Oxovanadium(IV) salophen complex covalently anchored to multi-wall carbon nanotubes (MWNTs) as heterogeneous catalyst for oxidation of cyclooctene

► [VO(OH) 2-salophen] complex was covalently grafted on the MWNTs. ► The catalytic activity was tested in the oxidation of cyclooctene. ► Nanocomposites indicate good catalytic activity and selectivity in the oxidation. The chemical modification of multi-wall carbon nanotubes (MWNTs) is an emerging area in material science. In the present study, hydroxyl functionalized oxovanadium(IV) Schiff-base; ( N, N-bis(4-hydroxysalicylidene)phenylene-1,2-diamine)oxovanadium(IV), [VO((OH) 2-salophen)]; has been covalently anchored on modified MWNTs. The new modified MWNTs ([VO((OH) 2-salophen)]@MWNTs]) have been characterized by transmission electron microscopy (TEM), atomic absorption spectroscopic (AAS) analysis, X-ray diffraction (XRD), Diffuse reflectance (DRS) UV–vis, FT-IR spectroscopy and elemental analysis. The analytical data indicated a composition corresponding to the mononuclear complex of tetradentate Schiff-base ligand. The characterization of the data showed the absence of extraneous complex, retention of MWNTs and covalently anchored on modified MWNTs. Liquid-phase oxidation of cyclooctene with molecular oxygen to a mixture of cyclooctene-1-one, cyclooctene-1-ol and cyclooctene epoxide in CH 3CN have been reported using oxovanadium(IV) Schiff-base complex covalently anchored on modified MWNTs as catalysts.