The crystal structure of Me2AsCC(AsMe2)·CF2·CF2[Fe(CO)3]2

Abstract

Crystals of the novel compound Me₂As[graphic omited]F₂[Fe(CO)₃]₂ are monoclinic, a= 9·37, b= 14·15, c= 14·82 Å, β= 96·1°, Z= 4, space group Cc. The structure was determined from three-dimensional Patterson and electron-density maps, using Mo-K_α scintillation-counter data, and refined by least-squares methods; the final R is 0·057 for 900 observed reflexions. The molecule contains two bonded iron atoms, with Fe–Fe = 2·88 Å. One iron atom is octahedrally co-ordinated to three carbonyl groups and the two arsenic atoms, with the sixth position occupied by the Fe–Fe bond; the second iron atom has trigonal bipyramidal co-ordination, the equatorial positions involving two carbonyl groups and a π-bond from the cyclobutene system, with the apical positions occupied by the third carbonyl group and the Fe–Fe bond.