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  • The boron-boron single bond in diborane(4) as a non-classical electron donor for hydrogen bonding.

The boron-boron single bond in diborane(4) as a non-classical electron donor for hydrogen bonding.

Physical chemistry chemical physics : PCCP (2011-06-24)
Ibon Alkorta, Ignacio Soteras, José Elguero, Janet E Del Bene
ABSTRACT

An ab initio study of an isomer of diborane(4) [B(2)H(4)] has been carried out at MP2/aug-cc-pVTZ to investigate the ground-state properties of this unusual molecule, a derivative of which has been described in the recent literature. The geometric, electronic and orbital characteristics of B(2)H(4)(4) have been analyzed using AIM, NBO, and ELF methodologies. A region with a high concentration of electron density is located near and along the B-B bond, on the opposite side of this bond relative to the bridging H atoms. This site serves as an electron-donor site to electrophiles, resulting in hydrogen-bonded complexes of B(2)H(4) with proton donors HF, HNC, HCl, HCN, and HCCH, and a van der Waals complex with H(2). These complexes have C(2v) symmetry and stabilization energies that vary from 2 to 27 kJ mol(-1). The SAPT2 energy decomposition analysis shows that the relative importance of the various terms that contribute to the interaction energy depends on the strength of the interaction.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Diborane, 99.99% (diborane only), 9-11% (balance hydrogen), 10% in hydrogen, electronic grade