Heterogenization of Co II and CuII complexes containing a terpyridine-based Schiff base macrocyclic ligand on thiol- functionalized mesostructured silica

Abstract

Hexagonal mesoporous MCM-41-type molecular sieve has been functionalized with (3-mercaptopropyl)trimethoxysilane and used to heterogenize two large Co(II)- and Cu(II)-complexes containing a terpyridine-based Schiff base macrocyclic ligand. First, thiol groups were linked to the siliceous surface of the mesoporous host via grafting process. Some samples were characterized by FTIR, ICP-AES, SA-XRD, N2 physisorption, 13C-MAS-NMR, XPS and EPR. This set of characterization techniques confirmed a successful functionalization process, and also confirmed that the used experimental procedure allowed the heterogenization of Co(II)- and Cu(II)-complexes inside the pores of the functionalized host, retaining the mesoporous structure. The homo- and heterogeneous catalysts were active for cyclopentene oxidation. Co@MCM(F) sample was reported in this article as the best catalyst due to its higher activity and selectivity, as well as its low loss of catalytic activity after reuse.