Three Cu<sup>I</sup>‑Terpyridyl Coordination\nPolymers Regulated by π‑Conjugated Groups and SCN<sup>–</sup> Anions for Organic Dye Photodegradation

Developing novel materials for organic dye photodegradation\nis\nof great significance in wastewater treatment. Three Cu<sup>I</sup>-terpyridyl coordination polymers (CPs) [Cu<sub>2</sub>(L1)(SCN)<sub>2</sub>]<i><sub>n</sub></i> (<b>1</b>), [Cu<sub>3</sub>(L2)(SCN)<sub>3</sub>]<i><sub>n</sub></i> (<b>2</b>), and [Cu<sub>2</sub>(L3)(SCN)<sub>2</sub>]<i><sub>n</sub></i> (<b>3</b>) (L1 = 4-(naphthalen-1-yl)-2,6-di(pyridin-4-yl)pyridine,\nL2 = 4-(anthracen-1-yl)-2,6-di(pyridin-4-yl)pyridine, L3 = 4-(pyren-3-yl)-2,6-di(pyridin-4-yl)pyridine),\nhave been solvothermally synthesized and exhibit two-dimensional structures\nextended by Cu<sup>I</sup> centers, SCN<sup>–</sup>, anions,\nand terpyridyl ligands with different π-conjugated groups. Complexes <b>1</b>–<b>3</b> can decompose methylene blue (MB),\nRhodamine B (RhB), and methyl orange (MO) with photodegradation rates\nranging from 44.4 to 96.8% in 120 min. Owing to the more positive\nvalence band potential and lower band gap regulated by Cu(I) d-electrons\nand pi-electrons of terpyridyl ligands, complex <b>2</b> exhibits\nthe highest photocatalytic activity with the order of <b>2</b> > <b>1</b> > <b>3</b> and displays varied photodegradation\nefficiency for other dyes (Janus green B (JGB) and crystal violet\n(CV) with rates of 70.4 and 65.7% in 120 min, respectively). The degradation\nproducts and mechanism of MB by <b>2</b> have been proposed\nby liquid chromatography–mass spectrometry (LC-MS) and radical\nquenching experiments. These findings present an effective strategy\nfor designing and synthesizing CPs in photodegradation by increasing\nthe aromatic rings of π-conjugated groups and Cu<sup>I</sup> center numbers, which may exert important impacts in wastewater\ntreatment.