6533b854fe1ef96bd12adeaa

RESEARCH PRODUCT

Reactions of rhodium trifluoroacetate with triphenylphosphine and pyridine. Molecular structure of Rh2(O2CCF3)4(py)4

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Abstract Rh 2 (O 2 CCF 3 ) 4 reacts with two mol of triphenylphosphine forming the adduct Rh 2 (O 2 CCF 3 ) 4 (PPh 3 ) 2 . This compound in solution, even at room temperature, undergoes slow stepwise orthometalation of the phosphine ligands forming the doubly metalated compound Rh 2 (O 2 CCF 3 ) 2 [(C 6 H 4 )P(C 6 H 5 ) 2 ] 2 . This reaction has been monitored by 31 P NMR spectroscopy detecting in solution three reaction intermediates. Rh 2 (O 2 CCF 3 ) 4 reacts with excess of pyridine to form the compound Rh 2 (O 2 CCF 3 ) 4 (py) 4 that can be structurally classified as a class III adduct. It contains two bridging and two monodentate equatorial carboxylates and two equatorial and two axial pyridine ligands. The structure of this compound has been determined by X-ray diffraction. M r =974.3, monoclinic, space group P 2 1 / n , a =10.504(1), b =18.108(1), c =35.377(1) A, β=96.416(8)°, V =6686.6(8) A 3 , Z =8, D x =1.94 Mg/m 3 . Mo Kα radiation (graphite crystal monochromator, λ=0.71073 A), μ(Mo Kα)=10.89 cm −1 , F(000)=3824, T =293 K. Final conventional R factor=0.12 for 2258 ‘observed’ reflections and 312 variables. The structure was solved by Patterson interpretation using the program SHELXS86 and the Fourier synthesis.