Copper complexes easily crystallize over other metal complexes.
Is ther any methods that can be tried or any solvents for crystallizing them?
Aiswarya Hello
Concerning the iron, you can download our short monograph in the ResearchGate:
Pilchin, A.N. and Eppelbaum, L.V., 2006. Iron and its Unique Role in the Earth Evolution. Monogr., Mexican Geoph. Soc.,67 p.
Best
Lev
Select suitable solvent or mixture of solvent in which these complexes are soluble in cold and insoluble in
Hi there is no hard and fast rules for crystallization. For some systems the polar solvents might be good but for others they might not be. First make sure that your complexes are stable in the solvents that you wish to use for crystallization. In general do not use those solvents in which your complexes are highly soluble particularly for slow evaporation method. If you use direct diffusion you may opt for solvents where your complex is highly soluble.
Common ways are:
1. slow evaporation. You simply leave your solution open and wait. If the solvent has low boiling temperature you can provide slow evaporation rate decreasing outer temperature or making very small hole in your reaction vessel. Of course this method does not work when you have air-sencible compounds.
2. slow crystallization. Make concentrated saturated solution (usually at high temperature) and let it to be cooled slowly. Temperature controlled bath if you have it.
3. Slow diffusion. One solvent with big solubility another one with poor solubility. You can realize slow diffusion by accurate layering of your complex solution and solvent precipitating your complex. F.e. if toluene is "good" and diethyl ester is "bad" prepare the solution in toluene and slowly layer the ester on top of toluene solution without mixing (You always have to layer less density liquid on the top of high density liquid). This way works better at low temperature. Or you can organize diffusion through gas phase. Take two bulbs - one with toluene solution of complex another with ester and make the connection between them filled with argon (f.e., you can use nitrogen or air or other gas). If you leave it at the room temperature finally you will have toluene-ester mixture in both and probably crystals of you complex in one. Really you can use slow diffusion directly in synthesis, if soluble A and soluble B gives insoluble AB. Layer solution of B on the solution of A and wait – on the border you could have good crystals of AB.
Any way in first you have to obtain some knowledge about solubility of your complex. Generally the polar solvents are better to solute, while such as hexane – is good to precipitate.
The crystallization of these metal complexes depends on the solubility of these complexes in different solvent and you cann't use one common method for all. The crystallization needs trials to get the suitable solvent or mixture of the solvents.
You can use H- tube with ground joints consisting of your complex dissolved in minimum amount of solvent in one compartment and the other tube containing ether, both joined at its proximal end by a connecting tube. Ether vapour diffuses into the other tube drawing the other solvent upwards. In a day or two you can find crystals settling along the sides of the tube. This method is ideal for complexes.
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