Eisuke ITO,* Hiroshi OJI,* Tohru ARAKI,* Kazuyoshi OICHI,* Hisao ISHII,* Yukio OUCHI,* Toshiaki OHTA,** Nobuhiro KOSUGI, Yusei MARUYAMA,*** Toshio NAITO,**** Tamotsu INABE**** and Kazuhiko SEKI* (*Nagoya Univ., **Univ. Tokyo, ***Hosei Univ., ****Hokkaido Univ.)
[J. Am. Chem. Soc. 246, 475 (1997)]
The tautomerism for five N-salicylideneaniline derivatives in solid phase was studied by near-edge X-ray absorption fine structure (NEXAFS) spectroscopy at the N K- and O K-edges as well as X-ray photoelectron spectroscopy (XPS) in the N 1s and O 1s regions. The NEXAFS spectral features were assigned by the comparison with the core excitation spectra of reference compounds and ab initio MO calculations of the core-excited states by the improved virtual orbital method using the relaxed Hartree-Fock orbitals. The tautomeric structures were deduced by the intensity of peaks characteristic of the tautomers in OH- and NH-forms. These results demonstrate the usefulness of NEXAFS as well as XPS for studying the tautomerism in hydrogen bonded systems.