray diffraction data of borazine B3N3H6 (1) and B,B',B″-trichloroborazine (2) crystals. These data are compared to those obtained from HAR for benzene (4) and 1,3,5-trichlorobenzene (5) and further compared with values obtained from density functional theory calculations in the gas phase, where N,N',N″-trichloroborazine (3) was also included. The results confirm that, unlike benzene, borazines are only weakly aromatic with an island-like electronic delocalization within the B3N3 ring involving only the nitrogen atoms. Furthermore, delocalization indices and interacting quantum atom energy for bonded and non-bonded atoms were found to be highly suitable indicators capable of describing the origin of the discrepancies observed when the degree of aromaticity in 2 and 3 is evaluated using common aromaticity indices. Additionally, analysis of intermolecular interactions in the crystals brings further evidence of a weakly aromatic character of the borazines as it reveals surprising similarities between the crystal packing of borazine and benzene and also between B,B',B″-trichloroborazine and 1,3,5-trichlorobenzene.
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Affiliation(s)
- María Del Rosario Merino-García
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, km. 14.5, Toluca, Estado de México C.P. 50200, México
| | - Luis Antonio Soriano-Agueda
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Circuito Exterior s/n, Ciudad de México 04510, México
| | - Juan de Dios Guzmán-Hernández
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, km. 14.5, Toluca, Estado de México C.P. 50200, México
| | - Diego Martínez-Otero
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, km. 14.5, Toluca, Estado de México C.P. 50200, México.,Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Circuito Exterior s/n, Ciudad de México 04510, México
| | - Bruno Landeros Rivera
- CNRS, Laboratoire de Chimie Théorique, LCT, Sorbonne Université, Paris 75005, France
| | - Fernando Cortés-Guzmán
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, km. 14.5, Toluca, Estado de México C.P. 50200, México.,Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Circuito Exterior s/n, Ciudad de México 04510, México
| | - José Enrique Barquera-Lozada
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Circuito Exterior s/n, Ciudad de México 04510, México
| | - Vojtech Jancik
- Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM, Carretera Toluca-Atlacomulco, km. 14.5, Toluca, Estado de México C.P. 50200, México.,Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, Circuito Exterior s/n, Ciudad de México 04510, México
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56
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Xu HL, Tkachenko NV, Szczepanik DW, Popov IA, Muñoz-Castro A, Boldyrev AI, Sun ZM. Symmetry collapse due to the presence of multiple local aromaticity in Ge 244. Nat Commun 2022; 13:2149. [PMID: 35444180 PMCID: PMC9021308 DOI: 10.1038/s41467-022-29626-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 03/15/2022] [Indexed: 11/09/2022] Open
Abstract
Understanding the structural changes taking place during the assembly of single atoms leading to the formation of atomic clusters and bulk materials remains challenging. The isolation and theoretical characterization of medium-sized clusters can shed light on the processes that occur during the transition to a solid-state structure. In this work, we synthesize and isolate a continuous 24-atom cluster Ge244−, which is characterized by X-ray diffraction analysis and Energy-dispersive X-ray spectroscopy, showing an elongated structural characteristic. Theoretical analysis reveals that electron delocalization plays a vital role in the formation and stabilization of the prolate cluster. In contrast with carbon atoms, 4 s orbitals of Ge-atoms do not easily hybridize with 4p orbitals and s-type lone-pairs can be localized with high occupancy. Thus, there are not enough electrons to form a stable symmetrical fullerene-like structure such as C24 fullerene. Three aromatic units with two [Ge9] and one [Ge6] species, connected by classical 2c-2e Ge-Ge σ-bonds, are aligned together forming three independent shielding cones and eventually causing a collapse of the global symmetry of the Ge244− cluster. Gaining insight on the structural transformations from atomic clusters to bulk materials is challenging. Here the authors synthesize a continuous cluster of germanium Ge244−, which can be viewed as two terminal Ge9 units bridged via a Ge6 central fragment, and characterize it by several techniques including X-ray diffraction; theoretical analysis indicates the presence of three aligned independent aromatic fragments.
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Affiliation(s)
- Hong-Lei Xu
- State Key Laboratory of Elemento-Organic Chemistry, Tianjin Key Lab of Rare Earth Materials and Applications, School of Materials Science and Engineering, Nankai University, Tianjin, China
| | - Nikolay V Tkachenko
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA
| | - Dariusz W Szczepanik
- Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, Kraków, Poland
| | - Ivan A Popov
- Department of Chemistry, The University of Akron, Akron, OH, USA
| | - Alvaro Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares, Facultad de Ingeniería, Universidad Autonoma de Chile, El Llano Subercaseaux, Santiago, Chile
| | - Alexander I Boldyrev
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT, USA.
| | - Zhong-Ming Sun
- State Key Laboratory of Elemento-Organic Chemistry, Tianjin Key Lab of Rare Earth Materials and Applications, School of Materials Science and Engineering, Nankai University, Tianjin, China.
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57
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Radenković S, Tomović Ž. Tuning the structure and properties of N-doped positively charged polycyclic aromatic hydrocarbons. Chemphyschem 2022; 23:e202200125. [PMID: 35404503 DOI: 10.1002/cphc.202200125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/07/2022] [Indexed: 11/11/2022]
Abstract
A detailed study of the geometry, aromatic character, electronic and magnetic properties for a series of positively charged N-doped PAHs was performed. Magnetic properties of the examined molecules were analyzed by means of the magnetically induced current density calculated using the diamagnetic-zero version of the continuous transformation of origin of current density (CTOCD-DZ) method. The comparative study of the local aromaticity of the studied molecules was performed using several different indices: energy effect (ef), harmonic oscillator model of aromaticity (HOMA) index, six centre delocalization index (SCI) and nucleus independent chemical shifts (NICS). The presence of N-atoms in the inner rings was found to cause a planarity distortion in the studied N-doped systems. The geometric changes and charged nature of the studied N-doped systems do not significantly influence the current density and the local aromaticity distribution in comparison with the corresponding parent benzenoid hydrocarbons. The present study demonstrates how quantum chemical calculations can be used for rational design of novel PAHs and fine tuning of their properties.
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Affiliation(s)
- Slavko Radenković
- University of Kragujevac: Univerzitet u Kragujevcu, Department of Chemistry, 12 Radoja Domanovića, P.O. Box 60, 34000, Kragujevac, SERBIA
| | - Željko Tomović
- Eindhoven University of Technology: Technische Universiteit Eindhoven, Department of Chemical Engineering & Chemistry and Institute for Complex Molecular Systems, NETHERLANDS
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58
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Yang Y, Helili S, Kerim A. A study of the aromaticity of thia[7]circulene isomers. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2060146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Yang Yang
- College of Chemistry, Xinjiang University, Urumqi, People’s Republic of China
| | - Satewaerdi Helili
- School of Chemical Engineering and Technology, Xinjiang University, Urumqi, People’s Republic of China
| | - Ablikim Kerim
- School of Chemical Engineering and Technology, Xinjiang University, Urumqi, People’s Republic of China
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59
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Mahmood A, Dimitrova M, Wirz LN, Sundholm D. Magnetically Induced Current Densities in Zinc Porphyrin Nanoshells. J Phys Chem A 2022; 126:1936-1945. [PMID: 35302768 PMCID: PMC8978182 DOI: 10.1021/acs.jpca.1c10815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/08/2022] [Indexed: 12/21/2022]
Abstract
The molecular structures of porphyrinoid cages were obtained by constructing small polyhedral graphs whose vertices have degree-4. The initial structures were then fully optimized at the density functional theory (DFT) level using the generalized gradient approximation. Some of polyhedral vertices were replaced with Zn-porphyrin units and their edges were replaced with ethyne or butadiyne bridges or connected by fusing two neighboring Zn-porphyrin units. Molecule 1 is an ethyne-bridge porphyrinoid nanotube, whose ends are sealed with a Zn-porphyrin. Molecule 2 is the corresponding open porphyrinoid nanotube. Molecule 3 is a clam-like porphyrinoid cage, whose shells consist of fused Zn-porphyrins, and the two halves are connected via butadiyne bridges. Molecule 4 is a cross-belt of fused Zn-porphyrins, and molecule 5 is a cross-belt of Zn-porphyrins connected with butadiyne bridges. The magnetically induced current density of the optimized porphyrinoid cages was calculated for determining the aromatic character, the degree of aromaticity and the current-density pathways. The current-density calculations were performed at the DFT level with the gauge─including magnetically induced currents (GIMIC) method using the B3LYP hybrid functional and def2-SVP basis sets. Calculations of the current densities show that molecule 2 sustains a paratropic ring current around the nanotube, whereas sealing the ends as in molecule 1 leads to an almost nonaromatic nanotube. Fusing porphyrinoids as in molecules 3 and 4 results in complicated current-density pathways that differ from the ones usually appearing in porphyrinoids. The aromatic character of molecules 4 and 5 changes upon oxidation. The neutral molecule 4 is antiaromatic, whereas the dication is nonaromatic. Molecule 5 is nonaromatic, and its dication is aromatic.
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Affiliation(s)
- Atif Mahmood
- Department of Chemistry, University
of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland
| | - Maria Dimitrova
- Department of Chemistry, University
of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland
| | - Lukas N. Wirz
- Department of Chemistry, University
of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland
| | - Dage Sundholm
- Department of Chemistry, University
of Helsinki, P.O. Box 55, A. I. Virtasen aukio 1, FIN-00014 Helsinki, Finland
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60
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Summa FF, Monaco G, Zanasi R, Lazzeretti P. Origin Independent Current Density Vector Fields Induced by Time-Dependent Magnetic Field. I. The LiH molecule. J Chem Phys 2022; 156:154105. [DOI: 10.1063/5.0089605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The electronic current density, induced in a molecule by the optical magnetic field associated to a frequency dependent monochromatic plane wave, assumed to be spatially uniform within the electric quadrupole approximation, has been studied by a theoretical method based on continuous translation of its origin. The induced electronic current density vector field designated by this procedure, invariant of the origin for any point of the molecular domain, is obtained via a computational scheme formally annihilating the diamagnetic contribution of the conventional common-origin approach based on perturbation theory. In a preliminary application of the theoretical methods outlined in the present work, the simple molecule of lithium hydride has been investigated. Particular attention has been paid to the structure of induced electronic current density for several values of the magnetic field frequency, by investigating equilibrium points of four different types, organized in stagnation lines which constitute its stagnation graph, i.e., a topological fingerprint of the vector field conveying complete information in condensed form, to verify the fulfillment of fundamental requirements, e.g., the continuity equation and the Poincaré-Hopf theorem on spherical and toroidal surfaces.
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Affiliation(s)
| | - Guglielmo Monaco
- Dipartimento di Chimica, Università degli Studi di Salerno Dipartimento di Chimica e Biologia, Italy
| | - Riccardo Zanasi
- Chemistry and Biology, University of Salerno Department of Chemistry and Biology, Italy
| | - Paolo Lazzeretti
- University of Salerno Department of Chemistry and Biology, Italy
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61
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Pyykkö P, Taubert S. Saturnenes
Like Th@Au
6
D
6h
: Ring‐Current Evidence for Au−Au Bonding Along the Gold Ring. Isr J Chem 2022. [DOI: 10.1002/ijch.202100139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Pekka Pyykkö
- Department of Chemistry University of Helsinki P.O.B. 55 00014 Helsinki Finland
| | - Stefan Taubert
- Department of Chemistry University of Helsinki P.O.B. 55 00014 Helsinki Finland
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62
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Persistent Planar Tetracoordinate Carbon in Global Minima Structures of Silicon-Carbon Clusters. ATOMS 2022. [DOI: 10.3390/atoms10010027] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Recently, we reported a series of global minima whose structures consist of carbon rings decorated with heavier group 14 elements. Interestingly, these structures feature planar tetracoordinate carbons (ptCs) and result from the replacement of five or six protons (H+) from the cyclopentadienyl anion (C5H5−) or the pentalene dianion (C8H62−) by three or four E2+ dications (E = Si–Pb), respectively. The silicon derivatives of these series are the Si3C5 and Si4C8 clusters. Here we show that ptC persists in some clusters with an equivalent number of C and Si atoms, i.e., Si5C5, Si8C8, and Si9C9. In all these species, the ptC is embedded in a pentagonal C5 ring and participates in a three-center, two-electron (3c-2e) Si-ptC-Si σ-bond. Furthermore, these clusters are π-aromatic species according to chemical bonding analysis and magnetic criteria.
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63
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Hao F, Zhang T, Yu D, Yang X, Jiang HW, Xiao JC, Chen QY. Porphyriynes: 18-π-Conjugated Macrocycles Incorporating a Triple Bond. Org Lett 2022; 24:1716-1721. [PMID: 35199515 DOI: 10.1021/acs.orglett.2c00356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tetraphenylporphyriyne (Pyne1), a novel porphyrin analogue with a C≡C bond incorporated into an 18-π-conjugated system, has been created via cleavage of the N-confused pyrrolic ring in Ag(III) N-confused tetraphenylporphyrin. The structure of Pyne1 was confirmed by X-ray crystallography and 1H NMR, IR, and UV-vis spectroscopy. The mechanism of cleavage of the N-confused pyrrolic ring was investigated by theoretical calculations. The successful synthesis of other Pynes indicated the generality of this protocol.
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Affiliation(s)
- Fei Hao
- Shandong Provincial Key Laboratory of Molecular Engineering, Qilu University of Technology-Shandong Academy of Science, Ji'nan 250353, China.,Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Tian Zhang
- Shandong Provincial Key Laboratory of Molecular Engineering, Qilu University of Technology-Shandong Academy of Science, Ji'nan 250353, China
| | - Donghai Yu
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Xiaodeng Yang
- Shandong Provincial Key Laboratory of Molecular Engineering, Qilu University of Technology-Shandong Academy of Science, Ji'nan 250353, China
| | - Hua-Wei Jiang
- School of Chemistry, South China Normal University, Guangzhou 510006, China
| | - Ji-Chang Xiao
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Qing-Yun Chen
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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64
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Radenković S, Đorđević S. Spatial and electronic structures of BeB8 and MgB8. How far the analogy goes? Chemphyschem 2022; 23:e202200070. [PMID: 35188320 DOI: 10.1002/cphc.202200070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/18/2022] [Indexed: 11/09/2022]
Abstract
Doping of boron clusters with Be and its heavier alkaline-earth congener, Mg usually leads to complexes of different geometry and electronic structure. In this work we showed that both neutral BeB 8 and MgB 8 exhibit a singlet ground state umbrella-like form. In addition, the stability, electronic structure, and aromaticity of the target molecules were compared. The magnetically induced current densities showed that BeB 8 and MgB 8 are double aromatic systems: π and σ electrons induce strong diatropic currents. The current densities induced in the studied complexes are of very similar intensity, but with a different spatial distribution. The found differences between the current density patterns in BeB 8 and MgB 8 arise from the very nature of the bonding interactions between the M atom and B 8 fragment, as demonstrated through the energy decomposition analysis (EDA).
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Affiliation(s)
- Slavko Radenković
- University of Kragujevac: Univerzitet u Kragujevcu, Department of Chemistry, 12 Radoja Domanovića, P.O. Box 60, 34000, Kragujevac, SERBIA
| | - Slađana Đorđević
- University of Kragujevac: Univerzitet u Kragujevcu, Department of Chemistry, SERBIA
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65
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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.
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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
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66
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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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67
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Wang Y, Sun Y, Bai W, Zhou Y, Bao X, Li Y. Synthesis, structure and aromaticity of metallapyridinium complexes. Dalton Trans 2022; 51:2876-2882. [PMID: 35099489 DOI: 10.1039/d1dt04096k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The first rhena-analogues of pyridinium (cyclopropametalla-2-isoquinolinium complexes) are obtained from o-ethynyl benzonitriles. Structural analysis and DFT calculations confirm their aromatic nature. Compared to rhenapyrylium, rhenapyridinium has a slightly stronger Hückel π-aromaticity, while a chlorine substituent on the rhenapyridinium ring decreases its aromaticity, which is revealed by NICS, EDDB, MCI and ΔBV(ELFπ) analysis.
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Affiliation(s)
- Yilun Wang
- State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Liaoning 116024, P.R. China. .,School of Chemical Engineering, Dalian University of Technology, Panjin, Liaoning 124221, P.R. China
| | - Yue Sun
- State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Liaoning 116024, P.R. China.
| | - Wei Bai
- State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Liaoning 116024, P.R. China.
| | - Yan Zhou
- School of Chemistry and Chemical Engineering, Guangxi University for Nationalities, Guangxi Key Laboratory of Chemistry and Engineering of Forest Products, Key Laboratory of Guangxi Colleges and Universities for Food Safety and Pharmaceutical Analytical Chemistry, Nanning, 530008, P.R. China
| | - Xiao Bao
- State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Liaoning 116024, P.R. China.
| | - Yang Li
- State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Liaoning 116024, P.R. China. .,School of Chemical Engineering, Dalian University of Technology, Panjin, Liaoning 124221, P.R. China
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68
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Wang ZL, Chen TT, Chen WJ, Li WL, Zhao J, Jiang XL, Li J, Wang LS, Hu HS. The smallest 4f-metalla-aromatic molecule of cyclo-PrB 2− with Pr–B multiple bonds. Chem Sci 2022; 13:10082-10094. [PMID: 36128247 PMCID: PMC9430590 DOI: 10.1039/d2sc02852b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 07/18/2022] [Indexed: 11/25/2022] Open
Abstract
The concept of metalla-aromaticity proposed by Thorn–Hoffmann (Nouv. J. Chim. 1979, 3, 39) has been expanded to organometallic molecules of transition metals that have more than one independent electron-delocalized system. Lanthanides, with highly contracted 4f atomic orbitals, are rarely found in multiply aromatic systems. Here we report the discovery of a doubly aromatic triatomic lanthanide-boron molecule PrB2− based on a joint photoelectron spectroscopy and quantum chemical investigation. Global minimum structural searches reveal that PrB2− has a C2v triangular structure with a paramagnetic triplet 3B2 electronic ground state, which can be viewed as featuring a trivalent Pr(III,f2) and B24−. Chemical bonding analyses show that this cyclo-PrB2− species is the smallest 4f-metalla-aromatic system exhibiting σ and π double aromaticity and multiple Pr–B bonding characters. It also sheds light on the formation of the rare B24− tetraanion by the high-lying 5d orbitals of the 4f-elements, completing the isoelectronic B24−, C22−, N2, and O22+ series. We report the smallest 4f-metalla-aromatic molecule of PrB2− exhibiting σ and π double aromaticity and multiple Pr–B bond characters.![]()
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Affiliation(s)
- Zhen-Ling Wang
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084, China
| | - Teng-Teng Chen
- Department of Chemistry, Brown University, Providence 02912, Rhode Island, USA
| | - Wei-Jia Chen
- Department of Chemistry, Brown University, Providence 02912, Rhode Island, USA
| | - Wan-Lu Li
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084, China
| | - Jing Zhao
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084, China
| | - Xue-Lian Jiang
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jun Li
- Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055, China
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence 02912, Rhode Island, USA
| | - Han-Shi Hu
- Department of Chemistry & Key Laboratory of Organic Optoelectronics and Molecular Engineering of the Ministry of Education, Tsinghua University, Beijing, 100084, China
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69
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Buendia Zamudio F, Pham HT, Barquera-Lozada JE, Beltran MR, Nguyen MT. Formation of the quasi-planar B 56 boron cluster: topological path from B 12 and disk aromaticity. Phys Chem Chem Phys 2022; 24:21822-21832. [DOI: 10.1039/d2cp02571j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Formation and stability of the B56 boron cluster were investigated using a topological approach and the disk aromaticity model. An extensive global energy minimum search for the B56 system which...
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70
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McGrady JE, Weigend F, Dehnen S. Electronic structure and bonding in endohedral Zintl clusters. Chem Soc Rev 2021; 51:628-649. [PMID: 34931207 DOI: 10.1039/d1cs00775k] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Endohedral Zintl clusters-multi-metallic anionic molecules in which a d-block or f-block metal atom is enclosed by p-block (semi)metal atoms-are very topical in contemporary inorganic chemistry. Not only do they provide insight into the embryonic states of intermetallic compounds and show promise in catalytic applications, they also shed light on the nature of chemical bonding between metal atoms. Over the past two decades, a plethora of endohedral Zintl clusters have been synthesized, revealing a fascinating diversity of molecular architectures. Many different perspectives on the bonding in them have emerged in the literature, sometimes complementary and sometimes conflicting, and there has been no concerted effort to classify the entire family based on a small number of unifying principles. A closer look, however, reveals distinct patterns in structure and bonding that reflect the extent to which valence electrons are shared between the endohedral atom and the cluster shell. We show that there is a much more uniform relationship between the total valence electron count and the structure and bonding patterns of these clusters than previously anticipated. All of the p-block (semi)metal shells can be placed on a ladder of total valence electron count that ranges between 4n+2 (closo deltahedra), 5n (closed, three-bonded polyhedra) and 6n (crown-like structures). Although some structural isomerism can occur for a given electron count, the presence of a central metal cation imposes a preference for rather regular and approximately spherical structures which maximise electrostatic interactions between the metal and the shell. In cases where the endohedral metal has relatively accessible valence electrons (from the d or f shells), it can also contribute its valence electrons to the total electron count of the cluster shell, raising the effective electron count and often altering the structural preferences. The electronic situation in any given cluster is considered from different perspectives, some more physical and some more chemical, in a way that highlights the important point that, in the end, they explain the same situation. This article provides a unifying perspective of bonding that captures the structural diversity across this diverse family of multimetallic clusters.
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Affiliation(s)
- John E McGrady
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OX1 3QZ, UK.
| | - Florian Weigend
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften, Philipps University Marburg, Hans-Meerwein-Straße 4, 35043 Marburg, Germany.
| | - Stefanie Dehnen
- Fachbereich Chemie and Wissenschaftliches Zentrum für Materialwissenschaften, Philipps University Marburg, Hans-Meerwein-Straße 4, 35043 Marburg, Germany.
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71
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Baron T, Zarate X, Hidalgo-Rosa Y, Zambrano-Angulo M, Mall-Haidaraly K, Pino-Rios R, Pellegrin Y, Odobel F, Cárdenas-Jirón G. Zinc phthalocyanine absorbance in the near-infrared with application for transparent and colorless dye-sensitized solar cells. CR CHIM 2021. [DOI: 10.5802/crchim.113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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72
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Abstract
The aromaticity of [n]starphenes (n = 1, 4, 7, 10, 13, 16), as well as starphene-based [19]dendriphene, is addressed by calculating the magnetically induced current density and the induced magnetic field, using the pseudo-π model. When an external magnetic field is applied, these systems create diatropic currents that split into a global peripheral current surrounding the starphene skeleton and several local currents in the acene-based arms, resulting in large shielding cones above the arms. In particular, the arm currents are smaller than their linear analogs, and in general, the strengths of the ring currents tend to weaken as the starphene get larger.
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73
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Guzmán‐Espinoza CV, Ledesma‐Olvera LG, Barquera‐Lozada JE. Effect of Spectator Ligands on Haptotropic Rearrangements of Metal‐Azulene Complexes. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100669] [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)
- Carlos Víctor Guzmán‐Espinoza
- Instituto de Química Universidad Nacional Autónoma de México Circuito Exterior s/n, Ciudad Universitaria, Cd. Mx. 04510 México
| | - Lydia Gabriela Ledesma‐Olvera
- Instituto de Química Universidad Nacional Autónoma de México Circuito Exterior s/n, Ciudad Universitaria, Cd. Mx. 04510 México
| | - José Enrique Barquera‐Lozada
- Instituto de Química Universidad Nacional Autónoma de México Circuito Exterior s/n, Ciudad Universitaria, Cd. Mx. 04510 México
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74
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Gillhuber S, Franzke YJ, Weigend F. Paramagnetic NMR Shielding Tensors and Ring Currents: Efficient Implementation and Application to Heavy Element Compounds. J Phys Chem A 2021; 125:9707-9723. [PMID: 34723533 DOI: 10.1021/acs.jpca.1c07793] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present an efficient implementation of paramagnetic NMR shielding tensors and shifts in a nonrelativistic and scalar-relativistic density functional theory framework. For the latter, we make use of the scalar exact two-component Hamiltonian in its local approximation, and generally we apply the well established (multipole-accelerated) resolution of the identity approximation and the seminumerical exchange approximation. The perturbed density matrix of a paramagnetic NMR shielding calculation is further used to study the magnetically induced current density and ring currents of open-shell systems as illustrated for [U@Bi12]3-. [U@Bi12]3- features delocalized highest occupied molecular orbitals and sustains a net diatropic ring current of ca. 18 nA/T through the Bi12 torus similar to the all-metal aromatic heavy-element cluster [Th@Bi12]4-.
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Affiliation(s)
- Sebastian Gillhuber
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Yannick J Franzke
- Fachbereich Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany
| | - Florian Weigend
- Fachbereich Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany
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75
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Abstract
Even though metallacyclopentadienes (MCPs) are among the most common metallacycles, their electron delocalization (aromaticity) has received far less attention than other metallacycles, such as metallabenzenes. We systematically studied the aromaticity of MCPs with energetic (isomerization stabilization energy), density (delocalization index) and magnetic (current density) aromaticity indices. The indices agree that metallacyclopentadienes are, in general, weakly aromatic at most. The 18e− complexes showed the expected weak aromaticity, and only the d8 molecules are somewhat anti-aromatic. However, the theoretical account of the aromaticity of the 16e− MCPs is more convoluted. We find that the aromatic criteria for a 16e−d4 ruthenacyclopentadiene disagree. The lack of agreement shows that significant electron delocalization is not always related to great stability or to strong diatropic currents.
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76
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Zhao D, He X, Li M, Wang B, Guo C, Rong C, Chattaraj PK, Liu S. Density functional theory studies of boron clusters with exotic properties in bonding, aromaticity and reactivity. Phys Chem Chem Phys 2021; 23:24118-24124. [PMID: 34730137 DOI: 10.1039/d1cp02516c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atomic clusters are unique in many perspectives because of their size and structure features and are continuously being applied for different purposes. To unveil their unconventional properties, in this work, using neutral tetraboron clusters as illustrative examples, we study their exotic behaviors in bonding, aromaticity, and reactivity. We show that both double and triple bonds can be formed, ring current patterns can be totally different, and both electrophilic and nucleophilic reactivities can coexist simultaneously. These features are often in contrast with our conventional chemical wisdom and could enrich the possibility for their potential applications. The methodologies employed in this work can be readily applied to other systems. Our studies should help us better appreciate atomic clusters with many atypical properties and henceforth yield novel applications.
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Affiliation(s)
- Dongbo Zhao
- Institute of Biomedical Research, Yunnan University, Chenggong District, Kunming 650500, Yunnan, P. R. China.
| | - Xin He
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, Changsha, Hunan 410081, P. R. China.
| | - Meng Li
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, Changsha, Hunan 410081, P. R. China.
| | - Bin Wang
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, Changsha, Hunan 410081, P. R. China.
| | - Chunna Guo
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, Changsha, Hunan 410081, P. R. China.
| | - Chunying Rong
- Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education of China), Hunan Normal University, Changsha, Hunan 410081, P. R. China.
| | - Pratim K Chattaraj
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
| | - Shubin Liu
- Research Computing Center, University of North Carolina, Chapel Hill, North Carolina 27599-3420, USA. .,Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina, 27599-3290, USA
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77
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Báez-Grez R, Arrué L, Pino-Rios R. Quantitative analysis of aromaticity in azines by means of dissected descriptors based on the magnetic criteria. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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78
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Aysin R, Bukalov S. Four electron aromaticity in η3-Allyltetrylenes Ar-E-η3-Allyl E= Si, Ge, Sn, Pb. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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79
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Analysis of Local and Global Aromaticity in Si3C5 and Si4C8 Clusters. Aromatic Species Containing Planar Tetracoordinate Carbon. CHEMISTRY 2021. [DOI: 10.3390/chemistry3040080] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The minimum energy structures of the Si3C5 and Si4C8 clusters are planar and contain planar tetracoordinate carbons (ptCs). These species have been classified, qualitatively, as global (π) and local (σ) aromatics according to the adaptive natural density partitioning (AdNDP) method, which is an orbital localization method. This work evaluates these species’ aromaticity, focusing on confirming and quantifying their global and local aromatic character. For this purpose, we use an orbital localization method based on the partitioning of the molecular space according to the topology of the electronic localization function (LOC-ELF). In addition, the magnetically induced current density is analyzed. The LOC-ELF-based analysis coincides with the AdNDP study (double aromaticity, global, and local). Moreover, the current density analysis detects global and local ring currents. The strength of the global and local current circuit is significant, involving 4n + 2 π- and σ-electrons, respectively. The latter implicates the Si-ptC-Si fragment, which would be related to the 3c-2e σ-bond detected by the orbital localization methods in this fragment.
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80
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Abstract
Magnetically induced current densities, calculated at the M06-2X/def2-TZVP level using the diamagnetic-zero version of the continuous transformation of origin of current density (CTOCD-DZ) method, were employed to study the aromaticity in Li3B2− and Li4B2. It was found that the Li3/Li4 rings in Li3B2− and Li4B2 remarkably resemble the monocyclic Li3+ and Li42+ clusters. Unlike the parent Li3+ and Li42+ systems that sustain negligibly weak global current density circulation, the Li3B2− and Li4B2 clusters exhibit a strong diatropic current density. The present work demonstrates how structural modifications introduced by the B2 unit can be used for modulating the current density in cyclic Li-based clusters.
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81
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Abstract
A recently developed methodology for calculating, analyzing, and visualizing nuclear magnetic shielding densities is used for studying spatial contributions including ring-current contributions to 1H nuclear magnetic resonance (NMR) chemical shifts of aromatic and anti-aromatic free-base porphyrinoids. Our approach allows a visual inspection of the spatial origin of the positive (shielding) and negative (deshielding) contributions to the nuclear magnetic shielding constants. Diatropic and paratropic current-density fluxes yield both shielding and deshielding contributions implying that not merely the tropicity of the current density determines whether the contribution has a shielding or deshielding character. Instead the shielding or deshielding contribution is determined by the direction of the current-density flux with respect to the studied nucleus.
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82
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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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83
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Topological Analysis of Magnetically Induced Current Densities in Strong Magnetic Fields Using Stagnation Graphs. CHEMISTRY 2021. [DOI: 10.3390/chemistry3030067] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Stagnation graphs provide a useful tool to analyze the main topological features of the often complicated vector field associated with magnetically induced currents. Previously, these graphs have been constructed using response quantities appropriate for modest applied magnetic fields. We present an implementation capable of producing these graphs in arbitrarily strong magnetic fields, using current-density-functional theory. This enables us to study how the topology of the current vector field changes with the strength and orientation of the applied magnetic field. Applications to CH4, C2H2 and C2H4 are presented. In each case, we consider molecular geometries optimized in the presence of the magnetic field. The stagnation graphs reveal subtle changes to this vector field where the symmetry of the molecule remains constant. However, when the electronic state and symmetry of the corresponding equilibrium geometry changes with increasing field strength, the changes to the stagnation graph are extensive. We expect that the approach presented here will be helpful in interpreting changes in molecular structure and bonding in the strong-field regime.
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84
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Ganguly G, Pathak S, Paul A. Unraveling the stability of cyclobutadiene complexes using aromaticity markers. Phys Chem Chem Phys 2021; 23:16005-16012. [PMID: 34235525 DOI: 10.1039/d1cp01467f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cyclobutadiene (CBD) is the paradigmatic antiaromatic molecule but is known to form highly stable aromatic complexes, e.g. CBD-Fe(CO)3. This intriguing reversal of aromaticity from antiaromatic to aromatic terrain during the complexation process cannot be appropriately handled with single-reference-based theoretical techniques. We explore this aromaticity reversal, for the first time, by a detailed aromaticity analysis using magnetically induced current densities (MICD) and nucleus independent chemical shifts (NICS) using genuine ab initio multi-reference wavefunction-based theory. We trace the dramatic change of aromaticity for a prototypical cyclobutadiene complex, CBD-CH+ (CH+Fe(CO)3), considering a 3D potential energy surface for two independent parameters, namely the approach of CH+ and the automerization cross-section of cyclobutadiene. The 3D potential energy surfaces indicate the presence of a conical intersection/avoided crossing between the ground and the first excited state. The plot of aromaticity indices and the corresponding numerical values show that the change of aromaticity indices is drastic around the conical intersection/avoided crossing and automerization of cyclobutadiene plays a crucial role in the formation of cyclobutadiene complexes. Computations on analogous CBD-Be and CBD-CO systems (Be/COFe(CO)3) emphasize the generality of the conclusions drawn from the CBD-CH+ system.
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Affiliation(s)
- Gaurab Ganguly
- School of Chemical Sciences, Indian Association for the Cultivation of Science, 2A & 2B Raja S C Mullick Road, Kolkata 700032, India.
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85
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Yusufujiang A, Kerim A. A study on the aromaticity and ring currents of polycyclic neutral oxocarbon isomers. J PHYS ORG CHEM 2021. [DOI: 10.1002/poc.4271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Ablikim Kerim
- School of Chemical Engineering and Technology Xinjiang University Urumqi Xinjiang China
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86
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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: 33] [Impact Index Per Article: 11.0] [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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87
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Islas R, Arias-Olivares D, Becerra-Buitrago A, García-Sánchez LC, Méndez-Ayón LN, Zuniga-Gutierrez B. Metallaborazines: To Be or Not To Be Delocalized. ACS OMEGA 2021; 6:19629-19641. [PMID: 34368550 PMCID: PMC8340438 DOI: 10.1021/acsomega.1c02257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/13/2021] [Indexed: 06/13/2023]
Abstract
In the current work, the analysis of the electronic delocalization of some metallacycles, based on borazine, was realized by employing magnetic criteria, such as the induced magnetic field and magnetically induced current densities, and electronic criteria, such as adaptative natural density partitioning and the analysis of molecular orbitals. The current metallaborazines were generated from isoelectronic substitutions. The main question is whether the electronic delocalization increases or decreases. The results showed that metal-N bonded borazines could be cataloged as delocalized compounds. On the other hand, the metal-B bonded borazines could be cataloged as nonaromatic (or weak aromatic) compounds based on the results of this analysis.
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Affiliation(s)
- Rafael Islas
- Departamento
de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Avenida República 275, 8370146 Santiago, Chile
| | - David Arias-Olivares
- Departamento
de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Avenida República 275, 8370146 Santiago, Chile
- Center
of Applied Nanoscience (CANS), Facultad de Ciencias Exactas, Universidad Andres Bello, Avenida República 275, 8370146 Santiago, Chile
| | - Andrés Becerra-Buitrago
- Proyecto
Curricular Licenciatura en Química, Universidad Distrital Francisco José de Caldas, Carrera No. 26 B-54, 11021-110231588 Bogotá, Colombia
| | - Luis Carlos García-Sánchez
- Proyecto
Curricular Licenciatura en Química, Universidad Distrital Francisco José de Caldas, Carrera No. 26 B-54, 11021-110231588 Bogotá, Colombia
| | - Lya Neftaly Méndez-Ayón
- Departamento
de Química, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Boulevard Marcelino García
Barragán 1421, C.P. 44430 Guadalajara, Jalisco, Mexico
| | - Bernardo Zuniga-Gutierrez
- Departamento
de Química, Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Boulevard Marcelino García
Barragán 1421, C.P. 44430 Guadalajara, Jalisco, Mexico
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88
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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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89
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Aysin RR, Bukalov SS. Three dimensional aromaticity in pyramidanes C4R4E and Ge4R4Ge. MENDELEEV COMMUNICATIONS 2021. [DOI: 10.1016/j.mencom.2021.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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90
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Muñoz-Castro A. Aromaticity in Phenyl Decorated closo-Monocarboranes. Planar-Spherical Aggregates Involving 7-12-Vertex Cages. J Phys Chem A 2021; 125:4861-4866. [PMID: 34048262 DOI: 10.1021/acs.jpca.1c02934] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The characterized phenyl decorated closo-monocarboranes with variable sizes from 7- to 12-vertex cages, [Ph-closo-CBnHn]-, n = 6-11, allow us to address the role of the varying size and shape of the carborane cage in dual planar-spherical aromatic species. Our results show the formation of adjacent shielding cone characteristics enabled from both planar and spherical aromatic fragments, despite the different structures of the closo-monocarboranes. Under a field perpendicular to the phenyl ring, both shielding cones are enabled, which overlap at long-range regions, in contrast to other orientations leading to a short-range response from the planar aromatic fragment. Thus, a two- or one-aromatic circuit is enabled selectively within the same molecular unit, by controlling the orientation of the external field. Along with the series, a variable extension of the shielding cone from the carborane cage is observed, which is larger for the -CB11H11 case, decreasing toward -CB6H6, denoting a similar extension from both the planar and spherical aromatic regions at the [4-Ph-closo-4-CB8H8]- (4) counterpart. The analysis of such multiple aromatic structures shows that, despite the different sizes and shapes of the closo cages, a similar aromatic behavior remains. In addition, the anisotropy of the induced magnetic field is given graphically, denoting a larger anisotropy for the planar aromatic moiety owing to its two-dimensional structure, which is suggested to discriminate between planar and spherical aromatic fragments within the same molecule.
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Affiliation(s)
- Alvaro Muñoz-Castro
- Grupo de Química Inorgánica y Materiales Moleculares, Facultad de Ingeniería, Universidad Autonoma de Chile, El Llano Subercaseaux 2801 Santiago, Chile
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91
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Aysin RR, Andreev MV, Bogdanov VS, Bukalov SS, Korlyukov AA, Dorovatovskii PV, Burlakov VV. Structure and Conjugation Study of Organometallic [4]Radialenes of Group 4 Metallocenes. Synthesis of Zirconium [4]Radialene. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rinat R. Aysin
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Maxim V. Andreev
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Vyacheslav S. Bogdanov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Sergey S. Bukalov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Alexander A. Korlyukov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
| | - Pavel V. Dorovatovskii
- National Research Center “Kurchatov Institute”, Academician Kurchatov square 1, 123182 Moscow, Russia
| | - Vladimir V. Burlakov
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
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92
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Konishi A, Horii K, Iwasa H, Okada Y, Kishi R, Nakano M, Yasuda M. Characterization of Benzo[a]naphtho[2,3-f]pentalene: Interrelation between Open-shell and Antiaromatic Characters Governed by Mode of the Quinoidal Subunit and Molecular Symmetry. Chem Asian J 2021; 16:1553-1561. [PMID: 33861497 DOI: 10.1002/asia.202100398] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Indexed: 12/18/2022]
Abstract
The singlet open-shell character and antiaromaticity are intriguing features in π-conjugated carbocycles. These two exhibit similar chemical and physical properties. However, they rarely coexist in the same molecule. Understanding the interrelation between the open-shell and antiaromatic characteristics in the same molecule is crucial to control the electronic properties. Herein we describe the synthesis and characterization of a new member of diareno[a,f]pentalene, benzo[a]naphtho[2,3-f]pentalene 6. Unlike its isomer 5 with a closed-shell ground state, 6 exhibits an appreciable open-shell character and a moderate antiaromatic feature. The behaviors of the open-shell index (y0 ) against the difference of the proton chemical signal (Δδ(H1 )) between pentalenide dianions/neutral pentalenes for our reported pentalenes 1, 4, 5, and 6 give a thought-provoking conclusion about the interrelation between open-shell and antiaromatic characteristics in this series. The mode of the incorporated quinoidal moiety and the formal molecular symmetry are critical to balance these two characteristics.
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Affiliation(s)
- Akihito Konishi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka, 565-0871, Japan
| | - Koki Horii
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Haruna Iwasa
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yui Okada
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ryohei Kishi
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Center for Quantum Information and Quantum Biology, Institute for Open and Transdisciplinary Research Initiatives (QIQB-OTRI), Osaka University, Toyonaka, Osaka, 560-8531, Japan
| | - Masayoshi Nakano
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka, 565-0871, Japan.,Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan.,Center for Quantum Information and Quantum Biology, Institute for Open and Transdisciplinary Research Initiatives (QIQB-OTRI), Osaka University, Toyonaka, Osaka, 560-8531, Japan.,Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka, 560-8531, Japan
| | - Makoto Yasuda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka, 565-0871, Japan
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93
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Plasser F, Glöcklhofer F. Visualisation of Chemical Shielding Tensors (VIST) to Elucidate Aromaticity and Antiaromaticity. European J Org Chem 2021; 2021:2529-2539. [PMID: 34248413 PMCID: PMC8251739 DOI: 10.1002/ejoc.202100352] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/01/2021] [Indexed: 01/25/2023]
Abstract
Aromaticity is a central concept in chemistry, pervading areas from biochemistry to materials science. Recently, chemists also started to exploit intricate phenomena such as the interplay of local and global (anti)aromaticity or aromaticity in non-planar systems and three dimensions. These phenomena pose new challenges in terms of our fundamental understanding and the practical visualisation of aromaticity. To overcome these challenges, a method for the visualisation of chemical shielding tensors (VIST) is developed here that allows for a 3D visualisation with quantitative information about the local variations and anisotropy of the chemical shielding. After exemplifying the method in different planar hydrocarbons, we study two non-planar macrocycles to show the unique benefits of the VIST method for molecules with competing π-conjugated systems and conclude with a norcorrole dimer showing clear evidence of through-space aromaticity. We believe that the VIST method will be a highly valuable addition to the computational toolbox.
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Affiliation(s)
- Felix Plasser
- Department of ChemistryLoughborough UniversityLoughboroughLE11 3TUUnited Kingdom
| | - Florian Glöcklhofer
- Department of Chemistry andCentre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUnited Kingdom
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94
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López-Estrada O, Zuniga-Gutierrez B, Selenius E, Malola S, Häkkinen H. Magnetically induced currents and aromaticity in ligand-stabilized Au and AuPt superatoms. Nat Commun 2021; 12:2477. [PMID: 33931646 PMCID: PMC8087673 DOI: 10.1038/s41467-021-22715-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 03/23/2021] [Indexed: 02/02/2023] Open
Abstract
Understanding magnetically induced currents (MICs) in aromatic or metallic nanostructures is crucial for interpreting local magnetic shielding and NMR data. Direct measurements of the induced currents have been successful only in a few planar molecules but their indirect effects are seen in NMR shifts of probe nuclei. Here, we have implemented a numerically efficient method to calculate gauge-including MICs in the formalism of auxiliary density functional theory. We analyze the currents in two experimentally synthesized gold-based, hydrogen-containing ligand-stabilized nanoclusters [HAu9(PPh3)8]2+ and [PtHAu8(PPh3)8]+. Both clusters have a similar octet configuration of Au(6s)-derived delocalized "superatomic" electrons. Surprisingly, Pt-doping in gold increases the diatropic response of the superatomic electrons to an external magnetic field and enhances the aromaticity of [PtHAu8(PPh3)8]+. This is manifested by a stronger shielding of the hydrogen proton in the metal core of the cluster as compared to [HAu9(PPh3)8]2+, causing a significant upfield shift in agreement with experimental proton NMR data measured for these two clusters. Our method allows the determination of local magnetic shielding properties for any component in large 3D nanostructures, opening the door for detailed interpretation of complex NMR spectra.
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Affiliation(s)
- Omar López-Estrada
- grid.9681.60000 0001 1013 7965Department of Physics, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Bernardo Zuniga-Gutierrez
- grid.412890.60000 0001 2158 0196Departamento de Química, Universidad de Guadalajara, CUCEI, Guadalajara, Jalisco Mexico
| | - Elli Selenius
- grid.9681.60000 0001 1013 7965Department of Physics, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Sami Malola
- grid.9681.60000 0001 1013 7965Department of Physics, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Hannu Häkkinen
- grid.9681.60000 0001 1013 7965Department of Physics, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland ,grid.9681.60000 0001 1013 7965Department of Chemistry, Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
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95
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Nagami T, Sugimori R, Sakai R, Okada K, Nakano M. Theoretical Study on Singlet Fission in Aromatic Diaza s-Indacene Dimers. J Phys Chem A 2021; 125:3257-3267. [PMID: 33834780 DOI: 10.1021/acs.jpca.0c11598] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We theoretically show that diaza (N2)-substitution to s-indacene with 4n π-electrons, by which the number of π-electrons in N2-s-indacene amounts to 4n+2, is a new strategy to design efficient singlet fission (SF) molecules. By N2-substitution, the diradical character and the exchange integral are found to be tuned moderately, leading to satisfying the excitation energy level matching condition for SF with a large triplet excitation energy. On the basis of the effective electronic coupling related to the SF rate, we explore the optimal slip-stack dimer packings for fast SF. Their underlying mechanisms are well understood from the odd-electron density, resonance structure, and frontier orbital distribution, as the functions of the N2-substituted positions. Furthermore, aromaticities of N2-s-indacenes are evaluated explicitly on the basis of the magnetically induced current. Although N2-s-indacenes display strengths of aromaticities similar to that of anthracene, a local decrease in aromaticity is found to correlate to the spatial feature of diradical character, i.e., odd-electron density. The present findings not only newly propose N2-s-indacenes as feasible SF molecules but also contribute to comprehending the interplay between aromaticity and diradical electronic structures contributing to SF.
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Affiliation(s)
- Takanori Nagami
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Ryota Sugimori
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Ryota Sakai
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Kenji Okada
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Masayoshi Nakano
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.,Center for Spintronics Research Network (CSRN), Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.,Center for Quantum Information and Quantum Biology Division (QIQB), Institute for International Advanced Research Institute (IARI), Osaka University, Toyonaka, Osaka 560-8531, Japan.,Innovative Catalysis Science Division (ICS), Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Toyonaka, Osaka 560-8531, Japan.,Research Center for Solar Energy Chemistry (RCSEC), Osaka University, Toyonaka, Osaka 560-8531, Japan
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96
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Holzer C, Franzke YJ, Kehry M. Assessing the Accuracy of Local Hybrid Density Functional Approximations for Molecular Response Properties. J Chem Theory Comput 2021; 17:2928-2947. [PMID: 33914504 DOI: 10.1021/acs.jctc.1c00203] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A comprehensive overview of the performance of local hybrid functionals for molecular properties like excited states, ionization potentials within the GW framework, polarizabilities, magnetizabilities, NMR chemical shifts, and NMR spin-spin coupling constants is presented. We apply the generalization of the kinetic energy, τ, with the paramagnetic current density to all magnetic properties and the excitation energies from time-dependent density functional theory. This restores gauge invariance for these properties. Different ansätze for local mixing functions such as the iso-orbital indicator, the correlation length, the Görling-Levy second-order limit, and the spin polarization are compared. For the latter, we propose a modified version of the corresponding hyper-generalized gradient approximation functional of Perdew, Staroverov, Tao, and Scuseria (PSTS) [Phys. Rev. A 2008, 78, 052513] to allow for a numerically stable evaluation of the exchange-correlation kernel and hyperkernel. The PSTS functional leads to a very consistent improvement compared to the related TPSSh functional. It is further shown that the "best" choice of the local mixing function depends on the studied property and molecular class. While functionals based on the iso-orbital indicator lead to rather accurate excitation energies and ionization energies, the results are less impressive for NMR properties, for which a considerable dependence on the considered molecular test set and nuclei is observed. Johnson's local hybrid functional based on the correlation length yields remarkable results for NMR shifts of compounds featuring heavy elements and also for the excitation energies of organic compounds.
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Affiliation(s)
- Christof Holzer
- Institute of Theoretical Solid State Physics, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Yannick J Franzke
- Fachbereich Chemie, Philipps-Universität Marburg, 35032 Marburg, Germany.,Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Max Kehry
- Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
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97
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Wang MH, Orozco-Ic M, Leyva-Parra L, Tiznado W, Barroso J, Ding YH, Cui ZH, Merino G. Planar Tetracoordinate Carbons in Allene-Type Structures. J Phys Chem A 2021; 125:3009-3014. [PMID: 33797250 DOI: 10.1021/acs.jpca.1c02002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The exhaustive exploration of the potential energy surfaces of CE2M2 (E = Si-Pb; M = Li and Na) revealed seven global minima containing a planar tetracoordinate carbon (ptC). The design, based on a π-localization strategy, resulted in a ptC with two double bonds forming a linear or a bent allene-type E═C═E motif. The magnetic response of the bent E═C═E fragments support a σ-aromaticity. The bonding analysis indicated that the ptCs form C-E covalent bonds and C-M electrostatic interactions.
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Affiliation(s)
- Meng-Hui Wang
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, P. R. China
| | - 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, Mérida, Yucatán, México
| | - Luis Leyva-Parra
- Computational and Theoretical Chemistry Group, Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, República 498, Santiago, Chile
| | - William Tiznado
- Computational and Theoretical Chemistry Group, Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, República 498, Santiago, Chile
| | - 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, Mérida, Yucatán, México
| | - Yi-Hong Ding
- Key Laboratory of Carbon Materials of Zhejiang Province, College of Chemistry and Materials Engineering, Wenzhou University, Wenzhou 325035, P. R. China
| | - Zhong-Hua Cui
- Institute of Atomic and Molecular Physics, Jilin University, Changchun 130023, P. R. China.,Beijing National Laboratory for Molecular Sciences, Beijing 100190, P. R. China
| | - 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, Mérida, Yucatán, México
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98
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Arias-Olivares D, Becerra-Buitrago A, García-Sánchez LC, Islas R. In Silico Analysis of the Electronic Delocalization in Some Double Fused-Ring Metallabenzenes. ACS OMEGA 2021; 6:9887-9897. [PMID: 33869969 PMCID: PMC8047703 DOI: 10.1021/acsomega.1c00632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
In the current work, some metallabenzenes with one and several fused rings were analyzed in terms of their electronic delocalization. These fused-ring metallabenzenes are known as metallabenzenoids, and their aromatic character is not free of controversy. The systems of the current work were designed from crystallographic data of some synthesized molecules, and their electronic delocalization (aromaticity) was computationally examined in terms of the molecular orbital analysis (Hückel's rule), the induced magnetic field, and ring currents. The computational evidence allows us to understand if these molecules are or are not aromatic compounds.
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Affiliation(s)
- David Arias-Olivares
- Departamento
de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. República 275, 8370146 Santiago Chile
- Center
of Applied Nanoscience (CANS), Facultad de Ciencias Exactas, Universidad Andres Bello, Av. República 275, 8370146 Santiago, Chile
| | - Andrés Becerra-Buitrago
- Proyecto
Curricular Licenciatura en Química, Universidad Distrital Francisco José de Caldas, 11021-110231588 Bogotá, Colombia
| | - Luis Carlos García-Sánchez
- Proyecto
Curricular Licenciatura en Química, Universidad Distrital Francisco José de Caldas, 11021-110231588 Bogotá, Colombia
| | - Rafael Islas
- Departamento
de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. República 275, 8370146 Santiago Chile
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99
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Affiliation(s)
- R. R. Aysin
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova 28, Moscow 119991, Russia
| | - S. S. Bukalov
- A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova 28, Moscow 119991, Russia
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100
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Pino-Rios R, Montenegro-Pohlhammer N, Cárdenas-Jirón G. Assessment of New Expanded Porpholactones as UV/Vis/NIR Chromophores for Dye-Sensitized Solar Cell Applications. J Phys Chem A 2021; 125:2267-2275. [PMID: 33724841 DOI: 10.1021/acs.jpca.0c11188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Expanded porphyrins arise as an alternative for potential application as chromophores in dye-sensitized solar cells. (DSSCs). The modification of the core of these compounds provides remarkable changes in the photoelectronic behavior. In the present article, the improvement of its properties for a potential application as UV/vis/NIR chromophores in DSSCs has been studied, when an oxazolone moiety has replaced an imine ring in analogy to the porpholactones first synthesized by Crossley et al. ( J. Chem. Soc., Chem. Commun. 1984, 920-922). These expanded porpholactones present a noticeable red shift as well as an increase in the intensity of the Q-bands regarding the parent compounds. The photophysical properties of Sapphyrin have been explored through DFT calculations and vibrationally resolved absorption spectra simulations. Energetic parameters showed favorable electron injection from the chromophore to the TiO2 semiconductor. In addition, aromaticity was analyzed and rationalized using magnetic and delocalization criteria. Results showed qualitatively similar trends between aromaticity descriptors and Q bands giving a great opportunity to the use this property in the rational design of chromophores. Finally, the nonequilibrium Green's function formalism shows the ability of expanded porpholactones in electron transport.
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Affiliation(s)
- Ricardo Pino-Rios
- Laboratorio de Química Teórica, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), 8320000 Santiago, Chile
| | - Nicolás Montenegro-Pohlhammer
- Laboratorio de Química Teórica, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), 8320000 Santiago, Chile.,Departamento de Química Física, Universidad de Sevilla, c/Profesor García González, s/n, 41012 Sevilla, Spain
| | - Gloria Cárdenas-Jirón
- Laboratorio de Química Teórica, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), 8320000 Santiago, Chile
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