[Co(H2O)6]2+ and H3O+ encapsulated in a unique 3D anionic Co(II) framework with hydrophilic hexagonal and circular channels

A new metal-organic framework, [Co(H2O)(6)center dot(H3O)]center dot 3[Co-2(L)(H2O)(2)]center dot 0.5H(2)O (1), has been constructed from Co-2 clusters and a biphenyl-pentacarboxylate ligand with open hydrophilic channels. Uniquely, [Co(H2O)(6)](2+) and H3O+ as guest cations coexist in the channels. The magnetic study indicates that the title compound shows a significantly antiferromagnetic interaction.