Conformational Switching and Exciton Interactions in Hemicyanine-Based Bichromophores
- 24 July 2001
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 123 (32), 7859-7865
- https://doi.org/10.1021/ja010199v
Abstract
Conformational changes in two hemicyanine-based bichromophores were demonstrated by varying the polarity as well as temperature of the medium. Dramatic changes in the ground and excited singlet state properties were observed upon folding of the bichromophores, due to the formation of intramolecular aggregates of H-type. These aspects were studied, in detail, using steady-state absorption and time-resolved fluorescence spectroscopy. Time-resolved fluorescence studies indicate that both the bichromophores exhibit a monoexponential decay, with a short lifetime, in mixed toluene−CH2Cl2 solvents having lower proportions of toluene. Interestingly, biexponential decay with short and long-lived species was observed at higher proportions of toluene, due to the presence of unfolded and folded forms. Folding results in the intramolecular stacking of the chromophores which restrict their torsional dynamics, leading to a longer lifetime. Upon laser excitation, the folded form of the bichromophore undergoes rapid conformational changes, due to photoinduced thermal dissociation.This publication has 51 references indexed in Scilit:
- Synthesis and Conformational Characterization of Tethered, Self-Complexing 1,5-Dialkoxynaphthalene/1,4,5,8-Naphthalenetetracarboxylic Diimide SystemsJournal of the American Chemical Society, 2000
- Helical Bias in Solvophobically Folded Oligo(Phenylene Ethynylene)sJournal of the American Chemical Society, 1999
- Integration of Logic Functions and Sequential Operation of Gates at the Molecular-ScaleJournal of the American Chemical Society, 1999
- Use of photoinduced energy-transfer to probe solvent-dependent conformational changes in a flexible Ru/Os dinuclear complexChemical Communications, 1999
- Laser Temperature Jump Induced Protein RefoldingAccounts of Chemical Research, 1998
- Resonance Raman study of solvent dynamics on the spectral broadening and intramolecular charge transfer of a hemicyanine dye in aqueous solutionThe Journal of Chemical Physics, 1998
- Synthesis and Properties of Bismerocyanines Linked by a 1,8-Naphthylene Skeleton. Novel Solvatochromism Based on Change of Intramolecular Excitonic Coupling ModeJournal of the American Chemical Society, 1998
- Redox-Switched Exciton-Coupled Circular Dichroism: A Novel Strategy for Binary Molecular SwitchingAngewandte Chemie, 1998
- Synthetic molecules that fold into a pleated secondary structure in solutionNature, 1995
- ExcimersAngewandte Chemie, 1969