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

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, N-2 physisorption, C-13-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. (C) 2019 Elsevier B.V. All rights reserved.