column chromatography is not possible here because of chance of degradation through hydrolysis and washing also not possible because of same solubility.how can i isolate them and to get my desired final metal complex free from unreacted starting ligand?
I have similar situation but my Schiff base is completely soluble in chloroform but the complex is insoluble in chloroform. After drying the product I stir the solid mass in chloroform for few hours to remove the reactant. It will be best if you try to crystallize it.
You can try more solvents like ethanol, cyclohexane to recrystallization your desire product. There must be some difference between desire product and starting material if in different solvent.
Dear Ankit kumar Srivastava
When you say that you’re unable to use column due the possibility of hydrolysis of your compound, are you referring only to silica or alumina column? You don´t describe your ligand besides that is a schiff base, but I think that you can use Sephadex Column. On these columns, I think that the chances of hydrolysis of your compound are very low. I hope that suggestion would be useful for you. Regards.
Juan
I suggest you using equal mol starting matel and schiff base to perform the reaction and drying the solvent after the reaction finished. Then recrystallization you metal complex use proper sovelent.
There are methods of slow crystallization. Metal complexes crystallize slightly better than ligands. You shall introduce vapors of a volatile solvent, in which is the material poorly soluble, into the solution of the material in a solvent providing good solubility. Vapors can be introduced by bent glass tube, piece of PTFE or steel tubing through septum, etc. a yield of such process will be low though.
If you are afraid of hydrolysis due to silica gel during chromatography, you can try NaHCO3-washed silica gel. Here is a procedure for making it. Commercial TLC plates (aluminium support) can be washed with an NaHCO3 solution and dried in an oven, they are useful to test the stability of your compound.
Good luck,
Luca
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Ordinary flash-chromatography grade silica gel was slurried with about twice its volume of an aqueous NaHCO3 solution (approx. 50 g/L), washed with water on a Buchner funnel, then with acetone and dried in high vacuum overnight at 140 °C.
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