posted on 2021-04-08, 21:00authored byMary C. Eaton, Vincent J. Catalano, Jason Shearer, Leslie J. Murray
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
CoI3 cluster, Co3LEt/Me (2). Upon reaction of 2 with dinitrogen, all metal–metal bonds are broken,
steric conflicts are relaxed, and dinitrogen is incorporated within
the internal cavity to yield a formally (μ3-η1:η2:η1-dinitrogen)tricobalt(I)
complex, 3. Broken symmetry DFT calculations (PBE0/def2-tzvp/D3)
support an N–N bond order of 2.1 in the bound N2 with the calculated N–N stretching frequency (1743 cm–1) comparable to the experimental value (1752 cm–1). Reduction of 3 under Ar in the presence
of Me3SiBr results in N2 scission with tris(trimethylsilyl)amine
afforded in good yield.