Synthesis, characterization of cobalt(II) complex nanoparticles encapsulated within nanoreactors of zeolite-Y and their catalytic activities

Abstract

Cobalt(II) complex nanoparticles of [14]aneN 4: 1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane; [16]aneN 4: 1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane; Bzo 2[14]aneN 4: dibenzo-1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane and Bzo 2[16]aneN 4: dibenzo-1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane have been encapsulated in the nanopores of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of [bis(diamine)cobalt(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, 1,3-diaminobenzene); [Co(N–N) 2] 2+–NaY; in the nanopores of the zeolite-Y, and (ii) in situ condensation of the cobalt(II) precursor complex with ethylcinnamate. The new complex nanoparticles entrapped in the nanoreactor of zeolite-Y were characterized by several techniques: BET, chemical analysis and spectroscopic methods (FT-IR, UV–vis, XRD, and DRS). These complexes (neat and encapsulated) were used for epoxidation of styrene with O 2 as oxidant in different solvents. Electronic spectra of the reaction mixture indicated that the oxidation proceeds through a free radical mechanism.