Masao TAKAYANAGI (Tokyo Univ. Agric. and Tech. and IMS), Munetaka NAKATA (Tokyo Univ. Agric. and Tech.), Yukihiro OZAKI (Kwansei-Gakuin Univ.), Keiji IRIYAMA (The Jikei Univ. School of Medicine) and Mitsuo TASUMI (Univ. Tokyo)
[J. Mol. Struct. 407, 85 (1997)]
Intermolecular interactions of merocyanine dyes, 5-[2-(3-ethyl-2-benzothiazolylidene)-1-methyl-ethylidene]-3-ethyl-2-thioxo-4-thiazolidinone [Et(Me)MD] and 5-[2-(3-ethyl-2-benzothiazolylidene)ethylidene]-3-ethyl-2-thioxo-4-thiazolidinone [EtMD], in various solvents were studied. The spectra of the dyes in an argon matrix-isolated state and in a thin-film state were also measured. In addition to the well-known solvent effects appearing in visible absorption spectra, the solvent dependence of resonance Raman and infrared absorption spectra was examined. The visible absorption bands shift to the longer wavelength region as the polarity of the solvent increases, while the C=O and C=C stretching bands shift to the lower frequency region. Correlation between the visible absorption maximum and C=C stretching vibrational frequency was found, for the first time. The solvent effects on the spectra are explained in term of intermolecular interactions between merocyanine dyes and solvent molecules.