A series of pyridyl-amide-based ZnII/CdII coordination polymers and their polypyrrole-functionalized composite materials for tuning their photocatalytic properties

Abstract

In continuation of our research interest in bis-pyridyl-bis-amide-based multifunctional coordination polymer (CPs) materials, we report here six Zn^II/Cd^II CPs, [Cd(L)(5-NIP)(H₂O)]·H₂O (CP1), [Cd(L)(2,5-TPD)]·DMA (CP2), [Cd(L)(2,5-TPD)]·2H₂O (CP3), [Zn(L)(2,5-TPD)]·2H₂O (CP4), [Zn(L)(1,3-BDC)]·H₂O (CP5) and [Zn₂(L)(5-AIP)₂]·2H₂O (CP6) constructed from L and various aromatic polycarboxyates co-ligands and their polypyrrole (PPy)-functionalized composite materials (L = N,N′-bis(pyridine-3-yl)-4,4′-oxybis(benzoic) dicarboxamide, 5-H₂NIP = 5-nitroisophthalic acid, 2,5-H₂TPD = 2,5-thiophenedicarboxylic acid, 1,3-H₂BDC = 1,3-benzenedicarboxylic acid, 5-H₂AIP = 5-aminoisophthalic acid). The title complexes were solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction analyses, IR spectra, UV-vis diffuse-reflectance spectra (DRS), powder X-ray diffraction (PXRD) and thermal gravimetric analyses (TG). Single-crystal X-ray analysis reveals that CP1–CP6 display 2D architectures with versatile coordination features. The PPy-functionalized CP1–CP6 composite materials (named as PPy/CPn (n = 1, 2, 3, 4, 5, 6)) were fabricated by the combination of micro-sized CPs particles and PPy via a facile in situ chemical oxidation polymerization process under the initiation of ammonium persulfate (APS). The fluorescent properties of the title complexes have been investigated. In particular, the photocatalytic activities of the micro-sized particles of CP1–CP6 and their PPy-functionalized composite materials have also been investigated. These PPy-functionalized composite materials show superior photocatalytic activities for the degradation of rhodamine B (RhB) under visible light irradiation.