Solvent effect on the charge-transfer complexes of chloranil with mesitylene and benzene

Abstract

The thermodynamic and spectrophotometric properties of the charge-transfer (CT) complexes of chloranil with mesitylene and benzene have been studied in different solvents such as n-hexane, cyclohexane, n-heptane, carbon tetrachloride, chloroform, dichloromethane and in addition, the properties of the former complex have been studied in benzene. The results show that the oscillator strengths ( f) of the CT absorption bands of these complexes in different solvents increase with the heats of formation (− Δ H°). The role of the solvent in changing both thermodynamic as well as spectrophotometric properties of these complexes is assumed to be due to the solvent interaction with chloranil. An attempt has been made to calculate the thermodynamic and spectrophotometric properties of the solvent—chloranil interaction. Moreover, the CT absorption band positions of chloranil complexes with mesitylene and benzene in the gas phase have been determined from the corresponding values in different solvents.