Luminescence and white-light emitting luminescent sensor of tetrafluoroterephthalate-lanthanide metal-organic frameworks.

Two types of sixteen complexes 1-16, namely, {[Ln(TFBDC)(HO)]·2HO} [Ln = Pr (1) and Nd (2)] and {[Ln(TFBDC)(HO)]·HO} [Ln = Ce (3), Pr (4), Nd (5), Sm (6), Eu (7), Gd (8), Tb (9), Dy (10), Ho (11), Er (12), Yb (13) and Lu (14)], {[DyEu(TFBDC)(HO)]·HO} (15) and {[GdEuTb(TFBDC)(HO)]·HO} (16), were isolated by the reaction of LnCl·6HO with 2,3,5,6-tetrafluoroterephthalic acid (HTFBDC). X-ray crystallographic analysis revealed that 1 and 2 exhibit 3D network structures and complexes 3-14 feature 2D network structures formed via three different coordination modes of the ligand. Luminescence spectra revealed that these complexes exhibit broad-spectrum luminescence from the visible to the near-infrared (NIR) region. Unexpectedly, complex 1 exhibits a unique NIR luminescence pattern and the longest lifetime among reported molecular praseodymium complexes. White-light emission was realized via three approaches using the single-component complex 6 (Sm), the two-component complex 15 (Eu and Dy) and the three-component complex 16 (Eu, Tb and Gd). Complex 9 exhibits high sensitivity and selectivity in its luminescence response to benzaldehyde, which provides a promising luminescent sensor for the detection of benzaldehyde.