Thermal and photochemical reactions of charge-transfer complexes of tetracyanoethylene–toluene systems

Abstract

Irradiation of the charge-transfer (CT) absorption bands of tetra cyanoethylene (TCNE)–toluene systems gave 3-phenylpropane-1,1,2,2-tetracarbonitrile. TCNE-xylene systems gave a similar addition product on both irradiation of the CT bands and heating under reflux. These reactions proceed through electron-transfer followed by proton-transfer. TCNE reacts with methanol thermally in the presence of NN-dimethyl-p-toluidine to yield dicyanoketen dimethylacetal which alkylates the toluidine to give eventually NNN-trimethyl-p-toluidinium 2,2-dicyano-1-methoxyethenolate. m-Toluidine reacted similarly and the corresponding toluidinium salt was obtained in addition to a tricyanovinylated product. Irradiation of NN-dimethyl-p-toluidine with TCNE in methanol gave a diphenyl derivative together with N-cyanomethyl-N-methyl-p-toluidine through radical reactions of the thermal reaction products, NNN-trimethyl-p-toluidinium salts.