The synthesis and reactivity of late-metal complexes with heteroatomic π-donating ligands have received significant recent attention. [1][2][3][4][5][6] Efforts in this area have been prompted in part due to the expectation that the combination of "soft" late metals with "hard" donor ligands (e.g., oxygen-and nitrogen-based ligands) can result in weak bonds and reactive ligand moieties; however, thermochemical studies of metal-heteroatom bond strengths suggest that homolytic bond strengths between late metals and heteroatom ligands are not inherently weak. 7,8 Additionally, it has been suggested that the scarcity of late-metal systems with π-donating ligands is due to the presence of π-conflict between filled metal dπ orbitals and lone electron pairs residing on the π-donating ligands. 1,9 Recently, application of Drago's E-C bonding theory to understanding the bonding and reactivity of such complexes has been reported and raises questions as to the importance of π-π repulsion in such systems. 3 Bergman et al.'s recent reports of the synthesis and reactivity of the Ru(II) complex trans-(DMPE) 2 Ru(H)-(NH 2 ) (DMPE ) 1,2-bis(dimethylphosphinoethane)) provide a striking example of a highly reactive ruthenium amido moiety. 10,11 The parent amido ligand of this complex exhibits remarkable reactivity, including the ability to deprotonate several C-H bonds. Such extraordinary basicity and reactivity raises several questions, including the following: (1) is the enhanced basicity a general feature of such complexes and (2) what features control the amido reactivity? To begin to answer these questions, complexes with variable ancillary ligands must be accessed. We now report the synthesis and preliminary reactivity of the first example (to our knowledge) of a series of octahedral and d 6 parent amido complexes in which the ancillary ligands are systematically varied. Particularly germane here are CpRu II (Cp ) cyclopentadienyl) phosphine complexes with amido ligands reported by Roundhill et al. 12 {TpRu(L)(L′)} complexes have received significant recent attention. 13 These fragments offer the significant synthetic advantage of being able to systematically control the steric and electronic features of the metal coordination sphere via variation of L and L′. Reflux of the known complex TpRu(PPh 3 ) 2 (Cl) 14 with excess trimethylphosphine or trimethyl phosphite in toluene yields TpRu(PMe 3 ) 2 (Cl) (1) and TpRu{P(OMe) 3 } 2 (Cl) (2) in high yields (95% and 87%, respectively) after workup. Reactions of 1, 2, TpRu(CO)(PPh 3 )(Cl), 15 and TpRu-(PPh 3 ) 2 (Cl) with AgOTf yield the corresponding triflate complexes TpRu(PMe 3 ) 2 (OTf) (3), TpRu{P(OMe) 3 } 2 (OTf) (4), TpRu(CO)(PPh 3 )(OTf) (5), and TpRu(PPh 3 ) 2 (OTf) (6). Complexes 3-5 can be isolated cleanly, while the triphenylphosphine complex 6 has eluded isolation and is generated in situ. Reactions of complexes 3-6 in different solvents at variable temperatures with metal amides (e.g., NaNH 2 or LiNH 2 ) or metal amides in combination with ammonia result in no reaction...