Rational design of three Co(II) coordination polymers based on a semirigid tricarboxylate ligand: Syntheses, structural variability, electrochemical behavior, magnetic and photocatalytic properties

Abstract

Three novel Co(II) based coordination polymers (CPs) are fabricated using the 5-(2-carboxylphenoxy)isophthalic acid (H3L) and different N-donor configuration under the solvothermal conditions, namely, [Co2(L)(1,4-bibt)(μ3OH)]n (1), [Co(HL)(4,4′-bidpe)]n (2), and [Co(HL)(tib)]n (3) (1,4-bibt = 1,4-bis(imidazol-1-yl)butane, 4,4′-bidpe = 4,4′-bis(imidazolyl)diphenylether, tib = 1,3,5-tris(1-imidazolyl)benzene). The configuration of 1–3 are confirmed by various characterization analysis. The CP 1 possesses an unprecedented (3,10)-connected 3D architecture with a unique tetranuclear [Co4(µ3OH)2(COO)4]2+cluster. Interestingly, when the H3L ligands are not calculated, the whole structure of N-donor still shows a 3-fold interpenetrating dia 3D framework (3D + 3D → 3D). Moreover, CPs 2 and 3 are 3D supramolecular structure with significant differences structures. The CP 2 shows a 2D sql uninodal 4-connected 2D network with the Schläfli symbol (44•62), while CP 3 exhibits an unprecedented 2D framework. And both 2 and 3 construct 3D supramolecular architecture through H-bonds between the two adjacent 2D networks. Comparing CPs 1–3 shows that the N-donor ligands play a key role in adjusting the final structures. Furthermore, the electrochemical behavior, magnetic properties and photocatalytic activity of 1–3 are also discussed in details.