Synthesis, Structure, and Spectroscopy of the Biscarboranyl Stannylenes ()Sn·THF and K[()Sn] ( = 1,1'(-Biscarborane)) and Dibiscarboranyl Ethene ()CH=CH().

Two compounds containing a Sn(II) atom supported by a bidentate biscarborane ligand have been synthesized via salt metathesis. The synthetic procedures for ()Sn·THF ( = 1,1' (-carborane) () and K[()Sn] () involved the reaction of K[] with SnCl in either a THF solution () or in a benzene/dichloromethane solvent mixture (). Using the same solvent conditions as those used for but using a shorter reaction time gave a dibiscarboranyl ethene (). The products were characterized by H, C, B, Sn NMR, UV-vis, and IR spectroscopy, and by X-ray crystallography. The diffraction data for and show that the Sn atom has a trigonal pyramid environment and is constrained by the ligand in a planar five-membered CSn heterocycle. The Sn NMR spectrum of displays a triplet of triplets pattern signal, which is unexpected given the absence of a Sn-H signal in the H NMR, IR spectrum, and X-ray crystallographic data. However, a comparison with other organotin compounds featuring a Sn atom bonded to carboranes reveal similar multiplets in their Sn NMR spectra, likely arising from long-range nuclear spin-spin coupling between the carboranyl B and Sn nuclei. Compound displays structural and spectroscopic characteristics typical of conjugated alkenes.