Synthesis and reactivity of intramolecularly stabilized organotin compounds containing the C,N-chelating o-carboranylamino ligand [o-C2B10H10(CH2NMe2)-C,N](-) (Cab(C,N)). X-ray structures of (Cab(C,N))SnR2X (R = Me, X = Cl; R = Ph, X = Cl), (Cab(C,N))(2)Hg, and [(Cab(C,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 organot in halides or tin tetrachloride. In this way, the tetraorganotin compound ( Cab(C,N))SnMe3 (2), triorganotin halide (Cab(C,N))SnMe3 (3: R = Me, X = Cl, 3a; R = Ph, X = Cl, 3b; R = Me, X = Pr, 3c), diorganotin dichloride (Cab(C ,N))SnPhCl2 (4), and monoorganotin trichloride (Cab(C,N))SnCl3 (5) have bee n synthesized and characterized. H-1 and Sn-119 NMR spectroscopy indicates that the tin center in the tetraorganotin compound 2 is tetracoordinate, wh ereas this center in mono-, di-, and triorganotin compounds 3-5 is pentacoo rdinate as a result; of intramolecular Sn-N coordination. Complexes 3a,c we re also formed by redistribution of(Cab(C,N))SnMe3 (2) with the correspondi ng Me2SnX2 (X = Cl, Pr). The molecular structures of 3a,b were determined b y X-ray analysis. As a result of the Sn-N interaction, the tin atoms in 3a, b exhibit distorted-trigonal-bipyramidal configurations with the electroneg ative atoms (N and Cl) in apical positions. The reaction of 2 equiv of 2 wi th HgCl2 resulted in transmetalation of (Cab(C,N))SnMe3 (2), giving the dio rganomercury compound (Cab(C,N))(2)Hg (6). The structure of 6 was determine d by an X-ray structural study. The mercury atom is four-coordinate, both n itrogen atoms being involved in intramolecular coordination. The reaction o f 3c with Na in a 1:1 ratio afforded the bis(o-carboranylamino)distannane [ (Cab(C,N))SnMe2](2) (7). The crystal structure of 7 was determined by an X- ray structural study. The two four-coordinate tin moieties exhibit approxim ately pseudotetrahedral geometries showing only negligible, if any, interac tions between the tin atoms and the amino nitrogen atoms.