ESR STUDY OF MORPHOLINIUM TCNQ COMPLEXES

Electron paramagnetic resonance studies have been carried out on three morpholinium-TCNQ charge resonance salts of varying stoichiometry. The three salts which have been studied include the previously known 1:1 and 2:3 complexes as well as a new, relatively unstable salt believed to be a 3:4 complex. All three materials exhibit resonance behavior similar to that found in other triplet-exciton-containing systems. A phase transition in the 1:1 salt has been discovered at 151°C which is accompanied by only minor changes in the zero-field splitting tensor parameters and principal axes. The morpholinium salts are characterized by an anomolous impurity" resonance which occurs along with the zero-field doublet (s). The behavior of this "impurity" signal as a function of temperature suggests that it may be a characteristic property of the system."