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Full-Text Articles in Physical Sciences and Mathematics
Solid State Proton Spin Relaxation And T-Butyl And Methyl Group Reorientation In 1-Bromo-2,4,6-Tri-T-Butylbenzene, Anne M. Fry, Peter A. Beckmann, Albert J. Fry, Peter C. Fox, Ari Isenstadt
Solid State Proton Spin Relaxation And T-Butyl And Methyl Group Reorientation In 1-Bromo-2,4,6-Tri-T-Butylbenzene, Anne M. Fry, Peter A. Beckmann, Albert J. Fry, Peter C. Fox, Ari Isenstadt
Physics Faculty Research and Scholarship
We have used the solid state proton spin relaxation technique to investigate the barriers for methyl and t-butyl group reorientation in polycrystalline 1-bromo-2,4,6-tri-t-butylbenzene. The barriers in the range of 15-19 kJ/mol (3-5 kcal/mol) are compared with those found in related molecules. It is shown that the neighboring ring bromine atom has an effect on the barrier for t-butyl group reorientation similar to that of a neighboring hydrogen atom despite the significantly larger van der Waals' radius of a bromine atom. This most likely occurs because of the relatively long carbon-bromine bond, the distorted ring geometry, and the relatively high polarizability …
Solid State Proton Spin Relaxation In Ethylbenzenes: Methyl Reorientation Barriers And Molecular Structure, Peter A. Beckmann, Laura Happersett, Antonia V. Herzog, William M. Tong
Solid State Proton Spin Relaxation In Ethylbenzenes: Methyl Reorientation Barriers And Molecular Structure, Peter A. Beckmann, Laura Happersett, Antonia V. Herzog, William M. Tong
Physics Faculty Research and Scholarship
We have investigated the dynamics of the ethyl groups and their constituent methyl groups in polycrystalline ethylbenzene (EB), 1,2-diethylbenzene (1,2-DEB), 1,3-DEB, and 1,4-DEB using the solid state proton spin relaxation (SSPSR) technique. The temperature and Larmor frequency dependence of the Zeeman spin-lattice relaxation rate is reported and interpreted in terms of the molecular dynamics. We determine that only the methyl groups are reorienting on the nuclear magnetic resonance time scale. The observed barrier of about 12 kJ/mol for methyl group reorientation in the solid samples of EB, 1,2-DEB, and 1,3-DEB is consistent with that of the isolated molecule, implying that …