Charge-transfer complexes in organic chemistry. Part VI. Solvent effects on charge-transfer absorption bands. Interpretation of the behaviour of n-donor solvents

Abstract

The charge-transfer complex formed between acenaphthene and tetrachlorophthalic anhydride has been examined in 32 solvents. In order to explain the general and specific solvent effects, the solvents have been divided into several groups namely protic, dipolar aprotic, aromatic with or without functional groups, and n-donor solvents. The results show that if special effects contribute strongly to the solute–solvent interaction, then they will determine the overall solvent effect. An explanation is suggested for the case of n-donor solvents. The possibility of predicting polarity changes during excitation is explored.