Dinitrogen Binding at a Trititanium Chloride Complex and Its Conversion to Ammonia under Ambient Conditions

Abstract

AbstractReaction of [TiCp*Cl3] (Cp*=η5‐C5Me5) with one equivalent of magnesium in tetrahydrofuran at room temperature affords the paramagnetic trinuclear complex [{TiCp*(μ‐Cl)}3(μ3‐Cl)], which reacts with dinitrogen under ambient conditions to give the diamagnetic derivative [{TiCp*(μ‐Cl)}3(μ3‐η1 : η2 : η2‐N2)] and the titanium(III) dimer [{TiCp*Cl(μ‐Cl)}2]. The structure of the trinuclear mixed‐valence complexes has been studied by experimental and theoretical methods and the latter compound represents the first well‐defined example of the μ3‐η1 : η2 : η2 coordination mode of the dinitrogen molecule. The reaction of [{TiCp*(μ‐Cl)}3(μ3‐η1 : η2 : η2‐N2)] with excess HCl in tetrahydrofuran results in clean NH4Cl formation with regeneration of the starting material [TiCp*Cl3]. Therefore, a cyclic ammonia synthesis under ambient conditions can be envisioned by alternating N2/HCl atmospheres in a [TiCp*Cl3]/Mg(excess) reaction mixture in tetrahydrofuran.