A synthetic strategy for the construction of zeolite-entrapped organized molecular assemblies. Preparation and photophysical characterization of interacting adjacent cage dyads comprised of two polypyridine complexes of Ru(II)

A novel synthetic strategy for the preparation of organized molecular assemblies entrapped within the supercage network of Y-zeolite is described. A molecular assembly composed of two Ru(II)-polypyridine complexes, Ru(bpy)(2)bpz(2+) and Ru(mmb)(3)(2+) (when bpy = 2,2'-bipyridine, bpz = 2,2'-bipyrazine, and mmb = 5-methyl-2,2'-bipyridine), entrapped in adjacent supercages, has been prepared and characterized by diffuse reflectance, resonance Raman and electronic emission spectroscopy, and excited-state lifetime measurements. A dramatic (similar to 2.5-4-fold) decrease in the emission intensity of the adjacent cage assembly, compared to a sample in which the two complexes are distributed randomly (RM) or in separate particles (MM), indicates strong interaction between the adjacent complexes. The results of the excited-state lifetime measurements are consistent with this observation. Thus, in the emission decay profile of the assembly, a new short-lived component (similar to 30 ns), attributable to the emission from the interacting dyad molecules, has been observed. While this short component dominates the emission decay for the adjacent cage assembly, it is not observed in the mechanical mixture (MM) and is too small to be accurately determined in the randomized sample (RM).