Optimizing the optical and biological properties of 6-(1 H -benzimidazole)-2-naphthalenol as a fluorescent probe for the detection of thiophenols: a theoretical study.

The study presents the influence of structure modulation by introduction of selected donor and acceptor substituents on the properties of 6-(1 H -benzimidazole)-2(2,4-dinitrobenzenesulfonate)naphthalene used in thiophenol identification. The presence of -OH and -OR groups enhances the non-linear optics (NLO) response of the marker. The -NO 2 substituent maximizes the non-linear response and increases the amount of transferred charge and the charge-transfer distance. The introduction of the -OH, -NO 2 and -CN groups into the marker structure significantly improves the solubility and optical availability. The -NO 2 group however contributes to mutagenicity and carcinogenicity. The -OH and -OR groups can be successfully used in bioimaging to detect specific molecules containing the -SH group in their structure. At the same time, the -OR group minimizes the energy barrier necessary to break the bond between the chromophore and the linker. The paper also includes a comparison of optical and biological properties of structures before and after identification of thiophenols.