Robust salen-typed Ce-MOFs supported Fe(III) catalyst fabricated by metalloligand strategy for catalytic epoxides with alcohols

Abstract

A salen-based Ce-MOFs contained rich uncoordinated imine (−CH=N−) groups (termed as N-Ce-salen) has been synthesized by using solution-diffusion method. Furthermore, the as-synthesized N-Ce-salen MOFs served as a “metalloligand” could coordinate with Fe(III) ions forming a MOFs supported Fe(III) ions catalyst via a coordination assisted preparation strategy (named as Fe-N@Ce-salen-CAP). The coordination between the uncoordinated imine (−CH=N−) and Fe(III) ions was characterized by 13C solid-state NMR, N 1s XPS, FT-IR and UV-Vis techniques. The developed Fe-N@Ce-salen-CAP catalyst delivers excellent performance for ring-opening of epoxides with alcohols reaction in comparison with that Ce-salen MOFs (using the same organic linker) without containing uncoordinated imine groups supported Fe(III) catalyst (named as Fe/Ce-salen-IWI) prepared by classic incipient wetness impregnation (IWI) method. Various characterization techniques, e.g. XPS, TEM, HADDF-STEM, were employed to reveal the origin of enhanced performance of Fe-N@Ce-salen-CAP catalyst for ring-opening of epoxides with alcohols. We anticipate that this coordination-assisted preparation strategy may provide a new avenue for synthesis of other highly efficient MOFs supported catalysts for other heterogeneous catalytic reactions.