The search for metal‐free organic photocatalysts for H2 production from water using visible light remains a key challenge. Reported herein is a molecular structural design of pure organic ...photocatalysts, derived from conjugated polybenzothiadiazoles, for photocatalytic H2 evolution using visible light. By alternating the substitution position of the electron‐withdrawing benzothiadizole unit on the phenyl unit as a comonomer, various polymers with either one‐ or three‐dimensional structures were synthesized and the effect of the molecular structure on their catalytic activity was investigated. Photocatalytic H2 evolution efficiencies up to 116 μmol h−1 were observed by employing the linear polymer based on a phenyl‐benzothiadiazole alternating main chain, with an apparent quantum yield (AQY) of 4.01 % at 420 nm using triethanolamine as the sacrificial agent.
Bring to light: Conjugated polybenzothiadiazoles were introduced as a new family of organic photocatalysts for H2 evolution from water in the presence of electron donors with visible‐light irradiation. The molecular engineering of the electron‐withdrawing benzothiadiazole unit on the phenyl unit allows the construction of either one‐ or three‐dimensional polybenzothiadiazoles, and the effect of the structure on the photocatalytic H2 evolution activity was investigated.
High surface area porous conjugated polymers were synthesized via the high internal phase emulsion polymerization technique and micropore engineering as efficient heterogeneous photocatalysts for ...highly selective oxidation of organic sulfides to sulfoxides under visible light.
We herein report a new design route to stable, heterophase photocatalysts, which function as highly dispersible conjugated polymer nanoparticles and porous monoliths under visible light in aqueous ...medium. They were constructed by attachment of the ionic‐liquid species 1‐alkyl‐3‐vinylimidazolium bromide onto the side chains of a photoactive polymer. The structure configuration allows not only photocatalysis in aqueous environment but also a unique self‐initiation radical cross‐linking process to transform the water‐soluble photoactive polymer into a heterophase system, either as nanoparticles or a porous monolith. High photocatalytic activity and reusability of the heterophase system were demonstrated in the degradation of organic dyes and reduction of CrVI into CrIII in water under visible‐light irradiation.
Photoactive polymer‐based nanoparticles and porous materials were formed by the side‐product‐ and surfactant‐free self‐initiated cross‐linking of a conjugated polymer bearing vinylimidazolium side groups. The polymer acts as both a photosensitizer and a stabilizer for colloidal systems. The obtained cross‐linked polymers serve as efficient, recyclable, cost‐effective heterogeneous photocatalysts under visible‐light irradiation.
Herein, we report a novel trifluoromethanesulfonic acid vapor-assisted solid phase synthetic method to construct nanoporous covalent triazine frameworks with highly ordered hollow interconnected ...pores under mild reaction conditions. This unique solid state synthetic route allows not only the avoidance of undesired side reactions caused by traditional high temperature synthesis, but also the maintaining of defined and precise optical and electronic properties of the nonporous triazine frameworks. Promising photocatalytic activity of the polytriazine networks was demonstrated in the photoreduction reaction of 4-nitrophenol into 4-aminophenol under visible light irradiation.
A synthetic and modification method to obtain water‐compatible, visible‐light‐active, conjugated, microporous polyazulene networks as pure organic, highly stable, reusable, and heterogeneous ...photocatalysts in aqueous medium by a simple protonation method was investigated. The water compatibility and photocatalytic activity of the hydrophilic polyazulenes were demonstrated in the photoreduction reaction of CrVI to CrIII for heavy‐metal‐contaminated waste‐water treatment. Furthermore, a light‐induced cascade reaction mechanism with the use of additional abundant metal cations such as FeIII or CuII as co‐catalysts was also described. This design strategy could offer a clean and cost‐effective solution to obtain water‐compatible, pure organic, photoactive polymers with a broader potential for other applications in aqueous media under sustainable and environmentally friendly conditions.
Feeling a little blue: Water‐compatible, visible‐light‐active, conjugated, microporous polyazulene networks are synthesized as highly stable heterogeneous photocatalysts for the photoreduction reaction of CrVI to CrIII in aqueous medium. This design strategy could offer a clean and cost‐effective solution to obtain water‐compatible, pure organic, photoactive polymers under sustainable and environmentally friendly conditions.
The Stille coupling reaction is a versatile method to mainly form aromatic CC bonds. However, up to now, the use of palladium catalysts is necessary. Here, a palladium‐free and photocatalytic ...Stille‐type coupling reaction of aryl iodides and aryl stannanes catalyzing a conjugated microporous polymer‐based phototcatalyst under visible light irradiation at room temperature is reported. The novel coupling reaction mechanism occurs between the photogenerated aryl radical under oxidative destannylation of the aryl stannane, and the electron‐activated aryl iodide, resulting into the aromatic CC bond formation reaction. The visible light‐promoted Stille‐type coupling reaction using the polymer‐based pure organic photocatalyst offers a simple, sustainable, and more economic synthetic pathway toward palladium‐free aromatic CC bond formation.
Bye‐bye palladium. A photocatalytic, Pd‐free Stille‐type coupling reaction between aryl iodides and aryl stannanes succeeds using conjugated organic phototcatalysts under visible light irradiation at room temperature.
Polyfluorene‐bearing bromohexyl side chains are quaternized by 1‐vinylimidazole in order to attach dialkylimidazolium bromide ionic liquid (IL) species along the conjugated backbone. Subsequently, ...polyfluorene polyelectrolyte nanoparticles (NPs) of 40 nm in average size are created via radical cross‐linking of the pendant vinylimidazolium groups. Anion exchange from Br− to BF4−, PF6−, and bis(trifluoromethylsulfonyl)imide anion (TFSI−) renders NPs adjustable dispersability in various organic solvents. The hydrophobic‐conjugated backbone and the hydrophilic dialkylimidazolium bromide IL moieties depict an amphiphilic profile, which allows the NPs to be deployed as conductive stabilizer in the emulsion polymerization of styrene. The resultant latexes are fluorescent, tunable in size and can be transferred to organic solvents without forfeiting their colloidal stability.
Polyfluorene‐bearing bromohexyl side chains are quaternized by 1‐vinylimidazole to attach dialkylimidazolium bromide ionic liquid (IL) species along the conjugated backbone. Subsequently, polyfluorene polyelectrolyte nanoparticles (NPs) are created via radical cross‐linking of the pendant vinylimidazolium groups. They can be deployed as conductive stabilizer in the emulsion polymerization of styrene.
A simple structural design principle and band position alignment of conjugated microporous polymers for enhanced photocatalytic efficiency is presented. The valence and conduction band positions of ...the polymer networks can be fine‐tuned by altering the substitution positions on the centered phenyl unit to match the required redox potential of the catalytic reactions under visible light.
Pure organic, heterogeneous, metal-free, and visible light-active photocatalysts offer a more sustainable and environmentally friendly alternative to traditional metal-based catalysts. Here we report ...a series of microporous organic polymers containing photoactive conjugated organic semiconductor units as heterogeneous photocatalysts for a visible-light-promoted, highly selective bromination reaction of electron-rich aromatic compounds using HBr as a bromine source and molecular oxygen as a clean oxidant. Via a simple Friedel–Crafts alkylation reaction, the microporous organic polymers were obtained by cross-linking of organic semiconductor compounds with defined valence and conduction band positions. The utilization of the simply prepared porous polymer-based photocatalytic systems opens new opportunities toward a sustainable and efficient material design for catalysis.
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