Substituent and solvent effects on intramolecular charge transfer of 5-arylidene-2,4-thiazolidinediones

The absorption spectra of twelve 5-arylidene-2,4-thiazolidinediones were recorded in twenty one solvents in the range from 300 to 600 nm. The effect of specific and non-specific solvent–solute interactions on the absorption maxima shifts were evaluated by using the Catalán solvent parameter set. Furthermore, the experimental findings were interpreted with the aid of ab initio MP2 and time-dependent density functional (TD-DFT) methods. It was found that different substituents significantly change the extent of conjugation in the molecules and further affect their intramolecular charge transfer character.

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► The UV/vis spectra of twelve 5-arylidene-2,4-thiazolidinediones were studied in 21 solvents.
► The UV/vis spectral characteristics are more substituent-dependent than solvent-dependent.
► The LSER analysis imply that solvent polarizability is the main factor influencing the shifts of λmax.
► Different substituents change conjugation effect and affect the ICT character of these molecules.