Naslov
An EPR Study of the Transfer and Trapping of Holes Produced by Radiation in Guanine(Thioguanine) Hydrochloride Single Crystals

Autori
Herak, Janko N. ; Sanković, Krešimir ; Krilov, Dubravka ; Huetermann, Juergen

Izvornik
Radiation Research 151 (1999); 319-324

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
energy transfer; EPR; free radicals; thioguanine

Sažetak
Single crystals of guanine hydrochloride monohydrate, guanine hydrochloride dihydrate and anhydrous guanine dihydrochloride, doped with thioguanine, were irradiated with X and gamma-rays. In all three systems the dominant radicals were associated with thioguanine. In the former two systems the stabilized species is the thiyl radical, formed by initial loss of an electron at some of the guanines in the crystal lattice, followed by hole migration to thioguanine and subsequent deprotonation of the radical formed. In the anhydrous guanine(thioguanine) dihydrochloride, that process is followed by acquisition of a chlorine ion. In the guanine hydrochloride monohydrate and guanine hydrochloride dihydrate lattices, systems of interacting closely spaced stacked bases and strings of chloride ions might support the migration of electrons and/or holes. In anhydrous guanine dihydrochloride, neither the bases nor the Cl(minus) ions alone are capable of providing the means for the long-range electron, energy and spin transfer. It is the interchangeable sequence of the charged bases and the Cl(minus) ions that makes the suppotring strings or networks. The ultimate chlorination of the thioguanine-centered electron-loss radicals depends mainly on the availability of the Cl(minus) ions and the space for their accomodation in the vicinity of the sulfur atom.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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