Control Over Charge Separation in Phthalocyanine-Anthraquinone Conjugates as a Function of the Aggregation Status
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- 作者：Andreas Gouloumis ; David Gonzá ; lez-Rodrí ; guez ; Purificació ; n Vá ; zquez ; Tomá ; s Torres ; Shenggao Liu ; Luis Echegoyen ; Jeff Ramey ; Gordon L. Hug ; Dirk M. Guldi
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：October 4, 2006
- 年：2006
- 卷：128
- 期：39
- 页码：12674 - 12684
- 全文大小：368K
- 年卷期：v.128,no.39(October 4, 2006)
- ISSN：1520-5126
文摘
We have prepared three isomeric donor-acceptor systems, in which two phthalocyanine (Pc)units have been attached to the 1-,5- (1a), 1-,8- (1b), or 2-,6- (1c) positions of a central anthraquinone(AQ) moiety, leading to packed (1b) or extended (1a and 1c) topologies. The electronic interactions betweenthe donor and the acceptor in the ground state or in the excited states have been studied by differentelectrochemical and photophysical techniques. Due to the markedly different topologies, we have beenable to modify these interactions at the intramolecular level and, by a proper choice of the solventenvironment, at the intermolecular level within aggregates. In triad 1b, the ZnPc units are forced to 
-stackcofacially and out of the plane of the AQ ring. Consequently, this molecule shows strong inter-Pc interactionsthat give rise to intramolecular excitonic coupling but a relatively small electronic communication with theAQ acceptor through the vinyl spacers. On the contrary, the 1-,5- or 2-,6-connections of triads 1a and 1callow for an efficient -conjugation between the active units that extends over the entire planar system.These two molecules tend to aggregate in aromatic solvents by - stacking, giving rise to J-type oligomers.Photoexcitation of the Pc units of 1a-c results in the formation of the Pc
+-AQ- charge transfer state.We have demonstrated that the kinetics of these electron transfer reactions is greatly dependent on theaggregation status of the triads.
-stackcofacially and out of the plane of the AQ ring. Consequently, this molecule shows strong inter-Pc interactionsthat give rise to intramolecular excitonic coupling but a relatively small electronic communication with theAQ acceptor through the vinyl spacers. On the contrary, the 1-,5- or 2-,6-connections of triads 1a and 1callow for an efficient -conjugation between the active units that extends over the entire planar system.These two molecules tend to aggregate in aromatic solvents by - stacking, giving rise to J-type oligomers.Photoexcitation of the Pc units of 1a-c results in the formation of the Pc+-AQ- charge transfer state.We have demonstrated that the kinetics of these electron transfer reactions is greatly dependent on theaggregation status of the triads.