Modulated self-assembly of three flexible Cr(iii) PCPs for SO2 adsorption and detection

Modulated self-assembly protocols are used to develop facile, HF-free syntheses of the archetypal flexible PCP, MIL-53(Cr), and novel isoreticular analogues MIL-53(Cr)-Br and MIL-53(Cr)-NO2. All three PCPs show good SO2 uptake (298 K, 1 bar) and high chemical stabilities against dry and wet SO2. Solid-state photoluminescence spectroscopy indicates all three PCPs exhibit turn-off sensing of SO2, in particular MIL-53(Cr)-Br, which shows a 2.7-fold decrease in emission on exposure to SO2 at room temperature, indicating potential sensing applications.

Automated summary

Modulated self-assembly protocols have been used to develop efficient, HF-free syntheses of flexible PCPs (metal-organic framework materials) MIL-53(Cr), MIL-53(Cr)-Br, and MIL-53(Cr)-NO2. These PCPs exhibit excellent SO2 uptake and high chemical stability against dry and wet SO2. Solid-state photoluminescence spectroscopy reveals that all three PCPs can effectively sense SO2, especially MIL-53(Cr)-Br, which shows a 2.7-fold decrease in emission upon exposure to SO2 at room temperature, suggesting potential sensing applications.