DIOXYGEN COMPLEXES OF CO(TETREN) IN ZEOLITES-A AND ZEOLITES-Y - INFLUENCE OF ZEOLITIC ARCHITECTURE

The formation of dioxygen complexes of Co(II) complexed to tetraethylenepentamine inside the supercages of zeolite A and Y have been investigated. Various spectroscopic probes show that the size constraint of the cages allows for the formation of the superoxo complex in zeolite A and mu-peroxo complex in zeolite Y. The superoxo complex loses the O2 in an atmosphere of N2 and can recombine with O2 at an equilibrium constant of 2.2 x 10(3) M-1. The rapid and efficient formation of these complexes in an aqueous environment under mild conditions, yet constrained by the zeolite architecture to make different complexes, makes this an interesting system. Also, the pentadentate nature of the ligand does not require the addition of an axial base, limiting problems of diffusion through the zeolite.