摘要
为了研究铝(Ⅲ)与生命体中重要的有机分子α-酮戊二酸的作用机制,我们采用了电位滴对酸性溶液中的反应体系的配位作用和互变异构进行了分析,并采用电喷雾质谱以及应体系中的沉淀,来说明铝?对α-酮戊二酸的催化脱羧反应过程。得到如下实验结论性溶液中配位形成1∶1犤AlLH2+,AlL+,AlLH-1犦和1∶2犤AlL2-,AlL2H-23-犦的单核形态以构:在酸性溶液中Al3+通过配位作用促进α-酮戊二酸烯醇化,生成易于脱羧的β、γ-的电子沉降作用,使β、γ-不饱和酸更易脱羧,如果是1∶2的形态,则脱羧生成沉淀。
The complexation and decarboxylati on ofα-ketoglutaric acid with Al in acidic aqueous solution and solid state were studied with various analytica l techniques.In a dilute aqueous acidic solution(<10 -3 mol·L -1 ),α-KG binds Al in a bidentate manner(L∶Al =1∶1)[AlLH 2+ ,AlL + ,AlLH -1 ]at the carboxyl and carbonyl moietie s while the decarboxylation tendency is very weak.However,in a high dose r eactant solution(>10 -2 mol·L -1 ),Al ion coordinates withα-ketoglutarate in a bidentate manner(L∶Al =2∶1)[AlL 2- ,AlL 2 H -23- ]at pH 4～6.Then,it promotesα-ketoglutarate tautomerization toβ,γ-unsaturated acid enolic structure,which is readily to decarboxylate in the presence of Al 's electron-withdrawing effect.Fin ally,the decarboxylation product i s also formed.These results may help to fur ther understand metal ions-catalyzed decarboxylation mechanism and Al in-fluences on enzyme reactions in biological system.
出处
《无机化学学报》
SCIE
CAS
CSCD
北大核心
2002年第10期981-986,共6页
Chinese Journal of Inorganic Chemistry
基金
国家自然科学基金资助项目(No.20075011)
教育部青年教师基金和配位化学国家重点实验室开放基金资助项目(No.2017)。
