ISSN:
0749-1581
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The conformations of the isopropyl groups and the barriers to conformational interconversion in N,N-diiso-propylbenzamide (1), and its thio (2) and seleno (3) analogues have been studied by dynamic 1H NMR spectroscopy. In 1 only one conformation is observed, whereas 2 and 3 exist as mixtures of three conformations. The use of the strongly deshielding C=X (X = O, S, Se) group and comparison with earlier results on similar systems allows total assignment, in the case of 2, rectifying an earlier proposal. The temperature dependence of the NMR spectra of 2 and 3 clearly shows that the E- and Z-isopropyl groups rotate with very different rates, thus providing experimental evidence for the stepwise nature of the conformational interchange.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260230711
