Deuterium isotope effects on O-17 chemical shifts of intramolecularly hydrogen bonded systems

Deuterium isotope effects on O-17 chemical shifts are studied in a series o f intramolecularly hydrogen bonded o-hydroxy acyl aromatics and beta-diketo nes. Geometries and chemical shifts are calculated using DFT ab initio meth ods, Relationships between hydrogen bond strength represented as either R-O ... O, RO-H or R-O ... H, and the experimental parameters, (5)Delta(17)O(O D) and delta(17)O are demonstrated for non-tautomeric compounds. These plot s do also provide a method for establishing tautomerism in new compounds. ( 5)Delta(17)O(OD) as well as delta(17)O are found to be dominated by hydroge n bonding in terms of RO-H or R-O ... H distances and not influenced very m uch by the R-O ... O distance. (C) 1999 Elsevier Science B.V. All rights re served.