Theoretical investigation of substituent effects on the relative stabilities and electronic structure of [BnXn](2-) clusters


TAHAOĞLU D. , ALKAN F. , DURANDURDU M.

JOURNAL OF MOLECULAR MODELING, vol.27, no.12, 2021 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 27 Issue: 12
  • Publication Date: 2021
  • Doi Number: 10.1007/s00894-021-04980-1
  • Title of Journal : JOURNAL OF MOLECULAR MODELING
  • Keywords: Boron clusters, Icosahedral barrier, Mesomeric effect, Inductive effect, Substitution, BORANE ANIONS, BUILDING-BLOCKS, BORON HYDRIDES, DENSITY, CARBORANES, BOND, LITHIUM, CL, THERMOCHEMISTRY, APPROXIMATION

Abstract

In this study, we provide a theoretical evaluation of relative stabilities and electronic structure for [BnXn](2-) clusters (n = 10, 12, 13, 14, 15, 16). Structural and electronic characteristics of [BnXn](2-) clusters are examined by comparison with the [B12X12](2-) counterparts with a focus on the substituent effects (X = H, F, Cl, Br, CN, BO, OH, NH2) on the electronic structure, electron detachment energies, formation enthalpies, and charge distributions. For the electronic structure and electron detachment energies, substituent effects on boron clusters are shown to follow a very similar trend to the mesomeric and inductive effects (+/- M and +/- I) of pi-conjugated systems, and the most stable derivatives in terms of HOMO/LUMO and electron detachment energies are calculated for CN and BO substituents due to strong -M effects. In the case of formation enthalpies for larger boron clusters (n >= 13), the icosahedral barrier is shown to increase with the halogen and CN substitution, whereas it is possible to reduce the icosahedral barrier for the cases of X = OH and NH2. It is shown that this reduction results from destabilizing the [B12X12](2-) cluster with electronic (+ M) and symmetry effects induced by OH and NH2 ligands.