Space-confined indicator displacement assay inside a metal-organic framework for fluorescence turn-on sensing.

The indicator displacement assay (IDA) is for the first time performed within a metal-organic framework (MOF) to achieve ultrasensitive fluorescence turn-on sensing. A Zr(iv) ion MOF (UiO-67-DQ-PsO) furnished with electron-deficient diquat units (DQ, as the receptor) on the wall and electron-rich 1-pyrenesulfonate anions (PsO, as the fluorescent indicator) in the pores was prepared by postsynthetic anion exchange. The MOF is capable of sensing alkylamines owing to the competing PsO-DQ and alkylamine-DQ charge-transfer interactions, the former interaction causing a fluorescence OFF state and the latter displacing PsO to trigger its emission.

A Facile and Versatile "Click" Approach Toward Multifunctional Ionic Metal-organic Frameworks for Efficient Conversion of CO.

Ionic metal-organic frameworks (IMOFs) that integrate synergistic Lewis-acid sites (intrinsic metal centers of the frameworks) and nucleophilic anions (halides encapsulated within pores) are intriguing platforms for the design of fully heterogeneous catalytic systems for cycloaddition of CO to epoxides. A new, facile and versatile synthetic approach has been used to fabricate triazolium-based IMOFs for the first time. The approach makes use of azide-alkyne click chemistry and subsequent N-alkylation to post-synthetically create a cationic triazolium ring and introduce exchangeable counteranions at the same time.

Versatile and Switchable Responsive Properties of a Lanthanide-Viologen Metal-Organic Framework.

Metal-organic frameworks (MOFs) provide intriguing platforms for the design of responsive materials. It is challenging to mobilize as many components as possible of a MOF to collaboratively accomplish multiple responsive properties. Here, reversible photochromism, piezochromism, hydrochromism, ionochromism, and luminescence modulation of an ionic Eu(III) MOF is reported furnished by cationic electron-deficient viologen units and exchangeable guest anions.

Switchable Ferro-, Ferri-, and Antiferromagnetic States in a Piezo- and Hydrochromic Metal-Organic Framework.

The Mn(II) metal-organic framework with a viologen-based tetracarboxylate ligand exhibits reversible optical (color) and magnetic changes concomitant with stimuli-induced electron transfer from carboxylate to viologen. Compression causes a magnetic transformation from ferro- to ferrimagnetic, while water release/reuptake switches the magnetic behavior between ferro- and antiferromagnetic.

A highly luminescent entangled metal-organic framework based on pyridine-substituted tetraphenylethene for efficient pesticide detection.

A novel pillared-layered entangled luminescent metal-organic framework [Zn(bpdc)(BPyTPE)] (1) (BPyTPE = (E)-1,2-diphenyl-1,2-bis(4-(pyridin-4-yl)phenyl)ethene) has been designed and constructed. The solvent-free 1 exhibits strong blue-green emission with an excellent fluorescence quantum yield of 99% and provides a facile and reversible method to sensitively and quantitatively detect trace pesticide of 2,6-dichloro-4-nitroaniline.