Redox-Active Behavior of the [{Ti(η⁵‑C₅Me₅)(μ-NH)}₃(μ₃‑N)] Metalloligand

Treatment of [Cl₃Y­{(μ₃-NH)₃Ti₃(η⁵-C₅Me₅)₃(μ₃-N)}] with [K­(C₅Me₅)] in toluene gives C₁₀Me₁₀ and the paramagnetic [K­(μ-Cl)₃Y­{(μ₃-NH)₃Ti₃(η⁵-C₅Me₅)₃(μ₃-N)}] (<b>3</b>) derivative. Crystallization of <b>3</b> in pyridine affords the potassium-free [Cl₂(py)₂Y­{(μ₃-NH)₃Ti₃(η⁵-C₅Me₅)₃(μ₃-N)}] (<b>4</b>) complex. Whereas the reaction of <b>3</b> with 1 equiv of 18-crown-6 leads to the molecular complex [(18-crown-6)­K­(μ-Cl)₃Y­{(μ₃-NH)₃Ti₃(η⁵-C₅Me₅)₃(μ₃-N)}] (<b>5</b>), the analogous treatment of <b>3</b> with cryptand-222 affords the ion pair [K­(crypt-222)]­[Cl₃Y­{(μ₃-NH)₃Ti₃(η⁵-C₅Me₅)₃(μ₃-N)}] (<b>6</b>). The X-ray crystal structures of <b>4</b>, <b>5</b>, and <b>6</b> have been determined. Density functional theory (DFT) calculations have elucidated the electronic structure of these species, which should be regarded as containing trivalent Y bonded to the {(μ₃-NH)₃Ti₃(η⁵-C₅Me₅)₃(μ₃-N)} metalloligand radical anion