engleski

EPR spectroscopy of superhyperfine interaction in the copper paramagnetic center in the crystal of cytosine monohydrate

The planar complex of Cu(II) with two cytosine bases was formed by gamma irradiation of the cytosine monohydrate crystal, containing copper impurities. The paramagnetic complex was probably formed by trapping the radiation-induced migrating holes by Cu(I), that is originally present in the crystal lattice. The structure of the complex was analyzed from the superhyperfine pattern of its EPR spectra. The experimentally evaluated tensor elements of the three 14N couplings and the observation of an additional proton coupling unequivocally confirm the structure. The ab initio B3LYP density functional method calculations are in good agreement with the experiments. Both experiments and the calculations demonstrate large spin delocalization in the cytosine ring plane.

copper complex. cytosine; EPR spectroscopy; suprehyperfine interaction

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