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

Abstract

A synthesis of novel benzimidazo[1,2- a]quinolines, substituted with piperidine, pyrrolidine and piperazine nuclei has been accomplished using an uncatalyzed amination protocol under microwave heating. All compounds were characterized by means of 1H, 13C 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.