Intrastrand electron and energy transfer between polypyridyl complexes on a soluble polymer
| Autor: | Thomas J. Meyer, Wayne E. Jones, Geoffrey F. Strouse, Steven M. Baxter |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Journal of the American Chemical Society. 115:7363-7373 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | Intrastrand electron and energy transfer between pendant sites in a derivatized 1:1 copolymer of styrene and p-(chloromethyl)styrene have been studied by laser flash photolysis. The polymer [p-PS-Ru[sub 22][sup II]Os[sub 5][sup II]](PF[sub 6])[sub 54], in which 22 of the approximately 27 repeat units of an average strand were Ru[sup II] and 5 Os[sup II], was prepared by nucleophilic displacement of chloride by [M(bpy)[sub 2](bpyCH[sub 2]OH)][sup 2+] (M is Ru or Os: bpy is 2,2[prime]-bipyridine; bpyCH[sub 2]OH is 4-Me-4[prime]-CH[sub 2]OH-2,2[prime]-bipyridine) under basic conditions. Following Ru[sup II] [yields] bpy laser flash excitation there was evidence for a rapid ([tau] 2 x 10[sup 8] s[sup [minus]1], but only to Os[sup II] sites that are adjacent to Ru[sup II*]. Energy transfer self-exchange from Ru[sup II*] to Ru[sup II] ([Delta]G[degrees] = 0.0 eV) is slow with k < 1 x 10[sup 6] s[sup [minus]1]. In the presence ofmore » 35 mM of the irreversible, oxidative quencher [p-CH[sub 3]OC[sub 6]H[sub 4]N[sub 2]](BF[sub 4]) in CH[sub 3]CN [approximately]94% of the emission from [p-PS-Ru[sup II][sub 22]Os[sup II][sub 5]](PF[sub 6])[sub 54] is quenched. Transient absorption measurements under these conditions show an instantaneous loss of Os[sup II] [yields] bpy, Ru[sup II] [yields] bpy absorption (bleaching) in the visible, consistent with excitation and oxidative quenching during the laser pulse. 43 refs., 9 figs., 1 tab.« less |
| Databáze: | OpenAIRE |
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