Novel aminated benzimidazo[1,2-a]quinolines as potential fluorescent probes for DNA detection: Microwave-assisted synthesis, spectroscopic characterization and crystal structure determination

摘要

A synthesis of novel benzimidazo[1,2-a]quinolines, substituted with piperidine, pyrrolidine and pipera-zine nuclei has been accomplished using an uncatalyzed amination protocol under microwave heating. All compounds were characterized by means of ~1H, ~(13)C NMR, IR, UV/Vis and fluorescence spectroscopy. Crystal and molecular structures of 2-chloro- and 2-piperidinyl-benzimidazo[1,2-a]quinoline-6-carbonitrile were determined by X-ray diffractometry. These molecules are essentially planar. Their molecular assembly is characterized by the existence of weak intermolecular hydrogen bonds of C—H···N type and π—π aromatic interactions. The π-π aromatic stacking observed in the solid state structures of the 2-chloro-and 2-piperidinyl- derivatives are not analogous. The spectroscopic properties of these amino substituted benzimidazo[1,2-a]quinolines as their hydrochloride salts in the presence of ct-DNA were studied by means of fluorescence spectroscopy. Comparison of binding properties of amino substituted benzimidazo [1,2-a]quinoline hydrochloride salts to ct-DNA revealed significantly enhanced fluorescence emission intensity and thus offer the potential applications as a DNA-specific fluorescent probes.