On prediction of OH stretching frequencies in intramolecularly hydrogen bonded systems

详细信息	查看全文 | 推荐本文 |

• 作者：Poul Erik Hansen ; ^{poulerik@ruc.dk} ; Jens Spanget-Larsen ; ^{spanget@ruc.dk}
• 关键词：OH stretching frequencies ; Two-bond isotope effects ; OH chemical shifts ; DFT calculations ; Intramolecular hydrogen bonding
• 刊名：Journal of Molecular Structure
• 出版年：2012
• 期刊代码：62_00222860
• 类别：ch
• 出版时间：27 June, 2012
• 卷：1018
• 期：Complete
• 页码：8-13
• 文件大小：504 K

摘要

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 (未_H) and two-bond deuterium isotope effects on ¹³C chemical shifts (²螖C_OD). 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^鈭? 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.