Synthesis and Reactivity of Intramolecularly Stabilized Organotin Compounds Containing the C,N-Chelating o-Carboranylamino Ligand [o-C2B10H10(CH2NMe2)-C,N]- (CabC,N). X-ray Structures of (CabC,N)SnR2X (R = Me, X = Cl; R = Ph, X = Cl), (CabC,N)2Hg, and [(CabC,N)SnMe2]2

A variety of organotin complexes, containing the o -carboranylamino ligand (Cab C,N ), has been prepared by the reaction of LiCab C,N ( 1 ) with organotin halides or tin tetrachloride. In this way, the tetraorganotin compound (Cab C,N )SnMe 3 ( 2 ), triorganotin halide (Cab C,N )SnR 2 X ( 3: R = Me, X = Cl, 3a; R = Ph, X = Cl, 3b; R = Me, X = Br, 3c ), diorganotin dichloride (Cab C,N )SnPhCl 2 ( 4 ), and monoorganotin trichloride (Cab C,N )SnCl 3 ( 5 ) have been synthesized and characterized. 1 H and 119 Sn NMR spectroscopy indicates that the tin center in the tetraorganotin compound 2 is tetracoordinate, whereas this center in mono-, di-, and triorganotin compounds 3 − 5 is pentacoordinate as a result of intramolecular Sn−N coordination. Complexes 3a, c were also formed by redistribution of (Cab C,N )SnMe 3 ( 2 ) with the corresponding Me 2 SnX 2 (X = Cl, Br). The molecular structures of 3a, b were determined by X-ray analysis. As a result of the Sn−N interaction, the tin atoms in 3a, b exhibit distorted-trigonal-bipyramidal configurations with the electronegative atoms (N and Cl) in apical positions. The reaction of 2 equiv of 2 with HgCl 2 resulted in transmetalation of (Cab C,N )SnMe 3 ( 2 ), giving the diorganomercury compound (Cab C,N ) 2 Hg ( 6 ). The structure of 6 was determined by an X-ray structural study. The mercury atom is four-coordinate, both nitrogen atoms being involved in intramolecular coordination. The reaction of 3c with Na in a 1:1 ratio afforded the bis( o -carboranylamino)distannane [(Cab C,N )SnMe 2 ] 2 ( 7 ). The crystal structure of 7 was determined by an X-ray structural study. The two four-coordinate tin moieties exhibit approximately pseudotetrahedral geometries showing only negligible, if any, interactions between the tin atoms and the amino nitrogen atoms.