Crystal structure of di-iodo[ethylenebis(oxyethylene)]bis(diphenylphosphine)nickel(II)

Abstract

The structure of the Ni(poop)I₂ complex {poop =[ethylenebis(oxyethylene)]bis(diphenylphosphine)} has been determined by X-ray analysis. The crystals are monoclinic, space group P2₁/c, with Z= 4 in a unit cell of dimensions a= 11·56 ± 0·01, b= 18·32 ± 0·03, c= 14·88 ± 0·03 Å, and β= 111·5 ± 0·2°. The structure has been solved by the heavy-atom technique and refined by full-matrix least-squares to R 0·091 over 1654 independent observed reflections, collected by photographic methods.

This is the first low-spin nickel(II) complex whose structure has been shown by X-ray to be an example of co-ordination intermediate between square planar and tetrahedral. The donor set is formed by two iodine and two phosphorus atoms. Statistically the oxygen atoms occupy two positions: in the position closer to the metal, the Ni ⋯ O distances are 3·20(7) and 3·16(6)Å. These contacts contribute to the stabilization of this unusual co-ordination.