EFFECT OF AMINO-ACID RESIDUE MODEL ON THE PHOTOINDUCED LONG-DISTANCE ELECTRON-TRANSFER FROM THE EXCITED RU(BPY)(3)(2+) TO METHYLVIOLOGEN INA POLYMER FILM

Photoluminescent Ru(bpy)(3)(2+) complex, electron-accepting methylviol ogen, and an amino acid residue model compound were dispersed in a pol ysiloxane film, and photoinduced electron transfer from the excited Ru (bpy)(3)(2+) to methylviologen and the effect of amino acid residue mo del on the electron-transfer distance have been studied. The electron- transfer reaction was analyzed by a static model, and the electron-tra nsfer distance was calculated considering the distance distribution be tween the nearest neighboring molecules as well as their excluded volu me effect. In the absence of the amino acid residue model, the electro n-transfer distance was obtained to be 1.4 nm. p-Cresol, a model compo und of tyrosine residue, did not affect the electron-transfer distance , but 3-methylindole, a model of tryptophan residue, increased the ele ctron-transfer distance to twice (2.7 nm) that without it.