Two 1,8- Naphthalimides as Proton-Receptor Fluorescent Sensors for Detecting PH

• DOI: 10.1007/s10812-017-0386-6
• Publication Date: 2017-01-26T06:16:37Z
• Authors: H.-L. Wu; H.-P. Peng; F. Wang; H. Zhang; C.-G. Chen; J.-W. Zhang; Z.-H. Yang
• Keywords: Buffer solution

Two proton-receptor sensors for detecting pH change based on 1,8-naphthalimide, N-allyl-4-(4'-N,N-dioctylpropionamide-acetamido-piperazinyl)-1,8-naphthalimide (1), and N-(N,N-dioctylpropionamide-acetamido)-4-allyl-1-piperazinyl-1,8-naphthalimide (2), were designed, synthesized, and characterized. Photophysical characteristics of the sensors were investigated in different organic solvents and Britton–Robinson buffer/EtOH (1:1, v/v) solution. Sensor 2 displayed a good sensor activity towards protons within the pH range from 3.29 to 6.59, while sensor 1 demonstrated sensitivity to lower pH values from 2.21 to 4.35. The selectivity of the pH sensors toward protons in commonly used buffer solutions and in the presence of metal cations (Na+, K+, Ca2+, Mg2+, Al3+, Pb2+, Fe3+, Ni2+, Zn2+, Cu2+, Hg2+, Ag+, Co2+, Cr3+, Mn2+, and Cd2+) was studied by monitoring the changes in their fluorescence intensity. The results obtained indicate that the synthesized derivatives hold potential for monitoring pH variations between 2.21 and 6.59 in strong acid environments and bio-samples.