Solvent‐Assisted Metal Metathesis: A Highly Efficient and Versatile Route towards Synthetically Demanding Chromium Metal–Organic Frameworks

Abstract Chromium(III)‐based metal–organic frameworks (Cr‐MOFs) are very attractive in a wide range of investigations because of their robustness and high porosity. However, reports on Cr‐MOFs are scarce owing to the difficulties in their direct synthesis. Recently developed postsynthetic routes to obtain Cr‐MOFs suffered from complicated procedures and a lack of general applicability. Herein, we report a highly efficient and versatile strategy, namely solvent‐assisted metal metathesis, to obtain Cr‐MOFs from a variety of Fe III ‐MOFs, including several well‐known MOFs and a newly synthesized one, through judicious selection of a coordinating solvent. The versatility of this strategy was demonstrated by producing Cr‐MIL‐100, Cr‐MIL‐142A/C, Cr‐PCN‐333, and Cr‐PCN‐600 from their Fe III analogues and Cr‐SXU‐1 from a newly synthesized MOF precursor, Fe‐SXU‐1, in acetone as the solvent under very mild conditions. We have thus developed a general approach for the preparation of robust Cr‐MOFs, which are difficult to synthesize by direct methods.