Formation of Dimers in the Gamma Radiolysis of Aqueous Solutions of Pyrimidines and N2O

• Published in: JOURNAL OF RADIATION RESEARCH 1979, Vol.20 (1), p.84-94
• Main Author: Ali, K M
• Format: Article
• Language: English
• Subjects: Gamma Rays; Nitrous Oxide - radiation effects; Pyrimidines - radiation effects; Radiochemistry; Solutions
• ISSN: 0449-3060; 1349-9157
• DOI: 10.1269/jrr.20.84

Dimers/Radiolysis/Pyrimidines/N2O Aqueous solutions of pyrimidines (such as uracil and thymine) containing N2O (125mM) were irradiated with Co-60 gamma rays source and analysed with paper chromatography technique using suitable solvent developing systems. Among the various radiation-induced products, the three different products located with lower Rf values are U. V. absorbing in character. Spectroscopic analysis such as N. M. R. , U. V. and mass spectrometry showed tentatively that these products are dimeric compounds; silylation technique assisted for such investigation. These dimers are the major products in the radiolysis of the pyrimidines and N2O system ; uracil produced dimers which constituted 71% of the total uracil loss and thymine 33%. Most of the previous studies of the radiolysis of pyrimidine aqueous solutions have been concerned either with systems containing oxygen or deaerated systems. In the former, reaction with OH radicals is followed by peroxy radical formation which, in turn, can lead to hydroperoxides and other products ; these have been isolated and identified ; Teoule and Cadet detected 23 different products in the radiolysis of slightly acidic aerated aqueous solutions of thymine and were able to identify 21 products accounting over 90% of the starting material. In the deaerated system, in addition to OH attack, H atoms and e-aq may also react with the solute thus complicating the radiation chemistry. Significant back reactions are observed to occur between adduct intermediates.