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

Abstract

The 31P chemical shift anisotropies have been measured for solid triphenyl phosphite, P(OPh)3 (at 128 K), and the complex with the tricarbonyl(thiocarbonyl)chromium(0) moiety, me/V/-ti/M-Cr(CO)3(CS) [P(OPh)3] 2 (at 298 K). The shift tensor is axially symmetric in the phosphite ligand, and the major change upon complexation occurs for the components of the shift tensor perpendicular to the bond direction. The crystal structure of the chromium complex has been determined by single-crystal X-ray diffraction at 293 K. The complex crystallizes in the centric P2\/n (No. 14) space group with cell constants (at 20 °C) a = 8.166(3) Á, b = 11.530(2) Á, c = 20.183(2) Á, ß = 96.43(1)°, and Z = 2. The molecule is disordered on a crystallographically imposed inversion center so that the thiocarbonyl ligand is superimposed on the trans carbonyl ligand (50:50).

Calorimetric and Dielectric Investigations of the Phase Transformations and Glass Transition of Triphenyl Phosphite

“…One of the crystal phases of TPP is undoubtedly an ordinary crystalline phase whose space group seems to be unknown. A brief interpretation of its powder pattern indicated that isotropic rotation of the TPP molecule occurs in the crystal phase, 20 and thus this is a plastic phase. If that rotation was about the dipolar, 3-fold axis of the molecule, it would have no dielectric consequences.…”

Metastable Solid Phase at the Crystalline-Amorphous Border: The Glacial Phase of Triphenyl Phosphite

“…23 Earlier, before identification of and focus on the glacial phase, 31 P NMR studies were carried out on low-T TPP. 24 To all these we add our present studies.…”

“…There followed careful adiabatic calorimetry measurements; calorimetric and dielectric studies; a wide range of 31 P nmr, dynamic light scattering, dielectric relaxation, and calorimetric studies; , Raman and X-ray studies; , dielectric, X-ray diffraction and adiabatic calorimetric measurements; and neutron scattering studies . Earlier, before identification of and focus on the glacial phase, 31 P NMR studies were carried out on low-T TPP . To all these we add our present studies.…”

“…Our only current interest in 31 P NMR arises from the fact that Huang et al reported a narrow Lorentzian component (characteristic of a liquid well above the glass transition) at T's as low as 156 K, i.e., well below the glass transition. 24 We checked, and no such liquidlike component exists below 210 K in the glass, molecular crystal, or glacial phase.…”