苯并咪唑衍生物对痕量三价铬离子和铋离子的选择性识别

发布时间：2018-10-20 14:03

【摘要】：金属离子对环境和生物体都具有重要意义,但当金属离子浓度较高时,就会对环境和生物体造成严重危害。建立痕量水平上对金属离子进行分析检测的技术十分必要。紫外可见分光光度法由于具备应用广泛、灵敏度和准确度高、选择性好、适用浓度范围广、仪器价格相对低廉、分析成本低、操作简便、快速等优势,而被广泛应用于金属离子的检测中。苯并咪唑衍生物不仅具有良好的生物活性和药理活性,还可对分子和离子进行识别。例如,苯并咪唑环上的氮原子可与金属阳离子发生络合,形成稳定性较好的苯并咪唑金属配合物。因此,被广泛应用于金属离子的识别。本论文设计合成了五种苯并咪唑衍生物,发现它们能够选择性地识别Cr~(3+)或Bi~(3+)离子。研究内容包括以下两个方面:(1)苄基官能团化的苯并咪唑配体对Cr~(3+)识别性能的研究合成了两种新型的苄基官能团化的苯并咪唑配体1-苄基-3-吡啶甲基苯并咪唑氯化物(L1)和1-苄基-3-((2-1H-苯并[d]咪唑甲基)-1-甲基)苯并咪唑氯化物(L2)。通过对分析实验条件的优化和筛选,最终确立在C2H5OH/H2O(v:v=1:1)体系中用紫外分光光度法测定铬(III)的分析方法。结果表明Cr~(3+)与配体在207 nm处有最大吸收,在最优条件下,Cr~(3+)-L配合物的吸光度与Cr~(3+)浓度在0.05~2.60μg·mL-1范围内符从朗伯比尔定律,检出限分别为0.026和0.034μg·mL-1,化学计量比为1:1,结合常数分别为1.45×104和8.36×103 dm3·mol-1。两配体与三价铬之间的络合反应为放热反应,且可以自发进行。通过红外光谱与量子化学计算对配体上Cr~(3+)的结合位点进行了推测,研究了配体结构对Cr~(3+)络合能力的影响。并将该方法成功应用于实际样品中Cr~(3+)含量的测定。(2)苯并咪唑酰腙类配体对Bi~(3+)识别性能的研究合成了三种苯并咪唑酰腙类配体(E)-N'-(4-硝基苯亚甲基)-1H-苯并咪唑-2-酰腙(L3)、(E)-N'-(2,4-二氯苯亚甲基)-1H-苯并咪唑-2-酰腙(L4)和(E)-N'-(3-甲基-4-羟基苯亚甲基)-1H-苯并咪唑-2-酰腙(L5)。通过对分析实验条件的优化,最终确立在CH3OH体系中用紫外分光光度法测定铋(III)的分析方法。结果表明配体L3、L4和L5与Bi~(3+)络合时伴有特征吸收峰红移和吸光度增强的现象。在最佳实验条件下,Bi~(3+)-L配合物的吸光度与Bi~(3+)浓度在0.21~6.48μg·m L-1范围内符从朗伯比尔定律,最低检测限分别为95.51、92.16和55.80 ng·mL-1。通过Job′s plot方法可知L3、L4和L5与Bi~(3+)的化学计量比为1:1。通过Benesi-Hildebrand方程式可得结合常数分别为1.42×104、1.45×104和1.47×104dm3·mol-1。三种配体与三价铋之间的络合反应为放热反应,且自发进行。使用红外光谱与量子化学计算推测了Bi~(3+)与配体的结合位点,研究了配体结构对Bi~(3+)络合性能的影响。该方法在应用于水样和胃药中铋含量的检测中获得了满意的结果。
[Abstract]:Metal ions are of great significance to both environment and organism, but when the concentration of metal ions is high, it will cause serious harm to environment and organism. It is necessary to establish a technique for the analysis and detection of metal ions at trace level. UV-Vis spectrophotometry has the advantages of wide application, high sensitivity and accuracy, good selectivity, wide range of suitable concentration, relatively low price of instrument, low cost of analysis, simple and rapid operation, etc. It is widely used in the detection of metal ions. Benzimidazole derivatives not only have good bioactivity and pharmacological activity, but also recognize molecules and ions. For example, nitrogen atoms on benzimidazole ring can complexate with metal cations to form stable benzimidazole metal complexes. Therefore, it is widely used in the recognition of metal ions. In this paper, five benzimidazole derivatives were designed and synthesized. It was found that they could selectively recognize Cr~ (3) or Bi~ (3) ions. The research contents include the following two aspects: (1) study on the recognition performance of benzimidazole ligands to Cr~ (3) two novel benzimidazole ligands 1-benzyl-3-pyridyl benzimidazolium chloride were synthesized. Compounds (L1) and 1-benzyl-3- (2-1H-benzo [d] imidazolomethyl) -1-methyl) benzimidazole chloride (L2). Through the optimization and screening of the experimental conditions, an analytical method for the determination of chromium (III) by ultraviolet spectrophotometry in C2H5OH/H2O (v:v=1:1) system was established. The results show that the maximum absorption of Cr~ (3) with ligand is at 207 nm. Under the optimum conditions, the absorbance of Cr~ (3) -L complexes with Cr~ (3) concentration is in the range of 0.05 ~ 2.60 渭 g mL-1. The detection limits were 0.026 and 0.034 渭 g mL-1, stoichiometric ratios were 1: 1, and the binding constants were 1.45 脳 10 ~ 4 and 8.36 脳 10 ~ 3 dm3 mol-1., respectively. The complexation reaction between the two ligands and trivalent chromium is exothermic and can occur spontaneously. The binding sites of Cr~ (3) on ligands were speculated by IR spectra and quantum chemistry calculations. The effect of ligand structure on the complexation ability of Cr~ (3) was studied. The method has been successfully applied to the determination of Cr~ (3) in practical samples. (2) the recognition properties of benzimidazolyl Hydrazone ligands to Bi~ (3) have been studied. Three benzimidazolyl hydrazone ligands, (E) N- (4-nitrophenyl methylene) -1H-benzimidazole-2-acyl, have been synthesized. Hydrazone (L3), (E)-N- (2H4-dichlorophenyl)-1H-benzimidazole-2-acylhydrazone (L4) and (E)-N- (3-methyl-4-hydroxyphenylene methyl) -1H-benzimidazole-2-acylhydrazone (L5). By optimizing the experimental conditions, an analytical method for the determination of bismuth (III) in CH3OH system was established by ultraviolet spectrophotometry. The results show that the complexation of ligand L3, L4 and L5 with Bi~ (3) is accompanied by red shift of absorption peak and enhancement of absorbance. Under the optimum experimental conditions, the absorbance of Bi~ (3) -L complex and the concentration of Bi~ (3) in the range of 0.21 ~ 6.48 渭 g 路m ~ (-1) ~ (-1) from Lamberbilt's law, the detection limits are 95.51 ~ 92.16 and 55.80 ng mL-1., respectively. By Job's plot method, the stoichiometric ratio of L3, L4 and L5 to Bi~ (3) is 1: 1. The binding constants obtained by Benesi-Hildebrand equation are 1.42 脳 104 and 1.47 脳 104dm3 mol-1., respectively. The complexation reaction between three ligands and trivalent bismuth is exothermic and spontaneous. The binding sites of Bi~ (3) to ligands were deduced by IR spectra and quantum chemistry calculations. The effects of ligand structure on the complexation properties of Bi~ (3) were studied. The method has been applied to the determination of bismuth in water and gastric medicine with satisfactory results.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O626.23;O657.3

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