Heterocyclic-based Schiff base material designed as optochemical sensor for the sensitive detection of chlorinated solvent vapours

Abstract

Herein, a newly synthesized intermediate, piperazine-based Schiff base (PBSB) gas sensor was fabricated by the Schiff base condensation of amino functionalized methylpiperazine with aromatic aldehyde containing nitro substituent. This organic sensor material was structurally identified with spectroscopic techniques such as FTIR, HRMS, 1H- and 13C-NMR. The designed sensor candidate was explored for its optical response to chlorinated volatile organic compounds, namely trichloroethylene, dichloromethane and chloroform in the light of structure–property relationship investigation by using surface plasmon resonance (SPR) technique. The results showed that Schiff bases could be candidates for chlorinated vapour sensing materials with their good response and reversibility. Concordantly, compound PBSB exhibited good response against chlorinated solvent vapours aided by the electron-withdrawing group on benzene ring that promoted better intermolecular interactions and opened up a new strategy to create a novel set of responsive materials for gas sensing applications. In addition, the adsorption kinetics of SPR data obtained from PBSB spun film on exposure to these chlorinated vapours at different concentrations was also evaluated using the Elovich Model. The values of the initial adsorption rate, a and Elovich constant, b were analysed depending on the concentration values and the highest values were obtained for dichloromethane between 372.92 and 4377.53 ppm/mm2.Graphical abstract