Maybe this can help you

http://pubs.acs.org/doi/abs/10.1021/ic00331a030

in my opinion CO or urea (to test)

Maybe this can help you

http://pubs.acs.org/doi/abs/10.1021/ic00331a030

in my opinion CO or urea (to test)

I think PPh3 in alcohol is a good reducing agent and keeping the system in Ru(II). 

What about using ascorbic acid?

Oxalic acid reduces V(+5)2O5 to V(+4) and V(+3).  The stoichiometry is a bit tricky but it can be worked out.  I did this in sulfuric acid.

Why didn't you try by electrolysis at a fixed potential ? To my opinion, this is the most powerful tool for a redox transformation. Another interest of such a procedure lies in that you do not add potential ligand (such a phosphine) in your reactor...

Luca Patauner sir really very good paper sir. I think this paper very  useful to your question Dr. Nidal Saleh

We usually reduce Ru(III) to Ru(II) using an excess of Zinc dust in a solvent such as dichloromethane or THF. I guess that other solvents will also do

read

J. Chem. Soc., Dalton Trans., 2000, 85-92

Thanks for your answers

Dear Manuel, I already tried some zinc dust but it didn't work, I think the cause is that my complex is Ru(III) charged but not neutral, and the redox potential differs betwwen the charged and neutral complexes even they are Ru(III), and consequently it differs from the potential of Zn dust 

What about hydrazine? I know that its potential is within that range, does anyone has any idea or procedure about that?

Thanks Richard, but I would like to do it chemically 

If think is not enough, you can use Magnesium turnings. Alternativelym if you want an efficient homogeneous reducing agent, you can try sodium naphtalenide in THF. Once you establish the concentration of the solution of NaNaph, you adjust the amount depending on the number of electrons that you want to reduce. In your case, is one electron reduction. The green color of NaNaph disappears upon reaction, so the rective is also self-indicator that the reduction has occured.

Hi Nidal,

I have been using Zn or H3PO2 to generate Ru(II) in situ from RuCl3 and they both worked well. But be sure to have a ligand to "catch" the Ru(II) once is formed.

Good luck.

Chem. Commun., 2013, 49, 8320-8322

Zn works well, usually. However it strongly depends on the ability of your ligand(s) to stabilize Ru(II). Moreover, Zn is safer and easier to handle than many other reducing agents.

Depending on how valuable is the ligand sphere for you: There is an old publication from Stephenson and Wilkinson, where they make triphosphanedichlororithenim from ruthenium trichloride hydrate. So a non-innocent ligand as reducing agent.

Na/Hg amalgam in THF is powerful but may do the trick for you. Plus, its easy to separate after. 

If you are working with polypyridine ligands the following answer would help you otherwise pls ignore.

Inmost of the Ru(II) polypyridine complex formation RuCl3 is used as the metal salt by just using ethylene glycol as solvent and carrying out reflux the reduction can be effected. In the case of ligands like terpyrdine the Ru(III) to Ru(II), can be carried out by using few drops of N-methyl morpholine as the mild reducing agent during complexation in low boiling solvents.