Porous Cu(I) Triazolate Framework and Derived Hybrid Membrane with Exceptionally High Sensing Efficiency for Gaseous Oxygen

Abstract

Phosphorescent complexes of precious metal ions are widely studied as optical sensing materials for molecular oxygen. Combining the advantages of luminescent complexes and porous matrixes, porous coordination polymers show great potential for oxygen‐sensing, although their sensitivity, requirement of precious metal, and device fabrication remain challenging issues. In this work, the photoluminescence and oxygen‐sensing properties of the porous Cu(I) triazolate framework [Cu(detz)] (MAF‐2, Hdetz = 3,5‐diethyl‐1,2,4‐trizole) is studied in detail, which shows high chemical stability in moisture and water, very long phosphorescent lifetime (116 μs) and large Stokes shift (14 562 cm−1), as well as considerable oxygen permeability (1.7 × 10−11 mol cm−1 s−1 bar−1) at ambient conditions, giving rise to exceptionally high luminescence quenching efficiency of 99.7% at 1 bar O2 (I 0/I 100 = 356) with a perfectly linear Stern‐Volmer plot (K SV = 356 bar−1, R 2 = 0.9998), fast response and good reversibility. Further, a counter‐diffusion crystal‐growth method was developed to fabricate MAF‐2 thin films protected by silicone rubbers as the first example of soft membrane oxygen sensor based on coordination polymer or metal‐organic framework, which exhibited extraordinary oxygen‐sensing performance (limit of detection = 0.047 mbar) and outstanding mechanical property, as well as outstanding chemical stability even in an acidic atmosphere.

Oxygen Sensing, Hypoxia Tracing and in Vivo Imaging with Functional Metalloprobes for the Early Detection of Non-communicable Diseases

“…The vast majority of Ir-based O 2 sensors reported thus far, have been developed by incorporating and dispersing the iridium molecules or the phosphorescent Ir compounds into porous matrices. In the solid state, small molecule complexes have shown limited oxygen permeability which, in turn, results in a poor optical response toward oxygen (Liu et al, 2014 ). The formation of polymer-free self-inclusive O 2 sensors based on organometallic molecules was investigated by Mann (Smith and Mann, 2009 , 2012 ).…”

Improving MOF stability: approaches and applications

“…Unlike these chemical sensors, a Cu(I) triazolate framework, MAF-2, was designed as a gaseous oxygen sensor based on its high moisture stability, fast uptake and sorption kinetics for oxygen and other optical properties. 192 Additionally, upon combining MAF-2 with silicone rubbers, the resultant MAF-2 thin lm exhibited extraordinary sensitivity to oxygen and superior stability even in an acidic atmosphere due to the protection provided by the silicone rubbers.…”

Tuning the Photoinduced Electron Transfer in a Zr‐MOF: Toward Solid‐State Fluorescent Molecular Switch and Turn‐On Sensor

“…Metal–organic frameworks (MOFs), an emerging class of crystalline porous organic–inorganic hybrid materials, have gained intensive attention for applications in gas absorption and separation, catalysis, sensors, drug delivery, energy storage, etc. Considering their inherent structural characteristics, MOFs provide an ideal platform for immobilizing fluorescent PET switches/sensors into solid state while retaining their identical properties in solution .…”