Vibrational and NMR Spectroscopic Studies of Some Inorganic and Organic Crystalline Solids.

The vibrational spectra of (eta ^5-C_5H_5 )Re(CO)_3, (eta^5 -C_5Me_5)Re(CO) _3, (eta^6-C _6H_6)Cr(CO) _2(CS), Cr(CO)_5(CS), Re(CO)_5Cl, CH_3 Re(CO)_5 and CH_3 Mn(CO)_5 have been recorded under high pressures (< 50kbar). Several phase transitions have been detected. The effects of pressure on the metal-ligand bonding interactions have been evaluated. The phase behaviour of C_{60}, K_2SnBr_6, K_2WO_4, K_2CrO_4 and Cs_2 (B_{10 }Cl_{10}) has also been examined by high-pressure vibrational spectroscopy. ^{13}C chemical shift tensors and anisotropies have been obtained for (eta^6-C_6H _6)Cr(CO)_2(CS), (eta^6-C_6 H_6)Cr(CO)_3 , K (PtCl_3(eta^2 -C_2H_4)) and trans- (PtCl_2(eta^2 -C_2H_4)) _2. The CS ligand shielding ansiotropy is the largest ever observed for a ^{13 }C nucleus (530 ppm). ^{31 }P chemical shielding tensors have been determined for PPh_3, P(OPh)_3, trans-Cr(CO)_4(CS)(PPh _3) and trans-Cr(CO)_3(CS) (P(OPh)_3) _2. The results provide new insights into metal-phosphorus bonding interactions. The molecular dynamics of the orientationally -disordered, cage hydrocarbons, 1-bromo- and 1-chloroadamantane, 1-adamantanecarboxylic acid and 2-adamantanone, have been investigated by ^{13}C spin-lattice relaxation and dipolar dephasing time measurements. The motions in the disordered phases are different from those proposed on the basis of neutron scattering data. The phase behaviour of 1,3-dimethyladamantane has been studied by a combination of vibrational and proton NMR spectroscopy. The phase transitions in the cyclic hydrocarbons, cyclooctane, cyclooctanone and cyclohexanone, have been probed by vibrational spectroscopy. Unit cell symmetries have been proposed for all three compounds in their ordered phases. Cyclooctane and cyclooctanone form metastable phases. The different molecular motions in solid cyclohexanone have been established by ^2H NMR lineshape analysis.