Two-Dimensional, Acene-Containing Conjugated Polymers That Show Ratiometric Fluorescent Response to Singlet Oxygen

Abstract

This paper describes two-dimensional conjugated poly(phenylene−ethynylene)s (PPEs) linked to singlet oxygen-reactive diethynyltetracene units through phenylene− ethynylene (PE) bridges that are conjugated to the polymer backbones. Successive Sonogashira coupling reactions enabled the preparation of the tetracene-containing PE pendants, the linking of the pendants to the monomer unit, and the polymerization reactions. Small molecule models of the polymers showed ratiometric responses of fluorescence upon exposure to photogenerated singlet oxygen due to cycloaddition reactions increasing the excited state of individual chromophores. The fluorescent responses of the tetracenelinked PPEs, however, showed markedly different behavior: (i) an initial increase in fluorescence intensity and fluorescence lifetime of the side-chain tetracenes upon exposure to 1 O 2 indicated an analyte-induced slowing of self-quenching due to high local acene concentration, and (ii) ratiometric blue-shifted response did not occur until approximately 75% of pendant acenes were oxidized, highlighting the potential utility of analyte-induced removal of traps in light-harvesting fluorescent materials.

Site‐Selective Arylation of Naphthalenes: a Key Entry towards Extended Fluorenones and Phenanthridinones

“…Indeed, the twisted or helical shape but also the properties of these naphthalene‐based angular architectures can be modulated by extending of the naphthalene core with fused cycles on these two positions. [1i], In contrast, extension towards linear molecules is obtained from positions 2 and 3 of the naphthalene unit and, acenes, lignans, prodans, or benzofluorenes and their related analogues are representative congeners …”

Kinetic Control in the Regioselective Alkylation of Pterin Sensitizers: A Synthetic, Photochemical, and Theoretical Study

“…Various sensitizers such as porphyrins and chlorins have also had alkyl substituents or PEG substituents attached to enhance their solubility (13)(14)(15)(16). Conjugated polymers with a ratiometric fluorescent response to singlet oxygen have also been solubilized with ethyl and hexyl substituents (17). There are other uses for alkyl-substituted sensitizers, for example, 5 (18), such as membrane binding (19)(20)(21)(22)(23)(24)(25), but little information exists in this vein for pterins.…”

Water‐soluble fluorescent polymers that respond to singlet oxygen

“…24,25 We have used in several instances tetracene derivatives as 1 O 2reactive energy acceptors, together with energy donating conjugated polymers, to show ratiometric fluorescent responses to 1 O 2 . [26][27][28] Other examples of ratiometric luminescent responses to 1 O 2 are also reported in the literature. 29 The hydrophobic nature of acenes, however, presents a challenge for our approach of using large acenes in aqueous environments.…”