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

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