The Synthesis of a Corrole Analogue of Aquacobalamin (Vitamin B<sub>12a</sub>) and Its Ligand Substitution Reactions
作者:Caitlin F. Zipp、Joseph P. Michael、Manuel A. Fernandes、Sadhna Mathura、Christopher B. Perry、Isabelle Navizet、Penny P. Govender、Helder M. Marques
DOI:10.1021/ic5000793
日期:2014.5.5
The synthesis of a Co(III) corrole, [10-(2-[[4-(1H-imidazol-1-ylmethyl)benzoyl]amino]phenyl)-5,15-diphenylcorrolato]cobalt(III), DPTC-Co, bearing a tail motif terminating in an imidazole ligand that coordinates Co(III), is described. The corrole therefore places Co(III) in a similar environment to that in aquacobalamin (vitamin B12a, H2OCbl+) but with a different equatorial ligand. In coordinating
Co(III)钴,[10-(2-[[4-(1 H-咪唑-1-基甲基)苯甲酰基]氨基]苯基)-5,15-二苯基Corrolato]钴(III),DPTC-的合成描述了带有终止于与Co(III)配位的咪唑配体的尾部基序的Co。因此,该钴将Co(III)置于与水钴胺(维生素B 12a,H 2 OCbl +)类似的环境中,但具有不同的赤道配体。在配位溶剂中,DPTC-Co是五配位和六配位物质的混合物,溶剂分子占据了向近端咪唑配体的轴向配位位点。在80:20的MeOH / H 2 O溶液中,陈化大约1小时,主要的物种是六配位水族物种[H 2O–DPTC-Co]。至少为60μM浓度时它是单体的。配位的H 2 O具有ap K a= 9.76(6)。在相同条件下,H 2 OCbl +具有ap K a = 7.40(2)。据报道,外源性配体取代配体H 2 O的平衡常数为中性N-,P-和S-供体配体以及CN –,NO