Dinitrogen complexation and reduction at low-valent calcium

Here we report that attempted preparation of low-valent Ca-I complexes in the form of LCa-CaL (where L is a bulky beta-diketiminate ligand) under dinitrogen (N-2) atmosphere led to isolation of LCa(N-2)CaL, which was characterized crystallographically. The N-2(2-) anion in this complex reacted in most cases as a very potent two-electron donor. Therefore, LCa(N-2)CaL acts as a synthon for the low-valent Ca-I complex LCa-CaL, which was the target of our studies. The N-2(2-) anion could also be protonated to diazene ( N2H2) that disproportionated to hydrazine and N-2. The role of Ca d orbitals for N-2 activation is discussed.

Automated summary

The attempted preparation of low-valent Ca-I complexes in the form of LCa-CaL under dinitrogen atmosphere led to the isolation of LCa(N-2)CaL, which acts as a synthon for the target LCa-CaL.The N-2(2-) anion in this complex reacted as a potent two-electron donor and could be protonated to diazene. The role of Ca d orbitals in N-2 activation is also discussed.