Simultaneous dehalogenation of polychloroarenes and chlorination of HSiEt3catalyzed by complexes of the groups 8 and 9

The catalytic activity of the complexes FeCl2(PPh3)(2), RuHCl (PPh3)(3), Ru H2(CO)(PPh3)(3), RuHCl(CO)(AsPh3)(3), RuHCl(CO) ((PPr3)-Pr-i)(2), OsHCl(CO) ((PPr3)-Pr-i)(2), OsH2Cl2((PPr3)-Pr-i)(3), CoCl(PPh3)(3), RhH2Cl((PPr3)-Pr- i)(2), IrH2Cl((PPr3)-Pr-i)(2), IrCl(PPh3)(3), and IrH2(SiEt3) (COD)(PCy3) ( COD = 1,5-cyclooctadiene) in the simultaneous dehalogenation of 1,2,4-trich lorobenzene and the chlorination of HSiEt3 has been studied. The 3d metal c omplexes and the derivative IrH2(SiEt3)(COD)(PCy3) are unactive, while the 4d and 5d metal compounds simultaneously catalyze the dehalogenation of 1,2 ,4-trichlorobenzene and the chlorination of HSiEt3. The osmium and iridium derivatives are less effective catalysts than the derivatives of ruthenium and rhodium and undergo deactivation. Complexes RuHCl(PPh3)(3) and RhH2Cl(( PPr3)-Pr-i)(2) also catalyze the dehalogenation of 1,2-, 1,3-, and 1,4-dich lorobenzene and chlorobenzene. The dehalogenation of 1,3- and 1,4-dichlorob enzene is favored over the dehalogenation of the 1,2-isomer. (C) 2000 Acade mic Press.