Interactions between bioactive diperoxovanadate complexes and imidazole: Insights into their solution structures by NMR and ESI-MS
Yu, X. Y.
Cai, S. H.
- 物理技术－已发表论文 
The interactions between four high bioactive diperoxovanadate complexes K-n[OV(O-2)(2)L].mH(2)O (n = 1similar to3, m = 1similar to5, L = oxalate (abbr. oxa), picolinate (abbr. pic), bipyridine (abbr. bipy) and 1,10-phenanthroline (abbr. phen); their corresponding complexes abbreviated as bpV(oxa), bpV(pic), bpV(bipy) and bpV(phen), respectively) and imidazole (abbr. imi) in solution were studied by several NMR techniques: multinuclear (H-1, C-13 and V-51) and variable temperature V-51 NMR. Competitive coordination interactions were observed and the order of the interaction strength of the four complexes with imidazole is as follows: bpV(oxa) > bpV(pic) > bpV(bipy) > bpV(phen), which is deeply affected by the identity of the ligands and has the same order as their inhibition effect toward bovine heart phosphotyrosyl protein phosphatase. The species [OV-(O-2)(2)(imi)](-) was formed in all cases. Both of the NMR data and equilibrium constants of the interaction systems were reported. The experimental results indicate that the species of bpV(oxa) and [OV(O-2)(2)(imi)](-) are six-coordinated, while bpV(pic), bpV(bipy) and bpV(phen) are seven-coordinated in solution. ESI-MS results support the conclusions obtained by NMR.