Flexible ligand synthesis, characterization and catalytic oxidation of cyclohexane with host (nanocavity of zeolite-Y)/guest (Mn(II), Co(II), Ni(II) and Cu(II) complexes of tetrahydro-salophen) nanocomposite materials

Transition metal (M = Mn(II), Co(II), Ni(II) and Cu(II)) complexes with tetrahydro-salophen (salophen = N,N-bis-(salycilidene)-1,2-phenylenediamine: H-2[H(4)salophen] = 2-({2-[(2-hydroxybenzyl)amino]anilino}methyl)phenol) have been encapsulated in nanopores of zeolite-Y; [M(H(4)salophen)]-NaY; with Flexible Ligand Method for the first time. The new Host-Guest Nanocomposite Materials (HGNM) was characterized by several techniques: chemical analysis, spectroscopic methods (DRS, FTIR and UV/Vis), BET technique, conductometric and magnetic measurements. The catalytic activities for oxidation of cyclohexane with HGNM complexes are reported. Zeolite-encapsulated tetrahydro-salophen copper(II) complexes; [Cu(H(4)salophen)]-NaY; was found to be more active than the corresponding cobalt(II), manganese(II) and nickel(II) complexes for cyclohexane oxidation. The catalytic properties of the complexes are influenced by their geometry and by the steric environment of the active sites. HGNM are stable enough to be reused and are suitable to be utilized as partial oxidation catalysts. The encapsulated catalysts systems; [M(H(4)salophen)]-NaY; were more active than the corresponding neat complexes; [M(H(4)salophen)]. (C) 2008 Elsevier Inc. All rights reserved.