Synthesis, structure and magnetic properties of pyrazolate-bridged dinuclear complexes [{M(NCS)(4-Phpy)}2(μ-bpypz)2] (M=Co2+ and Fe2+)

Abstract: The synthesis and magnetic characterization of pyrazolato-bridged dinuclear complexes [{M(NCS)(4-Phpy)}2(μ-bpypz)2] (Hbpypz=3,5-bis(2-pyridyl)-pyrazole; 4-Phpy=4-phenylpyridine; M=Co2+ (1) and Fe2+ (2)) are described together with the X-ray crystal analysis of the cobalt complex. The structure of 1 shows that the desired coordination has been achieved with the cobalt atoms being coordinated to two bpypz to form the dimer. The X-ray diffraction patterns show 1 and 2 to be isomorphous at room temperature. 2 displays a single spin-crossover transition between the [HS–HS] and [LS–LS] states with T c =150K. [Copyright &y& Elsevier]