Blending Through-Space and Through-Bond π-π-Coupling in [2,2']-Paracyclophane-oligophenylenevinylene Molecular Wires

Wielopolski M, Molina-Ontoria A, Schubert C, Margraf J, Krokos E, Kirschner J, Gouloumis A, Clark T, Guldi DM, Martin N (2013)

Publication Type: Journal article

Publication year: 2013

Journal

Book Volume: 135

Pages Range: 10372-10381

Journal Issue: 28

DOI: 10.1021/ja401239r

Abstract

A series of ZnP-pCp-oPPV-C60 conjugates covalently connected through [2,2$\prime$]-paracyclophane-oligophenylenevinylene (pCp-oPPV) bridges containing one, two, and three [2,2$\prime$]-paracyclophanes (pCps) has been prepared in multistep synthetic procedures involving Horner--Wadsworth--Emmons olefination reactions and/or Heck type Pd-catalyzed reactions. Molecular modeling suggests that charge transfer is effectively mediated by the pCp-oPPVs through a predominant hole-transfer mechanism. Photophysical investigation supports molecular modeling and reveals two major trends. On one hand, C60 excitation of 1, 2, and 3 leads exclusively to charge transfer between pCp and C60 to afford a ZnP-(pCp-oPPV)•+-C60•-- radical ion pair state without giving rise to a subsequent charge shift to yield the ZnP•+-pCp-oPPV-C60•-- radical ion pair state. On the other hand, ZnP excitation of 1, 2, and 3 results in a rather slow charge transfer between ZnP and C60, after which the ZnP•+-pCp-oPPV-C60•-- radical ion pair state evolves. In temperature-dependent ZnP fluorescence experiments, which were performed in the temperature range from 273 to 338 K, two domains are discernible: low and high temperature behaviors. In the low temperature range (i.e., below 30 °C) the rate constants do not change, suggesting that a superexchange mechanism is the modus operandi. In the high temperature range (i.e., >30 °C) the rate constants increase. Moreover, we find rather strong distance dependence for 1 and 2 and weak distance dependence for 2 and 3. A damping factor of 0.145 Å--1 is derived for the former pair and 0.012 Å--1 for the latter.

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Universidad Complutense de Madrid (UCM) Spain (ES)

How to cite

APA:

Wielopolski, M., Molina-Ontoria, A., Schubert, C., Margraf, J., Krokos, E., Kirschner, J.,... Martin, N. (2013). Blending Through-Space and Through-Bond π-π-Coupling in [2,2']-Paracyclophane-oligophenylenevinylene Molecular Wires. Journal of the American Chemical Society, 135(28), 10372-10381. https://doi.org/10.1021/ja401239r

MLA:

Wielopolski, Mateusz, et al. "Blending Through-Space and Through-Bond π-π-Coupling in [2,2']-Paracyclophane-oligophenylenevinylene Molecular Wires." Journal of the American Chemical Society 135.28 (2013): 10372-10381.

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