中文摘要：

为探讨咪唑环上取代基团对反应平衡的影响，在模拟生理条件（0．15mol·L^-1 NaCl溶液）下，应用多核（^1H、^13C和^51V）、扩散排序谱（DOSY）以及变温NMR等谱学技术研究双过氧钒配合物NH4[OV（O2）2{2-（2＇-Pyri—dine）-Imidazole}]·4H2O（简写为bpV（Imi-Py））和咪唑类配体（咪唑、2-甲基-咪唑、4-甲基-咪唑和组氨酸）的相互作用，其从强到弱的顺序为咪唑-4-甲基-咪唑〉2-甲基-咪唑〉组氨酸．研究结果表明，咪唑环上取代基团空间位阻对反应平衡产生较大影响，同时竞争配位的结果导致新的6配位过氧物种[OV（O2）3L]^-（L为咪唑类配体）的生成，当配体为4-甲基-咪唑和组氨酸时，生成的则是一对异构体．

英文摘要：

To understand the substituting effects of imidazole ring on the reaction equilibrium, the interactions between diperoxovanadate complex NH4[OV（O2）2{ 2-（2＇-Pyridine）-Imidazole}]·4H2O （abbr. bpV（Imi-Py）） and a series of imidazole-like ligands （imidazole, 2-methyl-imidazole, 4-methyl-imidazole, and histidine） in solution were explored using multinuclear （^1H, ^13C, and ^51V） magnetic resonance, diffusion ordered spectroscopy （DOSY）, and variable temperature NMR in 0.15 mol .L^-1 NaCl ionic medium for mimicking the physiological conditions. The experimental results indicated that the activities ofbpV（Imi-Py） and organic ligands were as follows： imidazole ≈4-methyl-imidazole〉2-methyl- imidazole〉histidine. The steric effect of the organic ligands affects the reaction equilibrium. At the same time, new six- coordinated peroxovanadate species [OV（O2）2L]- （L= imidazole-like ligands） were formed due to the competitive coordination between 2-（2＇-pyridyl）-imidazole and the imidazole-like ligands. When the ligand was 4-methyl- imidazole or histidine, a pair of isomers was formed.