1422011-92-4Relevant academic research and scientific papers
Halide bridged trinuclear rhodium complexes and their inhibiting influence on catalysis
Preetz, Angelika,Kohrt, Christina,Meissner, Antje,Wei, Siping,Drexler, Hans-Joachim,Buschmann, Helmut,Heller, Detlef
, p. 462 - 468 (2013/03/28)
The addition of halides to the cationic solvate complexes of the type [Rh(PP)(solvent)2][anion] leads to the formation of trinuclear μ3-halide-bridged complexes. The corresponding complexes [Rh 3(PP)3(μ3-X)2][BF4] with X = Cl or Br and diphosphines PP Me-DuPHOS, Et-DuPHOS, DIPAMP, t-Bu-BisP* and Tangphos were characterized-in most cases-also by X-ray analysis. By reducing the concentration of the active catalyst, the in situ formation of these μ-halide-bridged multinuclear complexes in catalytic reactions leads to a decrease in activity or even to a total inactivity. The required halides-in most cases chloride-are usually present as impurities in the substrates (also when produced industrially). The extent of deactivation, known from enzyme catalysis as competitive inhibition, depends on several factors: the type of halide, the ratio of stability constants of multinuclear halide complexes and of substrate complexes, and the concentration of halide and substrate in solution. The Royal Society of Chemistry 2013.
