Nanosized Porphyrinic Metal–Organic Frameworks for the Construction of Transparent Membranes as a Multiresponsive Optical Gas Sensor

The well‐known and excellent colorimetric sensing capacity of porphyrins, along with the exceptional structural properties of metal–organic frameworks (MOFs), make porphyrin‐based MOFs, such as PCN‐222, ideal candidates for the construction of a chemical sensor based on absorbance. However, to the best of authors’ knowledge, no high‐quality porphyrin‐based MOF gas sensors have been developed to date, most likely due to the difficulties in: 1) preparing nanosized porphyrin‐MOFs to minimize scattering in absorbance measurements; and 2) incorporating MOFs into transparent membranes for practical use. Herein, a simple and fast microwave‐assisted method for preparing high‐quality nanosized PCN‐222 crystals and their metalated derivatives PCN‐222(M) is reported to finely tune the sensing response. Next, the successful dispersion of these PCN‐222(M) nanoparticles into poly(dimethylsiloxane) to create flexible and transparent membranes is demonstrated. This integration yields a multiresponsive optical gas sensor exhibiting excellent sensitivity and the ability to discriminate between various volatile organic compounds via pattern recognition identification. Preparation of a multiresponsive optical gas sensor based on absorbance detection is detailed, leveraging: 1) the potential of microwave‐assisted methods for the synthesis and postmetalation of nanosized PCN‐222; 2) the exceptional sensing properties of PCN‐222 metalated with different metals for selectively modulate its response toward volatile organic compounds; and 3) the successful incorporation of PCN‐222(M) into poly(dimethylsiloxane) flexible membranes.