Crystal structures of tris(diethyldithiocarbamato)-rhodium(III) and -arsenic(III)

Abstract

The crystal structures of the title compounds, [Rh(CS2·NEt2)3], (I), and [As(CS2·NEt2)3], (II) have been determined by-X-ray diffraction from diffractometer data, and refined by least-squares to R 0.080 (I) and 0.058 (II) for 1 582 and 1 877 reflections. Crystals are monoclinic, space group P21/a, with Z= 4 in unit cells of dimensions : (I)a= 18.07(3), b= 8.276(3), c= 15.80(1)A, β= 96.35(4)°; (II)a= 18.543(4), b= 8.387(2), c= 15.870(3)A, β= 101.05(2)°. The compounds are isomorphous also with the manganese(III) derivative; whereas the MS6 core in (I) is quite close to D3 symmetry (mean Rh–S 2.368A), that of (II) is grossly distorted (as previously described) toward C3 symmetry (mean As–S 2.84 and 2.349A). In (II), the usual equality in the ligand C–S distances is destroyed as a result (mean C–S 1.68 and 1.76 A) and the surrounding angular geometry of the ligand also distorted. The arsenic has a close hydrogen contact (3.2 A) along the pseudo threefold axis from a neighbouring molecule.