I am synthesizing metal complexes and now the compound bearing an organic part and inorganic metal part. But the metal complexes are very difficult to dissolve in organic solvents, I tried sonication, but it get dissolved partially in solvent DMSO. This issue will definitely affected the further characterization and application process. Any one please suggest a solution
For better solution for the solubility of metal complexes use solvents like ethanol, DMF or DMSO which are polar solvents.
Trying ionic liquid or supercritical CO2 solvent to control a polar level of solvent.
Depending on the type of characterization you are referring to; you can try mixed solvents for re-crystallization (Crystal growth). If your metal center is NMR active, check what is in the partially dissolved DMSO solution.
How did you obtain you product? Did it precipitate out of a solution? What solvent did you used for the synthesis?
@Ekemini Daniel Akpan
It was precipitated out form the reaction mixture during stirring. I used methanol
Dear Anjali, thank you for asking this interesting question. Unfortunately, asking for "a better solution for the solubility of metal complexes" is very general. Thus it is difficult to give you a qualified answer without knowing a few more details about the type of metal complexes you use. As mentioned by Madhukar Baburao Deshmukh highly polar solvents like DMSO old DMF might be a solution. However, think about the well-known red nickel dimethylglyoxime complex (https://en.wikipedia.org/wiki/Nickel_bis(dimethylglyoximate)). This complex is insoluble in water and common organic solvents. You could also have coordination polymers which are insoluble in all organic solvents. Often a modification of the ligand system or the use of additional ligands can lead to more soluble complexes.
Dear Anjali,
Most of the coordination chemists more than often face the solubility problem. There are two ways to tackle it. i) Ligand can be modified and ii) nature of the metal complex can be altered. How? For example, if you are using a aromatic group based ligand, try to add a few alkyl groups on it. Choose or design ligands in a such way that you have methyl, ethyl or nbutyl groups or ether, amine functionalities. If you have amine functionalities which can be quaternised to make salts so that they dissolve in polar solvents. When it comes to metal, try to make it an anionic or cationic complex, instead of neutral, and try to replace counter ion, say, anion such as Cl or Br by perchlorate, triflate, which can dissolve well and also give good crystals for single crystal X-ray analysis. Otherwise, you have to try various combination of solvents to dissolve them. There is no method for solubilizing something which is highly insoluble. If the solubility is very poor, you can use Soxhlet method for purification and crystallization as well.
All the best
Balakrishna
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