Phosphines sulfato

The dioxygen complex shows oxygen transfer reactions characteristic of species containing coordinated peroxide (42), and, for example, we have isolated a sulfato complex from the reaction with S02 and a carbonato complex from a reaction with C02 in the presence of excess phosphine, and we have detected a peroxycarbonato species from the reaction with C02 (44). A reaction with H2 simply replaces the 02 to yield H2IrCl(PCy3)2, Complex 7 (44). 

The structure of mer-Mo(CO)3(S02)(PPr 3)2 was found to contain j -planar rather than if SO2 geometry. The phosphines are mutually trans, and the rotational orientation is such that the S-O and M-CO bonds eclipse one another. Although the M-S bond is the longest reported for / -planar SO2, the SO2 is not labile. The complex reacts with molecular oxygen in solution with decomposition rather than sulfato formation. 

A. Electrophilic attack at the terminal sulfur atom has been observed in several studies of if-CSi complexes This is one of the few examples which indicate that a similar chemistry may exist for tj -S02. It is conceivable that XXVI is an intermediate in this unusual sulfato reaction and that a subsequent step involves direct attack at one of the sulfur sites by phosphine. 

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