KCS

A novel Schiff base probe (N,N′?bis(N?dimethylcarbamoyl?salicyl?2?imine)carbohydrazone) was synthesized and investigated for chemosensing purposes. Strongly selective ‘Turn?ON’ fluorescence signals were found for Cu2+ at 345 nm (85?fold) and for Al3+ at 445 nm (771?fold). Biothiols (L?cysteine, homocysteine, glutathione, N?acetyl cysteine) showed partial reversibility for Cu2+ fluorescence. Cu+, in the presence of Al3+, presented strong fluorescence at 360 nm (32?fold), likely occurring from H+ generated by Al3+ hydrolysis. H+ generated by Al3+ highly enables Cu+ fluorescence signaling based on proposed redox non?innocence. Reliability of Cu+ probing in this system was reasonable by verification via EPR analysis and lifetime measurements, which were collected under inert and ambient conditions. This probe is novel for Cu+ chemosensing in terms of having no soft donor atoms typical for such probes and serves as the first discriminator of mono? and divalent copper by a fluorescence ‘turn?ON’ signal via non-innocent mechanism.