Heterogeneous Catalysts Fixed on Ionites

SCN L = Me2SO, Et2SO, Et2S, NH3), based on the strong-base anionite AB-17-8 and the strong-acid cationite KY-2-8. Many of these metal complexes exhibit catalytic activity during styrene hydrosilation by methyldichlorosilane and are stable enough to be used repeatedly. 

The internal coordination sphere of Ni(II), Co(II), Rh(III), Pd(II), Pt(II,IV) and Ir(III, IV) complexes is maintained during ion exchange. However, Ru, Os, and Pd(IV) complexes break down thereby causing heterogenized metal complexes (HMC) based on them to lose their catalytic activity. Catalysis in the presence of HMC proceeds directly on ionic group sites. 

The application of ionites as substrates makes it possible to obtain metal complexes with high stability under hydrosilation reaction conditions associated with hindrance of intermolecular exchange of ligands [177]. Fixation of complex ions on ionites increases the regioselectivity of catalysis (Thble 18, see p. 103). 

Catalyst Metal content m Degree of exchange W Styrene hydrosilation by methyl-dichlorosilane  

One suggested means of preserving the ligand environment of the central metal ion is to attach transition metal complexes containing sulfurized triphenylphosphine to different lER (Molselect, DEAE-25, Varion) [181]. 

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