Efficient Catalytic Performance for Acylation-Nazarov Cyclization Based on an Unusual Postsynthetic Oxidization...

A rare example of SC-SC triggered by Cu²⁺ heterogeneous oxidation was demonstrated in a Fe(II)-based MOF {[Fe^II₃(L)₂(H₂O)₆]·3H₂O} _n (1), which occurred a slow conversion into an oxidized MOF 2 ({[Fe^III₃(L)₂(H₂O)₆]·3(OH)} _n) with retention of single crystallinity. The Fe^II → Fe^III progress of the reaction oxidation was proved by single crystal XRD, PXRD, XPS, ⁵⁷Fe Mössbauer spectroscopy, and UV-vis. We used 1 and 2 as catalysts to catalyze the tandem Nazarov cyclization, and the results show that acylation products were only harvested when 1 was a catalyst, while the oxidized transformer 2 lead mainly to the formation of cyclization products under identical conditions. Through the test of different substrates, 2 can be a good heterogeneous catalyst candidate for the formation of cyclopentenone[ b] benzenes. This work provides a new way to design efficient and hard-synthesized heterogeneous catalyst materials.