Two polymorphs of bisphenol-A diacetate [2,2-bis(p-acetoxyphenyl)propane] were characterized by solid-state 13C cross-polarization magic-angle spinning NMR, X-ray powder diffraction and differential scanning calorimetic measurements. The structure of one polymorph was determined by single-crystal x-ray diffraction methods, and shown to have two molecules in the asymmetric unit. The two polymorphs show markedly different molecular mobilities, as reflected in variable-temperature solid-state NMR measurements, with one polymorph exhibiting motional heterogeneity in the flipping of the phenylene rings.
Motional Heterogeneity and Polimorphysm of Bisphenol-A-Diacetate.
CASARINI, Daniele;
1993-01-01
Abstract
Two polymorphs of bisphenol-A diacetate [2,2-bis(p-acetoxyphenyl)propane] were characterized by solid-state 13C cross-polarization magic-angle spinning NMR, X-ray powder diffraction and differential scanning calorimetic measurements. The structure of one polymorph was determined by single-crystal x-ray diffraction methods, and shown to have two molecules in the asymmetric unit. The two polymorphs show markedly different molecular mobilities, as reflected in variable-temperature solid-state NMR measurements, with one polymorph exhibiting motional heterogeneity in the flipping of the phenylene rings.File in questo prodotto:
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