UNUSUAL HYDROGEN-BONDS WITH A HYDRIDE ATOM IN BORON HYDRIDES ACTING AS PROTON ACCEPTOR - SPECTROSCOPIC AND THEORETICAL-STUDIES

The interaction of different proton donors with ionic (Bu4NBH4) and ne utral (BH3NEt3, BH3(OEt)(3)) boron hydrides was studied by IR and NMR spectroscopy in solution (CH2Cl2, C6H14, and C6D12). A close similarit y was observed between the spectral and thermodynamic properties of th ese unusual BH ... HX and those of classical Ii bonds. The typical cha racteristics of hydrogen bonding, such as linearity of the fragment K ... HX, lengthening of X-H and H-B bonds, and strong electron redistri bution, were confirmed by ab initio calculations.