配位化合物的重要性.doc

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，再用适当的还原剂还原成金属。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，随后在加压下用氢还原得镍粉。 NiS+6NH3(aq)加压Ni(NH3)62+ Ni(NH3)62+H2加压Ni(粉)+ NH4+4NH3其他如Au的提取至今多是利用CN-配合成Au（CN）2-，再以Zn还原成单质金。 4Au+8 CN-+2H2O+O24Au（CN）2-+4OH- Zn+ 2Au（CN）2-2 Au+ Zn（CN）2-（2） 分离提纯由于制备高纯物质的需要，对于那些性质相近的稀有金属，常是利用生成配合物来扩大一些性质上的差别，从而达到分离、提纯的目的。例如Zr4+与Hf4+的离子半径几乎相等，性质非常相似。但在0.125mol/dm3HF中K2ZrF6与K2HfF6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铪的锆。又如三价稀土元素离子，半径相差很小（平均约1pm），分离极为困难。近年来利用它们和含氧螯合剂螯合能力的不同，因此可用萃取分离法对稀土元素进行分离。较轻较大的稀土金属离子如 等可以同二苯基-18-冠-6（ 简称冠醚）生成易溶于有机溶剂的 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。这种较大的八面体空穴（冠醚的空穴半径为320-360pm）只能和半径较大的轻稀土离子如 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（若用冠醚做成吸附柱时，则轻稀土留在吸附柱上），重稀土仍留在水中，从而达到分离的目的。（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。如图 所示，该图表明每个分子都是平面型的，中间有一个铂金属原子，它周围有四个硫原子。每个铂原子的上面和下面各有一个属于上一层或下一层分子的铂原子。所以，有很多条可供电子穿越的“铂-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卟啉配合物制成的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 pressure 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 CN extraction combined with (CN) into Au 2-again with Zn reductive into elemental gold.4 Au + 8 CN-+ 2 H2O + O2 4 Au (CN) 2-+ 4 OH-Zn + 2 Au (CN) 2- 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, 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 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 chelated chelating extraction separation is different, so it can be of rare 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 chelatesChelates around in 6 five yuan ring, and oxygen atoms form octahedron coordination. 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 cant form a stable complexes. Such light re can be extraction to 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 performance moleculesProfessor Underhill, a research team led the design of molecular metal, each molecules of the metal 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 figure, 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 or the next layer of molecules platinum atoms. So, there are a lot of available for electronic article through platinum-sulfur atoms chain 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. Obviously, this requires chemist wants elaborate design, adjust the structure of molecules, make electronic can depend on the designers 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