Iridium complexes sulfur dioxide

Scheme 15. The reactions of sulfur dioxide with dioxygen complexes of iridium.

The elimination of sulfur dioxide from arenesulfonyl chlorides is catalyzed by Vaska s complex,502 while this same iridium complex apparently catalyzes the aromatization of various 1,4-dihydro derivatives of aromatic hydrocarbons.500... 

The reaction of tra 3 -IrCl(CO)(PPh3)2 with carbon disulfide in the presence of NaBPli4 yields [(49)](BPli4) in which the S-donor ligand is the zwitterion S2C PPh3+. Sulfur dioxide is S-bonded to an iridium(I) atom in the trigonal bipyramidal complex IrH(PPh3)2(CO)(S02) in the related chloro complex (50), the Ir-S distance is 2.45 A. ... 

Sulfur dioxide also forms 1 1 adducts with four-coordinate d complexes (see Table I) 82, 121, 122). An X-ray diffraction study of the adduct IrCl(S02)(C0)(PPh3)2 revealed a tetragonal pyramidal structure with sulfur dioxide at the apex 83), Sulfur is directly bound to iridium by a long bond (2.49 A). 

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