Three Cd(II) coordination polymers based on rigid 2,6-bis(3-(pyrid-3-yl)-1,2,4-triazolyl)pyridine ligand: Syntheses, crystal structures, and photocatalytic properties

Three Cd(II) coordination polymers, namely, {[Cd2(bptp)2(H2O)4]·3H2O}n (1), {[Cd2(Hbptp)(BTC)(H2O)]·4H2O}n (2) and {[Cd2(H2bptp)(BTEC)]·H2O}n (3) (1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid and H4BTEC = 1,2,4,5-benzenetetracarboxylic acid), have been successfully isolated by employing the rigid N-heterocyclic ligand 2,6-bis(3-(pyrid-3-yl)-1,2,4-triazolyl)pyridine (H2bptp) and different aromatic polycarboxylates. Complex 1 performs a helical chain structure, which is extended into 3D supermolecular framework due to its strong hydrogen bonding interactions. 2 demonstrates a binodal 3,4-connected 2D grid with the point symbol of (42·62·8)(42·6), while complex 3 features an interesting 2D structure with its 1D double chain looking like a folded paper lantern. The optical band gaps were analyzed by diffuse-reflectance UV–Vis spectra. The photocatalytic experiments for these complexes reflect well on their activities for the decomposition of MB under the irradiation of high-pressure mercury lamp. Complexes 1 and 2 present extremely good photocatalytic properties with their photocatalytic activities increasing from 17% (without any catalyst) to 87% for 1 and 96% for 2 after 2 h of irradiation. In addition, the luminescent properties of 1–3 have also been investigated.

Graphical abstractThree different CdII polymers based on ligand H2bptp and two different aromatic polycarboxylates have been successfully obtained under hydrothermal conditions. The optical band gaps analyzed by diffuse-reflectance UV–Vis spectra manifest that complexes 1–3 are potential semiconductive materials. Photocatalytic experiments for these complexes indicate that complex 1 and 2 present extremely good photocatalytic properties and can be rational candidates for the photocatalytic degradation of organic dyes pollutants.Figure optionsDownload full-size imageDownload as PowerPoint slide