Structural characterization of rare-earth chain-based metal—organic frameworks with a pyrene linker and their performance in the detoxification of a mustard gas simulant

In this work, the pyrene-based linker 1,3,6,8-tetrakis(p-benzoic acid)pyrene (H4TBAPy) is used for the synthesis of rare-earth (RE) metal–organic frameworks (MOFs) featuring chain-based secondary building units with Y(III) and the series of fifteen lanthanoids, yielding two different MOFs. One named RE-CU-05 with Y(III) and Gd(III) to Lu(III), and the second named RE-CU-06 with La(III) to Eu(III). Synchrotron X-ray diffraction measurements were used to determine the local structure of the nine RE-CU-05 analogues through pair distribution function (PDF) analysis, while electron diffraction (ED) and Rietveld refinement were used for structure solution of the six RE-CU-06 analogues. RE-CU-05 and RE-CU-06 were studied for the selective photooxidation of the sulfur mustard simulant 2-chloroethyl ethyl sulfide to 2-chloroethyl ethyl sulfoxide, achieving over 98% conversion in 15 min (Tb-, Tm- and Yb-CU-05) or 10 min (La-CU-06), with half-lives of 3.4 min and 4.6 min for La-CU-06 and Tb-CU-05, respectively. These half-lives are competitive with those reported for other pyrene-based MOFs with much larger BET areas such as RE-CU-10 and Zr-NU-1000 under the same reaction conditions. The outstanding performance of RE-CU-05 and RE-CU-06 is attributed to the balance between chromophore density, pyrene-core spacing and orientation, surface area, and pore accessibility, which enables efficient light utilization and fast mass-transfer processes, highlighting the potential of chain-based MOFs as efficient photocatalysts.