A novel bis-β-diketonate ligand stabilizes a [Co(II)8] cage that encapsulates a (μ3-O)⋯H⋯(μ3-O) moiety

The novel ligand 1,3-bis-(3-oxo-3-(2-hydroxyphenyl)-propionyl)-2-pyridine, H4L, is used here for the first time. In a reaction with Co(II) it produces the complex salt [Co8O(OH)(H2L)6]NO3 (1), containing an octametallic cluster cation. The topology of this cluster, which encapsulates a rare (μ3-O)⋯H⋯(μ3-O) at its interior, exhibits a remarkable similarity to the cofactor of nitrogenase FeMoco. It features intramolecular antiferromagnetic interactions, which can be simulated using a spin-only model, yielding an S = 0 spin ground state, lying very close to numerous excited states.

Graphical abstractThe complex salt [Co8O(OH)(H2L)6]NO3 (1; H4L is a bis-β-diketonepyridine ligand) containing an octametallic cluster cation has been prepared and studied. The cluster encapsulates a rare (μ3-O)⋯H⋯(μ3-O) at its interior and its topology exhibits a remarkable similarity to the cofactor of nitrogenase FeMoco. It features intramolecular antiferromagnetic interactions yielding an S = 0 spin ground state, lying very close to numerous excited states.Figure optionsDownload full-size imageDownload as PowerPoint slide