Heterobimetallic cerium() oxo clusters supported by a tripodal oxygen ligand

Heterometallic Ce IV /M (M = Mo VI , Re VII , V V ) oxo clusters supported by the Kläui tripodal oxygen ligand [(η 5 -C 5 H 5 )Co{P(O)(OEt) 2 } 3 ] − (L OEt − ) have been synthesized and structurally characterized, and the catalytic activity of the Ce IV /V V oxo cluster in the oxidation of thioanisoles has been studied. Treatment of [Ce(L OEt )Cl 3 ] ( 1 ) with [Ag 2 MoO 4 ] afforded the reported Ce IV /Mo VI cluster [H 4 (CeL OEt ) 6 Mo 9 O 38 ] ( 2 ), whereas that with [AgReO 4 ] yielded the Ce IV /Re VII cluster [{L OEt Ce(ReO 4 ) 2 (H 2 O)(μ-ReO 4 )} 2 ] ( 3 ) that contains an 8-membered Ce 2 Re 2 O 4 ring. Treatment of 1 with [Ag 3 VO 4 ] afforded the Ce IV /V V cluster [H 2 (CeL OEt ) 4 (V&z.dbd;O) 4 (μ 4 -O)(μ 3 -O) 12 ] ( 4 ) containing a {Ce 4 V 4 O 13 } oxo-metallic core. The solid-state structure of 4 consists of four {VO 4 } 3− units bridged by four {L OEt Ce 3+ } moieties and a μ 4 -oxo ligand. Each Ce atom in 4 is 9-coordinated, whereas the geometry around each V atom is pseudo square pyramidal with a terminal oxo at the apical position. Cluster 4 is an active catalyst for the oxidation of substituted thioanisoles with tert -butyl hydroperoxide. For example, the oxidation of thioanisole with tert -butyl hydroperoxide in the presence of 0.01 mol% of 4 gave a ca. 30 : 1 mixture of the sulfoxide and sulfone products in 96% yield. Heterometallic Ce IV /M (M = Mo VI , Re VII , V V ) oxo clusters supported by the Kläui tripodal oxygen ligand [(η 5 -C 5 H 5 )Co{P(O)(OEt) 2 } 3 ] − (L OEt − ) have been synthesized and the catalytic activity of the Ce IV /V V oxo cluster in the oxidation of thioanisoles has been studied.