A direct white-light-emitting coordination polymers with tunable green–white photoluminescence by variation of counterion

• Two of the new of Ag(I) coordination polymers have been synthesized.
• Complex (1) adopts the polymeric linear chain-like structure bridged by L.
• Complex (2) proved to be one-dimensional zigzag polymeric chain.
• The luminescent properties of both compounds were investigated.
• The counter-ion in the Ag salts plays fundamental role in the physical properties.

Two Ag(I) coordination polymers, namely [Ag(L)(NO3)]∞ (1), [Ag(L)(CF3SO3)]∞ (2) and {L = butane-1,4-diyl-bis(pyridine-3-carboxylate)}, have been synthesized and characterized by X-ray diffraction and FTIR spectra. The counter-ion in the Ag(I) salts plays fundamental roles in the formation of Ag(I) complexes having different crystal structures and thermal properties. The Ag(I) ions in (1) and (2) are both two-coordinate, but they are tetra-coordinate in (1). Complex (1) adopts the polymeric linear chain-like structure bridged by L, while (2) proved to be one-dimensional zigzag polymeric chain. For all compounds the chains are assembled into 2D sheets by hydrogen bonds interactions and for (2) are further packed into 3D network by π-π interactions. Complexes (1)–(2) in solid state display at room temperature photoluminescence in the visible region. Although these complexes have emission bands centred in similar wavelengths when are excited at 320 nm at 275 K, (1) emits white light (CIE coordinates 0.33, 0.38) with a maximum emission at 514 nm, meanwhile (2) emits greenish light (CIE coordinates 0.20, 0.51) with a maximum emission at 513 nm. Hence, the complexes [Ag(L)X]∞ (X = NO3−, CF3SO3−) are tunable from green to white based on the structural variation through the counterion change.

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