Interaction of lanthanide shift reagents with 5-R-3-thiazolylchromones. Slow exchange in the LSR-substrate complex

Abstract

The interaction of Eu(FOD)₃ with 5-substituted 3-hetarylchromones has been studied. It has been shown that the nature of the substituent at position 5 of the chromone nucleus affects the direction of coordination of the LSR and the rate of exchange between coordinated and free substrate molecules. The latter caused large exchange broadening of those signals for which a large lanthanide induced shift was observed. Complex formation with the LSR may change the conformational composition of substrate molecules and lead the molecule to change to a conformation which reacts more effectively with the LSR. Exchange broadening is explained by chelation of the LSR by the bidentate substrate molecule.

How to Cite
Turov, A. V.; Khilya, V. P. Chem. Heterocycl. Compd. 1995, 31, 1108. [Khim. Geterotsikl. Soedin. 1995, 1264.]

For this article in the English edition, see DOI https://doi.org/10.1007/BF01165058