PREPARATION AND PHOTOPHYSICAL PROPERTIES OF 4-(9-ANTHRYLETHENYL)-4'-METHYL-2,2'-BIPYRIDINE AND ITS RUTHENIUM BIPYRIDYL COMPLEX [RU(BPY)(2)(T-AEMB)](PF6)(2)

rans-4-(9-anthrylethenyl)-4'-methyl-2,2'bipyridine (t-aemb) and its bi pyridyl Ru complex [Ru(bpy)(2)(t-aemb)] (PF6)(2) (bpy=2,2'-bipyridine) 1 have been prepared and their excited state properties have been stu died. t-Aemb exhibits solvent-dependent fluorescence and efficient tra ns-->cis phstoisomerization. 1 shows very weak fluorescence and is pho tochemically reactive. Fluorescence is wavelength-dependent. While the excitation into the MLCT band makes the complex-fluorescent, direct a bsorption by the t-aemb ligand lends to the photoreaction of t-aemb li gand and no fluorescence is observed. 1 is considered to behave in par t as bichromophoric molecule in which [Ru(bpy)(3)](PF6)(2) and anthryl group are covalently linked by ethenyl linkage. Because anthryl moiet y is not effectively conjugated with bipyridylethenyl moiety due to st eric hindrance, weak fluorescence can be explained due to the efficien t energy or electron transfer.