Synthesis, Spectroscopic, Physicochemical, Crystal Structure and DFT Studies of 4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile Based Azomethine Dyes

摘要

Three new azomethine dyes were synthesized via a simple condensation method using 2-amino- 4,5,6,7-tetrahydro-benzo[b]thiophene-3-carbonitrile and a variety of aldehydes. The structures of1 13 synthesized compounds were established by spectroscopic (FT-IR, H NMR, C NMR, MS) andelemental analyses. UV-Vis and fluorescence spectroscopy measurements proved that all compoundshave good absorbance and fluorescence properties. Fluorescence polarity studies demonstrated thatthese compounds were sensitive to the polarity of the microenvironment provided by differentsolvents. In addition, spectroscopic and physicochemical parameters, including singlet absorption,extinction coefficient, Stokes shift, oscillator strength and dipole moment, were investigated in order toexplore the analytical potential of the synthesized compounds. Three-dimensional structures werestudied using single crystal x-ray diffraction. Optimized geometries, electronic structure and frontiermolecular orbital energies were studied theoretically, and the energy gap (E) of II was found to berelatively greater than those for I and III, while I and III have almost the same energy gaps.