Crystal structure and absolute configuration of (+)-tris[(–)-1,2-diphenylethylenediamine]cobalt(III) nitrate monohydrate

Abstract

The crystal structure and absolute configuration of the title compound has been determined from single-crystal X-ray data and refined by full-matrix least squares to R 0.085. The orange trigonal crystal has the unit-cell dimensions: a= 16.623(4), c= 14.834(9)Å, space group P3₂21, with Z= 3. The complex ion has strict C₂ symmetry but, excluding the phenyl substituents, approximates to D₃ symmetry. The average Co–N distance is 1.98 Å and the mean N–Co–N angle within a chelate ring is 83.4°. The [CoN₆] chromophore is compressed along the trigonal axis and azimuthally contracted. The complex ion is a lel isomer with the absolute configuration Λδδδ, while the ligand (–)dpen [(–)-1,2-diphenylethylenadiamine] has the S,S configuration.