Chemosensors are prepared through condensation reactions between polymeric amines and three different aldehydes;the activities of the three products were evaluated in DMF-H_(2)O(7:3,v/v)solvent system.Chemosensor 2c d...Chemosensors are prepared through condensation reactions between polymeric amines and three different aldehydes;the activities of the three products were evaluated in DMF-H_(2)O(7:3,v/v)solvent system.Chemosensor 2c demonstrated selectivity for Zn^(2+)enhancement of the fluorescence intensity at 420 nm.Upon binding of 2c with Zn^(2+),an approximately 9 fold enhancement in fluorescence intensity was observed due to the combined effect of ESIPT,CvN isomerisation and the two-channel quenching of PET.The investigation of the photophysical properties of 2c revealed that the sensor at low pH led to a shift in the emission profile because of the presence of two types of nitrogen i.e.sp^(2) and sp^(3) nitrogens and the pH dependent fluorescence profile is due to the protonation at sp^(3) hybridised nitrogen that influences the charge transfer transitions of 2c.However,the salt effect has not much influence on the photophysical properties of 2c;and 2c was found to form organic nano-particles(ONP)in a DMF-H_(2)O(1:99,v/v)solvent system and this material was found to detect a minimum of 40 nM concentration of Zn^(2+).The receptor 2c was found to be biocompatible through MTT assay and potent to detect Zn^(2+)in real biological conditions of microbial cells.The compounds 2a,2b and 2c while immobilized in PVC based membrane,exhibited their selectivity for zinc ions as ion selective electrodes.These electrodes responded linearly in a wide concentration range with a lower detection limit of 10μM.The electrodes have been successfully used as indicator electrodes in potentiometric titration of zinc ions with EDTA.展开更多
基金supported with research grant(SR/FT/CS-97/2010(G)from Department of Science and Technology(DST),Government of India.
文摘Chemosensors are prepared through condensation reactions between polymeric amines and three different aldehydes;the activities of the three products were evaluated in DMF-H_(2)O(7:3,v/v)solvent system.Chemosensor 2c demonstrated selectivity for Zn^(2+)enhancement of the fluorescence intensity at 420 nm.Upon binding of 2c with Zn^(2+),an approximately 9 fold enhancement in fluorescence intensity was observed due to the combined effect of ESIPT,CvN isomerisation and the two-channel quenching of PET.The investigation of the photophysical properties of 2c revealed that the sensor at low pH led to a shift in the emission profile because of the presence of two types of nitrogen i.e.sp^(2) and sp^(3) nitrogens and the pH dependent fluorescence profile is due to the protonation at sp^(3) hybridised nitrogen that influences the charge transfer transitions of 2c.However,the salt effect has not much influence on the photophysical properties of 2c;and 2c was found to form organic nano-particles(ONP)in a DMF-H_(2)O(1:99,v/v)solvent system and this material was found to detect a minimum of 40 nM concentration of Zn^(2+).The receptor 2c was found to be biocompatible through MTT assay and potent to detect Zn^(2+)in real biological conditions of microbial cells.The compounds 2a,2b and 2c while immobilized in PVC based membrane,exhibited their selectivity for zinc ions as ion selective electrodes.These electrodes responded linearly in a wide concentration range with a lower detection limit of 10μM.The electrodes have been successfully used as indicator electrodes in potentiometric titration of zinc ions with EDTA.
