1
|
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.
Collapse
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
| |
Collapse
|