Novel hemicyanine dyes and aza-hemicyanine dyes having the nucleus of furo [(3,2- )imidazol] iodide salt were prepared. The electronic visible absorption spectra of all the synthesized hemicyanine dyes and aza-hemicyanine dyes were investigated and in 95 % ethanol solution to evaluate their spectral characterization. The antimicrobial effects of some selected dyes were tested against various bacterial and fungal strains (Escherichia coli, Staphylococcus aureus, Aspergillus flavus and Candida albicans) to assess their antimicrobial (bactericidal and fungicidal) properties. The results discussed in this study revealed that both the spectral characterization and the antimicrobial properties of the examined dyes is highly effected by the type of the X substituted in the phenyl ring system for the hemicyanine dyes and by the type of the phenyl and/or the naphthyl ring system for the aza-hemicyanine dyes. Structural confirmations were identified by elemental analysis, visible spectra, IR and 1 H NMR spectroscopic data.Keywords: cyanine dyes, hemicyanine dyes, synthesis, absorption spectra, antimicrobial activity, aza-hemicyanine dyes.
IntroductionHemicyanine dyes (Kim, 2006;Hammer, 1964;Raue, 1990; Pardal et al., 2002;Deligeorgiev, 2005;Mazinres, 2007;Nagarajan, Perumal, 2004; Lai et al., 1997;Kabatc et al., 2015;Malegoll et al., 2005; Narayan, Ansari, 2008;Davis et al., 2004) are one of the most widely used and important class of functional dyes. They are used as sensitizers and other additives in the photographic industry, chemosensors, indicator dyes, in optical recording media in laser disks, as flexible dyes, in textile industry, laser dyes, as optical sensitizers and in various other fields, for example dye-sensitized solar cells and dyes with non-linear optical properties. The most important applications for these dyes are in bio-labeling and in medicinal analysis. In addition, hemicyanine dyes (Davis et al., 2004;Shindy, Koraiem, 2008;Shindy et al., 2014;Davis et al., 2006;Wuskell et al., 2006;Banerji et al., 1982;Jha, Banerji, 1985;Jha, 1986;Heilbron, Walter, 1925;Ren et al., 2012; Shindy, 2015;Shindy, 2007) is common fluorescence probe for electrical membrane potential in biochemistry and biophysical area. It is also a very important fluorescence dyes applied in lasers, molecular electronics and nonlinear optical photolimiting devices. Besides,