Ligand dissociation in octahedral ruthenium(II) complexes containing both unidentate and bidentate phosphine ligands

Nucleophilic Addition to Complexes of (Ph2P)2CCH2as a Route to Functionalized, Redox-Active Ruthenium(II)−Diphosphine Complexes

“…The peak positions and relative intensities could be approximately simulated by employing the following values for the coupling constants of the AA‘XX‘ spin system appropriate for the 31 P{ 1 H} NMR spectrum of cis -[RuCl 2 (dppen) 2 ]) (Figure A): J AA ‘ +405 Hz, J AX +40 Hz, J AX ‘ −44 Hz, and J XX ‘ −30 Hz. The absolute values of these coupling constants are reasonable for octahedral Ru(II). , For the signals at 101.2 MHz to appear as singlets, it is clear that J AX (= J A ‘ X ‘ ) must be similar in magnitude, but opposite in sign, to J AX ‘ (= J A ‘ X ) and J XX ‘ . Whereas P− cis -P coupling constants are negative if the coupling is exclusively “through-the-metal” (typically ca .…”

“…The CCH 2 protons resonate as a pseudoquintet (apparent J PH 12.6 Hz) at δ = 6.18 ppm. This is a “virtual” quintet and arises as a result of the strong P− trans -P coupling (300−350 Hz) typically observed for Ru(II)−phosphine complexes. , The four CCH 2 protons and the four phosphorus nuclei formally comprise an AA‘A‘‘A‘‘‘XX‘X‘‘X‘‘‘ spin system. On the addition of nucleophiles to give 3a − g , this resonance is replaced by multiplets at ca .…”

Complexes of 2,3-bis(diphenylphosphino)propene with PtII, PdII and RuII: synthesis, characterisation and rearrangements to complexes of cis-1,2-bis(diphenylphosphino)propene

“…Although it has not so far been possible to determine whether 11 is a 1,2-dpppn or 2,3-dpppn complex, this spectrum does show that chemically different phosphorus atoms must be mutually cis, since P-trans-P coupling constants for ruthenium() complexes are typically 400 Hz. 22,23 Treatment of [RuCl 2 (PPh 3 ) 3 ] with 2 equivalents of other five-membered ring chelate diphosphines under similarly mild conditions usually gives trans-[RuCl 2 (diphosphine) 2 ]. 24 It might be expected that 11 would also adopt this geometry, and that therefore it is either all-trans-[RuCl 2 (1,2-dpppn) 2 ] or all-trans-[RuCl 2 (2,3-dpppn) 2 ].…”

Ruthenium(II) complexes with the atropisomeric diphosphine 2,2′-bis(diphenylphosphino)-6,6′-dimethylbiphenyl in the enantioselective hydrogenation of pentane-2,4-dione

“…Both the catalytic reaction (runs 2-4, 11, 14) and the NMR investigations indicate that the double reduction of Hacac proceeds stepwise via the monohydrogenated keto alcohol 4-hydroxypentan-2-one 9. With all catalyst precursors the sense of induction is the same, (S)-biphemp giving rise to (S) chiral centres in the substrate.…”