PHOSPHORUS CHEMICAL-SHIFT ANISOTROPIES IN SOLID TRIPHENYL PHOSPHITE AND MER,TRANS-BIS(TRIPHENYL PHOSPHITE)TRICARBONYL(THIOCARBONYL)CHROMIUM(0), CR(CO)3(CS)[P(OPH)3]2

The P-31 chemical shift anisotropies have been measured for solid trip henyl phosphite, P(OPh)3 (at 128 K), and the complex with the tricarbo nyl(thiocarbonyl)chromium(0) moiety, mer,trans-Cr(CO)3(CS)[P(OPh)3]2 ( at 298 K). The shift tensor is axially symmetric in the phosphite liga nd, and the major change upon complexation occurs for the components o f the shift tensor perpendicular to the bond direction. The crystal st ructure of the chromium complex has been determined by single-crystal X-ray diffraction at 293 K. The complex crystallizes in the centric P2 (1)/n (No. 14) space group with cell constants (at 20-degrees-C) a = 8 .166(3) angstrom, b = 11.530(2) angstrom, c = 20.183(2) angstrom, beta = 96.43(1)degrees, and Z = 2. The molecule is disordered on a crystal lographically imposed inversion center so that the thiocarbonyl ligand is superimposed on the trans carbonyl ligand (50:50).