An Insight Into Experimental and Theoretical Investigation of Structure, Photophysical Property by ESIPT Processes and Biological Activities of Schiff Base Copper Complex

A novel Schiff base (BSSMO) and its copper complex have been synthesized, and their structure was delineated using single crystal XRD studies. Computational techniques were used to design and evaluate BSSMO-based luminophores, revealing a significant intramolecular hydrogen bond within the molecule. Understanding ESIPT is crucial for optimizing photophysical and luminophore properties of organic molecules, especially for advancing optoelectronic devices. The study also explored the mechanisms of GSIPT and ESIPT for these BSSMO-based luminophores using transition state theory, charge distribution, molecular orbital analysis, and quantum theory of atoms in molecules. Results advocated that BSSMO-L2 exhibits higher absorption compared with BSSMO-L1 and the same trend is observed in emission spectral studies. However, the intensity of enol emissions in BSSMO-L2 is lower than that of keto (BSSMO-L3) emissions and the S1 (Keto form) emission of BSSMO-L3 shows significantly larger values, making it attractive for optoelectronic devices. The findings offer valuable insights for the development of ESIPT emitters with distinct photophysical properties. The in silico antidiabetic study of BSSMO-L2 explores the interaction with PPAR-gamma protein, revealing a moderate affinity and stable complex, enhancing its bio-potential for future applications. The in vitro anticancer study of Cu-BSSMO-L2 complex shows a potential anticancer effect through mitochondrial and extrinsic death receptor mediated pathways. These insights contribute to the design of novel benzenesulfonamide-based bioactive molecules.