Zeolite-Based Organized Molecular Assemblies. Photophysical Characterization and Documentation of Donor Oxidation Upon Photosensitized Charge Separation

Document Type

Article

Publication Date

8-13-2001

Department

Physical & Earth Sciences

Abstract

An organized molecular assembly composed of two ruthenium polypyridine complexes, Ru(bpy) (bpz) and Ru(bpy) (H O) (where bpy = 2, 2′-bipyridine and bpz = 2, 2′-bipyrazine), has been prepared in adjacent supercages of Y-zeolite. This material has been characterized by diffuse reflectance, electronic absorption, electronic emission, and resonance Raman (RR) spectroscopy, as well as lifetime measurements. The spectral results confirm the identity of the entrapped complexes and resonance Raman measurements show that the relative concentrations of the two complexes within the zeolite particles are identical. A dramatic decrease in emission intensity observed for the adjacent cage assembly, relative to that observed for an appropriate reference material composed of a mixture of zeolite particles containing the separated complexes, indicates strong interaction between the adjacent complexes which provides an additional nonradiative decay pathway. The excited state lifetime measurements implicate a very short-lived component, dominating the decay curve at early times, which is most reasonably attributed to excited-state electron-transfer quenching of the adjacent cage pair. More importantly, analysis of diffuse reflectance spectra acquired during selective (sensitizer) irradiation of a sample of this material, wherein the remaining cages are filled with a suitable acceptor (MV ), provides direct evidence for oxidation of the Ru(bpy) (H O) donor complex, confirming the targeted synergy of the adjacent cage assembly.

DOI

10.1021/ic010191m

First Page

4464

Last Page

4471

Volume

40

Issue

17

Publication Title

Inorganic Chemistry

ISSN

00201669

Comments

At the time of publication, Anwar A. Bhuiyan was affiliated with Marquette University.

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