Dinitrogen Insertion and Cleavage by a Metal-Metal Bonded Tricobalt(I) Cluster.

Reduction of a tricobalt(II) tri(bromide) cluster supported by a tris(β-diketiminate) cyclophane results in halide loss, ligand compression, and metal-metal bond formation to yield a 48-electron Co cluster, Co (). Upon reaction of with dinitrogen, all metal-metal bonds are broken, steric conflicts are relaxed, and dinitrogen is incorporated within the internal cavity to yield a formally (μ-η:η:η-dinitrogen)tricobalt(I) complex, . Broken symmetry DFT calculations (PBE0/def2-tzvp/D3) support an N-N bond order of 2.1 in the bound N with the calculated N-N stretching frequency (1743 cm) comparable to the experimental value (1752 cm). Reduction of under Ar in the presence of MeSiBr results in N scission with tris(trimethylsilyl)amine afforded in good yield.