【作者】 李国斌；

【导师】 易平贵； 于贤勇；

【作者基本信息】 湖南科技大学 ， 应用化学， 2008， 硕士

【摘要】 在过去的三十多年里，双过氧钒化合物的合成及其与小分子相互作用一直是化学和生物科学研究的重点和热点之一。本文在合成并表征数种双过氧钒化合物的基础上，采用多核(¹H、¹³C和⁵¹V)、多维（¹H-¹H COSY和DOSY）和变温NMR等谱学手段，系统研究了相互作用前后体系中各物种的溶液结构，对一些实验现象进行了解释，探讨了相互作用的模式和规律。主要结果总结如下：1．为探讨有机配体中取代基团对反应平衡的影响，在模拟生理条件下研究了双过氧钒配合物[OV（O₂）₂（D₂O）]^-／[OV（O₂）₂（HOD）]^-（缩写为bpV）与N-取代皮考啉酰胺的相互作用。它们反应性从强到弱的顺序为：N-甲基-皮考啉酰胺≈N-（2-羟乙基）-皮考啉酰胺>N-乙基-皮考啉酰胺>N-丙基-皮考啉酰胺，这说明了皮考啉酰胺N上取代基通过电子效应影响反应。竞争配位导致一系列新的7配位的过氧钒物种生成。2．为探讨双过氧钒配合物上有机配体对反应平衡的影响，研究了双过氧钒配合物[OV（O₂）₂LL’]^n-[LL’=草酸根、皮考啉酸根、2，2’-联吡啶和1，10-邻菲啰啉，配合物分别缩写为bpV（oxa），bpV（pic），bpV（bipy）和bpV（phen）]与N-甲基咪唑（N-Me-Im）的相互作用，结果表明N-Me-Imi与4种双过氧钒配合物的反应活性从强到弱的顺序为：bpV（oxa）>bpV（pic）>bpV（bipy）>bpV（phen），这说明金属离子中心的配体配位能力和空间位阻都对反应平衡产生较大的影响，同时竞争配位的结果导致新物种[OV（O₂）₂（N-Me-Imi）]^-的生成。3．为探讨咪唑环上取代基团对相互作用体系反应平衡的影响，研究了双过氧钒配合物NH₄[OV（O₂）₂（2-（2’-Py）-Imi）]·4H₂O（缩写为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。实验结果表明，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）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。4．为探讨吡啶环上取代基团对反应平衡的影响，研究了双过氧钒配合物bpV与4-取代吡啶的相互作用，实验结果表明其反应性从强到弱的顺序为：吡啶>异烟酸根>异烟酸甲酰胺>异烟酸甲酯。吸电子的诱导作用和吸电子的共轭效应影响反应平衡。利用多种NMR谱学方法系统研究了双过氧钒化合物和有机配体的相互作用，建立了适合研究过氧钒化合物与有机小分子相互作用的谱学方法，特别是利用核磁共振中扩散排序（DOSY）技术，实现了混合物中各组分在样品管中的“虚”分离，它是一种非常有应用前景的研究混合物的谱学方法。更多还原

【Abstract】 In the past three decades, the interactions between peroxovanadates and organic ligands have attracted great interest in both chemistry and biology. In this work, multinuclear NMR (¹H, ¹³C and ⁵¹V), multidimensional （DOSY and ¹H-¹H COSY）, and variable temperature NMR were used to study the above interaction systems. Through the combination of these methods, structures of all species in interaction systems were obtained and a better understanding of the experimental phenomena was achieved. The possible interaction modes and mechanism of the interaction systems are discussed. The main conclusions are summarized as follows:1. To understand the substituting effects of organic ligands on the reaction equilibrium, the interactions between diperoxovanadate complex [OV（O₂）₂（D₂O）]^-/[OV（O₂）₂（HOD）]^-（abbr. bpV） and a series of N-substituted-picolinamide ligands in solution were explored for mimicking the physiological conditions. The order of reactive capability of the picolinamide-like ligands with bpV is as follows: N-methylpicolinamide≈N-（2-hydroxyethyl）-picolinamide > N-ethylpicolinamide > N-propylpicolinamide. The substituting group influences the reactivity by an electron effect. Competitive coordination interactions result in a series of new seven-coordinated peroxovanadate species.2. To understand the effects of organic ligands of the diperoxovanadate complexes on the reaction equilibrium, the interactions between a series of diperoxovanadate complexes [OV（O₂）₂LL’]^n- （LL’ = oxalate, picolinate, 2,2’-bipyridine and 1,10-phenanthroline, the corresponding peroxovanadate species abbreviate bpV（oxa）, bpV（pic）, bpV（bipy）） and 1-methylimidazole （N-Me-Imi） in solution were explored for mimicking the physiological conditions. The experimental results indicated the activity order of these complexes with 1-methylimidazole as follows: bpV（oxa） > bpV（pic） > bpV（bipy） > bpV（phen）. Both the coordinating capability and the steric effect of the organic ligands affect the reaction equilibrium. At the same time, a new six-coordinated peroxovanadate species [OV（O₂）₂（N-Me-Imi）]^- is formed due to the competitive coordination.3. To understand the substituting effects of imidazole ring on the reaction equilibrium, the interactions between diperoxovanadate complex NH₄[OV（O₂）₂（2-（2’-Py）-Imi）] 2222 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 for mimicking the physiological conditions. The experimental results indicated that the activities of bpV（Imi-Py） and organic ligands 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]^- were formed due to the competitive coordination between 2-（2’-Py）-Imi and the imidazole-like ligands. When the ligand was 4-methyl-imidazole or histidine, a pair of isomers was formed.4. To understand the substitutinged effects of pyridine ring on the reaction equilibrium, the interactions between diperoxovanadate complex bpV and 4-substituted pyridine for mimicking the physiological conditions. The experimental results indicated that the activities of bpV and organic ligands as follows: pyridine > isonicotinate > N-methyl isonicotinamide > methyl isonicotinate. Both the electron-withdrawing induction effect and electron-withdrawing conjugated effects of the organic ligands affect the reaction equilibrium.NMR were used to study the interactions between diperoxovanadates and small organic molecules. A spectroscopic method was established to explore this type of interactions. It is worth mentioning that DOSY can be used to analyze the chemical structures and components of mixtures without chemical separation. This makes it important for the investigation of complicated mixtures avoiding time-consuming separation and purification that may destroy the inspected system.更多还原