MAGNETIC-FIELD EFFECTS ON THE LUMINESCENCE OF P-PHENYLENEDIAMINE DERIVATIVES

A positive magnetic field effect (MFE) on the luminescence of three di fferent N,N,N',N'-tetraalkyl-p-phenylenediamines (TAPD) has been detec ted by field-modulated MARY (MAgnetic Field Effects on Reaction Yields ) spectroscopy in a binary solvent mixture of toluene/ dimethylsulfoxi de containing more than 20% vol. dimethylsulfoxide and in neat dimethy lsulfoxide. The p-phenylenediamine derivatives' luminescence in these solvents could be increased by application of small external magnetic fields in the order of less than 30 mT (1 T = 10(4) G) and the B-1/2 v alues could be measured. In a comparative experiment the N,N-dimethyla niline (DMA) fluorescence did not show such a behaviour. In conclusion a reaction scheme involving an electron transfer process between the p-phenylenediamines and the solvent dimethylsulfoxide is suggested.