Ferromagnetic interactions in a bis(μ-end-on azido)cobalt(II) linear trimer

A linear trinuclear Co(II) compound, [Co3(μ1,1-N3)4(N3)2(H2O)2(bpbp)2] · 2H2O (1, bpbp = 3,3′-bis-Dimethylamino-1,1′-pyridine-2,6-diyl-bispropenone), is reported. The central Co(II) ion is bridged to Co(II) ions on both sides by four end-on azide (image) ligands resulting in a centrosymmetric trimer with adjacent Co⋯Co distance of 3.233 Å. Each Co(II) ion possesses distorted octahedral geometry, the central one is coordinated by two aqua ligands and four image nitrogen atoms and each terminal Co(II) is coordinated by two image nitrogen atoms, one terminal image nitrogen atom and capped by terminal tridentate bpbp ligand. Variable temperature magnetic studies indicate ferromagnetic coupling between adjacent Co(II) ions within the trimer.