Hello,
I'm currently working on organometallic complexes which has Ti, Zr, Hf. After the synthesis of complex, I checked H-NMR results, I understood that my product is not pure. So, there are impurities such as ligand, other possible complexes. Do you have any purification methods that can be done in Glovebox?
Dear Berkay Şahin inside the glove box you can use the vapor diffusion technique for crystallization of you organometallic compounds. For more information please see this link:
https://www.chemistryviews.org/details/education/2538941/Tips_and_Tricks_for_the_Lab_Growing_Crystals_Part_3.html
You have to identify a correct metal to ligand ratio first. Once, there is no unreacted ligand present into the reaction mixture, you can try to grow crystals of the metal complexes. Follow my papers. I have also worked on Ti, Zr, and Hf.
Frank T. Edelmann
Thank you so much for sharing the link. I have gone through the tricks and tips for growing crystals. I thoroughly enjoyed reading this.
Berkay Şahin
I am sure, the answer from Edelmann would be very useful for you.
With best wishes,
You may use column chromatography. This will work at low temperature and for complexes which are almost stable under nitrogen/argon.
Cornelius C. Kreiter and his group showed many examples for such separations. Unfortunately most papers are not open access. I added a link to one of his successors.
http://www.znaturforsch.com/ab/v48b/48b1431.pdf
If you have an Elsevier access you may find many examples from the Kreiter group.
Best regards
Guido
Purify Organo-metallic Complexes by crystallization. Choose the correct solvent in which the complex is soluble by heating. Usually we use DMF as a solvent for purification. Dissolve complex by heating , filter through cotton, cool gently. The solid pure crystalline product will separate out, filer to get pure solid..
Dear Guido J. Reiss thanks for mentioning the pioneering work by C. G. Kreiter. I fully agree with you in theat in the case of Group 6 organometallic compounds column chromatography is an excellent purification / separation method. However, I'm afraid that this method will not work with most Group 4 organometallic compounds due to the high oxophilicity of Ti, Zr, Hf.
Dear Frank T. Edelmann thank you very much for your correction as I disregarded the early transition metal characteristics. I vaguely remember that the solid phase may be modified to reduce this problem?!
Best regards G
Dear Guido J. Reiss yes, perhaps the surface of the silica gel can be modified by silylation.However, chromatographic purification methods are generally uncommon in the organometallic chemistry of the early transition metals and lanthanides. Here, crystallization is normally the method of choice.
Many organometallic compounds have significant vapour pressure, so perhaps you can try vacuum sublimation. Examples of compounds I have sublimed are Cyclopentadienyl Thallium, Rhodium Carbonyl Chloride, and MethylManganesePentacarbonyl.
Sublimation of some Zr and HF compounds is mentioned here:
Chapter Zirconium & Hafnium: Organometallic ChemistryBased in part o...
Mr. B. Sahin,
It is always suggestible to do re-crystallization with different solvent mixtures first. If unable to get crystals, then proceed with column chromatography.
Dear Berkay Şahin in the case of early transition metals (Group 4) I would always go for recrystallization. Both sublimation and column chromatography work better with middle and late transition metal complexes.
Frank T. Edelmann Thank you for all the information, I appreciated it. I will consider your recommendation on my next round.
Dear Berkay Şahin you're welcome. Please feel free to recommend my answers! 😎
Der Berkay Şahin
by recrystallization from a solvent by cooling. first dissolved the organometallic compound in a solvent forming a solution and the purified organometallic compound is then recrystallized, under cooling conditions, from the solvent.
Low temperature crystallization is always favored, repeat the process several times and observe for improvements.
Dear Berkay Şahin please also see this closely related RG thread with a number of useful answers:
https://www.researchgate.net/post/Producing_a_single_crystal_of_metal_complexes2
Attached please find a guide to "Growing Quality Crystals"
It is always preferable to crystallize using different solvents with different and lower temperatures, and the process must be repeated several times, sometimes using a mixture of solvents, and we follow up the results and improvements, sometimes we need column chromatography.
Dear Berkay Şahin your original question has been asked more than four months ago. In the meantime, have you been able to successfully purify your organometallic complexes? It would certainly be interesting for the RG members who answered your question to hear what the outcome was.
@Frank T. Edelmann , unfortunately i couldn't synthesize the product. NMR results are not clear to move forward to purificiation step
To Purify Organometallic Complexes use DMF as a solvent.Dissolve complex by heating on water bath , filter , keep the solution overnight to get the product.
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