Iridium complexes arsenic ligands

Although trialkyl- and triarylbismuthines are much weaker donors than the corresponding phosphoms, arsenic, and antimony compounds, they have nevertheless been employed to a considerable extent as ligands in transition metal complexes. The metals coordinated to the bismuth in these complexes include chromium (72—77), cobalt (78,79), iridium (80), iron (77,81,82), manganese (83,84), molybdenum (72,75—77,85—89), nickel (75,79,90,91), niobium (92), rhodium (93,94), silver (95—97), tungsten (72,75—77,87,89), uranium (98), and vanadium (99). The coordination compounds formed from tertiary bismuthines are less stable than those formed from tertiary phosphines, arsines, or stibines. 

The ligands triphos or/ and np in presence of compounds of iron, cobalt, nickel, rhodium, iridium and palladium, by reaction with THF solutions of white phosphorus, P, or yellow arsenic, As, form mononuclear or dinuclear sandwich complexes containing the cyclo-triphosphorus or cyclo-triarsenic units which behave as 3n-electrons rings. 

Iridium(IV), d, salts of halides, hydroxide, sulfide, se-lenide, and telluride have been reported. The commercial product H2[IrCl6] 6H2O is water soluble and acts as a catalyst. Ir02 is prepared from the hexahydroxo complex. Iridium(IV) does not form many complexes, but the six-coordinate halides (excluding the iodo species), and some amine and pyridine complexes are known. Compounds with phosphorus, arsenic, and sulfur donor atoms are not stable these ligands reduce iridium(IV) to the iridium(in) state. 

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