文摘
Postsynthetic modification of metal–organic frameworks (MOFs) has proven an effective method of synthesizing architectures that have proven challenging to produce via classic solvothermal means. Herein we report the anion–cation assisted solid-state transformation of a three-dimensional MOF (ATF-1) to a series of two-dimensional structures (YCM-21-Z) via treatment with quaternary ammonium halides. It is important to note that this reaction requires no exogoneous building blocks (inorganic cation and/or organic linker) for conversion to occur. This reaction led to the synthesis of a chemically unique framework YCM-21-Bnpy in which phase-pure synthesis cannot be achieved by solvothermal means. The mechanism of transformation was studied with data supporting a nucleophilic halide (Br, Cl, or F) mediated de-intercalation and cation-assisted flattening of the In secondary building unit as the key mechanistic steps.