Synthesis and characterization of a large heterometallic alkoxide cation: Self-assembly and rational route to

Ionic or ionogenic alkoxides are attractive potential catalysts for polymerization reactions. Direct interaction between CoCl2 and [Ta(OMe)5] produced, by self-assembly, a small amount of ionic aggregate clathrate with acetonitrile, image. The structure of 1 contains a planar M4(μ3-OR)2(μ-OR)4-core that can be considered as a fragment of hexagonal packing of metal and ligand atoms completed by 6 (3 + 3) terminal alkoxide ligands at the tantalum and 4 (2 + 2) terminal acetonitrile molecules at the cobalt atoms that are bearing the (+1) positive charge each. A rational synthesis of this compound was achieved by reaction between [NaTa(OMe)6] with four equivalents of CoCl2 in toluene/acetonitrile to give a new crystallographic form [Co2Ta2(OMe)12(MeCN)4] [CoCl3(MeCN)]2 (2), not containing interstitial solvent molecules.