Encapsulation of copper(II) complexes with pentadentate N3O2 Schiff base ligands derived from acetylacetone in NaX zeolite

Copper(II) complexes with two five co-ordinate Schiff base ligands derived from acetylacetone and which provide a N3O2 co-ordination sphere, bis(acetylacetonate)-3-amino-bis(propyldiimine) and bis(acetylacetonate)-3-methylamino-bis(propyldiimine), were entrapped in the supercages of zeolite NaX by a two-step process in the liquid phase: (i) adsorption of copper(II) acetylacetonate in the supercages of the zeolite, and (ii) in situ Schiff condensation of the copper(II) precursor complex with the corresponding triamines. The new materials were characterised by several techniques: chemical analysis, morphological and surface analysis, spectroscopic methods (FTIR, UV/VIS) and electron paramagnetic resonance. Analysis of the data indicates that the Cu(II) complexes are encapsulated in the NaX zeolite supercages and exhibit structural and electronic properties that are different from those of the free complexes, which can arise from distortions caused by steric effects due to the presence of sodium cations, or from interactions with the zeolite matrix. (C) 2000 Elsevier Science B.V. All rights reserved.