Influence of filled dπ-manifold and L/L′ ligands on the structure, basicity, and bond rotations of the octahedral and d6 amido complexes TpRu(L)(L′)(NHPh) (Tp = hydridotris(pyrazolyl)borate;: L= L′ = PMe3 or P(OMe)3, or L = CO and L′ = PPh3):: Solid-state structures of [TpRu(PMe3)2(NH2Ph)][OTf], [TpRu{P(OMe)3}2(NH2Ph)][OTf], and TpRu{P(OMe)3}2(NHPh)

It has been suggested that the reactivity of pi-donating ligands bound to late-transition-metal complexes is heightened due to high d-electron counts. Herein, the synthesis and characterization of the Ru(II) amine and Ru(II) amido complexes [TpRuL(2)(NH2Ph)][OTf] (OTf = trifluoromethanesulfonate) and TpRuL2(NHPh) (L = PMe3 or P(OMe)(3)) are presented, including solid-state X-ray diffraction studies of [TpRu(PMe3)(2)(NH2Ph)][OTf], [TpRu{P(OMe)(3)}(2)(NH2Ph)][OTf], and TpRu{P(OMe)(3)}(2)(NHPh). The pK(a)'s of the Ru(II) amine complexes and the previously reported [TpRu(CO)(PPh3)(NH2Ph)](+) have been estimated to be comparable to that of malononitrile in methylene chloride. In addition, the impact of the filled dpi-manifold (i.e., Ru(II) and d(6) octahedral systems) on barriers to rotation of the Ru-NHPh moieties has been studied. For TpRu(PMe3)(2)(NHPh) and TpRu{P(OMe)(3)}(2)(NHPh), evidence for hindered rotation about the amido nitrogen and phenyl ipso carbon has been observed, and the relative N-C and Ru-N bond rotational barriers for the series of three amido complexes are discussed in terms of the pi-conflict.