Syntheses, structures and luminescent properties of five new Ag(I)-based coordination polymers

Abstract

In this work, five Ag(I)-based coordination polymers (CPs), namely, [Ag(HL)(H2L)]n (1), [Ag(HL)(2,2′-bpy)(H2O)0.5] (2), [Ag(HL)(phen)(H2O)0.5] (3), {[Ag2(HL)2(4,4′-bpy)(H2O)2]∙H2O} (4) and [Ag(HL)(thpy)]n (5), were synthesized under hydrothermal conditions (H2L = 1-(3-carboxybenzyl)-1H-pyrazole-4-carboxylic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline, 4,4′-bpy = 4,4′-bipyridine and thpy = 2-(2-thienyl)pyridine). These coordination polymers were characterized by single-crystal X-ray diffraction, elemental analyses, infrared spectroscopy, thermogravimetric analyses and powder X-ray diffraction. Compound 1 displays a one-dimensional (1D) chain structure which can be further extended into a three-dimensional (3D) supramolecular structure via intermolecular hydrogen bond. In compounds 2 and 3, the binuclear zero dimensional (0D) units are extended to 3D supramolecular frameworks by intermolecular hydrogen bond and π–π stacking interaction. In compound 4, the 0D units constructed by HL− anions, 4,4′-bpy and metal ions are expanded to form a two-dimensional (2D) supramolecular network. Compound 5 shows a different 2D supramolecular structure extended from 1D chain by intermolecular hydrogen bond. The results suggest that organic ligand plays a key role in the formation of the final structures. The solid-state luminescent properties of compounds 1–5 were studied in detail. The results show that the luminescent color of compounds 1–5 can be tunable by varying excitation wavelengths.