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

Cobalt(II) complex nanoparticles of [14]aneN4: 1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane; [16]aneN4: 1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane; Bzo2[14]aneN4: dibenzo-1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane and Bzo2[16]aneN4: 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 O2 as oxidant in different solvents. Electronic spectra of the reaction mixture indicated that the oxidation proceeds through a free radical mechanism.

Graphical abstractCobalt(II) complex nanoparticles of [14]aneN4: 1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane; [16]aneN4: 1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane; Bzo2[14]aneN4: dibenzo-1,5,8,12-tetraaza-2,9-dioxo-4,11-diphenylcyclotetradecane and Bzo2[16]aneN4: dibenzo-1,5,9,13-tetraaza-2,10-dioxo-4,12-diphenylcyclohexadecane have been encapsulated in the nanopores of zeolite-Y. The new complex nanoparticles entrapped in the nanoreactor of zeolite-Y were characterized by deferent techniques. These complexes (neat and encapsulated) were used for epoxidation of styrene with O2 as oxidant in different solvents.Figure optionsDownload full-size imageDownload as PowerPoint slide