Structure of dibromobis(triphenylarsine oxide)nickel(II), NiBr2(Ph3AsO)2

Abstract

C36H3oms2Br2NiO2, Mr=863.01, ortho- rhombic, Pca21, a = 18-826 (5), b = 10.594(6), c = 17.402 (6) A., V= 3470 (4) A 3, Z = 4, Dx = 1.652 g cm -3, A(Mo Ka) = 071073 A, /.~ = 47.60 cm -1, F(000) = 1704, T= 298 K, R = 0-059 for 724 observed reflections. The Ni H atom is coordi- nated to two Br ions (Br--Ni = 2.39 (1), 2.364 (8) A) and to the O atoms of the (Ph3AsO) groups (Ni--O = 1.94 (3), 2.00 (3) A) in a distorted tetrahedral con- figuration (Br--Ni--Br = 123.1 (5)°). Experimental. Synthesis of the title compound was performed as previously reported (Oliva, CasteUano, Zukerman-Schpector & Massabni, 1984). The data collection and refinement parameters for the title compound are summarized in Table 1. The structure was solved by Patterson and difference Fourier synthesis techniques. In the final cycles of blocked-matrix refinement only the heavy atoms As, Br and Ni were refined anisotropically; the phenyl rings were treated as rigid groups with indivi- dual isotropic temperature factors for the C atoms and a fixed isotropic temperature factor (B = 4.7 A 2) for the H atoms. Scattering factors for non-H atoms were taken from Cromer & Mann (1968) with corrections for anomalous dispersion from Cromer & Liberman (1970) and for H atoms from Stewart, Davidson & Simpson (1965). Programs used were SHELX76 (Sheldrick, 1976) and ORTEP (Johnson,