论文总字数：57849字

摘 要

多钒氧酸盐作为多金属氧酸盐的一个重要分支，是一种性能优异的材料，具有多变的配位几何形状和多种氧化还原活性，使得其能够拥有趣的分子磁性，良好的光学活性，以及优异的催化性能，受到广泛的关注。

本文采用溶剂热法与挥发法相结合的方法，使用配体乙二胺、1,2-丙二胺和1,2-环己二胺，成功地合成出了四个风车状的八核的无机-有机杂化多氧钒酸盐：[(C₂N₂H₈)₄(CH₃O)₈V₈O₁₂]·(CH₃OH)_1.5 (V₈-1a)，[(C₂N₂H₈)₄(CH₃O)₄V₈O₁₆]·6H₂O (V₈-1)，[(C₃N₂H₁₀)₄(CH₃O)₄V₈O₁₆]·5H₂O (V₈-2)和[(C₆N₂H₁₄)₄(CH₃O)₄V₈O₁₆]·6H₂O (V₈-3)，使用单晶X-射线衍射测定其晶体结构，并通过红外、粉末X-射线衍射、元素分析等手段进行表征。通过使用双齿的柔性有机胺配体进修饰，我们发现有机胺的引入将原本的五价钒部分还原成了四价钒。其中，在化合物V₈-1a的合成过程中，我们加入了谷氨酸，虽然谷氨酸最终没有出现在结构中，但是由于谷氨酸的引入，化合物V₈-1a中的钒离子全部被还原成了四价的钒，并且甲醇的配位数也达到了最多的8个。而在没有谷氨酸的条件下，化合物V₈-1被合成出来，与V₈-1a不同的是，V₈-1中只有四个与有机胺配位的钒离子被还原到四价，并且甲醇的配位数也减少到4个。此外，由于不同有机胺配体的引入，使得化合物V₈-1中上下{V4}单元的间距变大，导致部分钒有六配位变为五配位。

由于V₈化合物中存在低价态的钒，适合于部分催化反应，此外，化合物V₈-1可以大量合成并有很高的纯度，我们进一步研究了化合物V₈-1对CO₂环加成反应和硫化物的氧化反应的催化性能研究。实验结果表明，化合物V₈-1对部分环氧化合物以及硫氧化合物都有很高的催化活性，对于环氧丙烷和二苯基硫醚等底物的催化活性都分别达到了100%，而且在反应过程中，化合物V₈-1都没有溶解，可以过滤洗涤后进行循环利用，其中对环氧丙烷的二次循环的收率能达到94.6%，对二苯基硫醚的五次循环的转化率能达到90.55%。说明化合物V₈-1是催化这两种反应有效的双功能非均相催化剂。

此外，由于四个化合物中都存在 4价的钒，我们对四个化合物分别进行了磁性研究，磁性研究结果表明，四个化合物均呈现反铁磁耦合相互作用。

关键词：多钒氧酸盐 CO₂环加成 硫化物氧化 磁性

Synthesis and Catalytic Properties of Novel Vanadium-Based Polyoxovanadates

Abstract

As an important branch of polyoxometallate, polyvanadate is an excellent material with variable coordination geometry and various redox activities, which makes it interesting molecular magnetic, good optical activity, as well as excellent catalytic properties, have received wide attention.

In this paper, a combination of solvothermal method and volatilization method was used to synthesize four windmill-like eight-core inorganic-organic hybrid polyoxovanates using ligands ethylenediamine, 1,2-propylenediamine and 1,2-cyclohexanediamine: [(C₂N₂H₈)₄(CH₃O)₈V₈O₁₂]·(CH₃OH)_1.5 (V₈-1a), [(C₂N₂H₈)₄(CH₃O)₄V₈O₁₆]·6H₂O (V₈-1), [(C₃N₂H₁₀)₄(CH₃O)₄V₈O₁₆]·5H₂O (V₈-2) and [(C₆N₂H₁₄)₄(CH₃O)₄V₈O₁₆]·6H₂O (V₈-3), the crystal structure was determined by single crystal X-ray diffraction, and characterized by IR, Powder X-ray diffraction, Elemental analysis and etc. By using a bidentate flexible organic amine ligand, we found that the introduction of an organic amine partially reduced the original pentavalent vanadium to tetravalent vanadium. Among them, in the synthesis of compound V₈-1a, we added glutamic acid, although glutamic acid did not appear in the structure at the end, but due to the introduction of glutamic acid, the vanadium ions in compound V₈-1a were all reduced to Four-valent vanadium is used, and the coordination number of methanol has reached the maximum of eight. In the absence of glutamic acid, compound V₈-1 was synthesized. Unlike V₈-1a, only four vanadium ions coordinated to the organic amine in V₈-1 were reduced to tetravalent, and methanol. The number of coordination digits has also been reduced to four. In addition, due to the introduction of different organic amine ligands, the spacing of the upper and lower {V₄} units in the compound V₈-1 becomes larger, resulting in a partial coordination of the vanadium with a six-coordinate.

Due to the presence of low-valent vanadium in the V₈ compound, it is suitable for partial catalytic reaction. In addition, compound V₈-1 can be synthesized in a large amount and has high purity. We further studied the catalytic performance of the CO₂ cyclic addition reaction and sulfide oxidation reaction by compound V₈-1. The experimental results show that the compound V₈-1 has high catalytic activity for some epoxy compounds and sulfur oxides, and the catalytic activity for substrates such as propylene oxide and diphenyl sulfide was up to 100%, respectively. During the reaction, the compound V₈-1 was not dissolved, and it could be recycled after filtration and washing, wherein the yield of the secondary cycle of propylene oxide was 94.6%, and the conversion rate of the diphenyl sulfide can reach 90.55% after five cycles. The compound is a bifunctional heterogeneous catalyst that catalyzes the effectiveness of both reactions.

In addition, due to the presence of 4 valence vanadium in all four compounds, we performed magnetic studies on four compounds. The magnetic results show that all four compounds exhibit antiferromagnetic coupling interactions.

KEYWORDS: Polyoxovanadates; CO₂ cycloaddition; Sulfide oxidation; Magnetis

目录

摘 要 I

Abstract II

第一章 文献综述 1

1.1 多金属氧酸盐简述 1

1.2 多酸的应用 2

1.2.1 多酸在含硫化合物催化方面的应用 2

1.2.2 多酸在催化CO₂环加成方面的应用 3

1.2.3 多酸在磁性方面的应用 5

1.3 多金属钒酸盐催化研究进展 7

1.3.1 钒多酸在催化含硫化合物方面的应用 7

1.3.2 钒多酸在催化CO₂环加成方面的应用 10

1.4 选题思想和意义 11

1.5 仪器与试剂 12

1.5.1 实验试剂 12

1.5.2 实验仪器 13

第二章 新型风车状八核钒氧簇的合成、晶体结构与催化性能研究 14

2.1 引言 14

2.2 单晶培养 15

2.2.1 [(C₂N₂H₈)₄(CH₃O)₈V₈O₁₂]·(CH₃OH)_1.5 (V₈-1a)的合成 15

2.2.2 [(C₂N₂H₈)₄(CH₃O)₄V₈O₁₆]·6H₂O (V₈-1)的合成 15

2.2.3 [(C₂N₂H₈)₄(CH₃O)₄V₈O₁₆]·5H₂O (V₈-2)的合成 15

2.2.4 [(C₆N₂H₁₄)₄(CH₃O)₄V₈O₁₆]·6H₂O (V₈-3)的合成 16

2.3 晶体结构 16

2.3.1 [(C₂N₂H₈)₄(CH₃O)₈V₈O₁₂]·(CH₃OH)_1.5 (V₈-1a) 的晶体结构 17

2.3.2 [(C₂N₂H₈)₄(CH₃O)₄V₈O₁₆]·6H₂O (V₈-1)的晶体结构 20

2.3.3 [(C₂N₂H₈)₄(CH₃O)₄V₈O₁₆]·5H₂O (V₈-2)的晶体结构 22

2.3.4 [(C₆N₂H₁₄)₄(CH₃O)₄V₈O₁₆]·6H₂O (V₈-3)的晶体结构 24

2.4 化合物V₈-1a, 1, 2, 3的基本表征 27

2.4.1 红外光谱 27

2.4.2 X-射线粉末衍射 28

2.5 CO₂环加成反应 29

2.6 硫化物的催化氧化 32

2.7 磁性 35

2.5 本章小结 36

第三章 结论与展望 38

3.1 结论 38

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