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Kenouche S, Bachir N, Bouchal W, Martínez-Araya JI. Aromaticity of six-membered nitro energetic compounds through molecular electrostatic potential, magnetic, electronic delocalization and reactivity-based indices. J Mol Graph Model 2024; 129:108728. [PMID: 38412811 DOI: 10.1016/j.jmgm.2024.108728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/06/2024] [Accepted: 02/13/2024] [Indexed: 02/29/2024]
Abstract
The electron density depletion associated with π-hole at the ring center typical of energetic compounds was clearly revealed by the molecular electrostatic potential (ESP). In addition, the spatial arrangement of NO2 groups appears to affect the ESP value in the ring center, and therefore sensitivity to detonation. Indeed, for monocyclic nitrobenzene compounds with the same number of NO2 groups, the ESP value in the ring center decreases as the NO2 groups are more closely spaced. As expected, the central rings become less aromatic as NO2 groups are added. The MCI, PDI, PLR, NICSzz(1), FLU indices are all strongly correlated with the ESP values observed in the ring center of the set of nitrobenzenes. Aromaticity indices based on electron delocalization criteria appear to be very sensitive to small variations in aromaticity. Among magnetic-based indices, only NICSzz(1) is capable to predict small changes in aromaticity. The PLR index derived from conceptual DFT is quite relevant for predicting small variations in aromaticity. According to our results, the most suitable aromaticity index is not based on a single criterion, and that selecting it is more subtle. Therefore, it is important to combine information from several criteria to obtain a more complete description of the aromaticity of the studied compounds.
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Affiliation(s)
- Samir Kenouche
- Group of Modeling of Chemical Systems using Quantum Calculations, Applied Chemistry Laboratory (LCA). University M. Khider of Biskra, 07000 Biskra, Algeria
| | - Nassima Bachir
- Group of Modeling of Chemical Systems using Quantum Calculations, Applied Chemistry Laboratory (LCA). University M. Khider of Biskra, 07000 Biskra, Algeria
| | - Wissam Bouchal
- Molecular Chemistry and Environment Laboratory, University of Mohammed Khider of Biskra, BP 145 RP, Biskra 07000, Algeria
| | - Jorge I Martínez-Araya
- Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello (UNAB), Av. República 275, 8370146 Santiago, Chile; Centro de Química Teórica y Computacional (CQT&C). Facultad de Ciencias Exactas, Santiago, Chile.
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2
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Chagas JCV, Milanez BD, Oliveira VP, Pinheiro M, Ferrão LFA, Aquino AJA, Lischka H, Machado FBC. A multi-descriptor analysis of substituent effects on the structure and aromaticity of benzene derivatives: π-Conjugation versus charge effects. J Comput Chem 2024; 45:863-877. [PMID: 38153839 DOI: 10.1002/jcc.27296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/29/2023] [Accepted: 12/10/2023] [Indexed: 12/30/2023]
Abstract
This work provides a detailed multi-component analysis of aromaticity in monosubstituted (X = CH3, CH 2 - , CH 2 + , NH2, NH-, NH+, OH, O-, and O+) and para-homodisubstituted (X = CH3, CH2, NH2, NH, OH, and O) benzene derivatives. We investigate the effects of substituents using single-reference (B3LYP/DFT) and multireference (CASSCF/MRCI) methods, focusing on structural (HOMA), vibrational (AI(vib)), topological (ELFπ), electronic (MCI), magnetic (NICS), and stability (S0-T1 splitting) properties. The findings reveal that appropriate π-electron-donating and π-electron-accepting substituents with suitable size and symmetry can interact with the π-system of the ring, significantly influencing π-electron delocalization. While the charge factor has a minimal impact on π-electron delocalization, the presence of a pz orbital capable of interacting with the π-electron delocalization is the primary factor leading to a deviation from the typical aromaticity characteristics observed in benzene.
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Affiliation(s)
- Julio C V Chagas
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Bruno D Milanez
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Vytor P Oliveira
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Max Pinheiro
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Luiz F A Ferrão
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Adelia J A Aquino
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Francisco B C Machado
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
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Nikulshin PV, Makarov AY, Koskin IP, Becker CS, Kazantsev MS, Beckmann J, Balmohammadi Y, Grabowsky S, Mebs S, Naumova OV, Protasov DY, Svit KA, Irtegova IG, Radiush EA, Bagryanskaya IY, Shundrin LA, Zibarev AV. 1,2,3,4-Tetrafluorobiphenylene: A Prototype Janus-Headed Scaffold for Ambipolar Materials. Chempluschem 2024; 89:e202300692. [PMID: 38052725 DOI: 10.1002/cplu.202300692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/01/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
The title compound was synthesized by Ullmann cross-coupling in low yield as the first representative of [n]phenylene containing hydrocarbon and fluorocarbon rings. Stille/Suzuki-Miyaura cross-coupling reactions, as well as substitution of fluorine in suitable starting compounds, failed to give the same product. The geometric and electronic structures of the title compound were studied by X-ray diffraction, cyclic voltammetry and density functional theory calculations, together with Hirshfeld surface and reduced density gradient analyses. The crystal structure features head-to-tail π-stacking and other fluorine-related secondary bonding interactions. From the nucleus-independent chemical shifts descriptor, the four-membered ring of the title compound is antiaromatic, and the six-membered rings are aromatic. The Janus molecule is highly polarized; and the six-membered fluoro- and hydrocarbon rings are Lewis π-acidic and π-basic, respectively. The electrochemically-generated radical cation of the title compound is long-lived as characterized by electron paramagnetic resonance, whereas the radical anion is unstable in solution. The title compound reveals electrical properties of an insulator. On expanding its molecular scaffold towards partially fluorinated [n]phenylenes (n≥2), the properties presumably can be transformed into those of semiconductors. In this context, the title compound is suggested as a prototype scaffold for ambipolar materials for organic electronics and spintronics.
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Affiliation(s)
- Pavel V Nikulshin
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
- Current address: Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 119991, Moscow, Russia
| | - Alexander Yu Makarov
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Igor P Koskin
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Christina S Becker
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Maxim S Kazantsev
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Jens Beckmann
- Institute for Inorganic Chemistry and Crystallography, University of Bremen, 28359, Bremen, Germany
| | - Yaser Balmohammadi
- Department of Chemistry, Biochemistry and Pharmaceutical Science, University of Bern, 3012, Bern, Switzerland
| | - Simon Grabowsky
- Department of Chemistry, Biochemistry and Pharmaceutical Science, University of Bern, 3012, Bern, Switzerland
| | - Stefan Mebs
- Institute for Experimental Physics, Free University of Berlin, 14195, Berlin, Germany
| | - Olga V Naumova
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Dmitry Yu Protasov
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Kirill A Svit
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Irina G Irtegova
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Ekaterina A Radiush
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Irina Yu Bagryanskaya
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Leonid A Shundrin
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Andrey V Zibarev
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
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Ko MS, Roh TH, Desale PP, Choi SW, Cho DG. Effects of Electron-Withdrawing and Electron-Donating Groups on Aromaticity in Cyclic Conjugated Polyenes. J Am Chem Soc 2024; 146:6266-6273. [PMID: 38394690 DOI: 10.1021/jacs.3c14390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Determining the aromaticity of various fluorinated benzenes is challenging as easily obtained experimental aromaticity [Δδ(Houter - Hinner)] necessitates the chemical shifts of inner and outer protons. This issue was addressed in porphyrinoids by replacing the electron-withdrawing (E.W.) groups at the meso-positions of porphyrins and allyliporphyrins. Electronic effects on aromaticity in porphyrinoids have not been thoroughly examined in the literature. In porphyrins, the effect of E.W. groups is minimal, making it difficult to establish a clear relationship between the aromaticity strength and E.W. groups. Conversely, in allyliporphyrins, stronger E.W. groups, such as indandione (IND) derivatives, significantly reduce the aromaticity of the parent structure. The IND derivatives disrupted the aromatic pathway of allyliporphyrin more effectively than those attached to porphyrins. This is attributed to the absence of β-carbons in allyliporphyrins. The effect of electron-donating (E.D.) groups on porphyrins and allyliporphyrins was further investigated. Contrary to the initial assumption that the E.D. groups might enhance aromaticity owing to their ability to increase electron density, as the strength of the E.D. groups increased, the aromaticity of the porphyrinoids decreased. Despite the modest reduction in aromaticity, any form of electron perturbation reduces aromaticity. The aromaticity of various fluorinated benzenes is expected to parallel our observations of porphyrinoids as representative aromatic polyenes.
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Affiliation(s)
- Min-Sung Ko
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Tae-Ho Roh
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Pradeep P Desale
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Sung-Wook Choi
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Dong-Gyu Cho
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
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Leyva-Parra L, Pino-Rios R. Update for Isomerization Stabilization Energies: The Fulvenization Approach. ACS OMEGA 2024; 9:1436-1442. [PMID: 38222592 PMCID: PMC10785285 DOI: 10.1021/acsomega.3c07881] [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: 10/09/2023] [Revised: 11/28/2023] [Accepted: 12/04/2023] [Indexed: 01/16/2024]
Abstract
An alternative approach for calculating aromatic stabilization energies is proposed based on transforming an (anti)aromatic ring into a fulvene isomer. This fulvenization process gives a value of 34.05 kcal·mol-1 for benzene in the singlet state and a value of -17.85 kcal·mol-1 in the triplet state. Additionally, it is possible to use experimental values (as long as they exist) for the calculation as the gas-phase formation enthalpies of benzene and fulvene, whose difference is 33.72 kcal·mol-1. On the other hand, this same approach has been evaluated on several six-membered rings, including those persubstituted, biradicals, azines, and inorganic analogues, giving results in agreement with those reported in the literature using different criteria. Additionally, it is possible to differentiate the aromaticity of the rings in polycyclic aromatic hydrocarbons according to Clar's rules. Assigning the (anti)aromatic character in various nonbenzenoid rings (neutral and charged), except for five- and seven-membered rings, is also possible. The construction of the fulvene isomers in PAHs is set such that nonaromaticity-related effects are not considered. The results show that the fulvenization approach is an effective and efficient approach that can serve as an alternative or complement to existing tools.
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Affiliation(s)
- Luis Leyva-Parra
- Departamento
de Ciencias Químicas, Centro de Química Teórica
& Computacional (CQT&C), Universidad
Andrés Bello, Facultad de Ciencias Exactas, Avenida República 275, 8370146 Santiago de Chile, Chile
| | - Ricardo Pino-Rios
- Instituto
de Estudios de la Salud, Universidad Arturo
Prat, 1100000 Iquique, Chile
- Química
y Farmacia, Facultad de Ciencias de la Salud, Universidad Arturo Prat, Casilla 121, 1100000 Iquique, Chile
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