Synthesis, Structure, and Magnetic Properties of a Novel Polyoxometalate–Organic Framework with Unusual (5,6)-Connected Topology

A novel three-dimensional (3D) polyoxometalate–organic framework [Cu2(4,4′-bpz)4(Cu2Mo6O22)]n (1) with unprecedented transition metal substituted octametalates has been hydrothermally synthesized and structurally characterized. Two [Cu2Mo6O22]4– polyoxometalate units are linked by two Cu2+ ions into a polymeric chain running along the b-axis, and the resulting chains are further interconnected by 4,4′-bpz (4,4′-bpz = 3,3′,5,5′-tetramethyl-4,4′-bipyrazole) ligands into a 3D framework with interesting (5,6)-connected topology. The variable temperature magnetic study of 1 indicates the presence of four independent Cu2+ centers and a weak ferromagnetic coupling behavior between them.