Reductive reactivity of the organolanthanide hydrides, [(C5Me5)2LnH]x, leads to ansa-allyl cyclopentadienyl (η5-C5Me4CH2-C5Me4CH2-η3)2- and trianionic cyclooctatetraenyl (C8H7)3- ligands

The reductive reactivity of lanthanide hydride ligands in the [(C5Me5)(2)LnH](x) complexes (Ln = Sm, La, Y) was examined to see if these hydride ligands would react like the actinide hydrides in [(C5Me5)(2)AnH(2)](2) (An = U, Th) and [(C5Me5)(2)UH](2). Each lanthanide hydride complex reduces PhSSPh to make [(C5Me5)(2)Ln(mu-SPh)](2) in similar to 90% yield. [(C5Me5)(2)SmH](2) reduces phenazine and anthracene to make [(C5Me5)(2)Sm](2)(mu-eta(3):eta(3)-C12H8N2) and [(C5Me5)(2)Sm](2)(mu-eta(3):eta(3)-C10H14), respectively, but the analogous [(C5Me5)(2)LaH](x) and [(C5Me5)(2)YH](2) reactions are more complicated. All three lanthanide hydrides reduce C8H8 to make (C5Me5)Ln(C8H8) and (C5Me5)(3)Ln, a reaction that constitutes another synthetic route to (C5Me5)(3)Ln complexes. In the reaction of [(C5Me5)(2)YH](2) with C8H8, two unusual byproducts are obtained. In benzene, a (C5Me5)Y[(eta(5)-C5Me4CH2-C5Me4CH2-eta(3))] complex forms in which two (C5Me5)(1-) rings are linked to make a new type of ansa-allyl-cyclopentadienyl dianion that binds as a pentahapto-trihapto chelate. In cyclohexane, a (C5Me5)(2)Y(mu-eta(8):eta(1)-C8H7)Y(C5Me5) complex forms in which a (C8H8)(2-) ring is metalated to form a bridging (C8H7)(3-) trianion.