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Substituent Effects on B−N Bonding and Coupling Constants in Fivemembered Rings N₃B₂H₄X and N₂B₃H₄X, for X = H, F, and Li

Janet E. Del Bene ; Department of Chemistry, Youngstown State University, Youngstown, Ohio 44555, USA
Otilia Mó ; Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, 28094-Madrid, Spain
Manuel Yáñez ; Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, 28094-Madrid, Spain

Sažetak

Ab initio calculations have been carried out to investigate bonding patterns and B−N coupling constants in five-membered rings N₃B₂H₄X and N₂B₃H₄X, for X = H, F, and Li, with substitution occurring only at N. F-substitution results in the formation of a covalent N−F bond, whereas Li-substitution leads to an ion-pair with little covalency. Substitution has a highly localized effect, changing the electron density only at the substituted N. F-substitution also has a very localized effect on coupling constants, at most only changing 1J(B−N) involving the substituted N. Li-substitution has a more delocalized effect. It always decreases 1J(B−N) involving the substituted N, and may also decrease 1J(B−N) of a proximal B−N bond if the B atom is bonded to the substituted N.

Ključne riječi

5-membered rings; B−N bonding; spin-spin coupling constants

Hrčak ID:

38656

URI

https://hrcak.srce.hr/38656

Datum izdavanja:

30.6.2009.

Posjeta: 1.330 *