Energy redistribution dynamics in triarylamine-triarylborane containing hexaarylbenzenes.
Two hexaarylbenzenes (HAB) 1 and 2 each decorated by three triarylamines (TAA) as electron donors and three triarylboranes (TAB) as electron acceptors in a symmetric (1) and asymmetric (2) fashion as well as one model compound (3) with only one donor-acceptor pair were investigated by ultrafast transient absorption and fluorescence upconversion spectroscopy. Fluorescence anisotropy measurements revealed energy redistribution between localised, partly relaxed CT-states of the HABs 1 and 2 induced by dipole-dipole interaction with energy transfer time constants of ca. 3 ps. These results manifest symmetry breaking in the formally symmetric HAB 1 upon photoexcitation.
Institut für Organische Chemie, Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Center for Nanosystems Chemistry, Am Hubland, 97074 Würzburg, Germany. christoph.lambert@uni-wuerzburg.de.
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