Preparation and x-ray crystal structure of (benzonitrile)tris(triphenylphosphorane)nickel(0)

Abstract

Treatment of triphenylphosphine with bis(cycloocta-1,5-diene)nickel(0) in toluene followed by addition of benzonitrile gave two nickel(O) complexes. When the nickel/phosphine ratio was 1 : 3 the (benzonitrile)tris(triphenylphosphorane)- nickel(0) complex was obtained. With a nickel/phosphine ratio of 1 : 2, along with the first complex a quite different (unidentified) product was obtained. The crystal and molecular structure of (benzonitrile)tris(triphenylphos- phorane)nickel(0) was determined from X-ray diffractometer data. The structure was solved by Patterson and Fourier methods and refined by least-squares techniques to R = 0.103 for 3580 independent reflections. Crystals are monoclinic, space group C2/ c, with Z = 8, in a unit cell of dimensions: a = 42.035(29), b = 10.677(9), c = 25.095(10) Å;β = 109.75(6)°. The coordination of the nickel atom is nearly tetrahedral. The benzonitrile residue is linked to the metal through its N atom (NiN distance = 1.889(11) Å). The overall shape of the molecule is determined by the juxtaposition around the metal of the phosphorous atoms, which have nearly tetrahedral coordinations. Three of the nine PC(Phen) bonds take up nearly eclipsed conformations while the other six are in nearly staggered positions. The triphenylphosphorane groups assume a propeller-like shape.