A SYNTHETIC STRATEGY FOR THE CONSTRUCTION OF ZEOLITE-ENTRAPPED ORGANIZED MOLECULAR ASSEMBLIES - PREPARATION AND PHOTOPHYSICAL CHARACTERIZATION OF INTERACTING ADJACENT CAGE DYADS COMPRISED OF 2 POLYPYRIDINE COMPLEXES OF RU(II)
M. Sykora et al., A SYNTHETIC STRATEGY FOR THE CONSTRUCTION OF ZEOLITE-ENTRAPPED ORGANIZED MOLECULAR ASSEMBLIES - PREPARATION AND PHOTOPHYSICAL CHARACTERIZATION OF INTERACTING ADJACENT CAGE DYADS COMPRISED OF 2 POLYPYRIDINE COMPLEXES OF RU(II), Journal of the American Chemical Society, 120(14), 1998, pp. 3490-3498
A novel synthetic strategy for the preparation of organized molecular
assemblies entrapped within the supercage network of Y-zeolite is desc
ribed. A molecular assembly composed of two Ru(II)-polypyridine comple
xes, 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 diffus
e reflectance, resonance Raman and electronic emission spectroscopy, a
nd excited-state lifetime measurements. A dramatic (similar to 2.5-4-f
old) decrease in the emission intensity of the adjacent cage assembly,
compared to a sample in which the two complexes are distributed rando
mly (RM) or in separate particles (MM), indicates strong interaction b
etween the adjacent complexes. The results of the excited-state lifeti
me measurements are consistent with this observation. Thus, in the emi
ssion decay profile of the assembly, a new short-lived component (simi
lar 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 determin
ed in the randomized sample (RM).