1 Funktionelle Biomaterialer, Department of Science and Environment, Roskilde University2 The Department of Science, Systems and Models, Roskilde University3 Department of Science and Environment, Roskilde University
OH stretching frequencies are investigated for a series of non-tautomerizing systems with intramolecular hydrogen bonds. Effective OH stretching wavenumbers are predicted by the application of empirical correlation procedures based on the results of B3LYP/6-31G(d) theoretical calculations in the harmonic and PT2 anharmonic approximations, as well as on experimental NMR parameters, i.e., proton chemical shifts (δH) and two-bond deuterium isotope effects on 13C chemical shifts (2ΔCOD). The procedures are applied in a discussion of the spectra of 2,6-dihydroxy-4-methylbenzaldehyde and 8-hydroxyquinoline N-oxide. The spectrum of the former displays a broad, composite band between 3500 and 2500 cm–1 which can be assigned to overlapping monomer and dimer contributions. In the latter case, the results support a reassignment of the OH stretching band of 8-hydroxyquinoline N-oxide; the reassignment is supported by correlation with the IR spectra of a series of substituted derivatives.
Journal of Molecular Structure, 2012, Vol 1018, p. 8-13