Synthesis and crystal structures of two new Cd(II) complexes with 3-(2-pyridy)pyrazole-based ligand: influence of anions

Two new Cd(II) complexes with a 3-(2-pyridyl)pyrazole-based ligand, [Cd(L)2(SCN)2] (1) and {[Cd(L)2N3](ClO4)}n (2) (LZ3-(2- pyridyl)pyrazol-1-ylmethylbenzene) were synthesized and structurally characterized by elemental analyses, IR and single crystal X-ray diffraction analysis. Complex 1 crystallizes in the monoclinic system, space group C2/c, with aZ14.833(3), bZ13.790(3), cZ15.970(3) A ° , bZ110.89(3)8 and ZZ4, while 2 crystallizes in the monoclinic system, space group P21/c, with aZ13.622(4), bZ23.286(7), cZ10.547(3) A ° , bZ111.084(6)8 and ZZ4. In the two complexes, the Cd(II) centers are coordinated by six nitrogen atoms, in which four from two distinct L ligands and two from thiocyanato (1) or azido (2) anions. Complex 1 has a mononuclear structure, whereas 2 has a 1D chain structure bridged by azido anions. In 2, the azido adopts a m-1,3-trans coordination mode, which is not common in the azide Cd(II) complexes. In addition, in the structure of 2, the 1D chains were further assembled into a quasi-3D supramolecular network by the C–H/O hydrogenbonding interactions. The structural difference of the two complexes is attributable to the different anions, which have different coordination natures. q 2005 Published by Elsevier B.V.