Crystal structure of mer-trichloro(dimethylformamide)(1,10-phenanthroline) chromium(III)

Abstract

The crystal structure of the least-soluble isomer of trichloro(dimethylformamide)(1,10-phenanthroline)chromium(III) has been determined from photographic data collected about the c crystallographic axis. The monoclinic crystals have space group P2₁, with Z= 2, unit-cell dimensions a= 9.77 ± 0.02, b= 13.19 ± 0.04, c= 6.66 ± 0.02 Å, β= 104.7 ± 0.2°. Parameters for non-hydrogen atoms were refined by least-squares methods to R 8.7% for 1 189 reflections.

The chloro-ligands are disposed in a meridional configuration about the chromium atom which has essentially octahedral geometry. The equatorial Cr–Cl is markedly shorter (6σ) that the two axial Cr–Cl bonds and the difference is interpreted in terms of π bonding. The dimethylformamide is bound via the oxygen atom. The related new complexes [CrCl₃(terpy)](terpy = 2,2′,2″-terpyridine) and [CrCl₃(phen)](phen = 1,10-phenanthroline) are reported together with i.r. spectra and other physical measurements.