ZEOLITE-ENTRAPPED RUTHENIUM(II) COMPLEXES WITH BIPYRIDINE AND RELATEDLIGANDS - ELIMINATION OF LIGAND-FIELD-STATE DEACTIVATION AND INCREASEIN (3)MLCT STATE LIFETIMES

Several homoleptic and bis-heteroleptic tris-ligated polypyridine comp lexes of Ru(II) have been prepared in the zeolite Y supercages. Ru(L)n (L')3-n-Y (where n = 0, 1, 2, 3 and L, L' = bpy, dmb, mmb, and bpz) co mplexes have been investigated by electronic absorption, electronic em ission, resonance Raman, and time-resolved resonance Raman spectroscop ies. Excited-state lifetimes of the entrapped complexes have been meas ured and their temperature dependence established. While entrapment of the complexes in the zeolite matrix introduces no major modifications in structure or electron distribution, it does induce changes in the efficiency of various excited state energy dissipation pathways, the m ajor effect being an increase in the energy of the metal-centered dd e xcited states which leads to elimination of one of the major decay and decomposition pathways.