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(0.15 mol·L^(-1)NaCl溶液)下,应用多核(~1H、^(13)C和^(51)V)、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NH_4[OV(O_2)_2{2-(2'-Pyri-dine)- [midazole}]·4H_2O(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(O_2)_2L]^-(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.
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.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2007年第11期1765-1770,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20772027)
973子课题(2003CB716005)
湖南省自然科学基金(06JJ30004)
中国博士后科学基金(20070410805)
湖南省教育厅青年项目(068028)
卫生部(福建省)卫生教育联合攻关计划(3502220051027)
厦门市重大疾病攻关研究基金(Wkj2005-2-019)
固体表面物理化学国家重点实验室开放基金和湖南科技大学博士基金(E55107)资助
