Tetranuclear Zn/4f coordination clusters as highly efficient catalysts for Friedel–Crafts alkylation

Kieran Griffiths,Simon J. Coles,Graham J. Tizzard,Alaa Abdul-Sada,George E. Kostakis,Geoffrey R. Akien,Prashant Kumar,Nicholas F. Chilton

doi:10.1039/c6cc03608b

Abstract

A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel-Crafts alkylation are described for the first time. The possibility of altering the 4f centers in these catalysts without altering the core topology allows us to further confirm their stability via EPR and NMR, as well to gain insights into the plausible reaction mechanism, showcasing the usefulness of these bimetallic systems as catalysts.

Highlights

A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel–Crafts alkylation are described for the first time
In 3d/4f chemistry, 4f centres may be replaced by YIII or GdIII without altering the core topology,[19] permitting 89Y NMR20 or EPR21 for characterization of the solution species, as well as allowing study of the catalytic reaction in situ to gain mechanistic insights
We recently committed to studying the catalytic properties of tetranuclear 3d/4f coordination clusters (CCs) possessing a rigid defective dicubane topology assembled solely by the Schiff base organic ligand (E)-2-(2-hydroxy-3-methoxybenzylidene-amino)phenol) H2L (Scheme S1, Electronic supplementary information (ESI)†)

Summary

Introduction

A series of custom-designed, high yield, isoskeletal tetranuclear Zn/4f coordination clusters showing high efficiency as catalysts with low catalytic loadings in Friedel–Crafts alkylation are described for the first time. The possibility of altering the 4f centers in these catalysts without altering the core topology allows us to further confirm their stability via EPR and NMR, as well to gain insights into the plausible reaction mechanism, showcasing the usefulness of these bimetallic systems as catalysts.

Results

Conclusion