Dicarboxylic ligands directing two Zn(II)-organic frameworks with distinct structures and significantly enhanced luminescence detection performances

Abstract Choosing different dicarboxylic ligands to construct MOFs with different structures and significantly improved luminescence detection properties has been studied. [Zn(L)(BDC)]n (1), [Zn4(L)4(ISO)4]n (2) (L = 1,4-Bis(4-pyridyl)naphthalene, H2BDC = terephthalic acid, H2ISO = isophthalic acid) have been successfully synthesized and characterized. Their structural features vary from a 3D pillar-layered 5-fold interpenetrated dia framework (1) to a 2D double-layered non-interpenetrated sql net (2). The different structures between 1 and 2 can be attributed to distinct bridging angles from dicarboxylic ligands. Furthermore, luminescent sensing experiments exhibit that 1 and 2 are efficient dual-responsive sensors for the detection of acetylacetone (acac) and Cr2O72−. Especially, 2 performs very highly sensitive quenching response towards acac in aqueous medium. More interestingly, 2 exhibits significantly enhanced quenching efficiencies than 1 (Ksv of detecting acac: 7.87 × 103 M−1 for 1 and 4.9 × 104 M−1 for 2; Ksv of detecting Cr2O72−: 3.95 × 103 M−1 for 1 and 1.41 × 104 M−1 for 2). The cause for higher quenching efficiencies of 2 has been preliminary discussed. The efficient luminescence quenching mechanisms of 1/2 towards acac/Cr2O72− have been elucidated.