Dicarbocyanine and tricarbocyanine dyes: Novel synthetic approaches, photosensitization evaluation and antimicrobial screening

Hassan Abazied Shindy, Mohamed Abdallah El-Maghraby, Maha Mubark Goma and Nemat Abdelrahman Harb

Abstract

Novel dicarbocyanine dyes (pentamethine cyanine dyes), bis dicarbocyanine dyes (bis pentamethine cyanine dyes), tricarbocyanine dyes (heptamethine cyanine dyes) and bis tricarbocyanine dyes (bis heptamethine cyanine dyes) derived from the nucleus of furo[(3,2-d)pyrazole; (3',2'-d)oxazole] were prepared using novel synthetic approaches. The electronic visible absorption spectra were investigated in 95% ethanol to evaluate the photosensitization properties. The cyanine dyes were better photosensitizers in visible light to initiate the electronic transitions at higher wavelength bands (bathochromic shifted and/or red shifted dyes). Consequently, the photosensitization of the cyanine dyes decreases in visible light to initiate the electronic transitions at lower wavelength bands (hypsochromic shifted and/or blue shifted dyes). Antimicrobial activity of ten selected compounds was tested against four bacterial strains (Bacillus subtilis, Escherichia coli, Pseudomona aeruginosa and Staphylococcus aureus). The compounds were thought to be better antimicrobial active when they give higher inhibition zone against the tested strains. Consequently, the antimicrobial activity was promising and variable among all synthesized compounds against tested strains. Structural characterization and confirmations were determined by elemental analysis, visible, mass, IR and 1H NMR spectral data.