Sulfur monoxide metal complexes

Sulfur ligands, 633-655 coordination ability, 516 Sulfur monoxide metal complexes instability, 636 Superoxide dismutase, 773 copper complexes, 772 Superoxo complexes, 315-330 binuclear, 323, 325 reactions, 330 bridged... 

Transition metal complexes catalyze desulfurization of thiiranes. Complexes of Rh <1986TL3573>, Re <1997TL7701, 1999CC1003>, and Mo <2003JA3871> have been successfully employed in catalytic quantities. The presence of a stoichiometric sulfur acceptor such as carbon monoxide or an alkene, phosphine, or arsine is required. In Re-catalyzed desulfurization, the formation of an intermediate Re =S species via initial coordination of the thiirene ligand has been suggested (Schemes 12 and 13) <1997TL7701>. Kinetics and mechanism of sulfur... 

This chapter is concerned entirely with the insertion of carbon monoxide into transition metal-carbon cr-bonds. Sulfur dioxide insertion 154, 239), also common among transition metal-carbon complexes, will be treated in a complementary review, which is to appear later. Subject to the restrictions given at the beginning of Section VI, an attempt has been made at a complete literature coverage of the insertion of CO. Particular emphasis focuses on recent results, especially those of a kinetic and stereochemical nature. 

Palladium(II) complexes possessing bidentate ligands are known to efficiently catalyze the copolymerization of olefins with carbon monoxide to form polyketones.594-596 Sulfur dioxide is an attractive monomer for catalytic copolymerizations with olefins since S02, like CO, is known to undergo facile insertion reactions into a variety of transition metal-alkyl bonds. Indeed, Drent has patented alternating copolymerization of ethylene with S02 using various palladium(II) complexes.597 In 1998, Sen and coworkers also reported that [(dppp)PdMe(NCMe)]BF4 was an effective catalyst for the copolymerization of S02 with ethylene, propylene, and cyclopentene.598 There is a report of the insertion reactions of S02 into PdII-methyl bonds and the attempted spectroscopic detection of the copolymerization of ethylene and S02.599... 

The dimeric Pd(I) complex Pd2(dpm)2X2 involves two planar metal centers linked by a metal-metal bond. The Pd-Pd separation in these molecules is about 2.7 A. (16,17) These dimers readily undergo insertion of small molecules to give molecular A-frames via reaction (10). (14,18-22) Carbon monoxide and sulfur dioxide... 

Fluorine migration from the CF3 group to the metal occurs with Cr", Fe ", Co ", Pt" and Zn" but not with Ru ", Rh" , Ni" and Pd". The reaction pathway for the zinc complexes is shown in Scheme 3. The molecular ion (48) loses a CFj radical from one monothio-)8-diketone moiety to give the ion (49), which then loses carbon monoxide to yield the fragment (50). Sulfur is ejected from (50) with the concomitant formation of a zinc-carbon bond in the species (51), which can subsequently lose the alkyne RC=CH to give the mono-ligand ion [ZnL] (52). The second ligand moiety loses Cp2 with the formation of a zinc-fluorine bond in the ion (53). 

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