Ethynylmonocarba-closo-dodecaborates: M[12-HCC-closo-1-CB11H11] and M[7,12-(HCC)2-closo-1-CB11H10] (M = Cs+, [Et4N]+)

Cesium and tetraethylammonium salts of the ethynyl functionalized monocarba-closo-dodecaborate anions [12-HCC-closo-1-CB11H11] and [7,12-(HCC)2-closo-1-CB11H10] were obtained by desilylation of [(EtN)-N-4][12-Me3SiCC-closo-1-CB11H11] and [Et4N][7,12-(Me3SiCC)(2)-closo-1-CB11H10], respectively. Their thermal properties were examined by differential scanning calorimetry. The compounds were characterized by multi-NMR, IR, and Raman spectroscopy, (-)-MALDI mass spectrometry, and elemental analysis. Single-crystals of Cs[12-HCC-closo-1-CB11H11] and [Et4N][7,12-(HCC)(2)-closo-1-CB11H10] were studied by X-ray diffraction. The discussion of the spectroscopic and structural properties is supported by data derived from theoretical calculations using density functional theory as well as perturbation theory. (C) 2010 Elsevier B. V. All rights reserved.