Complexes of Molecular Nitrogen

Abstract

The review deals with problems associated with the formation and structure of complexes of molecular nitrogen with transition metal compounds, metals, and other active species. Nitrogen interacts very weakly with acceptors of the type BF 3 but is capable of forming more stable systems (of the type of diazo-compounds) with species having both acceptor and donor properties (CH 2 , CH, 0). On the surface of metals (nickel, palladium, platinum), nitrogen forms complexes with the linear configuration of the fragment M-N=N. A large number of stable complexes (nitrogenyls), also with a linear configuration of the M-N=N fragment and analogous to the carbonyls and diazo-compounds, have been obtained recently with compounds of iron(ll), ruthenium(ll), osmium(ll), cobalt(l), rhodium(l), iridium(l), and nickel(O). In addition, dinitrogenyl compounds L n M(N 2 ) 2s and dinuclear complexes Μ-ΝΞΝ-Μ are known. In nitrogenyl compounds nitrogen behaves as a π-electron acceptor ligand and therefore donor ligands stabilise the M-N 2 bond in the complex and acceptor ligands weaken it. The method of synthesis of nitrogenyl complexes, their properties, and the mechanism of their formation have been examined. The possibility of the involvement of dinuclear complexes in nitrogen fixation under mild conditions is discussed. The bibliography includes 121 references. CONTENTS

Tantalum Nitride Atomic Layer Deposition Using (tert-Butylimido)tris(diethylamido)tantalum and Hydrazine

“…The small feature located at 2060 cm −1 has been previously identified as a N w N surface species. [55][56][57] This surface species is most likely associated with the decomposition of neighboring Ta v NC͑CH 3 ͒ 3 surface species that undergo ␤-hydride elimination. After the N 2 H 4 exposure, there is a loss of all CH 2 and CH 3 absorption features and the N w N stretching, the NCC antisymmetric stretching, and the CC stretching vibrations.…”

“…The small feature located at 2060 cm −1 has been previously identified as a N w N surface species. [55][56][57] This surface species is most likely associated with the decomposition of neighboring Ta v NC͑CH 3 ͒ 3 surface species that undergo ␤-hydride elimination.…”

Stereochemical Control of Valence and Its Application to the Reduction of Coordinated NO and N 2

“…The first step in this series of reactions is thermodynamically unfavorable by about 50 Cal and would presumably be the most difficult step of the overall reduction. In order to avoid the unfavorable thermodynamics of this step, other workers (2) have proposed a four-electron reduction of N2 to coordinated N2H22-. We report here definitive structural results for two metal nitrosyl complexes that suggest a feasible pathway for effecting the difficult first step in the reduction of N2.…”

Mechanistic interpretation of reactions with opposing signs of field and resonance reaction constants in the dual substituent parameter treatments of Taft, Yukawa-Tsuno, and Godfrey

“…Furthermore, photolysis of diazomethane or diazirine in 15N2 in the gas phase affords some conversion into labeled diazomethane. 50 In our own experience51 the reactivity of carbenes in a solvent is, however, too low for reaction with N2, either because the singlet -* triplet reaction is too fast or because of a very low intrinsic reactivity of the primarily formed singlet carbenes. Yamabe, Fukui, and co-workers52 discussed the reactivity of singlet methylene with N2 from a theoretical point of view.…”