Oxygen and Sulfur Donor Ligands

BIANCHINI AND ZOELLNER IV. Oxygen and Sulfur Donor Ligands 

The investigation of phosphine complexes of rhodium(I) as catalysts (or catalyst precursors) for the hydroformylation reaction continues both to better elucidate the reaction mechanism and to improve catalyst activity. The presence of dioxygen often decreases the catalytic activity (139), but can also, surprisingly, reactivate hydroformylation catalysts 

Several factors were found to affect dioxygen uptake by the metal catecholates. Of particular importance were (i) the coordination number of the metal, (ii) the relative basicity of both the catecholate ligand and the metal, (iii) the temperature, and (iv) the pressure of dioxygen. Under some circumstances, both the product containing reacted dioxygen and the unreacted starting catecholate complex existed in equilib- 

The catalytic reaction of complex 49 with dtbcH2 and dioxygen is less selective than that of 50. In addition to the formation of dtbq and 

These studies are part of a rare family of examples of the chemoselec-tive oxidation of catechols (150). The identification of the catalyst and the interception of the catalyst-dioxygen adduct are of particular relevance when the chemistry of catechol dioxygenase and tyrosinase enzymes is concerned. 

The sulfur-substituted anionic 7,8-dicarba-retdo-undecaborate(l ) ligands. 

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Titanium triiodide can be made by direct combination of the elements or by reducing the tetraiodide with aluminum at 280°C in a sealed tube. Til reacts with nitrogen, oxygen, and sulfur donor ligands to give the corresponding adducts (148). 

Complexes with oxygen and sulfur donor ligands 1331... 

Reactions of [Ml2(CO),(NCMe)21 with Neutral Oxygen and Sulfur Donor Ligands... 

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