Yttrium Hydride Complex Bearing CpPN/Amidinate Heteroleptic Ligands: Synthesis, Structure, and Reactivity

The reaction of the yttrium dialkyls (C5H4–PPh2N–C6H3 i Pr2)Y(CH2SiMe3)2(thf) (1) with an excess of N,N′-diisopropylcarbodiimide gave the yttrium monoalkyl complex (C5H4–PPh2N–C6H3 i Pr2)Y(CH2SiMe3)[ i PrNC(CH2SiMe3)–N i Pr] (2). 2 subsequently reacted with 1 equiv of PhSiH3 to generate the CpPN/amidinate heteroleptic yttrium hydride {(C5H4–PPh2N–C6H3 i Pr2)Y[ i PrNC(CH2SiMe3)–N i Pr](μ-H)}2 (3). Hydride 3 showed good reactivity toward various substrates containing unsaturated C–C, C–N, and N–N bonds, such as azobenzene, p-tolyacetylene, 1,4-bis(trimethylsilyl)-1,3-butanediyne, N,N′-diisopropylcarbodiimide, and 4-dimethylaminopyridine, affording the yttrium hydrazide complex 4 with a rare η2-Cp bonding mode, yttrium terminal alkynyl complex 5, yttrium η3-propargyl complex 6, yttrium amidinate complex 7, and yttrium 2-hydro-4-dimethylaminopyridyl product 8, respectively.