Title

Spectroscopic, Electrochemical, and Photochemical Properties of Molybdenum(II) and Tungsten(II) Halide Clusters

Document Type

Article

Publication Date

1-1-1983

Abstract

The cluster ions Mo6Cl142, Mo6Br142-, and W6Cl142 are luminescent, with emission maxima (lifetimes, quantum yields) of 805 (180, 0.19), 825 (130, 0.23), and 880 nm (2 μs, 0.02), respectively, in acetonitrile at room temperature. Absorption spectra at low temperature reveal weak shoulders at low energy (Mo6Cl142-, 530 and 590 nm; Mo6Br142-, 600 nm; and W6C1442-, 490 and 550 nm) that may be electronically closely related to the luminescences. Solid (Bu4N)2Mo6Cl14 is rigorously diamagnetic, and the paramagnetic Mo6Cl14- ion formed from it by one-electron oxidation gives an axial EPR spectrum (g± = 2.10; gf = 2.0). All three ions undergo facile electrochemical oxidation, at potentials of 1.60, 1.38, and 1.14 V, respectively, vs. SCE in CH3CN. Kinetics and rate constants are discussed for electron-transfer quenching of the luminescent excited state Mo6C1]42“* by several electron acceptors, both in aqueous and nonaqueous solutions, and for the subsequent electron-transfer reactions. © 1983, American Chemical Society. All rights reserved.

Publication Source (Journal or Book title)

Journal of the American Chemical Society

First Page

1878

Last Page

1882

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