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Tantalum carbide (TaC) is an ultra‐high‐temperature ceramic for potential applications as protective coating, furnace components, propulsion liners for space shuttles and aircrafts, etc. Microstructural and mechanical behavior of vacuum plasma‐sprayed (VPS) TaC has been investigated in the present study. Apart from major TaC phase, microstructural definitions elucidated Ta2C, non‐stoichiometric TaCx phases (0.83≤x≤0.94), partial grain formation, polygonization of grains, and inhomogeneous C/Ta ratios in the sprayed structure. Near‐isotropy in the fracture–toughness ratio (Kaxial/Ktrans=1.01) is attributed to compact coating, fine‐closed porosity, and distribution of non‐stoichiometric phases.

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Over the past decade, numerous reports have focused on the development and applications of Cu-mediated C−H functionalization reactions; however, to date, little is known about the Cu intermediates involved in these transformations. This paper details the observation and characterization of Cu II and Cu III intermediates in aminoquinoline-directed C(sp 2 )−H functionalization of a fluoroarene substrate. An initial C(sp 2 )−H activation at Cu II occurs at room temperature to afford an isolable anionic cyclometalated Cu II complex. This complex undergoes singleelectron oxidation with ferrocenium or Ag I salts under mild conditions (5 min at room temperature) to afford C(sp 2 )−C(sp 2 ) or C(sp 2 )−NO 2 coupling products. Spectroscopic studies implicate the formation of a transient diamagnetic Cu III -σ-aryl intermediate that undergoes either (i) a second C(sp 2 )−H activation at Cu III followed by C−C bond-forming reductive elimination or (ii) reaction with a NO 2 − nucleophile and C(sp 2 )−NO 2 coupling.