Fluorescence quenching of 6-chloro-2-phenyl [benz (b) pyrrole] -1-carboxaldehyde thiosemicarbazone by CCl4 in different solvents

The quenching of fluorescence of 6-chloro-2-phenyl [benz (b) pyrrole]-1-carboxaldehyde thiosemicarbazone by carbon tetrachloride has been studied in dioxan, acetonitrile, methanol and butanol solvents at room temperature to understand the quenching mechanism. The Stern-Volmer plot has been found to be non-linear with a positive deviation for all the solvents. Various rate constants for the quenching processes are determined using a modified S-V equation and have been found to be dependent on solvent polarity. The results suggest that both static and dynamic quenching processes are responsible for the observed positive deviation in the S-V plot.