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

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]center dot 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 7C-7C 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.