Encapsulation of copper(II) complexes with pentadentate N3O2 Schiff base ligands in a pillared layered clay

Two copper(II) complexes with five-coordinate Schiff-base ligands derived from acetylacetone and with a N3O2 coordination sphere, namely bis(acetylacetonate)-3-amino-bis(prop-yldiimine) and bis (acetylacetonate)-3-methylamino-bis(prop-yldiimine), were entrapped in the interlayers of a pillared layered clay (PILC). A two-step process in the liquid phase was used: (i) adsorption of copper(II) acetylacetonate in the porous structure of the PILC, and (ii) in situ Schiff condensation of the copper(ii) precursor complex with the corresponding triamine. The new materials were characterised by chemical analysis, surface techniques (SEM and XPS), X-ray powder diffraction, nitrogen adsorption isotherms and spectroscopic methods (FTIR, UV/Vis). These data indicate conclusively that the Cu-II complexes are encapsulated in the PILC, and that the entrapped complexes exhibit structural and electronic properties that are different from those of the free complexes. These differences can arise from distortions caused either by steric effects imposed by the structure of pillared clay, or by strong interactions with the matrix.