Thomas Carl Clarke

Molecular Structure and Dynamics in Organic Solids: High Resolution Low Temperature 13 C NMR Studies

Abstract The development of cross polarization-magic angle spinning (CPMAS) has resulted in the achievement of near-liquid resolution in solid state 13 C NMR spectra. Therefore, the structure and dynamics of organic solids can now be studied on a carbon-by-carbon basis. Low temperature CPMAS capability permits the investigation of molecular dynamics in solids, and in particular in a temperature range heretofore inaccessible to high resolution NMR (15-200 K). We have developed and used low temperature CPMAS to study solid state effects on chemical exchange processes in organic and organometallic compounds and in carbonium ions. We have also developed a technique for measuring carbon-carbon bond lengths in amorphous solids using NMR. The geometry of cis-and trans-polyacetylene has been determined using this method.