Evaluation of 4,4'-Diaminodiphenylmethane as a Platform for Proton, pH, and Metal Ion Responsive Fluorescent Probe

4,4'-Diaminodiphenylmethane (DPM)-based fluorescent probes have been reported.We designed a new fluorescent probe 1, having bis(4methoxyphenyl)maleimide and an amino group as a fluorophore and a sensing part, respectively, in which DPM was used as a platform for sensing molecules to utilize its advantage.The fluorescence intensity of 1 increased upon adding trifluoroacetic acid in MeCN, CH2Cl2, and toluene, indicating that 1 showed as a proton sensor.The fluorescence spectral change of 1 was observed in a mixture of MeCN and various pH buffers.Moreover, 1 behaved as a metal (zinc or nickel) ion sensor with 2-formylpyridine by forming the Schiff base skeleton.The metal ion sensing behavior of 1 could be applied to an AND circuit.