Spectroscopic study of the structure of bis(oxazoline)copper complexes in solution and immobilized on laponite clay. Influence of the structure on the catalytic performance

A bis(oxazoline)copper complex is immobilized in a synthetic Laponite clay by cationic exchange in different conditions. The structure of the exchange d complex is studied by several spectroscopic methods, mainly EPR and EXAFS , and compared with the homogeneous precursors in both solid state and solu tion. The exchanged copper complexes are isolated species with an almost sq uare-planar structure with the clay surface acting as a counterion of the c ationic complex. The strength of the copper-anion interaction, conditioned also by the solvent, allows one to explain the differences in catalytic act ivity and selectivities between the different homogeneous and supported cat alysts.