Luminescence sensing and photocatalytic activities of four Zn(ii)/Co(ii) coordination polymers based on a pyridinephenyl bifunctional ligand

Abstract

Based on a novel pyridinephenyl bifunctional ligand of 5-(6-carboxypyridin-2-yl)benzene-1,3-dicarboxylic acid (H₃L), four Zn(II)/Co(II) coordination polymers (CPs), {[Zn(BIMB)(HL)]·H₂O}_n (1), [Co(BIMB)(HL)(H₂O)]_n (2), {[Zn₂(BIBP)₂(HL)₂]·2H₂O}_n (3), and {[Co₃(BIBP)₃(L)₂(H₂O)₂]·5H₂O}_n (4), have been constructed with the introduction of two length-suitable bis(imidazole) linkers (BIMB = 4,4-bis(imidazol-1-ylmethyl)biphenyl; BIBP = 4,4-bis(imidazol-1-yl)diphenyl). Structural analysis shows that CP 1 exhibits a 2D wave 4-c {4⁴·6²} sql sheet, and CP 2 shows an interesting 2D + 2D → 2D interpenetrating structure with ABAB sql packing. CP 3 displays an unprecedented 3D (4,4)-c {4²·8³·10}-tcj net. CP 4 presents a 2D (3,4,4)-c {6²·7·8²·10}{6²·7³·8}₂{6³}₂ trilayer structure reported for the first time. Luminescence sensing exploration reflected two luminescent Zn(II) CPs possessing excellent performances in sensing Fe³⁺ cation, Cr₂O₇²⁻/CrO₄²⁻ anions, and NFT/NZF antibiotics in aqueous solution. Besides, the four obtained CPs also demonstrated outstanding potential as photocatalysts in the degradation of methylene blue (MB).