Cobalt Coordination Networks Based on the Linker (Phenazine-5,10-diyl)di- and Tetrabenzoate

The crystal structures of the cobalt(II) metal-organic frameworks or coordination networks [Co(pdb)(DMF)] and [Co2(pdi)(DMF)3]·2(DMF)·H2O (H2pdb = 3,3′-(phenazine-5,10-diyl)dibenzoic acid, H4pdi = 5,5′-(phenazine-5,10-diyl)diisophthalic acid, DMF = N,N-dimethylformamide) were synthesized solvothermally from cobalt(II) nitrate and the free acid of the linker in DMF. In catena-[(N,N-dimethylformamide)-μ4-3,3′-(phenazine-5,10-diyl)dibenzoate-cobalt(II)], [Co(pdb)(DMF)], the Co2 handles as secondary building units are surrounded by four carboxylate groups from four linkers in a paddle-wheel arrangement giving a three-dimensional (3D) network with cds (or CdSO4) topology in which the wide openings are filled by two symmetry related nets to a threefold interpenetrated structure. In catena-[tris(N,N-dimethylformamide)-μ8-5,5′-(phenazine-5,10-diyl)diisophthalate-dicobalt(II)] bis(N,N-dimethylformamide) hydrate, [Co2(pdi)(DMF)3]·2(DMF)·H2O, there are two different Co atoms from which only Co2 is connected to each of the four carboxyl groups of the tetracarboxyl linker and, thus, is responsible for the 3D network formation. The network topology in [Co2(pdi)(DMF)3] is pts (or platinum(II) sulfide) when taking the Co2 atom as a tetrahedral and the linker as a square-planar fourfold node which is, however, inverse from the common square-planar metal and tetrahedral linker nodes in PtS and most pts topologies.