A Fluorescent 1,5-Naphthalenedisulfonate Anion-Linked Cucurbit[6]uril Framework

Graphical A highly ordered 3D framework from 1,5-naphthalenedisulfonate (1,5-NDS) and cucurbit[6]uril (CB[6]) is synthesized, wherein the 1,5-NDS anions act as linkers to connect the CB[6] units together through C–H ··· O H-bonds. The fluorescence wavelength of the assembly structure is blueshifted relative to that of 1,5-NDS and the fluorescence intensity is decreased, which are ascribed to the formed H-bonds. A highly ordered 3D framework from 1,5-naphthalenedisulfonate (1,5-NDS) and cucurbit[6]uril was synthesized and structurally determined by single-crystal X-ray diffraction analysis. The crystal structure demonstrates that the 1,5-NDS anions act as linkers to connect the cucurbit[6]uril units together through C–H ··· O hydrogen bonds between the 1,5-NDS anions and cucurbit[6]uril. Furthermore, with 1,5-NDS as the fluorophore, the fluorescence properties of the corresponding assembly structure were investigated in the solid state. Relative to that observed for 1,5-NDS, the assembly exhibited a blueshift in the fluorescence wavelength from λ = 406 to 340 nm along with decreased fluorescence intensity. Theoretical calculations were in good agreement with the experimental results and disclosed that the fluorescence mechanism of the assembly structure could be ascribed to the hydrogen bonds formed between the 1,5-NDS anion and cucurbit[6]uril.