配位化合物的重要性

1、配位化合物的重要性(1) 湿法冶金 可以用配合剂的溶液直接从矿石中把金属浸取出来，再用适当的复原剂复原成金属。 例如早在40 年代，有些国家已研究出 NiS 等矿石在加压下的氨溶液中浸取，随后在加压下用氢复原 得镰粉。加压 2+NiS+6NH(aq) - Ni(NM )eNi(NHa) 62+H-加压 Ni(粉)+ NH4+4NH其他如 Au 的提取至今多是利用 CN 配合成 Au ( CN 2- 再以 Zn 复原成单质金 。4Au+8 CN+2H0+S4AU (CN 2 +4OHZn+ 2Au(CN 宀 2 Au + Zn (CN 2(2 别离提纯由于制备高纯物质的需要，对于那些性质相近的稀

2、有金属，常是利用生成配 合物来扩大一些性质上的差异，从而到达别离、提纯的目的。例如 Z +与Hf4+的离子半径几乎相等，性质非常相似。但在0.125mol/dm 3HF 中 KaZrFe 与 KaHfFe 的溶解度分别为 1.86 和 3.74克(20 C,100g H2O 中) ，后者约为前者的二倍 ，曾利用这种差 别用分 级结晶法制取无铃的铅°又如三价稀土元素离子，半径相差很小 (平均约1pm，别离极为困 难。近年来利用它们和含 氧螯合剂螯合能力的 不同，因此可用萃取别离法对稀土 元素进行别离。较轻较大的稀土金 属离子如等可以同二苯基-18- 冠-6(简称冠醸生成易溶于有机溶剂的

3、型螯合物螯合物中周围有 6 个五元环，与氧原子形成八面体配位。这种较轻稀土离子如 等生成稳定的配合物 ，而与半径较小的中、重稀土离子不能形成稳定的配合物。这样轻稀土 可被萃取到有机相中 ( 假设用冠醸做成吸附柱时，那么轻稀土留在吸附柱上) ，重稀土仍留在水中，从而到达别离的目的。(3)设计合成具有特殊功能的分子Underhill 教授领导的研究小组设计的“分子金属中，每个分子中的金属 原子都在某 一方向上排齐成行，电子就可以沿着这一金属原子链流动。如何 使这些金属原子进行组合 而恰到好处地堆砌起来，现已发现硫和硒是连接金 属的理想选择。如下图，该图说明每 个分子都是平面型的，中间有一个 钳金属

4、原子，它周围有四个硫原子。每个钳原子的上面 和下面各有一个属于 上一层或下一层分子的钳原子。所以，有很多条可供电子穿越的“钳 - 硫原 子链贯穿整个晶体。这些分子金属导电性能的优劣不仅取决于金属原子之间的间距，还取 决于不同堆砌方式中相邻分子间硫原子互相靠近的程度。 显然，这就要求化学 家要精心设计，调节分子的结构，使电子可依设计者 的意图在晶体中流动。这类“分子金 属可望对未来的“分子计算机有很 大的影响。类似的配合物还有金属吓咻配合物制成 的 LB 膜，光储材料，抗 癌药物等。教授设计的一种“分子金属， 用 X 射线法测定的结构图。 平面状的分 子呈现状堆砌， 因而电子能够横向地在分子之间

5、穿越。The importance of coordination compounds(1) the wet metallurgyWe can use chelating agent directly from the ore solution ontheleaching, reoccupy metal out appropriate reductant reductive into metal. For example, back in the early '40 s some countries have developed NiS etc ore in under the pre

6、ssure of ammonia solution, then the pressurized ontheleaching by hydrogen reduction to nickel powder.NiS + 6 NH3 (aq)-pressure Ni (NH3) 62 +Ni (NH3) 62 + + H2-pressure Ni (powder) + NH4 + + 4 NH3Other such as Au has many is using CNextraction combined with (CN) into Au 2-again with Zn reductive into

7、 elemental gold.4 Au+ 8 CN-+ 2 H20 + 02 二 4 Au (CN) 2-+ 4 OH ?Zn + 2 Au (CN) 2- 二 2 Au + Zn (CN) 2(2) Separation and purificationDue to the needs of the material preparation high purity, for those of a similar nature rare metal, often using formation complexes to expand some qualitative difference,

8、so as to achieve the purpose of separation and purification. For example Zr4 + and Hf4 + ion radius almost equally, nature is very similar. But in 0.125 mol/dm3HF K2ZrF6 and K2HfF6 in the solubility were 1.86 and 3.74 g (20. C, 100 g H2O), the latter to the former about twice, once to use this kind

9、of difference with grading crystallization of zirconium Ha naught legal system. And as three price rare earth elements ions, slightly different radius (an average of about 1 PM),separate extremely difficult.In recent years, use them and oxygen chelatedchelating extraction separation isdifferent, so

10、it can be ofrare earth elements to separation. Lighter larger rare earth metal ions, such as ErBenJi-18 May, with the crown-6 (hereinafter referred to as crown ether) generation is soluble in organic solvent type of chelates Chelates around in 6 five yuan ring, and oxygen atoms form octahedron coord

11、ination. Such a large octahedron hole (crown ether radius of the hole for 320 360 PM) can only and radius of the larger light of rare earth as generated steady complexes, etc, and the radius of the smaller and heavy rare earth ions can't form a stable complexes. Such light re can be extraction t

12、o organic phase (if use crown ether adsorption column, it made light of rare earth in adsorption column), heavy rare earth to remain in the water, so as to achieve the purpose of separation.(3) design synthesis of special performanee molecules Professor Underhill, a research team led the design of &

13、quot;molecular metal , each molecules of themetal atoms are in a certain direction, it ranks together electronic can along the metal atoms flow chain. How to make these metal atoms are combined and properly stack up, has now found sulfur and selenium is to connect metal ideal choice. As shown in fig

14、ure, this shows that every molecule is flat type, and there is a a platinum of atoms around it, there are four sulfur atoms.Each of the platinum atoms above and below each have a belong to a layer orthe next layer of molecules platinum atoms. So, there are a lot of available for electronic article t

15、hrough Hplatinum-sulfur atoms chain 1* throughout the crystal. These molecules of conductive metal performance depends not only on the merits of the metal atoms, the distance between still depends on the different way between the molecules in the stack adjacent sulfur atoms toward each other levels.

16、 Obviously,this requires chemistwants elaborate design, adjust thestructure of molecules, make electronic can depend on the designer's intent in the crystal,the flow. This kind of"molecular metal will be the future “ molecular computer has very big effect. Similar complexes and metallic porphyrin complexes LB film, made