Assembly of Dinuclear Cu II Rigid Blocks by Bridging Azido or Poly(thiocyanato)chromates: Synthesis, Structures and Magnetic Properties of Coordination Polymers and Polynuclear Complexes

Abstract

International audienceReaction of a dinuclear cationic copper(II) complex of 4,4′-[2-(3-hydroxyiminobutyl)imino]biphenyl [CuII2(LH)2]2+ with N3- resulted in the formation of a dinuclear azido [CuII2(LH)2(N3)2(H2O)2] complex or a 2D coordination polymer [CuII2(LH)2(N3)2]n. Reaction of the dinuclear complex with [CrIII(NCS)6]3- or [CrIII(NCS)4(NH3)2]- produced a 2D polymer {[CuII2(LH)2(CH3CN)2]3[CrIII(NCS)6]2}n or a 1D chain, constructed from tetranuclear units {[CuII2(LH)2][CrIII(NCS)4(NH3)2]2}n. Structures of the compounds were determined by X-ray crystallography and complexes were characterised by the temperature dependency of the magnetic susceptibility and by ESR spectroscopy. Magnetic properties of homometallic compounds were fit with the model of a dimer with the Hamiltonian Ĥ = -JŜ1*Ŝ2. For heterometallic complexes χMT curves were fit as the superposition of magnetism resulting from both [CuII2(LH)2]2+ and the adjacent CrIII-containing anion. J values for the complexes lie in the range from -12.74(4) to -17.77(8) cm-1. It was shown that the 4,4′-biphenyl bridge efficiently mediates exchange interactions