Bidentate Chelating and Bridging Biimidazole Ligands in Complexes of 2,2′-Biimidazole and N,N'-Dimethyl-2,2′-biimidazole with SnX4 (X = Cl, Br, I)

Abstract The complexes [(SnX4)n(LL)] (X = Cl, Br or I; n = 1, 2), where LL is 2,2′-biimidazole (H2BIm) or N,N'-dimethyl-2,2′-biimidazole (DMBIm) and [SnX4(H2BIm)2] (X = Cl or Br) were prepared from tin(IV) halides and the corresponding ligands and subsequently characterized. For complexes with n = 1, IR and Mossbauer data are in keeping with a hexa-coordinate tin atom chelated by the bidentate ligands LL. For n = 2, the tin atom is also hexa-coordinate: the species LL act as bidentate bridging ligands, and the coordination number is made up to six by SnXSn bridges. In [SnX4(H2BIm)2], one H2BIm is a bidentate chelating ligand and the other is occluded in the lattice. Conductivity measurements indicated that the compounds were not ionic in CH3CN, and NMR data suggest extensive dissociation in DMSO.