Dynamic electron-transfer quenching of the Tris(2,2`-bipyridyl)ruthenium(II)MLCT excited state by intrazeolitic methylviologen ions

Journal Article · Thu Apr 02 04:00:00 EST 1992 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100186a019· OSTI ID:263815

Kim, Y I; Mallouk, T E ^[1]

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1. Univ. of Texas, Austin, TX (United States)

Photoinduced electron-transfer reactions of tris(2,2`-bipyridyl)ruthenium(II) (Ru(bpy){sub 3}{sup 2+}) and methylviologen (MV{sup 2+}) ion-exchanged onto/into three different zeolites (L,Y, and mordenite) were studied-state and time-resolved spectroscopic techniques. Quenching of the metal-to-ligand charge-transfer (MLCT) excited state of the size-excluded Ru(bpy){sub 3}{sup 2+} ion was shown to be controlled by diffusion of MV{sup 2+} within the channels of both zeolite L and Y. Linear Stern-Volmer plots were derived from time-resolved emission and transient diffuse reflectance data for these two zeolites. Quantitive agreement with steady-state emission data showed that static quenching was not significant in these cases. In the case of mordenite, nonlinear Stern-Volmer plots were obtained. Using a modified Smoluchouski equation, the diffusion coefficients of MV{sup 2+} in zeolites L and Y were estimated as 1.28 x 10{sup -7} and 1.12 x 10{sup -7} cm{sup 2}s{sup -1}, respectively. The charge recombination kinetics of the photoproducts Ru(bpy){sub 3}{sup 3+} and MV{sup .+} in zeolites L and Y are complex and do not follow first-or second-order decays. The average lifetimes of charge separation were in the range of tens of microseconds. Quantum yields for charge separation and cage escape efficiencies for Ru(bpy){sub 3}{sup 3+} and MV{sup .+} in these zeolites were found on the order of 6-9%. 31 refs., 9 figs., 5 tabs.

• Sponsoring Organization: USDOE
• OSTI ID: 263815
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 7 Vol. 96; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
BIPYRIDINES
CHEMICAL REACTION KINETICS
ELECTRON TRANSFER
EMISSION SPECTROSCOPY
PHOTOCHEMISTRY
RUTHENIUM COMPLEXES
TIME RESOLUTION
ZEOLITES