Single-molecule orientations and photophysics in dyed salt crystals

ORGN 381

Kristin L. Wustholz, kwusthol@u.washington.edu, Bart Kahr, kahr@chem.washington.edu, and Philip J. Reid, preid@chem.washington.edu. Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195
Potassium acid phthalate (KAP) crystals, grown in the presence of organic fluorophores, often exhibit linear dichroism suggesting that single-crystal matrix isolation provides for intrinsic fluorophore alignment. However, the distribution of alignments can not be assessed by bulk-dichroism measurements which only yield average orientations. To obtain the underlying distributions, we employed single-molecule confocal microscopy. Specifically, the orientations of single DCM and Violamine R molecules in KAP were determined by excitation dichroism. While average orientations agree with bulk values, a surprisingly wide range of individual orientations is observed. To investigate the molecular details of fluorophore incorporation, computational studies were performed. These studies support the role of isochoric incorporation in defining fluorophore orientation.
 

Molecular Recognition and Self-Assembly
8:00 AM-12:00 PM, Tuesday, 12 September 2006 Moscone Center -- Room 132, Oral

Division of Organic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006