Synthesis, Structure, and Spectroscopy of the Biscarboranyl Stannylenes (bc)Sn·THF and K(2)[(bc)Sn](2) (bc = 1,1′(ortho-Biscarborane)) and Dibiscarboranyl Ethene (bc)CH=CH(bc)

[Image: see text] Two compounds containing a Sn(II) atom supported by a bidentate biscarborane ligand have been synthesized via salt metathesis. The synthetic procedures for (bc)Sn·THF (bc = 1,1′ (ortho-carborane) (1) and K(2)[(bc)Sn](2) (2) involved the reaction of K(2)[bc] with SnCl(2) in either a THF solution (1) or in a benzene/dichloromethane solvent mixture (2). Using the same solvent conditions as those used for 2 but using a shorter reaction time gave a dibiscarboranyl ethene (3). The products were characterized by (1)H, (13)C, (11)B, (119)Sn NMR, UV–vis, and IR spectroscopy, and by X-ray crystallography. The diffraction data for 1 and 2 show that the Sn atom has a trigonal pyramid environment and is constrained by the bc ligand in a planar five-membered C(4)Sn heterocycle. The (119)Sn NMR spectrum of 1 displays a triplet of triplets pattern signal, which is unexpected given the absence of a Sn–H signal in the (1)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 (119)Sn NMR spectra, likely arising from long-range nuclear spin–spin coupling between the carboranyl (11)B and (119)Sn nuclei. Compound 3 displays structural and spectroscopic characteristics typical of conjugated alkenes.