Phosphane ligands displacement

The presence of the P4 molecule was indicated by osmometric molecular weight determinations, mass spectrometry, and by the easy displacement, even at -78°C, of the intact P4 unit by carbon monoxide or phosphane ligands. The infra-red and Raman spectra showed bands attributable to a bound P4 molecule under 3 or Cg... 

Danopoulos and coworkers [473] then developed a ruthenium(II) pincer carbene complex exactly on the lines described above starting from the Grubbs catalyst. Reaction with the free carbene ligand results in displacement of the phosphane ligands and coordination of the central pyridine unit changes the coordination geometry from square pyramidal to octahedral (see Figure 3.157). 

Dicarboxylato complexes such as 4, 8, and 10 and cationic arene complexes, such as 6 and 9, all serve as efficient catalysts for enantioselective hydrogenation. (Diphosphane)bis(2-methylal-lyl)ruthenium(II) complexes, prepared from (cod)bis(2-methylallyl)ruthenium(II) and the corresponding diphosphane, have also been used7. Other versatile catalyst precursors are (diphosphane)(allyl)(l,l.l,5,5,5-hexafluoroacetylacetonato)ruthenium(II) complexes which are obtained from (cod)(allyl)(hexafluoroacetylacetonato)ruthenium by displacement of cy-clooctadiene with diphosphanes,B. Ruthenium diphosphane catalysts may also be generated in situ from suitable precursors, e.g., 7 and the corresponding phosphane ligand 76,77,1 27. 

Large numbers of derivatives are formed by displacement of CO by other ligands (see eqs. 24.29-24.33 and discussion). Whereas substitution by tertiary phosphane ligands usually gives terminal ligands, the introduction of a... 

From Figure 3.15 it is clear that the bulky, ortho-Mes substituted, pyridine donor cannot displace an anionic ligand (chloride, azide) from the coordination sphere of the rhodium(I) centre. Likewise, the bulky pyridine donor is displaced by triphenyl phosphane, whereas the... 

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