MOLECULAR-COMPLEXES OF TCNE WITH ACETANILIDES .1.

Molecular complexes of TCNE with some acetanilides have been studied using electronic spectroscopy. Each complex exhibits two charge transfer bands which are attributed to the formation of two isomeric complexes R(x) and R(y) differing in the orientation of the donor and acceptor molecules. The ionization potentials of highest occupied and penultimate molecular orbitals of the donors have been calculated from the positions of the CT bands. The stabilities of the complexes with R(x) configuration are found to be greater than those with R(y) configuration. The stabilities of both the complexes increase with increase in electron releasing ability of the substituents. In general, the stabilities of the acetanilide-TCNE complexes are found to be greater than those of the TCNE complexes with correspondingly substituted benzenes. This is attributed to the stronger dipole-dipole interactions in acetanilide-TCNE complexes than the dipole-induced dipole interactions in the benzene-TCNE complexes.