Microwave Assisted Synthesis of AIEE Responsive Isoniazid Based Schiff Base, DFT Studies and its Fluorometric Response Towards Cd2+ and Na.

A novel Isoniazid based Schiff base was synthesized utilizing a simple microwave assisted facile one-step method and was analysed using several spectroscopic methods i.e. ¹H NMR, ¹³C NMR, HRMS and IR spectroscopy. To illuminate the complexity of electronic structure of an ISB, DFT analysis was conducted. Along with the solvatochromic studies, AIEE analysis of synthesized schiff base was carried out revealing the fluorescence enhancement by eight folds in water: acetonitrile ratio (40:60) in comparison to acetonitrile sample. These results were validated by dynamic light scattering (DLS) analysis. The photophysical analysis unravels the fact that ISB acts as a dual probe for detection of Cd²⁺ (trace element) and Na⁺ with the limit of detection (LOD) 0.2 µM and 0.15 µM, respectively. The selectivity study divulged that ISB showed selectivity towards Cd²⁺. The DFT studies for the proposed mechanism have been carried out to support the results found in the analysis. For stoichiometry study, Job's plot was examined which revealed 1:1 complexation ratio in case of Cd²⁺: ISB and 3:2 complexation ratio for Na⁺: ISB. Anti interference analysis underpinned the fact that ISB show high selectivity and sensitivity towards Cd²⁺ and Na⁺ as no other metal interfered during the detection process.