8-Hydroxyquinolinate-Based Metal-Organic Frameworks: Synthesis, Tunable Luminescent Properties, and Highly Sensitive Detection of Small Molecules and Metal Ions

Five new metal organic frameworks, [Zn2L2]center dot 2DMF center dot 2MeOH (1), [Zn2L2(py)(2)] (2), [Cd2L2]center dot Diox-MeOH center dot 6H(2)O (3), [Mn2L2]center dot 2DMF center dot 2MeOH (4), and [Co2L2]center dot 2DMF center dot 4H(2)O (5), were assembled by using a novel 8-hydroxyquinolinate derivative H2L with different metal ions. Complex 1 features a 3D porous network consisting of mesa-helical chains (P + M) built from metal ligand coordination bonds. The adjacent dinuclear Zn-II building blocks in 2 are connected together to generate a 2D grid network. In complex 3, each binuclear motif is bound to four Zn-II ions to produce a 2D layer structure that stacks into a 3D porous structure. The framework of complex 4 is isostructural to 5, featuring a 2, helical chain built from [M2L2] units (M = Mn or Co). The adjacent meso-helices associated in parallel are interconnected by the phenolate mu(2)-O atoms of H2L to give rise to a 2D network. Distinct solid-state luminescence properties of 1-3 were observed, arising from their different metal nodes and frameworks. In particular, complex 1 exhibited excellent stability in both common organic and solvents H2O, thus facilitating its utility as a chemical sensor. Remarkably, luminescent 1 showed highly sensitive detection for nitroaromatic. molecules in methanol and Fe3+ ion in H2O even in the presence of other interfering metal cations.