Reactivity of the Y3+ Tuck-Over Hydride Complex, (C5Me5)2Y(μ-H)(μ-CH2C5Me4)Y(C5Me5)

The trivalent yttrium tuck-over hydride complex, (C5Me5)2Y­(μ-H)­(μ-η1:η5-CH2C5Me4)­Y­(C5Me5), 1, acts as a reductant in reactions in which the (μ-H)− hydride ligand and the bridging Y–C alkyl anion linkage in the (μ-η1:η5-CH2C5Me4)2– ligand combine to form a C–H bond in (C5Me5)− and deliver two electrons to a substrate. Complex 1 reacts with PhSSPh, AgOTf (OTf = OSO2CF3), and Et3NHBPh4 to form [(C5Me5)2Y­(μ-SPh)]2, [(C5Me5)2Y­(μ-OTf)]2, and (C5Me5)2Y­(μ-Ph)2BPh2, respectively. The reactivity of the Y–H and Y–CH2C5Me4 linkages in 1 was probed via carbodiimide insertion reactions. iPrNCNiPr inserts into both Y–H and Y–C bonds to yield (C5Me5)­[iPrNC­(H)­NiPr]­Y­{μ-η5-C5Me4CH2[iPrNCNiPr]}­Y­(C5Me5)2. Carbodiimide insertion with [(C5Me5)2YH]2, 2, was also examined for comparison, and (C5Me5)2Y­[iPrNC­(H)­NiPr-κ2N,N′] was isolated and structurally characterized. To examine the possibility of selective reactivity of the bridging ligands, μ-H versus μ-CH2C5Me4, trimethylsilylchloride was reacted with 1, and the tuck-over chloride complex, (C5Me5)2Y­(μ-Cl)­(μ-η1:η5-CH2C5Me4)­Y­(C5Me5), was isolated.