Single X-ray crystal and spectroscopic investigation of novel biologically active donor–acceptor chalcones as specific application for opto-electronics and photonics

Abstract

Chalcones were synthesized by reaction of 3-acetyl-2,5-dimethylthiophene with corresponding active aldehyde in ethanolic NaOH. The structure of these compounds was established by elemental analysis, IR, 1H NMR, 13C NMR and EI-MS spectral analysis. UV–Vis and fluorescence spectroscopy measurements provided that compounds are good absorbent and fluorescent. Fluorescence polarity study demonstrated that the compound 1 & 2 was sensitive to the polarity of the microenvironment provided by different solvents. In addition, spectroscopic and physicochemical parameters, including electronic absorption, extinction coefficient, Stokes shift, oscillator strength, transition dipole moment and photochemical quantum yield were investigated in order to explore the analytical potential of synthesized compound 1 & 2. The anti-bacterial activity of the compound 1 & 2 were first tested in vitro by the disk diffusion assay against two Gram-positive (Aeromonas hydrophila and Yersinia enterocolitica) and two Gram-negative (Listeria Monocytogenes and Pseudomonas aeruginosa) bacteria, and then the minimum inhibitory concentration was determined with the reference of standard drug tetracycline. The results showed that compound 2 is better inhibitor of both types of the bacteria (Gram-positive and Gram-negative) as compared to tetracycline.