ESR study on the charge transfer complexes of N-salicylideneanilines containing NHO hydrogen bond as a dynamic function

Temperature dependence of ESR line shape was measured for the charge transfer complexes of N-salicylideneaniline derivatives with particular reference to the delocalization or mobility of proton in their intramolecular NHO hydrogen bond. Concentration of paramagnetic centers depended on the various complexes and was in the region between 10−1 and 10−4 spins per unit formula. Spin susceptibility almost obeyed Curie law. It was found that the ESR line narrowed as temperature increased for the complexes with delocalized proton and the line shape deviated from the simple Lorentzian. The result suggests one dimensional motion of unpaired spins in the low temperature region.