Phosphine hydrides

Numerous phosphine and arsine complexes have been synthesized and characterized predominately with osmium in the +2, + 3 or +4 oxidation states. Examples include [OsCl2(dppm)2] [108341-10-2], [OsC13(P(CH3)2(C6H5)3] [20500-70-3], [0s2Cl6(dppm)2(0)] [87883-12-3], and [Os(AsC2Hb(C6Hb)2)4H2] [27498-19-7]. An example of an unusually low oxidation state is the Os(—2) complex K2[Os(PF3)4] [26876-74-4]. High coordination numbers and formal oxidation states are found in the phosphine hydrides, eg, [Os(P(CH3)(C(5HB)2)H6] [25895-55-0] and... 

A reaction mechanism involving the formation of a gold hydride intermediate was tentatively suggested, in analogy with mechanisms known to operate for soluble platinum group metal catalysts such as those of palladium or rhodium phosphine hydride complexes.47... 

The silica-supported Ta hydride (=SiO)2Ta-H (93a) reacts with PMc3 to give (=SiO)2Ta(H)(PMe3) (93b). In comparison to (93a), the phosphine hydrid (93b) is inactive toward metathesis of acyclic alkanes, but affords the oligomerization of ethylene into 1-butene and higher oligomers. 

Many of the octahedral phosphine hydride and halogenohydride complexes undergo a stepwise hydride/chloride exchange with hydrohalides. 

Finally, although ruthenium phosphine hydrides such as (151) do not react... 

One other phosphine-hydride complex has been prepared, specifically 759 OTf, which was obtained by treating methanol solutions of [Rh(NCMe)3(triphos)](OTf)3 with NaTp (Scheme 73). The identity of 759-OTf was established both spectroscopically and by a single crystal X-ray diffraction study (Fig. 15), but the material has received no more elaboration. 

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