I have got mass and single crystal data for Pd(II)triphenyl phosphine complex. But I am still getting a peak at -4 ppm in the 31P NMR. I have given enough hexane wash to remove excess PPh3.
Hello Priyanka,
many thanks for sharing this very interesting technical question with the RG community. Triphenylphosphine is well known for crystallizing rather easily. Thus it is often difficult to remove admixed small amounts of triphenylphosphine from its complexes. In any case I would suggest to recrystallize your palladium complex form a suitable solvent such as toluene / pentane or acetonitrile etc. When you have a palladium complex with more than two triphenylphosphine ligands, chances are that one PPh3 ligands readily dissociates in solution. This is long known for the famous palladium(0) catalyst tetrakis(triphenylphosphine)palladium (Pd(PPh3)4). This compound readily loses one or even two phosphines so that a substrate can be oxidatively added and then initiates a catalytic cycle. Chances are that your palladium(II) complex has also been made that way by an oxidative addition reaction.
For possible crystallization methods, please check the attached useful guides.
Good luck with your research work and best wishes, Frank Edelmann
Dear Prof.Frank Edelman,
Thank you very much for your suggestion. I will try to grow the crystal in the solvents which u have mentioned. And I will take the 31P NMR for the corresponding crystal. Many thanks once again!
If your compound is insoluble in diethyl ether then give a thorough diethyl ether wash to remove (better than hexane) unutilized PPh3. By the way which compound you tried to get structure done. Structure of PdCl2(PPh3)2 is known for decades. You simply said: Pd(II)PPh3, which is incomplete. In solution the compound may decompose generating free PPh3 and black residue of palladium(0). Unless you tell clearly what reaction you did, and what you expected and what you got, it is beyond others imagination. When you need suggestions, you have to give a clear picture of what actually you did and what you got. This is how it should go.
It's important to consider that the methods you use provide different information: NMR is characterising the entire/bulk material, whereas X-ray diffraction analyses one single crystal picked from the bulk, and MS provides you with the sole information that something with a certain mass is present in your sample.
This should be kept in mind, in addition to the facts mentioned b y Frank T. Edelmann and Balakrishna Maravanji .
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