New type of heterometallic 3d-4f rhomblike core in Weakley-like polyoxometalates

The first heterometallic copper-cerium polyoxometalate, [{Ce^IV(OAc)}Cu^II₃(H₂O)(B-α-GeW₉O₃₄)₂]^11- (1), is composed of an unprecedented copper(II)-trisubstituted Weakley-type tungstogermanate subunit stabilized by coordination of a {Ce(OAc)}³⁺ group at the vacant position. The title species contains a central {Ce^IVCu^II₃O₁₈} rhomblike cluster that belongs to a new {(4f_ext)(3d_ext)(3d_int)₂} type and magnetically behaves as a triangular Cu₃ system with overall antiferromagnetic exchange affected by the structural distortions the vicinity of diamagnetic Ce^IV induces.