Unique Single-Atom Binding of Pseudohalogeno Ligands to Four Metal Ions Induced by Their Trapping into High-Nuclearity Cages

μ4 end-on coordination (through the N atom) of the pseudohalogeno ligands X−=N3− and NCO− has been observed in the isostructural nonanuclear CoII cages with the general formula [Co9{(2-C5H4N)2CO2}4(O2CMe)8X2] (see picture); this mode is imposed by the trapping of anions X− into cavities formed inside the cage. The change of X− modulates the magnetic behavior of the cage from antiferromagnetic coupling to a ferrimagnetic high-spin ground state.