Novel Charge-Transfer Materials via Cocrystallization of Planar Aromatic Donors and Spherical Polyoxometalate Acceptors

Authors

P. Le Maguères, University of Houston
S. M. Hubig, University of Houston
Sergey V. Lindeman, Marquette UniversityFollow
P. Peya, University of Houston
Jay K. Kochi, University of Houston

Document Type

Article

Language

eng

Publication Date

2000

Publisher

American Chemical Society

Source Publication

Journal of the American Chemical Society

Source ISSN

0002-7863

Original Item ID

doi:10.1021/ja0019878

Abstract

Spherical polyoxometalates (POMs) such as M₆O₁₉^2- and SiM₁₂O₄₀^4- (with M = Mo or W) and planar arene donors (anthracenes and pyrenes) can be cocrystallized (despite their structural incompatibility) by attaching a cationic “anchor” onto the arene which then clings to the POM anion by Coulombic forces. As a result, novel charge-transfer (CT) salts are prepared from arene donors and Lindqvist-type [M₆O₁₉]^2- and Keggin-type [SiM₁₂O₄₀]^4- acceptors with overall 2:1 and 4:1 stoichiometry, respectively. The CT character of the dark-colored (yellow to red) crystalline materials is confirmed by the linear Mulliken correlation between the CT transition energies and the reduction potentials of the POM acceptors, as well as by the transient (diffuse reflectance) absorption spectra (upon picosecond laser excitation) of anthracene or pyrene cation radicals (in monomeric and π-dimeric forms). X-ray crystallographic studies reveal a unique “dimeric” arrangement of the cofacially oriented arene couples which show contact points with the oxygen surface of the POMs that vary with distance, depending on the POM/arene combination. Moreover, the combination of X-ray crystallographic and spectroscopic techniques results in the observation of a logical structure/property relationshipthe shorter the distance between the POM surface and the arene nucleus, the darker is the color of the CT crystal and the faster is the decay of the laser-excited charge-transfer state (due to back-electron transfer).

Comments

Accepted version. Journal of the American Chemical Society, Vol. 122, No. 41 (2000): 10073-10082. DOI. © 2000 American Chemical Society. Used with permission.

Sergey V. Lindeman was affiliated with the University of Houston at the time of publication.

Recommended Citation

Maguères, P. Le; Hubig, S. M.; Lindeman, Sergey V.; Peya, P.; and Kochi, Jay K., "Novel Charge-Transfer Materials via Cocrystallization of Planar Aromatic Donors and Spherical Polyoxometalate Acceptors" (2000). Chemistry Faculty Research and Publications. 690.
https://epublications.marquette.edu/chem_fac/690