The comparison of structure and bond between [Ni(pz ph) 4(NCS) 2] and [Ni(pz But) 4(NCS) 2

Abstract

Two nickel(II) complexes with thiocyanate and different substituted pyrazole ligands, [Ni(pz R) 4(SCN) 2] (R=ph for ( 1) and n-But for ( 2), pz R=3-substituted pyrazole), have been synthesized and their crystal structures have been determined. The compound 1 crystallizes in the monoclinic system, space group P2 1/ n, a=8.591(5) A ̊ , b=17.936(10) A ̊ , c=12.861(7) A ̊ , β=106.490(10)°, Z=2, R 1=0.0665, wR 2=0.1375. The compound 2 crystallizes in the monoclinic system, space group P2 1/ c, a=12.805(3) A ̊ , b=22.718(5) A ̊ , c=13.396(3) A ̊ , β=94.480(5)°, Z=4, R 1=0.0729, wR 2=0.1665. The nickel(II) ion in each complex is coordinated by four pyrazole nitrogen atoms and two nitrogen atoms of NCS − to form a distorted octahedron. The two nitrogen atoms of NCS − are located at axial positions and the four nitrogen atoms of pyrazoles are located at equatorial positions. The average Ni–N(pz R) and Ni–N(NCS) bond lengths are observed to be 2.111 and 2.068 Å for 1, 2.095 and 2.098 Å for 2, respectively. In 1, the intermolecular hydrogen bonds form quasi 1D structure. The intramolecular hydrogen bonds are found in 2. The spectroscopic and bond properties have also been discussed.