WANG

Well-defined in-chain norbornene-functionalized poly(ethylene oxide)-b-poly(ɛ-caprolactone) copolymers (NB-PEO-b-PCL) were synthesized from a dual clickable containing both hydroxyl- and alkyne-reactive groups, namely heterofunctional norbornene 3-exo-(2-exo-(hydroxymethyl)norborn-5-enyl)methyl hexynoate. A range of NB-PEO-b-PCL copolymers were obtained using a combination of orthogonal organocatalyzed ring-opening polymerization (ROP) and click copper-catalyzed azide–alkyne cycloaddition (CuAAC). Ring-opening metathesis polymerization (ROMP) of NB-PEO-b-PCL macromonomers using ruthenium-based Grubbs’ catalysts provides comb-like and umbrella-like graft copolymers bearing both PEO and PCL grafts on each monomer unit. Mikto-arm star A₂B₂ copolymers were obtained through a new strategy based on thiol–norbornene photoinitiated click chemistry between 1,3-propanedithiol and NB-PEO-b-PCL. The results demonstrate that in-chain NB-PEO-b-PCL copolymers can be used as a platform to prepare mikto-arm star, umbrella-, and comb-like graft copolymers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 4051–4061

Well-defined in-chain norbornene-functionalized poly(ethylene oxide)-b-poly(ɛ-caprolactone) copolymers (NB-PEO-b-PCL) are used as a platform to prepare mikto-arm star, umbrella-, and comb-like graft copolymers using ring-opening metathesis polymerization (ROMP) and thiol–norbornene photoinitiated click chemistry.

Photodynamic therapy (PDT) is widely used to treat diverse diseases, but its dependence on oxygen to produce cytotoxic reactive oxygen species (ROS) diminishes the therapeutic effect in a hypoxic environment, such as solid tumors. Herein, we developed a ROS-producing hybrid nanoparticle-based photosensitizer capable of maintaining high levels of ROS under both normoxic and hypoxic conditions. Conjugation of a ruthenium complex (N3) to a TiO₂ nanoparticle afforded TiO₂-N3. Upon exposure of TiO₂-N3 to light, the N3 injected electrons into TiO₂ to produce three- and four-fold more hydroxyl radicals and hydrogen peroxide, respectively, than TiO₂ at 160 mmHg. TiO₂-N3 maintained three-fold higher hydroxyl radicals than TiO₂ under hypoxic conditions via N3-facilitated electron–hole reduction of adsorbed water molecules. The incorporation of N3 transformed TiO₂ from a dual type I and II PDT agent to a predominantly type I photosensitizer, irrespective of the oxygen content.

Zwei zum Preis von einem: Ein duales Reagens für die photodynamische Therapie bestehend aus Titandioxid und einem Ruthenium-Nanophotosensibilisator (TiO₂-N3) produziert auf synergistische Weise Hydroxylradikale unter sowohl normoxischen als auch hypoxischen Bedingungen.

A novel naphtho[1,2-c:5,6-c′]bis([1,2,5]­thiadiazole)-based narrow-bandgap π-conjugated polymer is designed for application in polymer solar cells. Remarkable power conversion efficiencies over 10% can be achieved based on both conventional and inverted device architectures with thick photoactive layers, which are processed by using chlorinated or nonhalogenated solvents, suggesting its great promise toward practical applications based on high-throughput roll-to-roll processing.