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 [Et4N][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.

Graphical abstractThe syntheses, spectroscopic, and structural properties of the first carba-closo-dodecaborate anions with ethynyl groups bonded to the cluster boron atoms [12-HCC-closo-1-CB11H11]− and [7,12-(HCC)2-closo-1-CB11H10]− are described.Figure optionsDownload full-size imageDownload as PowerPoint slide