RESUMEN
The recently reported 19 F-detected dual-optimized inverted 1 JCC 1,n-ADEQUATE experiment and the previously reported 1 H-detected version have been modified to incorporate J-modulation, making it feasible to acquire all 1,1- and 1,n-ADEQUATE correlations as well as 1 JCC and n JCC homonuclear scalar couplings in a single experiment. The experiments are demonstrated using N,N-dimethylamino-2,5,6-trifluoro-3,4-phthalonitrile and N,N-dimethylamino-3,4-phthalonitrile.
RESUMEN
Modification of the recently reported 19 F-detected 1,1-ADEQUATE experiment that incorporates dual-optimization to selectively invert a wide range of 1 JCC correlations in a 1,n-ADEQUATE experiment is reported. Parameters for the dual-optimization segment of the pulse sequence were modified to accommodate the increased size of 1 JCC homonuclear coupling constants of poly- and perfluorinated molecules relative to protonated molecules to allow broadband inversion of the 1 JCC correlations. The observation and utility of isotope shifts are reported for the first time for 1,1- and 1,n-ADEQUATE correlations.
RESUMEN
Polyfluorinated and perfluorinated compounds in the environment are a growing health concern. 19 F-detected variants of commonly employed heteronuclear shift correlation experiments such as heteronuclear single quantum correlation (HSQC) and heteronuclear multiple bond correlation (HMBC) are available; 19 F-detected experiments that employ carbon-carbon homonuclear coupling, in contrast, have never been reported. Herein, we report the measurement of the 1 JCC and n JCC coupling constants of a simple perfluorinated phthalonitrile and the first demonstration of a 19 F-detected 1,1-ADEQUATE experiment.
RESUMEN
Poecillastrin A (1), a new polyketide-derived macrolide lactam, was isolated from a deep-water collection of the marine sponge Poecillastra species. The structure of poecillastrin A (1) was assigned using NMR data acquired at 500 MHz with an inverse-detection cryogenic probe and at 800 MHz with a room-temperature probe.