TRACE LEVEL RECOGNITION OF PB2+ AND I? IONS IN AQUEOUS MEDIUM USING A PYRIDO-PYRIMIDINE CHEMOSENSOR: EXPERIMENTAL AND DFT STUDIES

Samadhan R. Patil, Jitendra P. Nandre, Prashant A. Patil, Pritesh R. Jain, Suban K. Sahoo, Chullikkattil P. Pradeep, Debasis Das, Timothy J. Prior, Carl Redshaw, Umesh D. Patil, Ashok A. Patil*

ABSTRACT

The new chemosensor, 7-bromo-4-imino-2-(methylthio)-4H-pyrido[1,2-a]pyrimidine-3-carbonitrile (PP-1), which bears a pyrido-pyrimidine unit, has been synthesized and fully characterized. Whilst Pb2+ and I‾ ions caused distinguishable changes in the absorption spectrum of PP-1, the other common cations and anions which were tested had no effect. The sensor PP-1 exhibited detection limits down to 0.21 µM and 0.1 µM for Pb2+ and I‾ ions, respectively. HRMS analysis, 1H NMR titrations and DFT calculations have been performed to elucidate the binding interaction between the sensor PP-1 and the analytes (Pb2+ and I‾).

Keywords: Chemosensor, Pyrido-pyrimidine, Pb2+, I?, DFT.