If you have access through your science library or lab, I would encourage you to search within SciFinder Scholar and/or ISI Web of Knowledge (really science citation index).  You can find the papers through those if this data is known.  A good science librarian can aid in the search, because they have training to aid in drilling down into mountains of data.

One of the most convenient methods to access the cis or trans configuration of PR3 ligands on metal centers is phosphorous NMR ( 31PNMR ). A complex with trans phosphine configuration will in general have greater symmetry, thus there will be fewer peaks in 31PNMR. For example, if you have a square planar Pd complex with two P(Ph)3 ligands and two other ligands X and Y (say Ph and Br) you should observe a singlet in the 31PNMR if your phosphorous ligands are trans; if instead the phosphorous ligands adopt a cis configuration then the symmetry element is no longer present and you will observe two peaks in the 31PNMR. The same principle applies to transition metals in general. Mr. Law is correct or course, finding a good paper or book on the mater of analyzing metal complex configurations would be immensely helpful. I hope this helps.

Cis and trans 2J PP-couplings in square planar or octahedral transition metal complexes depend a bit, which can be sometimes quite significant, on the kind of P (on the groups, which are connected to it) and on the metal nucleus itself, but as a rule of thumb, a trans P-coupling should be about 10 times larger than a cis-coupling for the same or similar P.  Furthermore, the coupling constant may also vary depending on the position and sort of  non-P ligands present in your complex. Of course, you need to have different cis or trans P atoms in your Ru-complex in order to observe couplings. So, back to your question, if you have (PPh3=Pa) with a different phosphine ligand (Pb) coordinated to a (Pa)(Pb)Ru(A)(B)  (where A and B are non phosphorous ligands in an square planar or (Pa)(Pb)Ru(A)(B)(C)(D) in an octahedral complex your 2JPP is expected to be between 20-40 Hz and 300-400 Hz for cis and trans position of the two P-s, respectively (unless A-D not very unusual). The same applies for the cases: (Pa)2(Pb)Ru(A), (Pa)(Pb)2Ru(A), (Pa)(Pb)(Pc)Ru(A), (Pa)(Pb)(Pc)(Pd)Ru and for their octahedral analogues with a natural consequence of more complexity in the spectra. (AA'B, AA'B2,AA'B,B' etc, patterns can be even more complicated.) 2JPP couplings between inequivalent phosphines in trigonal or planar-apical positions can be somewhat smaller than the planar cis-couplings, although this is not straightforward especially in octahedral or trigonal bipyramidal complexes. As mentioned above, the functional group on the P (basisity of the P) influences the couplings greatly. For example, a trans coupling between PPh3 and a phosphite P or between two trans phosphite can be larger than 400 Hz. 

See for example: http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0471185876.html ,

In my experience (especially in the iron and manganese triads) I have never observed a J greater than 160 Hz for trans couplings between phosphites. The values depend both on the gemetrical relations (but cis and trans values are usually of the same order, max 1.5/2 times) and the row of the central metal, first transition series being larger for a factor even 2/3fold against second and third series (tipically 120 vs 60/50).

It was also pointed out in my answer above, that values of cis and trans coupling contants also depend on the nucleus itself (mainly of its size). For example, Pd gives usually smaller values than Pt or Rh. The question was about triphenylphosphine complexes of Ru. If you did not have the chance to see 2JPP  trans couplings greater 160 Hz in late transition metal complexes of triphenylphosphine, I can assure you that others and I did. Please consults the reference given above.

Dear dr. Toth, there's no doubt you're right !

I was talking of phosphite, phoshponite etc or mixed ligands phosphite/PPh3 complexes of the triads, and forgot to mention (important issue) the metals being usually d8 systems.  Of course, different ox. states (ie Ru(II) vs Ru(0) or others) and different metals can go different.

What I observed is that often PPh3 has smaller Js, so I wanted to warn that you can't every time expect to see J values over 200/300/400 Hz. This is a more than 30 years experience...

That's all !

 Dear Stefano,

Unfortunately, I have also close to 40 years of experience with 31P NMR. -:). The determination of the position of P-ligands on transition metals and of the configuration of the formed complexes were always in the focus of our research. If one includes all transition metals and all peculiar P-ligands, it is indeed difficult to set up a simple classification for cis-trans geometry, based solely on 2JPP.  However, as you also know it very well, triphenylphosphine complexes of late transition metals (including cis  and trans assignments) are among the most explored areas in 31P NMR spectroscopy. The range of cis and trans 2JPP of late transition metal complexes of triphenylphosphine, and more specifically, the analogous values for Ru complexes were suggested on this basis.  

Regards,  

                Imre

A difficult question to answer specifically, Ramasamy. You must specify what coupling constant you are discussing to elicit a specific answer. If 2J(31P-31P), then transoid  is large and positive; cisoid small and often negative.