Probing the nature of the Co(III) ion in corrins: The reactions of aquacyano-5-seco-cobyrinic acid heptamethyl ester with anionic ligands
作者:Monika Nowakowska、Susan M. Chemaly、Amanda L. Rousseau、Penny P. Govender、Pradeep R. Varadwaj、Arpita Varadwaj、Koichi Yamashita、Helder M. Marques
DOI:10.1016/j.ica.2018.09.073
日期:2019.1
[AC-5-seco-Cbs]+, shows Co(III) in this complex behaves much more like Co(III) in simple hexacoordinate complexes than in intact cobalt corrins. A comparison of log K values for coordination of CN–, SO32–, NO2–, N3– and S2O32– by [ACCbs]+ and [AC-5-seco-Cbs]+ demonstrates that cleavage of the corrin ring significantly decreases the affinity of Co(III) for the softer ligands CN–, SO32– and, more marginally
摘要在水中的Aquacyano-5,6-dioxo-5,6-seco-heptamethyl-cob(III)yrinate(aquacyano-5-seco-cobester,[AC-5-seco-Cbs] +)中的H2O取代据报道,这种维生素B12衍生物的corrin环的C5-C6键被各种阴离子配体裂解。在25°C(ΔH= –88±17 kJ mol−1和ΔS= –434±56 JK)下,用于配位水离子化的pKa从水合氰尿酸七甲酯(aquacyanocobester,[ACCbs] +)中的9.8±0.3降至7.28。 [AC-5-seco-Cbs] +中的-1 mol-1)。通过[AC-5-seco-Cbs] +确定SO32–配位的pH依赖性来确定pKa,表明该复合物中Co(III)的行为与简单的六配位络合物中的Co(III)相比,与完整的Co(III)相似。钴钴。比较CN-,SO32-,NO2-的log