posted on 2023-06-09, 07:23authored byKieran Griffiths, Athanassios C Tsipis, Prashant Kumar, Oliver P E Townrow, Alaa Abdul-Sada, Geoffrey R Akien, Amgalanbaatar Baldansuren, Alan C Spivey, George KostakisGeorge Kostakis
Michael addition (MA) is one of the most well studied chemical transformation in synthetic chemistry. Here, we re-port the synthesis and crystal structures of a library of 3d/4f coordination clusters (CCs) formulated as ZnII2YIII2L4(solv)X(Z)Y and study their catalytic properties towards the MA of nitrostyrenes with barbituric acid deriva-tives. Each CC presents two borderline hard/soft Lewis acidic ZnII centers and two hard Lewis acidic YIII centers in a defect dicubane topology that brings the two different metals into a proximity of {\~{}}3.3 {\AA}. DFT computational studies suggest that these tetrametallic CCs dissociate in solution to give two catalytically active dimers, each containing one 3d and one 4f metal which act cooperatively. The mechanism of catalysis has been corroborated via NMR, EPR and UV-Vis. The present work demonstrates for the first time the successful use of 3d/4f CCs as efficient and high diastereose-lective catalysts in MA reactions.
Funding
Defect dicubane 3d/Dy(III) Coordination Clusters: Heading for materials displaying catalytic properties; G1632; EPSRC-ENGINEERING & PHYSICAL SCIENCES RESEARCH COUNCIL; EP/M023834/1