Accession Number : AD0729332

Title :   NMR Relaxation Studies of Solid Hexamethylethane and Hexamethyldisilane.

Descriptive Note : Technical rept.,

Corporate Author : ILLINOIS UNIV URBANA NOYES CHEMICAL LAB

Personal Author(s) : Albert,S. ; Gutowsky,H. S. ; Ripmeester,J. A.

Report Date : 23 AUG 1971

Pagination or Media Count : 23

Abstract : Pulsed NMR studies in the static and rotating frames of the proton spin-lattice relaxation time were carried out on solid hexamethylethane (HME) (CH3)3CC(CH3)3 and hexamethyldisilane (HMDS) (CH3)3SiSi(CH3)3 beteen 77K and the melting point. In the low temperature phase of HMDS, the proton relaxation produced by reorientation of the CH3 group about its three-fold axis (C3 rotation) is resolved from that produced by reorientation of the molecule about its three-fold axis (C3' rotation). In HME the effects of the two types of rotation are combined, and have an apparent activation energy of 3.10 plus or minus 0.15 kcal/mole. In the high temperature phase of both solids, self diffusion as well as overall molecular reorientation or tumbling governs the proton relaxation. The properties of these two compounds are discussed briefly in relaxation to the NMR and thermodynamic studies of them. (Author)

Descriptors :   (*SILANES, *NUCLEAR MAGNETIC RESONANCE), (*ALKANES, NUCLEAR MAGNETIC RESONANCE), RELAXATION TIME, SOLIDS, ROTATION, DIFFUSION, TEMPERATURE

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE