EPR analysis of gamma irradiated single crystal cimetidine

The magnetic properties of gamma irradiated single crystal cimetidine were investigated between temperatures of 123 K and 418 K and between microwave power of 0.01 mW and 150 mW by electron paramagnetic resonance. Magnetic field orientation in each of the three perpendicular axes, microwave power, and temperature dependence of the EPR spectra has led to more than one radical being produced by gamma irradiation in the host crystal. The distinctive radical was attributed to being a ring type radical; however, the other radicals could not be identified because of the superimposition. The EPR parameters of the ring type radical were determined to be: a(Hα)av = 2.42 mT, a(Nα)av = 0.62 mT, a(Hβ)av = 1.08 mT, a(Hγ)av = 0.2 mT, a(Nβ)av = 0.3 mT, and (g)av = 2.0030, respectively.

► The irradiation effect on single crystal of cimetidine was determined firstly.
► Cimetidine, H2-receptor antagonist, is an important molecule.
► More than one radical were produced in the host crystal by gamma irradiation.
► The EPR spectra of cimetidine dependent on temperature and microwave power.
► The EPR parameters of produced radical, ring type radical, were determined.