title: Exciplex fluorescence emission from simple organic intramolecular constructs in non-polar and highly polar media as model systems for DNA-assembled exciplex detectors.
abstract: Organic intramolecular exciplexes, N-(4-dimethylaminobenzyl)-N-(1-pyrenemethyl)amine (1) and N'-4-dimethylaminonaphthyl-N-(1-pyrenemethyl)amine (2), were used as model systems to reveal major factors affecting their exciplex fluorescence, and thus lay the basis for developing emissive target-assembled exciplexes for DNA-mounted systems in solution. These models with an aromatic pyrenyl hydrocarbon moiety as an electron acceptor appropriately connected to an aromatic dimethylamino electron donor component (N,N-dimethylaminophenyl or N,N-dimethylaminonaphthyl) showed strong intramolecular exciplex emission in both non-polar and highly polar solvents. The effect of dielectric constant on the maximum wavelength for exciplex emission was studied, and emission was observed for 1 and 2 over the full range of solvent from non-polar hydrocarbons up to N-methylformamide with a dielectric constant of 182. Quantum yields were determined for these intramolecular exciplexes in a range of solvents relative to that for Hoechst 33,258. Conformational analysis of 1 was performed both computationally and via qualitative 2D NMR using (1)H-NOESY experiments. The results obtained indicated the contribution of pre-folded conformation(s) to the ground state of 1 conducive to exciplex emission. This research provides the initial background for design of self-assembled, DNA-mounted exciplexes and underpins further development of exciplex-based hybridisation bioassays.
authors.affiliation: Wolfson Centre for Structure-Based Rational Design of Molecular Diagnostics, School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester, UKM13 9PL. Elena.Bichenkova@manchester.ac.uk
authors.forename: Elena V
authors.initials: EV
authors.lastname: Bichenkova
authors.forename: Ali R
authors.initials: AR
authors.lastname: Sardarian
authors.forename: Amanda N
authors.initials: AN
authors.lastname: Wilton
authors.forename: Pascal
authors.initials: P
authors.lastname: Bonnet
authors.forename: Richard A
authors.initials: RA
authors.lastname: Bryce
authors.forename: Kenneth T
authors.initials: KT
authors.lastname: Douglas
mesh_terms: D004247:DNA / Q000737:chemistry*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006841:Hydrocarbons, Aromatic / Q000737:chemistry; D008968:Molecular Conformation; D012997:Solvents
chemical_list: D005456:Fluorescent Dyes; D006841:Hydrocarbons, Aromatic; D012997:Solvents; D004247:DNA