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Communication

Excitation Energy Transfer in Branched Dendritic Macromolecules at Low (4 K) Temperatures

Supporting Info

Mahinda I. Ranasinghe, Ying Wang, and Theodore Goodson, III*

Department of Chemistry, Wayne State University, Detroit, Michigan 48202

J. Am. Chem. Soc., 2003, 125 (18), pp 5258–5259

DOI: 10.1021/ja029242k

Publication Date (Web): April 9, 2003

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

tgoodson@chem.wayne.edu

Abstract

To understand the mode of energy transport in branched dendritic macromolecules, the optical excitation of a dendritic core (A-DSB) at low temperature (4.2 K) was investigated. Fluorescence depolarization measurements were utilized to probe the energy-transfer processes in the branching center at several different temperatures. We found that the anisotropy decay shows an interesting trend at low temperature where depolarization times decreased and the residual anisotropy value also decreased with decreasing temperature. The very fast anisotropy decay suggests a coherent mechanism of energy transport in these systems at low temperature. The contribution of inhomogeneous broadening is suggested as an important factor in the temperature dependence of the anisotropy decay and residual value. The change in inhomogeneous linewidth is responsible for this type of anisotropy behavior.

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