Adsorption

Photochemistry

Materials science

Turn (biochemistry)

Receptor

Crystal structure

Biochemistry

Physical chemistry

Physics

Ligand (biochemistry)

Nanotechnology

Organic chemistry

Optics

Amine gas treating

Coordination sphere

Luminescence

Fluorescence

Metal-organic framework

Crystallography

Chromophore

Chemistry

Lanthanide

Optoelectronics

Angewandte Chemie International Edition

Guided by a second-sphere interaction strategy, we fabricated a Tb(III)-based metal-organic framework (MMCF-4) for turn-on sensing of methyl amine with ultra-low detection limit and high turn-on efficiency. MMCF-4 features lanthanide nodes shielded in a nonacoordinate geometry along with secondary coordination spheres that are densely populated with H-bond interacting sites. Nonradiative routes were inhibited by binding-induced rigidification of the ligand on the second coordination sphere, resulting in luminescence amplification. Such remote interacting mechanism involved in the turn-on sensing event was confirmed by single-crystal X-ray diffraction and molecular dynamic simulation studies. The design of both primary and secondary coordination spheres of Tb(III) enabled the first turn-on sensing of organic amines in aqueous conditions. Our work suggests a promising strategy for high-performance turn-on sensing for Ln-MOFs and luminous materials driven by other metal chromophores.

Second‐Sphere Interaction Promoted Turn‐On Fluorescence for Selective Sensing of Organic Amines in a Tb<sup>III</sup>‐based Macrocyclic Framework

Second‐Sphere Interaction Promoted Turn‐On Fluorescence for Selective Sensing of Organic Amines in a TbIII‐based Macrocyclic Framework

Second‐Sphere Interaction Promoted Turn‐On Fluorescence for Selective Sensing of Organic Amines in a Tb^III‐based Macrocyclic Framework