THE CRYSTAL STRUCTURE OF TRIETHYLENETETRAMINENICKEL(II) PERCHLORATE

Abstract
The crystal structure of Ni(trien)(ClO4)2(trien = triethylenetetramine, NH2CH2CH2NHCH2CH2NHCH2CH2NH2) has eight formula units in an orthorhombic unit cell of dimensions: a = 14.67, b = 14.95, and c = 13.85 Å, with a space group of Pna21-C 9 2v . The structure was solved by Patterson and Fourier methods using film data and refined by least squares to a conventional R factor of 0.136 for the 1583 observed reflections. The coordination around each nickel atom is planar with four nitrogens in a trapezoidal arrangement. The perchlorate groups do not occupy the fifth and sixth coordination positions, but link, through hydrogen bonds, the essentially identical ligand complexes that comprise the asymmetric unit. The complex is the meso isomer with the central ring in the eclipsed cis form. Although the normal gauche conformation is not present in the central ring formed by the secondary nitrogens, the gauche conformation is present in the chelates formed between the secondary and primary nitrogens.