Amido-bridged double-cube nitrido complexes containing titanium and magnesium/calcium

Abstract

Treatment of the single cube nitrido complexes [(thf)_x{(Me₃Si)₂N}M{(µ₃-N)(µ₃-NH)₂Ti₃(η⁵-C₅Me₅)₃(µ₃-N)}] (M = Mg, x = 0; Ca, x = 1) with one equivalent of anilines NH₂Ar in toluene affords the arylamido complexes [(ArHN)M{(µ₃-N)(µ₃-NH)₂Ti₃(η⁵-C₅Me₅)₃(µ₃-N)}]_n [M = Mg (3), n = 1, Ar = 4-MeC₆H₄; Ca (4), n = 2, Ar = 2,4,6-Me₃C₆H₂]. The magnesium complex 3 has a single-cube structure whereas the X-ray crystal structure of the analogous calcium derivative 4 shows two cube-type azaheterometallocubane moieties “Ca{(µ₃-N)(µ₃-NH)₂Ti₃(η⁵-C₅Me₅)₃(µ₃-N)}” held together by two µ-2,4,6-trimethylanilido ligands. Complexes 3 and 4 react with chloroform-d₁ at room temperature to give the metal halide adducts [Cl₂M{(µ₃-NH)₃Ti₃(η⁵-C₅Me₅)₃(µ₃-N)}] (M = Mg, Ca). A solution of 3 in n-hexane gave complex [{Mg₂(µ₃-N)(µ₃-NH)₅[Ti₃(η⁵-C₅Me₅)₃(µ₃-N)]₂}(µ-NHAr)₃] which shows three µ-4-methylanilido ligands bridging two [MgTi₃N₄] cube type cores according to an X-ray crystal structure determination.