I have synthesized the Ruthenium(II) thioamide complexes containing OS donor. In the complex structure the pyrrolidine ring attached with C-N bond undergoes cleavage( pyrrolidine ring escape) resulting the octahedral ruthenium OS donor complexes. What is the experimental observations for the C-N bond cleavage upon complex formation. Could you correlate the literature reports?
I wonder if you could give an equation showing the reaction. I don't quite understand from the words.
Did you check these?
http://pubs.acs.org/doi/abs/10.1021/ja401553d
http://chem.chem.rochester.edu/~jones/pubs/024.pdf
http://pubs.acs.org/doi/10.1021/acs.chemrev.5b00386
Thank you Sudarsan venkatRamani Sir.
These papers are very useful related to this C-N bond cleavage.
Dr. Joseph S Merola sir, I have attached the reaction scheme in the bottom of the questions. The C-N bond cleavage occur in this reactions and the new product is formed. It is possible? Kindly explain the mechanism behind this complex formation.....
I have a few questions Raj:
a. Why do you use NEt3? I see no need for it. Even if you generated the expected product, you would have no need for the base. It seems you are simply evolving H2 (hydride from Ru and H+ from phenol).
b.Do you reflux your reactions? or Do they take place at ambient temp?
c. Have you performed these reactions in a sealed NMR tube to see what evolves? I am not sure if there is H2 evolution, although it seems likely. I am also not sure if that is from where you get the proton after C-N cleavage. If you can perform this reaction in a sealed NMR tube in C6D6, you can check if free pyrrolidine forms or when it forms.
d. Do you work under inert conditions? Have you tried to exclude water (in your solvents; atmosphere etc)?
Mr. Sudarsan VenkatRamani
Without the use of Et3N the reactions not proceeds.
The reactions were performed in reflux conditions at 80 oC and benzene was used as solvent.
The reactions was not performed in sealed NMR tubes such facilities is not available here.
Under inert conditions the reactions was not performed up to so far.
I got the X-Ray structure with C-N bond cleavage. I need how the reactions proceed? What is the plausible mechanism? Kindly explain sir...
You may use a pressure tube or just a standard reflux set up. It would be best if you can perform your reaction with deuterated benzene as solvent. This way, you can analyze what forms and when things form. Based on the information you have provided, I suspect there is concerted ligation, deprotonation. I am unsure if there is molecular H2 evolved; but your C-N cleavage is probably linked to the deprotonation event. It may be that you only need catalytic amounts of TEA for this reaction.
a) Do you use stoichiometric TEA? Have you tried to use catalytic amounts? Do you know what happens?
b) Have you tried to reflux in the absence of TEA? What do you observe by NMR?
c) What happens if your system is "closed"? What do you observe by NMR?
d) Can you perform this reaction at 60 C? If yes, mix your reagents (100 mg scale), and add stoichiometric TEA in C6D6 in a regular NMR tube (parafilm it; use electrical tape, and some N- or M-grease to seal the cap), heat for xx hours, then get a mass spec of one aliquot to see if you can detect pyrrolidine.
e) If you cannot perform the reaction in C6D6 then can you get a mass spec before you remove C6H6 (before you rotavap I mean)? See if you can locate pyrrolidine in your mass spec.
f) Have you tried to do your reaction with the salt of your ligand? (Deprotonate your ligand before you add it to the Ru substrate; no need for TEA).
You will need a little bit more experimentation before you can arrive at a possible mechanism. For now, it is clear that there is deprotonation of the phenol, loss of hydride (possibly evolution of H2); I can’t say with certainty if your C-N cleavage is H+ promoted or Hydride promoted, or if both play a role. Your experiments will / should guide you.
Mr, Sudarsan Venkatramani,
These set of reactions under the category of hydrodenitrogenation reactions?
Kindly explain the reaction mechanism sir.
From what little I know, this is a C-N cleavage, and not HDN. This could be mediated by anything from water in your C6H6 (since you said you were not carrying it under inert conditions; you're refluxing), to the [HNEt3]+ that you potentially generate in your case, or the H- on your Ru. YOu will need a series of rigorous experimentation before you can arrive at a plausible mechanism.
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