Dinitrogen complexation and reduction at low-valent calcium

Calcium catches dinitrogen Although lithium reduces dinitrogen, the other alkali and alkaline Earth metals have proven largely inert to the gas under ambient conditions. Rösch et al. report that with just the right β-diketiminate ligand and an assist from potassium as terminal reductant, calcium can mediate dinitrogen reduction. Crystallography and spectroscopic characterization revealed a product in which doubly reduced dinitrogen adopted a side-on bridging motif between two calcium centers. A subsequent reaction with coordinated tetrahydrofuran appeared to release diazene. Science , this issue p. 1125