Molecular complexes of anilines with DDQ

Molecular complexes of DDQ with anilines have been studied spectrophotometr ically by stabilising the complexes in a low polar solvent (CCl4), at low t emperatures and under low donor concentrations. All the complexes exhibit w ell resolved charge transfer bands in the. visible region where neither of the components has any absorption. The stoichiometry of each of the complex is found to be 1:1 and is unaffected by the variation of temperature. A li near relationship is observed between the v(CT) of DDQ-anilines and the: ve r of TCNE-anilines indicating a pi-pi: interaction between the DDQ and the donors. The stabilities and thermodynamic parameters have been determined f rom the absorption studies on the CT bands. A linear relationship has been observed between logarithmic functions of stability constants and Hammett s igma constants. Both ring and N-substituents affect the position of CT band and the stabilities of the complexes.