Synthesis and characterisation of novel heterobimetallic halide isopropoxides based on M(2)(OPri)(9)(-) (M=Sn, Zr or Ti) anions: Crystal and molecular structures of [CdI{Sn-2(OPri)(9)}] and [{SnI[Zr-2(OPri)(9)]}(2)]

New heterobimetallic halide isopropoxides based on the interaction of M(2)(OPri)(9)(-) (M - Sn-IV, Zr-IV or Ti-IV) units with Cd-II, Sn-II and Pb-II have been prepared. These complexes have been characterised by multinuclear solution and solid-state cross polarisation magic angle spinning (CP MAS) NMR spectroscopy, elemental analyses and cryoscopy. Single-crystal X-ray diffraction studies have been performed for [CdI{Sn-2(OPri)(9)}] 1 and [{SnI[Zr-2(OPri)(9)]}] 2. Compound 1 consists of a face-sharing bioctahedral Sn-2(OPri)(9)(-) unit which interacts with the central metal atom; cadmium, using two mu- and two terminal OPri groups. The cadmium atom is within a distorted trigonal bipyramid of oxygen and iodine atoms. The Cd-113 chemical shifts in the solution and solid-state CP MAS NMR spectra of 1 are consistent with the retention of its heterometallic nature in solution.:In contrast to the monomeric form of 1, compound 2 exists as an iodo-bridged dimer in the solid state. Cryoscopic measurements for 2 indicate a monomer-dimer equilibrium (eta = 1.6) in solution which has been confirmed by variable-temperature Sn-119 NMR studies. In the solid state the ligating mode of the Zr-2(OPri)(9)(-) unit in 2 is different from isostructural Sn-2(OPri)(9)(-) and it binds to tin via only three OPri groups, the fourth M-OPri interaction being hindered by the stereochemically active lone pair of electrons present at Sn-II. The central SnI2O6 core in 2 can be viewed as two SnI2O3 octahedra fused along a common axial-equatorial edge where one of the axial co-ordination Sites in each is occupied by the non-bonding electron pair of Sn-II.