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首页> 外文期刊>RSC Advances >Photolysis of carboxymethylflavin in aqueous and organic solvent: a kinetic study
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Photolysis of carboxymethylflavin in aqueous and organic solvent: a kinetic study

机译：羧甲基黄素在水和有机溶剂中的光解动力学研究

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This is the first study on the photolysis of carboxymethylflavin (CMF), an intermediate in the photolysis of riboflavin (RF). CMF is photodegraded by removal of side-chain to lumichrome (LC) in acid solution and to LC and lumiflavin (LF) in alkaline solution. It also undergoes alkaline hydrolysis to 1,2-dihydro-1-methyl-2-keto-3-quinoxaline carboxylic acid (KA) and 1,2,3,4-tetrahydro-1-methyl-2,3-dioxoquinoxaline (DQ) by cleavage of isoalloxazine ring. CMF degrades to LC in organic solvents. The formation of LC in acid solution and organic solvents takes place by second-order reaction and those of LC, LF, KA and DQ in alkaline solution by first-order reactions. The values of second-order rate constants for the photolysis of CMF at pH 2.0 to 7.0 are in the range of 1.13 to 2.45 M ~(?1) s ~(?1) and those of first-order rate constants ( k _(obs) ) at pH 8.0–12.0 from 1.53 to 4.18 × 10 ~(?4) s ~(?1) and for the formation of photoproducts from 0.37 to 16.6 × 10 ~(?5) s ~(?1) . The photolysis of CMF is enhanced, with pH, in the alkaline region since the excited state is sensitive to alkaline hydrolysis. The photolysis and fluorescence quantum yields of CMF in aqueous and organic solvents have been reported. CMF and photoproducts have been assayed spectrofluorimetrically. The mode of CMF photolysis is discussed.
机译：这是羧甲基黄素（CMF）（核黄素（RF）光解的中间体）的光解的首次研究。通过除去侧链，可将CMF光降解为酸性溶液中的Luminchrome（LC）和碱性溶液中的LC和Lumiflavin（LF）。它还会进行碱水解成1,2-二氢-1-甲基-2-酮-3-喹喔啉羧酸（KA）和1,2,3,4-四氢-1-甲基-2,3-二氧喹喔啉（DQ ）通过异异恶嗪环的裂解。 CMF在有机溶剂中降解为LC。酸性溶液和有机溶剂中的LC形成是通过二级反应，碱性溶液中的LC，LF，KA和DQ则是通过一级反应形成。在pH 2.0至7.0时CMF光解的二阶速率常数的值在1.13至2.45 M〜（？1）s〜（？1）的范围内，而一阶速率常数（k _（ obs））在pH 8.0-12.0时从1.53到4.18×10〜（？4）s〜（？1）形成光产物，从0.37到16.6×10〜（？5）s〜（？1）。由于激发态对碱性水解敏感，因此在pH值下，CMF在碱性区域的光解作用得以增强。已经报道了CMF在水性和有机溶剂中的光解和荧光量子产率。 CMF和光产物已通过荧光光谱法进行了测定。讨论了CMF光解的模式。

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