Hydration-Facilitated Coordination Tuning of Metal–Organic Frameworks toward Water-Responsive Fluorescence and Proton Conduction

Abstract

Developing smart stimuli-responsive metal–organic frameworks (MOFs) with diversified induced readable signals is highly desirable; however, reported multimode responsive MOFs are always achieved under strong environmental stimulations, making it difficult to keep MOF structures stable for practical applications. Herein, we reported a hydration-facilitated coordination tuning strategy to achieve the dual-mode water response in fluorescence and proton conduction from a single MOF. The designed MOF permitted reversible single-crystal transformation via the controllable hydration effect on metal nodes. The change in coordination modes leads to the regulation on conformations of optical ligands, contributing to the switch of fluorescence emissions. Moreover, the hydration effect adds additional hydrogen-bond sites in channels and optimizes hydrogen-bond networks, abruptly enhancing the proton conductivity by ∼20 times. These results pave new avenues for the exploitation of smart MOFs with multimode responsive behavior for on-demand sensing/detection applications.

Polarity‐Evolution Control and Luminescence Regulation in Multiple‐Site Hydrogen‐Bonded Organic Frameworks

“…(iii) F-TPPE follows the typical AIE molecular characteristics, providing the satisfactory fluorescence characteristics for HOF structures. [19] These make it possible to further adjust the structural and fluorescence changes in HOF polymorphs by simply controlling the solvent polarity.…”

Proton-induced switching of excitation-wavelength-dependent emission based on mixed-ligand metal–organic frameworks

“…[45][46][47] Furthermore, the specific functionalization of building units enables adjusting the excited states of ML-MOFs under physical/chemical stimuli, which provides the ability to modulate the luminescence properties of emission centers, making it possible to regulate the Ex-De emission behavior. [48][49][50][51] Therefore, luminescent ML-MOFs with a stimuliresponsive excited-state process might be an ideal platform for realizing controllable Ex-De emission behavior through reversible stimuli-responsive behaviors of functional groups.…”

A stable Mn(ii) coordination polymer demonstrating proton conductivity and quantitative sensing of oxytetracycline in aquaculture

“…[5][6][7] In addition to the natural properties of inorganic and organic parts, CPs can be bestowed on new applications such as fluorescence sensing and proton conduction by host-guest interactions and alter-able porous surroundings. [8][9][10] However, it is relatively rare to construct CPs with proton conduction and fluorescence sensing capabilities. Therefore, constructing CPs with the above dual-functional properties is of great significance for the development of multifunctional materials.…”