Solvothermal Syntheses of High‐Nuclearity Vanadium( III ) Clusters

Superheating alcohol solutions of simple trimetallic vanadium( III ) precursors gives the octa‐ and decametallic vanadium( III ) clusters [V 8 (OEt) 8 (OH) 4 (O 2 CPh) 12 ] ( 1 ) and [V 10 (OMe) 20 (O 2 CMe) 10 ] ( 2 ). Cluster 2 is the largest vanadium( III ) cluster synthesised to date. Thus solvothermal synthetic techniques are an excellent route to high‐nuclearity vanadium( III ) clusters. Both 1 and 2 consist of a planar or near‐planar array of V III ions. The metal ions in 1 are bridged by either a μ 2 ‐hydroxide and two μ 2 ‐benzoate groups or two μ 2 ‐ethoxides and a μ 2 ‐benzoate groups, the two bridging arrangements alternating around the ring. In 2 each pair of neighbouring metal ions is bridged by two μ 2 ‐methoxides and a μ 2 ‐acetate, and this molecule is the V III analogue of Lippard's famous “ferric wheel”. Preliminary magnetic susceptibility studies show the exchange coupling in both complexes to be antiferromagnetic in nature, with the coupling stronger in 1 than in 2 .