Steric factors in nitrite co-ordination. Part 1. Crystal structure of bis(NN′-diethylethylenediamine)(nitrito-OO′)nickel(II) tetrafluoroborate

Abstract

The preparations and electronic and i.r. spectra are reported for the complexes [NiL₂(NO₂)]X (X = BF₄ or ClO₄; L = RHNCH₂CH₂NHR or R₂NCH₂CH₂NH₂, R = Me or Et). The structure of the title complex has been determined from three-dimensional X-ray diffractometer data. The crystals are monoclinic, with unit-cell dimensions a= 11.338(1), b= 16.291(2), c= 11.934(1)Å, and β= 112.015(8)°, space group P2₁/c, and Z= 4. The structure has been refined by least squares to R 0.053 for 2 522 independent reflections. The complex is monomeric with a chelating nitrite group forming part of a distorted-octahedral environment about nickel. The diethylethylenediamine ligands are arranged in cis positions and there is an approximation to a diad in the cation. The steric factors leading to this geometry, as distinct from M–ONO–M bridging, are discussed.