N2 Activation in NiI–NN–NiI Units: The Influence of Alkali Metal Cations and CO Reactivity

After single electron reduction of the dinitrogen complex [LtBuNi(μ‐η1:η1‐N2)NiLtBu] (I) with KC8, reaction of the resulting compound K[LtBuNi(μ‐η1:η1‐N2)NiLtBu] (II) with sodium sand yields KNa[LtBuNi(μ‐η1:η1‐N2)NiLtBu] (1), which contains two different alkali metal ions. Treatment of I with two equivalents of sodium sand leads to the symmetric complex Na2[LtBuNi(μ‐η1:η1‐N2)NiLtBu] (2). Complexes 1 and 2 were investigated by single crystal X‐ray diffraction analysis as well as by Raman spectroscopy, and the results were compared with the data of K2[LtBuNi(μ‐η1:η1‐N2)NiLtBu] (III), which contains two K+ ions. Thus, it became obvious that the nature of the alkali metal ion M in compounds M2[LtBuNi(μ‐η1:η1‐N2)NiLtBu] has hardly any influence on the degree of NN bond activation. Furthermore, it was shown that treatment of the dinickel(I) complex III with CO leads to the dinickel(0) compound K2[LtBuNi(CO)]2 (4) and N2. Reaction of the unreduced dinickel(I) complex I with CO leads to a more simple replacement of the N2 ligand and formation of [LtBuNi(CO)] (3).