Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Department of Chemical Sciences, The Radical Research Center and the Schlesinger Family, Center for Compact Accelerators, Radiation Sources and Application, Ariel University, Ariel, Israel; Chemistry Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
Free Radic Biol Med. 2022 Feb 20;180:134-142. doi: 10.1016/j.freeradbiomed.2021.12.313. Epub 2021 Dec 30.
The mechanism of reaction of DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) with ·CH, CHO· and ·OH radicals were studied. The radicals were formed in situ radiolytically. The methyl radicals react orders of magnitude slower with DOTA and with M(DOTA) than the hydroxyl radicals. The various final products were identified and mechanisms for their formation are proposed. CHO· radicals do not react, or react too slowly to be observed, with DOTA and with M(DOTA) as long as the central cation is not oxidized by the peroxyl radical. The results imply that synthesis of the M(DOTA)(M = radioisotope) complexes in a water-organic solvent (ethanol or 2-propanol or acetonitrile) mixture is not only kinetically desired but the so formed complex also decreases the radiolytic decomposition of DOTA.
研究了 DOTA（1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸）与·CH、CHO·和·OH 自由基的反应机理。自由基是通过辐射原位生成的。甲基自由基与 DOTA 和 M(DOTA)的反应速度要比羟基自由基慢几个数量级。鉴定了各种最终产物，并提出了它们的形成机制。只要中心阳离子没有被过氧自由基氧化，CHO·自由基就不会与 DOTA 和 M(DOTA)反应，或者反应速度太慢而无法观察到。结果表明，在水-有机溶剂（乙醇或 2-丙醇或乙腈）混合物中合成 M(DOTA)（M=放射性同位素）配合物不仅在动力学上是有利的，而且形成的配合物还降低了 DOTA 的辐解分解。
