Dinitrogen complexation and reduction at low-valent calcium.

Here we report that attempted preparation of low-valent Ca complexes in the form of LCa-CaL (where L is a bulky β-diketiminate ligand) under dinitrogen (N) atmosphere led to isolation of LCa(N)CaL, which was characterized crystallographically. The N - anion in this complex reacted in most cases as a very potent two-electron donor. Therefore, LCa(N)CaL acts as a synthon for the low-valent Ca complex LCa-CaL, which was the target of our studies. The N - anion could also be protonated to diazene (NH) that disproportionated to hydrazine and N The role of Ca d orbitals for N activation is discussed.