Temperature dependent bond distance variation in Ni complexes with some polyamine ligands

Abstract

X-ray structure determinations of [NiCl(H2O)(232-tet)]Cl (1) and [Ni(H2O)2(323-tet)]Cl2.3/2H2O (2) were carried out at the temperature between 123 to 293K (232-tet = N,N-f-bis(2-aminoethyl)-1,3-propanediamine; 323-tet = N,N-f-bis(3-aminopropyl)ethylene-diamine). The polyamine ligands are both coordinated in planar conformation, and the bond lengths of Ni to axial ligands are largely affected by the temperature. For 1, Ni-Cl and Ni-O distances of 2.475 and 2.176 Å respectively at 130 K is elongated to 2.485 and 2.192 Å respectively at 293 K, while the averaged Ni-N length are 2.082 and 2.083 Å for 130 and 293 K, respectively. Those for 2 are 2.142 to 2.165 Å for averaged Ni-O distances and 2.100 to 2.098 Å for the averaged Ni-N length, respectively.