Detection of Structural Defect in Methoxymethyltriphenylphosphonium Chloride Single Crystal by Electron Paramagnetic Resonance

Single crystals of methoxymethyltriphenylphosphonium chloride (MOMTPPC) were analyzed by Electron Paramagnetic Resonance (EPR) spectroscopy method. Gamma radiation from Co-60 was used to create paramagnetic defects in MOMTPPC single crystal. EPR spectra of MOMTPPC single crystals were obtained at 120 K temperature by rotating around three orthogonal axes. The structure of the radical formed by the irradiation effect in MOMTPPC was found by detailed examination of the EPR spectra. With the effect of radiation, the C20-H24 bond was broken and a paramagnetic center was formed. It has been determined that the unpaired electron of the radical formed as a result of the breaking of the chemical bond is located mainly on the C20 atom. The anisotropic g-factor and hyperfine coupling constants of the radiation damage center were determined. While the isotropic value of the spectroscopic splitting factor is obtained as g = 2.00764, the isotropic values of the hyperfine structure constants are (a(H))(alpha) = 2.010 mT, (a(P))(beta) = 3.196 mT and (a(C6H5))(gamma) = (a(fenil))(gamma) = 0.472 mT. Direction cosines of EPR parameters were obtained. Simulation was also carried out to prove the accuracy of our experimental data.