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Early transition metal alkyl and hydride complexes have been widely explored for their propensity to faciltate C–H activation through a concerted σ-bond metathesis mechanism. Herein, we report the synthesis of a tris(amido) Zr(IV) alkyl complex 1 as a precursor of accessing a proposed transient Zr(IV)-hydride. Upon intramolecular C–H activation of a pendent methyl group, a strained cyclometalated complex 2 is obtained. Relief of ring strain and cooperative metal–ligand C–H activation provided access to Zr-acetylide complex 3, which is capable of undergoing insertion reactivity into carbonyl containing compounds, like aldehydes and ketones. Complexes 1–3 are characterized using multinuclear NMR spectroscopy, UV–vis spectroscopy, and X-ray crystallography. Newly reported electron-rich propargylic alcohols 6 and 7 are isolated and fully characterized using multinuclear NMR spectroscopy, ESI-MS, and FTIR. 

The use of redox-active ligands with the f-block elements has been employed to promote unique chemical transformations and explore their unique emergent electronic properties for a myriad of applications. In this study, we report eight new tris(amido) metal complexes: 1–Ln (Ln = Tb3+, Dy3+, Ho3+, Er3+, Tm3+, and Yb3+), 1–La, and 1–Ti (an early transition metal analogue). The one-electron oxidation of the tris(amido) ligand was conducted to generate semi-iminato complexes 2–Ln, 2–La, and 2–Ti, and these complexes were studied using EPR. Tris(amido) complexes 1–Ln, 1–La, and 1–Ti were fully characterized using a range of spectroscopic (NMR and UV–vis/NIR) and physical techniques (X–ray diffraction and cyclic voltammetry, with the exception of 1–La). Computational methods were employed to further elucidate the electronic structures of these complexes. Lastly, complexes 1–Ln, 1–La, and 1–Ti were probed as catalysts for alkyl–alkyl cross-coupling, and the initial rate of the reaction was measured to explore the influence of the metal ion.