Abstract: The interaction of (Bu4N)2[B12H11SCN] (1) with various proton donors (MeOH, indole, pyrazole, imidazole, PhOH, 4-NO2C6H4OH, CF3CH2OH, (CF3)2CHOH and (CF3)3COH) was investigated by IR spectroscopy at 190 – 290 K in dichloromethane. Both the hydride hydrogen and the nitrogen atom of the SCN group of 1 acted as proton-accepting sites. IR spectral evidence of BH ···· HO and N ···· HO hydrogen-bond formation was obtained by changes in the acid νXH stretches as well as in the νBH and νCN bands of the hydride. Spectral and thermodynamic characteristics of the H-complexes were determined. Interaction with NH-acids was also examined. The electronic effects of the SCN group and the boron cage on the proton-accepting properties of both sites in 1 were analyzed by comparison with previously studied hydrogen bonding to (Bu4N)2[B12H12] and (Bu4N)[SCN]. Both types of hydrogen bonds in the model complexes of [B12H11SCN]2− HOCF3 were studied using the B3LYP/6-31G(d,p) approximation.
Keywords: Undecahydro-thiocyanato-closo-dodecaborate(2−) anion, Hydrogen bond, IR spectroscopy, Quantum chemical calculations
