【作者】 杨未；

【导师】 刘文涵；

【作者基本信息】 浙江工业大学 ， 应用化学， 2008， 硕士

【摘要】 氨基酸是构成生物体内蛋白质、酶等的基本结构单元,金属氨基酸配合物参与人体内的各种代谢及生理生化过程,在生命过程中扮演着极其重要的角色。研究氨基酸金属配合物的配位机理,对于深入了解金属离子的生物效应及复杂生物体的生命活动具有重要意义。本论文主要以L-甘氨酸、L-丙氨酸、L-苏氨酸与锌的配合物为研究对象,测定了配合物的红外和拉曼光谱,讨论了氨基酸金属配合物的结构和配位机理。用电导法讨论了反应时间、反应温度对氨基酸锌配位体系的影响,确定了等电点条件下三种氨基酸锌配合物的配位比均为2∶1（氨基酸∶金属）。探讨了pH值、共存阴离子对氨基酸锌配位体系的影响,总结了氨基酸锌配合物的配位规律和反应机理。此外,还对此三种氨基酸与金属铜（Ⅱ）、铁（Ⅲ）的配合物进行了研究。研究结果表明:（1）在等电点条件下,氨基酸以羧基氧原子与Zn²⁺进行配位反应,其中L-甘氨酸、L-丙氨酸分子中的羧基氧原子以单齿配位方式与Zn²⁺配位,而L-苏氨酸分子中的羧基氧原子以双齿配位方式参与配位,形成正四面体的氨基酸锌配合物。（2）氨基酸及锌离子在不同的pH值下以不同的离子状态存在。当pH1.0时,氨基酸分子中的-NH₃⁺、-COOH基团均不含孤对电子,不能与Zn²⁺进行配位。当pH 13.0的碱性条件下,氨基酸以R-CH₂-CH（NH₂）-COO^-状态存在,此时分子中的-NH₂、-COO^-基团均能向Zn²⁺提供孤对电子,从而形成五元螯合环配合物。（3）反应体系中有不同阴离子(SO₄^2-、NO₃^-)共存时,SO₄^2-、NO₃^-均可作为单齿配体参与氨基酸与锌的配位反应,形成混配配合物。（4）在等电点条件下,氨基酸以羧基氧原子与金属铜（Ⅱ）、铁（Ⅲ）进行配位。其中氨基酸铜（Ⅱ）配合物中三种氨基酸的羧基均以单齿形式参与配位,构成dsp²的杂化,形成四配位的平面正方形氨基酸铜（Ⅱ）配合物;甘氨酸铁（Ⅲ）、丙氨酸铁（Ⅲ）配合物中的羧基以单齿形式,苏氨酸铁（Ⅲ）配合物中的羧基以双齿形式参与配位,采取sp³杂化,形成四配位的正四面体的氨基酸铁（Ⅲ）配合物。（5）三种氨基酸金属配合物中,氨基酸铜（Ⅱ）配合物的稳定性最大,其M-O键最牢固,M-O伸缩振动峰频率低。更多还原

【Abstract】 The amino acid is a basic structural unit composing the protein and enzyme in living body.The metal complex with amino acid is participating in various metabolism and physiology biochemistry process in human body,so it plays an important role in life process.Therefore,the study on coordination mechanism of metal complex with amino acid plays an important role of the biological effect of metal ions and the life activity of complicated biological system.The complex of L-glycine,L-alanine,L-threonine with zinc were studied in this paper.The Infrared and Raman spectrum of complexes were determined,the structure and coordination mechanism of metal complexes with amino acids were discussed.By the determination of amino acid zinc complexes’ conductance,the influencing factors of reaction time and reaction temperature have been discussed,and the coordination ratio at isoelectric point has been confirmed as 2:1（amino acid:metal ion）.Following these conclusions,the influence such as different pH value and co-existed negative ions to amino acid zinc system was discussed.Then the coordination law and reaction mechanism of amino acid zinc complex were generalized.Besides,the copper（Ⅱ） amino acid complex,the iron（Ⅲ）amino acid complex have been studied in the paper.The results can be concluded as follow:（1）The amino acid coordinated with Zn²⁺by -COO^- at isoelectric point.The L-glycine and L-alanine coordinated with Zn²⁺by the oxygen atom of carboxyl in monodentate mode,however,the theronine coordinated in bidentate mode.The amino acid zinc complex has the configuration of regular tetrahedron.（2）The amino acid and zinc ion have different states with different pH value.When the pH value is 1.0,the amino acid can not coordinate with Zn²⁺,because both -NH₃⁺ and -COOH group are not containing lone pair electrons.When amino acid exists in R-CH₂-CH（NH₂）-COO^- at pH 13.0,the -NH₂ and -COO^- can provide lone pair electrons which can coordinate with Zn²⁺to form chelating ring complex.（3）When the amino acid coexisted with different negative ion (SO₄^2-、NO₃^-),Both SO₄^2-and NO₃^- can react with Zn²⁺as monodentate ligand,and formed the mixed ligand complexes.（4）The amino acid coordinated with copper（Ⅱ）and iron（Ⅲ）by -COO^- at isoelectric point.And the oxygen atom of carboxyl was monodentate mode in amino acid copper complex.The complex was four-coordinated in a square planar configuration with the hybridization of dsp².And the oxygen atom of carboxyl was monodentate mode in glycine-iron and alanine-iron complex,it was bidentate mode in theronine-iron complex.The complex was four-coordinated in a regular tetrahedron configuration with the hybridization of sp³.（5）The results showed that the stabilization of amino acid copper （Ⅱ）complex is better than the other two complexes.In copper complex the bond M-O is the strongest,and the stretching vibration frequency of M-O is low.更多还原