5-Chlorosalicylaldehyde Based New Chromo-Fluorogenic Schiff base Probes for Cu(II), Mn(II), CN-, S2- and CO32- ions - Appositeness in Bioimaging and Molecular Logic Gate.

Two new multifunctional fluorescent Schiff base chemosensors 2,2'-(4-chlorophenyl)methylene)bis(azanylylidene))bis(methanylylidene))bis(4-chlorophenol) (CSCB) and 2,2'-(4-methoxyphenyl)methylene)bis(azanylylidene))bis(methanylylidene))bis(4-chlorophenol) (CSMB) were synthesized by following solvent free one pot synthesis approach for the colorimetric detection of Cu(II), Mn(II), CO32-, S2- and CN- ions. The Schiff base chemosensors showed a colorimetric response towards the ions, where there was appearance of yellow color over colorless Schiff base solution. The detection process was accomplished by absorption and emission methods in aqueous methanol medium. The binding modes of the cations and anions towards both the Schiff bases were explored by IR, 1H NMR and Mass titrations. The detection limit of the Schiff bases CSCB and CSMB towards the different detected ions was found to be in the order of 10-6 M for Cu(II), Mn(II), CN-, CO32- ions and 10-5 M for S2- ion. DFT studies of the Schiff bases CSCB and CSMB were performed with respect to Mulliken charge analysis, HOMO-LUMO energy gap, Molecular Electrostatic Potential and Total density for the substantial support of structure and interaction with various ions. Electronic spectral transitions of the Schiff bases are endorsed by TDDFT calculations. The sensing property was applied in bioimaging study on HeLa cell lines and logic gate construction.