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

• Published in: Journal of molecular structure 2005-11, Vol.754 (1), p.71-76
• Main Authors: Shi, Xue-Song, Liu, Chun-Sen, Li, Jian-Rong, Guo, Yue, Zhou, Jiang-Ning, Bu, Xian-He
• Format: Article
• Language: English
• Subjects: 3-(2-pyridyl)pyrazole-based ligand; Anion effects; Cd(II) complexes; Crystal structures
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2005.07.001

Two new Cd(II) complexes with a 3-(2-pyridyl)pyrazole-based ligand, [Cd( L) 2(SCN) 2] ( 1) and {[Cd( L) 2N 3](ClO 4)} n ( 2) ( L=3-(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 a=14.833(3), b=13.790(3), c=15.970(3) Å, β=110.89(3)° and Z=4, while 2 crystallizes in the monoclinic system, space group P2 1/ c, with a=13.622(4), b=23.286(7), c=10.547(3) Å, β=111.084(6)° and Z=4. 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 μ-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 hydrogen-bonding interactions. The structural difference of the two complexes is attributable to the different anions, which have different coordination natures.