formation of the molecular complexes between meso-tetraphenylporphyrin (tpp) and the p-acceptors 2,3-dichloro-5,6-dicyanobenzoquinone (ddq) and tetracyanothylene (tcne) in chloroform solution was investigated spectrophotometrically. the formation constants of the resulting 1:1 molecular complexes were determined using the benesi-hildebrand and nash methods. the tpp-ddq proved to be more stable ...