In a photo-catalyzed system based on Ru(bpy)3 complex, is it possible to prevent electron-transfer back-reactions and returning of the generated radical to the ground state due to presence of a radical scavenger like DTT?
UPDATE:
These info are also necessary for the question. The intended system is used for generation of radicals from and crosslinking of a protein (Tyrosine). In this way, formation of [Ru(bpy)3]3+ from the excited [Ru(bpy)3]2+* is necessary. But as I mentioned in the original question, is it possible to drive the system down the oxidative quenching pathway of [Ru(bpy)3]2+ by an oxidative quencher like ammonium/sodium/potassium persulfate, and at the same time, have a strong reducing agent like DTT present in the system? The presence of DTT is due to the need for activation of a Michael addition reaction after photo-activation of [Ru(bpy)3]2+.
The question is not clear. [Ru(bpy)3]3+ is formed in the reaction of the excited state [Ru(bpy)3]2+* with an electron acceptor. In the presence of a strong reducing agent such as DTT, the [Ru(bpy)3]2+* will be reduced to [Ru(bpy)3]+.
Dear Yurri,
Thank you very much for your input. I looked at my question again and I found out that I omitted an important part of the preliminary info. I have updated the question and would appreciate your feedback. Many thanks in advance.
I don't have an universal answer. Your system is very complex. Ru3+ is a strong electron acceptor. Radicals commonly react through a homolytic cleavage of C-H, S-H or O-H bonds. In this context Ru3 is not a radical. The photogeneration of Ru3 with persulfate also generates SO4(-.) radical, which is also rather strong electron than H-atom acceptor. You may need to generate some radical-like species but not Ru3+.
Dear Yurii,
Thanks for your feedback. Do you have any experience or advice similar to the attached paper, but for the case of oxidative quenching pathway in presence of a nucleophilic species to stabilize the back reactions? or in another words, is it even possible to think about these kind of designs? I am not sure if I asked the question in a right way because honestly, this is not much of my area of expertise and I am just getting used to using the right terminology. I appreciate your kind help.
Yes, you have problems with terminology. I don't understand well your question. The chemistry of Ru2/Ru3 is the electron transfer ET) processes. The concept "Nucleophilic" is not used in this area. A donor and acceptor of electrons are the right terms. The reaction can't be "stabilized." The back reaction can be replaced by another faster reaction using a sacrificial electron donor or acceptor. Ru2* can be reduced by an electron donor to form Ru1 and "oxidized" electron donor, which can recombine back. Commonly, you can direct the reaction in the desired way.
Thanks for your input and I really appreciate your help. I will dig more for finding a proper solution.
Many thanks.
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