title: Synthesis and characterization of water-soluble phenylene-vinylene-based singlet oxygen sensitizers for two-photon excitation.
abstract: [reaction: see text] The synthesis and characterization of water-soluble singlet oxygen sensitizers with a phenylene-vinylene motif is presented. The principal motivation for this study was to better understand specific features of a water-soluble molecule that influence the photosensitized production of singlet oxygen upon nonlinear, two-photon excitation of that molecule. To achieve water solubility, sensitizers were synthesized with ionic as well as nonionic substituents. In the ionic approach, salts of N-methylated pyridine, benzothiazole, and 1-methyl-piperazine moieties were used, as were aryl-substituted sulfonic acid moieties. In the nonionic approach, aryl-substituted triethylene glycol moieties were used. Selected photophysical properties of the compounds synthesized were determined, including singlet oxygen quantum yields. Of the molecules examined, the most efficient singlet oxygen sensitizers had triethylene glycol units as the functional group that imparted water solubility. Molecules containing the ionic moieties did not make singlet oxygen in appreciable yield nor did they efficiently fluoresce. Rather, for these latter molecules, rapid charge-transfer-mediated non-radiative processes appear to dominate excited state deactivation.
authors.affiliation: Polymer Department, Risø National Laboratory, Frederiksborgvej 399, DK-4000 Roskilde, Denmark.
authors.forename: Christian B
authors.initials: CB
authors.lastname: Nielsen
authors.forename: Mette
authors.initials: M
authors.lastname: Johnsen
authors.forename: Jacob
authors.initials: J
authors.lastname: Arnbjerg
authors.forename: Michael
authors.initials: M
authors.lastname: Pittelkow
authors.forename: Sean P
authors.initials: SP
authors.lastname: McIlroy
authors.forename: Peter R
authors.initials: PR
authors.lastname: Ogilby
authors.forename: Mikkel
authors.initials: M
authors.lastname: Jørgensen
mesh_terms: D004355:Drug Stability; D017785:Photons; D017319:Photosensitizing Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D026082:Singlet Oxygen / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D017319:Photosensitizing Agents; D026082:Singlet Oxygen