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

Abstract

Ionic or ionogenic alkoxides are attractive potential catalysts for polymerization reactions. Direct interaction between CoCl 2 and [Ta(OMe) 5] produced, by self-assembly, a small amount of ionic aggregate clathrate with acetonitrile, [ Co 2 Ta 2 ( OMe ) 12 ( MeCN ) 4 ] 2 + [ CoCl 3 ( MeCN ) ] 2 - · 2 MeCN ( 1 ) . The structure of 1 contains a planar M 4( μ 3-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 CoCl 2 in toluene/acetonitrile to give a new crystallographic form [Co 2Ta 2(OMe) 12(MeCN) 4] [CoCl 3(MeCN)] 2 ( 2), not containing interstitial solvent molecules.