ORGN 285 |
| J-aggregates of cyanine dyes have been the subject of high interest in the scientific community for years due to their unique optical properties. However, most of the research was accomplished using the methods of optical spectroscopy. Optical spectroscopy does not provide adequate information on structural changes or changes in the electronic density distribution taking place during the aggregation. At the same time, these changes could be responsible for the unique optical properties of J-aggregates. We applied 2D NMR spectroscopy to investigate possible structural changes of 1,1'- diethyl-2,2'-cyanine (PIC) iodide associated with the appearance of the J-band in its absorption spectrum in water solutions. 2D spectra allowed to separate and to assign signals from all 6 aromatic protons of PIC and to identify which protons are the most affected by J-aggregation and thus to make some conclusions on the origin of the J-band in the absorption spectra of PIC aggregates. |
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Materials, Molecular Recognition and Self-Assembly
8:00 AM-12:00 PM, Monday, 11 September 2006 Moscone Center -- Room 132, Oral
Division of Organic Chemistry |