Host (nanopores of zeolite-Y)/guest [manganese(II) with 12-membered tetradentate N2O2, N2S2 and N4 donor macrocyclic ligands] nanocatalysts:: flexible ligand synthesis, characterization and catalytic activity

Mn(II) complexes of 12-membered macrocyclic ligands with three different donating atom sets (N2O2, N2S2 and N-4) in the macrocyclic ring have been encapsulated in the nanopores of zeolite-Y by the Flexible-Ligand Method (FLM). The complexes were entrapped in the nanocavity of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of 1,2-di(o-aminophenyl-, amino, oxo, thio)ethane in the supercages of the zeolite and (ii) in situ condensation of the Mn(II) precursor complex ([Mn(N2X2)](2+)) with glyoxal or biacetyl. The new host-guest nanocatalysts, [Mn([R](2)-N2X2)](2+)-NaY (R = H, CH3; X = NH, O, S), have been characterized by various physico-chemical methods. These complexes, both in their free states and as host-guest nanocatalysts, were used for oxidation of cyclohexene with tert-butylhydroperoxide (TBHP) oxidant in different solvents. Di-2-cyclohexenylether was identified as the main product. 2-Cyclohexene-1-one, 2-cyclohexene-1-ol and 1-(tert-butylperoxy)-2-cyclohexene were obtained as minor products. [Mn([H](2)-N-4)](2+)-NaY was found to give the best reactivity and selectivity.