A stable amine functionalized montmorillonite supported Cu, Ni catalyst showing synergistic and co-operative effectiveness towards C–S coupling reactions

The objective of this work is to prepare a cheap and highly stable heterogeneous catalyst. This was done by a simple two step approach. The first step involved the preparation of an organic–inorganic hybrid material by covalent grafting of amines on K10 montmorillonite. In the second step the N atoms of the amine groups were co-ordinated to Cu and Ni ions. Both the covalent and co-ordination forces are strong enough to make the catalyst fairly stable during the catalytic runs. The amine functionalization was confirmed by 29Si CP MAS NMR spectroscopy, FTIR spectroscopy and XPS analysis. The XPS analysis revealed Cu and Ni were present in their +2 oxidation states. This bimetallic system was discovered somewhat by curiosity when Ni was added to a previously well-established Cu catalyzed C–S coupling reaction in an attempt to enhance the catalytic activity. When this catalyst was employed in the C–S coupling reaction, it showed wonderful activity with 99% product yield, due to the synergistic effect of the metal duo.