13C CPMAS NMR spectra of solid proton-exchanging p-substituted benzoylacetones: observation of 13C, 35,37Cl residual dipolar coupling in the p-chloro derivative

Abstract

Residual dipolar coupling to spin-3/2 ^35,37Cl nuclei appears as a symmetric doublet of 0.69 kHz in the ¹³C CPMAS NMR spectrum of p-chlorobenzoylacetone at 75.4 MHz, in agreement with theoretical calculations; carbon chemical shifts of a series of p-substituted benzoylacetones undergoing solid proton transfer are also reported, which show tautomeric populations similar to the solution ones.