Solvatochromism, optical and electronic properties of thiosemicarbazone derivatives in solution phase

The electronic structure, solvatochromic and some optoelectronic properties of five different thiosemicarbazone (TSCs) derivatives with different substituents consisted from indole ring, benzyl ring and conjugated thiosemicarbazide have been investigated in detail. UV–vis. absorption spectra of TSC compounds have been analyzed in solvent media with different polarity. The spectral changes are observed to forming of solvent effects and substituents. Spectral behaviors and electronic transitions are interpreted based on the UV-Vis. spectra. Solvatochromic behaviors were defined by linear solvation energy relationships via multiple linear regression analysis by using Kamlet-Abboud-Taft and Catalán parameters. In addition, the correlations of electronic absorption transition energy with Marcus optical dielectric parameter and Reichardt-Dimroth parameter were also determined. Some optoelectronic parameters such as forbidden band gap energy and refractive index have been determined in different solvent medium. Thiosemicarbazone derivatives have a global electronic absorption transition energy of about 3.351 eV. According to LSER calculations, polarizability-induction of electronic transitions of the investigated molecules is effective. The (E)-4-(4-nitrobenzyl)-1-(2-oxo-2H-indol-3(3aH)-ylidene)thiosemicarbazide (TSC-B) compound that does not a methoxy group and contain nitro group substituent and has the highest forbidden energy range.