Polyethylene glycol and montmorillonite clay anchored Schiff base ligand-metal complexes

Abstract

Three ligands were synthesized through condensation of o-phenylenediamine with salicylaldehyde (ligand 1) and 2-hydroxy-1-naphthaldehyde (ligand 2) and of 1,8-diaminonaphthalene with 2-hydroxy-1-naphthaldehyde (ligand 3) in 1:2 molar ratio; the ligands were characterized using NMR and FTIR techniques. The 1:1 complexes of ligand 1 with FeCl3 and CoSO4; ligand 2 with FeCl3, CoSO4·6H2O, and CoCl 2·6H2O; and ligand 3 with FeCl3 were prepared and characterized using FTIR and XRD techniques. These ligand-metal complexes were then anchored on polyethylene glycol (PEG, MW = 6000), montmorilonite (MMT), and organically modified montmorillonite (OMMT, Closite30B) clays and characterized by FTIR. The spectral data of the ligands and their complexes have been explained in terms of structural changes occurring due to complexation. The XRD data indicated that anchoring on the three supports resulted in the reduction the crystal size providing higher surface area to volume ratio and, hence, potentially enhanced catalytic activity. Additionally, catalytic activity of the complexes has been proven by chemically fixing carbon-dioxide to propylene carbonate using propylene oxide. © 2013 American Chemical Society.