Phosphinoindenyl and phosphazidoindenyl complexes of lanthanum and samarium: synthesis, characterisation, and hydroamination catalysis

Abstract

The phosphinoindenyl rare-earth metal complexes [1-(Ph₂P)-η⁵-C₉H₆]₂Ln^IIIN(SiMe₃)₂, Ln = La (1-La), Sm (1-Sm), were prepared by heating two equivalents of 1-(Ph₂P)C₉H₇ with Ln^III[N(SiMe₃)₂]₃ in toluene at 100 °C. The treatment of 1-La with one equivalent of benzonitrile gave (PhCN)[1-(Ph₂P)-η⁵-C₉H₆]₂La^IIIN(SiMe₃)₂, 2, while no adduct was formed in case of the samarium derivative 1-Sm. The reaction of 1-La and 1-Sm with two equivalents of benzyl azide yielded the (phosphazido)indenyl complexes {1-[BnN₃-κN(Ph₂)P]-η⁵-C₉H₆}{1-[BnN₃-κ²N,N′(Ph₂)P]C₉H₆}Ln^IIIN(SiMe₃)₂, Ln = La (3-La), Sm (3-Sm), respectively. The five complexes catalyse the intramolecular hydroamination/cyclisation of 2,2-diphenylpent-4-ene-1-amine using 2% catalyst loading. All compounds were characterised by NMR and UV-Vis spectroscopy, single-crystal X-ray diffraction, and elemental analysis and DFT calculations were performed for 3-La.