Nickel complexes dinitrogen

On hydrolysis of 14 in THF, 30-38% of the complexed dinitrogen is reduced to ammonia, and the remainder is liberated as free N2. In addition to Et20, LiOH, and benzene, further products are biphenyl and metallic nickel. Hydrogen is not evolved. 

Pfirrmann S, Limberg C, Herwig C, StoBer R, Ziemer B. A dinuclear nickel(I) dinitrogen complex and its reduction in single-electron steps. Angew Chem Int Ed. 2009 48 3357-3361. 

A number of new metal-dinitrogen complexes of type M(N2) have been detected in the reaction of metal atoms with N2 under matrix isolation conditions. Most strikingly, nickel atoms and nitrogen give Ni(N2)4 (45). However, this is strictly a matrix species, and it decomposes on removal of the matrix gases even at very low temperatures. It appears to be stable up to -150°C isolated in an SF6 matrix. Mixed CO/N2 complexes have also been prepared in matrices but their stabilities outside the matrix are not reported (72). 

The first nickel(0) complex containing coordinated dinitrogen, [ Ni(PCy3)2 2N2], was prepared by Jolly and Jonas in 1968, as an unstable dark-red compound (equation 56). 5... 

Relevant bond distances and angles of dinitrogen complexes whose X-ray structure has been determined are shown in Table 15. The complex [ Ni(PCy3)2 2N2] (Figure 1) is dimeric, with the N2 molecule coordinated end-on to the two nickel atoms. Each nickel atom is surrounded by four cyclohexyl groups of the phosphine ligands which give some steric protection.227 IR, 31P and HNMR spectra indicate that in toluene solutions of this complex the equilibrium shown in equation (60) operates.236... 

Unusual and complicated dinitrogen complexes have been reported to be formed by reactions (61)237,23S and (62).239 In both complexes (57) and (58) the N2 molecules are bound in a side-on mode to nickel atoms. The N—N bond distances (135 pm and 136 pm, respectively) are the longest ones found in any complex with coordinated dinitrogen. 

A special technique which has yielded highly unstable and simple dinitrogen complexes trapped in low-temperature solids (N2 or Ar) is the metal atom cocondensation technique in low-temperature matrices. By the cocondensation of nickel atoms and N2 at 4.2-10 K the binary compounds Ni(N2) (n = 1-4) result, whose structure has been inferred from IR and... 

Iron Pentacarbonyl. In its reactions with liquid dinitrogen tetroxide this compound follows the pattern outlined above, and the remarks on reactions of nickel carbonyl probably apply here also. The solvate, Fe(N03)3.N204, is produced (4). This has the structure N0+[Fe(N03)4] in the solid state it is volatile without decomposition, and is believed to be a five-coordinate complex, Fe(N0)(N03)4, in the vapor state. We have not yet succeeded in isolating the simple trinitrate, Fe(N03)3, by removal of N2O4. 

The olefin complexes of iron, nickel, rhodium, and iridium described in this chapter have found broad application in the synthesis of phosphine, phosphite, and carbonyl derivatives of these metals. In Chapter Two, the synthesis of another labile olefin complex, (ethylene)bis(tricyclohexylphosphine)nickel, is described as an initial step in synthesis of a complex of dinitrogen. 

Though carbon-nitrogen bond cleavage reaction is less explored, allylic C-N bond can be cleaved by low valent late transition metal complexes. Treatment of (/x-dinitrogen or carbon dioxide)nickel(O) complexes with allylammonium... 

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