On the correlation between bond lengths, chemical shifts, and cone angles in octahedral cobaloximes containing P-donor ligands. Crystal structure of trans-chlorobis(dimethylglyoximato)(phosphite)cobalt(III) complexes with phosphite = P(OMe)2Ph and P(OMe)Ph2

Abstract

The crystal structures of the title compounds, [CoCl(Hdmg)₂{P(OMe)₂Ph}](1) and [CoCl(Hdmg)₂{P(OMe)Ph₂}](2), are reported and discussed. Compound (1) crystallizes in the tetragonal system, space group I4₁/a, with unit-cell parameters a = 33.78(1), c= 8.421(6)Å, and Z= 16; (2) crystallizes in the orthorhombic system, space group Pbca, with unit-cell parameters a = 18.230(8), b= 15.725(7), c= 17.134(8)Å, and Z= 8. Both structures have been solved by Patterson and Fourier methods and refined by block-diagonal anisotropic least-squares methods to final R values of 0.030 for both compounds, using 1 359 (1) and 1 859 (2) independent reflections. The Co–Cl and Co–P bond lengths are 2.288(2) and 2.213(2)Å, in (1) and 2.290(1) and 2.242(1)Å in (2). The equatorial dimethylglyoximate ligands are nearly coplanar making dihedral angles of 2.3 and 0.9° in (1) and (2) respectively. Each unit of (1) clathrates 0.125 toluene molecules in large channels around a kind of tetrad rotatory inversion axis. Linear correlations between Co–P bond lengths, Tolman's cone angles, and ¹H n.m.r. chemical shifts are found and discussed in terms of the steric cis influence in the [CoX(Hdmg)₂(PR₃)] series.