We report the synthesis of 2-(4,5-diphenyl-1Himidazole-2-yl)phenol (TPI-9) as an interesting fluorescent molecule displaying Excited-State Intramolecular-Proton-Transfer (ESIPT) with stokes shift of 120 nm. Phenolic compounds with the ability to form intramolecular hydrogen bonds and subsequent proton transfer are known as ESIPT fluorophores. Proton accepting ability can increase significantly by tailoring electron-donating groups. With the assistance of an environment-friendly organocatalyst, 10camphor sulfonic acid (10-CSA), TPI-9 was synthesized to introduce substituents with electron-donating abilities to develop an efficient ESIPT mechanism. Factors influencing the emission, such as solvent, pH, and metal ions, are investigated. Quenching of fluorescence by Cu 2 + through chela-tion enhancement quenching effect with a high selectivity allowed the establishment of a Cu 2 + sensor with an LoD of 0.57 ppm and a ratiometric estimation with an LoD of 0.73 ppm. Metal binding (2 : 1) stoichiometry and quenching constant (0.0072 mol À 1 s À 1 ) are calculated from Job's and Stern-Volmer plots. Density functional theory (DFT) calculations are in accordance with the experimental results. Competitive replacement of TPI-9 by amino acids restores ESIPT, consequently, the fluorescence. Thus, an "off-on" fluorescence sensor for amino acid estimation is developed under 1 minute incubation. A linear relationship between amino acid concentration and fluorescence intensity is in 0-20 μg/mL range, and the LoD is less than 2.2 μg/mL.
Deoxyribose nucleic acid (DNA) is found to be the most efficient pharmacological target of many synthetic molecules which are deemed as potential drugs with clinical applications. DNA binding agents are known to regulate several cell functions (gene expression and replication) by adopting various protocols which include the annihilation of the cell membrane, interruption in protein synthesis, and irreversible binding to cell receptors. Recently, several studies have explored fundamental aspects of drug-DNA interactions, providing new insights into the driving forces that render the formation of the drug-DNA complex. In order to study and understand these biologically important reaction mechanisms, several screening tools have been devised and the specificity of drug molecules binding to DNA were studied in detail. This review will discuss the utilization of various analytical tools which include UV-vis spectroscopy, fluorescence spectroscopy, circular dichroism, viscosity measurement, Raman spectroscopy, cyclic voltammetry, and DNA fragmentation assay used for studying drug binding mode and the mechanism involved.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.