13C CP MAS NMR and GIAO-CHF calculations of coumarins

Abstract

13C cross-polarization magic-angle spinning NMR spectra were recorded for a series of solid coumarins. Ab initio calculations of shielding constants were performed with the use of GIAO-CHF method. The combined CPMAS NMR and theoretical approach was successful in characterizing solid-state conformations of coumarins; a relationship σ (ppm)=−1.032× δ+205.28 ( R 2=0.9845) can be used to obtain structural information for coumarins, for which solid-state NMR or crystal structure data are not available.