LIGHT-INDUCED EXCHANGE ENERGY-TRANSFER REACTIONS OF MICELLE-FORMING RU(II) DIIMINE COMPLEXES

Photoinduced energy transfer from two surfactant Ru(II) diimine comple xes of the type I(bpy)(2)Ru(L)(2+) (L=4-methyl-4'-heptadecyl-2,2'-bipy ridine and 4,4'-diheptadecyl-2,2'-bipyridine) to anthracene-9-carboxyl ate (ANC) was investigated in aqueous solutions of the complexes. The luminescence quenching behavior of both complexes is strongly dependen t on the complex concentration in solution and the ionic strength of t he solution. The complexes exhibit a 20 nm red shift of the emission m aximum upon micelle formation; the emission spectral changes illustrat e the dependence of the critical micelle concentration (cmc) on the so lution ionic strength. The quenching of the micellized complexes by AN C is dramatically enhanced relative to the complex in the aqueous phas e. The dynamics of exchange energy transfer quenching of the micellize d complex can be evaluated assuming a Poisson distribution of ANC quen chers among the micellized complex. The (3)[ANC] formed in the quenchi ng process can escape the micelle and react by electron transfer quenc hing with methyl viologen in the aqueous phase.