Encapsulation of copper(II) complexes with three dentate NO$_{2}$ ligands derived from 2,6-pyridinedicarboxylic acid in NaY zeolite

2,6-Pyridinedicarboxylic acid (H$_{2}$dipic) reacts with copper-exchanged zeolite NaY to form [Cu(dipic)(H$_{2}$O)$_{2}$]$_{n}$, which is encapsulated in the pores of the zeolite. In this zeolite-encapsulated form, the copper derivative functions as an efficient catalyst for the oxidation of cyclohexene, toluene, cyclohexane, and ethyl benzene in the presence of hydrogen peroxide (as an oxidant). The catalyst was readily recovered from the reaction mixture, and it could be reused for an additional three runs without perceptible loss of activity. The heterogeneous catalyst exhibited considerably higher activity and selectivity compared with [Cu(dipic)(H$_{2}$O)$_{2}$]$_{n}$ itself.