Porphyrin Catecholate Iron-Based Metal-Organic Framework for Efficient Visible Light-Promoted One-Pot Tandem C-C Couplings

Introduction of metal-organic frameworks (MOFs) beyond metal-carboxylate series and their applications are still challenging. An innovative porousporphyrin catecholate iron-based MOF (PorphCat-Fe) with a Brunauer-Emmett-Teller (BET) surface area of 700 m2g-1has been designed and synthesized through solvothermal self-assembling porphyrin catecholate linkers and iron(II) chloride asa cheap and earth-abundant node precursor. The structure was then evaluated with various techniques and utilized as an efficient and stable heterogeneous material fordomino one-pot selective benzyl alcohol oxidation/Knoevenagel condensationreaction under visible LED light irradiation. The photocatalytic performance wasremarkably improved as compared to individual components, affording excellentproduct yields (91%) with almost quantitative transformation of benzyl alcohol.The combination of Fe(III)-Lewis acidic sites and free-base porphyrin photo-sensitizers within the porous solid material make PorphCat-Fe able to showsuperior catalytic activity for this transformation. In addition, the MOF can easilyaccommodate the starting materials inside its mesopores and, thereby, make them easily accessible to active sites. This is an unusualexample of an all-in-one noble metal-free bio-inspired supramolecular chemistry for an advanced organic transformation without the need of any chemical additive or further structural modification using only visible LED light conservation