Reactions of a Niobium Nitride Complex Prepared from Dinitrogen: Synthesis of Imide and Ureate Complexes and Ammonia Formation

A nitride complex [K(thf) 2 ] 2 [{(O 3 )Nb} 2 (μ‐N) 2 ] ( 2 ), prepared from [K(DME)] 2 [{(O 3 )Nb} 2 (μ‐H) 4 ] ( 1 ) and N 2 , was protonated with 2,6‐lutidinium chloride to yield ammonia and [(O 3 )NbCl 3 ] – ( 3 ), where H 3 [O 3 ] = tris(3,5‐di‐ tert ‐butyl‐2‐hydroxy phenyl)methane. The reaction of 3 with KBHEt 3 regenerated [K(DME)] 2 [{(O 3 )Nb} 2 (μ‐H) 4 ] ( 1 ), thereby completing a synthetic cycle for the conversion of N 2 to NH 3 . Alkylation of 2 with methyl iodide led to formation of [K(thf)][{(O 3 )Nb} 2 (μ‐N)(μ‐NMe)] ( 4 ) and [{(O 3 )Nb} 2 (μ‐NMe) 2 ] ( 5 ). Treatment of 5 with pyridine afforded a terminal imide complex [(O 3 )Nb=NMe(py) 2 ] ( 6 ). The imide monomer 6 reacted with CO 2 to give [(O 3 )Nb{(MeN) 2 CO}(py)] ( 7 ) and [{(O 3 )Nb} 2 (μ‐O) 2 ] ( 8 ) in a 2:1 ratio, while the reaction of 6 with p ‐TolNCO gave an asymmetric ureate complex [(O 3 )Nb{ p ‐TolNC(O)NMe}(py)] ( 9 ).