Ruthenium Hydride Complexes of the Hindered Phosphine Ligand Tris(3-diisopropylphosphinopropyl)phosphine

The synthesis and characterization of the novel hindered tripodal phosphine ligand P(CH2CH2CH2PiPr2)3 (P3P3iPr) (1) are reported, along with the synthesis and characterization of ruthenium chloro and hydrido complexes of 1. Complexes [RuCl(P3P3iPr)][BPh4] (2[BPh4]), RuH2(P3P3iPr) (3), and [Ru(H2)(H)(P3P3iPr)][BPh4] (4[BPh4]) were characterized by crystallography. Complex 2 is fluxional in solution, and low-temperature NMR spectroscopy of the complex correlates well with two dynamic processes, an exchange between stereoisomers and a faster turnstile-type exchange within one of the stereoisomers.