Probing the chiroptical response of a single molecule
Probing the chiroptical response of a single molecule
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DOI：
10.1126/science.1134231
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发表时间：
2006-12-01
期刊：
影响因子：
56.9
通讯作者：
Barnes, Michael D.
中科院分区：
文献类型：
--
作者：
Hassey, Ruthanne;Swain, Ellen J.;Barnes, Michael D.
Chirally sensitive measurement techniques have generally been restricted to bulk samples. Here, we report the observation of fluorescence-detected circular dichroism (FDCD) from single (bridged-triarylamine) helicene molecules by using an excitation wavelength ( 457 nanometers) in the vicinity of an electronic transition that shows circular dichroism in bulk samples. The distributions of dissymmetry ( g) parameters by analysis of signals from pure M- and P-type diastereomers are almost perfect mirror images of one another, each spanning a range of both positive and negative values. In addition, we observe a well-defined structure in the histogram of dissymmetry parameters suggestive of specific molecular orientations at the polymer interface. These single-molecule results highlight strong intrinsic circular dichroism responses that can be obscured by cancellation effects in ensemble measurements of a randomly oriented bulk sample.
