The Synthesis And Electronic Spectral Properties Of Thiourea Derivatives With Push-pull Electronic Effects

The conjugation of molecules, degree of rigidity of the structures and nature of thesubstituents all have a strong influence on the fluorescence characteristics and intensity ofthe phosphors. The introduction of push-pull electronic groups to the molecules makessome of the molecules of conjugated structure emit charge transfer fluorescence. Thedouble proton channel of thiourea molecules has made this kind of phosphor widely usedin the development of the fluorescent ion probes. Inspired by the effects of substituents onfluorescence of benzanilide and its derivatives, the work of this paper has synthesized sixsubstituted diphenylthiourea and fourteen benzoylthiourea which have not ever beenreported with push-pull electronic effects.In this paper, elemental analysis, IR, NMR, X-ray single crystal diffraction and othermethods have been used for structural characterization of synthesized thiourea derivatives.On the basis of determination of the structures, the work of this paper also measuredUV-vis absorption, fluorescence and other electronic spectra of all compounds in differentsolvents, so that we can study the effects on the electronic spectra caused by intramolecularhydrogen bond interaction, hydrogen bond of solvent, polarity of solvent, substituents andothers.Besides, this paper has used MP2of HF ab initio and CASSCF methods to calculatethe ground-state and excited-state molecular structures and related structural information.While combining theory with experiment, this paper explained the mechanism of theralated electronic spectra as well. Calculating the absorption and emission spectra in thesolvents by using solvent model (PCM), this paper also interpreted the red shift and blueshift of electronic spectra occurred in the experiments, which provides the theoretical basisfor the development of the anionic probe and other applications of thiourea.