Solvothermal syntheses, crystal structures, and luminescent properties of two novel silver(I) coordination polymers containing 5-aryl-substituted tetrazolate ligands

The solvothermal reactions of AgNO3, NaN3, with benzonitrile or 4-cyanopyridine in methanol/water yield two novel metal–organic coordination polymers, [Ag(μ3-phtta)]n (1) (phtta = 5-phenyltetrazolate) and {Ag[μ4-(4-pytta)]}n (2) [4-pytta = 5-(4-pyridyl)tetrazolate], respectively. The two reactions were involved in the in situ formation of 5-aryl-substituted tetrazolate ligands (phtta and pytta) through [2 + 3] cycloaddition reactions of azide anion with benzonitrile or 4-cyanopyridine. Compounds 1 and 2 were characterized by elemental analysis, IR spectra, and single-crystal X-ray crystallography. Compound 1 has a one-dimensional double-chain structure in which centrosymmetric dimeric [Ag(phtta)]2 units are interconnected by four Ag–N bonds. These double-chains are further stacked into a 2D layer network through π–π interactions between tetrazolyl rings and interactions between Ag+ and phenyl group or tetrazolyl ring. Compound 2 has an intriguing 3D non-interpenetrated supramolecular structure in which a 2D layer network with (4.82)Ag(4.82)pytta topology holds the adjacent layers together via interactions of Ag+ ions in one layer with 4-N atoms of pytta ligands in the other. Photoluminescence studies revealed that solids 1 and 2 exhibit strong blue fluorescent emissions at λmax = 422 and 390 nm (λex = 345 nm), respectively, at ambient temperature.