Syntheses and Properties of Two New Multi-functional Cobalt(II) Complexes Derived from Two Different Semi-rigid Bis(pyridyl)–Bis(amide) Ligands

Two new cobalt(II) complexes with the formulas of [Co(3-ebpba)(Hcppa)]n (1) and [Co(3-bpcd)(Hcppa)]n (2) have been obtained under the solvothermal conditions by reacting of two semi-rigid bis(pyridyl)–bis(amide) ligands with different spacers [3-ebpba = (E)-4,4′-(ethene-1,2-diyl)bis(N-pyridin-3-yl)benzamide, 3-bpcd = N,N′-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide] and the aromatic tricarboxylic acid [H3cppa = 5-(4-carboxyl-phenoxy)-isophthalic acid]. Complex 1 represents a 2D polymeric layer constructed by the 1D [Co(Hcppa)]n ‘chinese knot’-shaped chains and µ2-bridging 3-ebpba ligands. Complex 2 is a 1D ribbon chain based on the 1D [Co(Hcppa)]n ‘comb’-liked chains and the bidentate 3-bpcd ligands. Finally, the adjacent 2D layers or 1D chains are extended to 3D supramolecular networks via hydrogen-bonding interactions for the title complexes. In addition, the electrochemical behaviors, fluorescent properties and the photocatalytic activities of two cobalt(II) complexes towards the degradation of organic dyes have been studied.