Keli Zhong,Jie Zhao,Xue Zhou,Shuhua Hou,Yanjiang Bian,Jianrong Li,Lijun Tang
A new (8-hydroxyquinolin-2-yl)methylene picolinohydrazide derivative ( L ) has been successfully synthesized and characterized. The probe L displays high selectivity to Co 2+ in CH 3 CN/HEPES (1:1, V / V , 10 mmol·L −1 , pH=7.4) with a fluorescence "ON-OFF" response. The Co 2+ ion recognition event possesses some distinct features including rapid response, high selectivity and sensitivity, good anti-interference ability and being applicable within a wide pH range. Based on job's plot and ESI-MS studies, the 1:1 binding mode was proposed. The binding constant of L and Co 2+ is 1.63×10 8 L·mol −1 and the detection limit is 1.15 µmol·L −1 . Natural water samples experiments revealed that probe L can be potentially applied to the detection of Co 2+ in real environment.
Five quinoline derivatives containing different alkyl chains ( QLACn , n = 2, 4, 6, 8, 12) were synthesized to investigate the effect of alkyl chains on their photophysical properties. The fluorescent properties of the QLACn were affected by the alkyl chains, which indicated obvious blue-shifting trend and fluorescence emission are alkyl chains length-dependent by grinding-induced spectral shifts (Δλ MFC ). Longer alkyl-length revealed larger Δλ MFC . Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) measurements indicated that the transformation between microcrystalline and amorphous states upon external stimuli should be responsible for the observed reversible MFC behavior.