ZIF-8 was used to perform photocatalytic degradation of methylene blue, a typical organic dye.

No abstract

We present herein the first visible-light-driven hydrocarboxylation as well as carbocarboxylation of alkynes using CO via an iridium/cobalt dual catalysis. Such transformations provide access to various pharmaceutically important heterocycles in a one-pot procedure from readily available alkynes. Coumarins, 2-quinolones, and 2-benzoxepinones were directly accessed through a one-pot alkyne hydrocarboxylation/alkene isomerization/cyclization sequence in which the Ir photocatalyst serves a dual role to promote single-electron transfer in alkyne hydrocarboxylation and energy transfer in the subsequent alkene isomerization. Moreover, an unprecedented cobalt carboxylation/acyl migration cascade enables alkyne difunctionalization to introduce γ-hydroxybutenolides with high efficiency. We expect that this cascade strategy will inspire new perspectives for alkyne and alkene difunctionalization.

Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.1002/anie.201811266. Scheme 1. Difunctionalization of simple alkenes via CÀHorSi ÀH activation. BPO = benzoyl peroxide;TBHP = tert-butyl hydroperoxide; DTBP = di-tert-butyl peroxide.

Flue gas from fossil fuel combustion contributes significantly to CO2 emissions. Due to the low CO2 concentration and the existence of reactive O2 in the flue gas, direct flue gas CO2 electrochemical conversion is a challenging task. Here we integrated both CO2 capture and electrochemical conversion into CO2 enriching catalysts by grafting alkanolamines on a tin oxide surface, which can electrochemically reduce simulated flue gas (SFG, 15% CO2, 8% O2, 77% N2) to formate. Maximum formate Faradaic efficiency of 84.2% has been reached by diethanolamine modified tin oxide (DEA–SnO x /C) at −0.75 V vs RHE with partial current density of 6.7 mA·cm–2 in 0.5 M KHCO3 under simulated flue gas atmosphere. Surface amino groups not only enrich CO2 locally but also inhibit O2 reduction, and in situ infrared (in situ IR) spectroscopy confirmed that amino groups accelerate CO2 reduction by promoting the formation of key intermediates (OCHO–*).

Here a simple low-cost yet robust route has been developed to prepare poly(dimethylsiloxane) (PDMS) microspheres with various surface wrinkle patterns. First, the aqueous-phase-synthesized PDMS microspheres are exposed to oxygen plasma (OP), yielding the oxidized SiOx layer and the corresponding stiff shell/compliant core system. The subsequent solvent swelling and solvent evaporation induce the spontaneous formation of a series of curvature and overstress-sensitive spherical wrinkles such as dimples, short rodlike depressions, and herringbone and labyrinth patterns. The effects of the experimental parameters, including the radius and Young's modulus of the microspheres, the OP exposure duration, and the nature of the solvents, on these tunable spherical wrinkles have been systematically studied. The experimental results reveal that a power-law dependence of the wrinkling wavelength on the microsphere radius exists. Furthermore, the induced wrinkling patterns are inherently characteristic of a memory effect and good reversibility. Meanwhile, the corresponding phase diagram of the wrinkle morphologies on the spherical surfaces vs the normalized radius of curvature and the excess swelling degree has been demonstrated. It is envisioned that the introduced strategy in principle could be applied to other curved surfaces for expeditious generation of well-defined wrinkle morphologies, which not only enables the fabrication of solids with multifunctional surface properties, but also provides important implications for the morphogenesis in soft materials and tissues.

A photoredox activation mode of formate salts for carboxylation was developed. Using a formate salt as the reductant, carbonyl source, and hydrogen atom transfer reagent, a wide range of alkenes can be converted into acid products via a carboxyl group transfer strategy in an additive-free fashion. Mechanistic studies revealed that radical anion species (CO2 •– and carbon radical anions derived from the reduction of alkenes) are key intermediates of the transformation. This method has the advantages of high catalytic efficiency and a simple catalytic system, which may allow this approach to become a promising strategy for industrial applications.

In recent decades, difunctionalization of alkenes has received considerable attention as an efficient and straightforward way to increase molecular complexity. However, examples of the difunctionalization of alkenes initiated by the intermolecular addition of alkoxycarbonyl radicals providing substituted alkanoates are still rare. Herein, we present the visible light-driven metal-free divergent difunctionalization of alkenes triggered by the intermolecular addition of alkoxycarbonyl radicals under ambient conditions. Employing alkyl formates as precursors of alkoxycarbonyl radicals and 4CzIPN as the photocatalyst, a variety of substituted alkanoates, including β-alkoxy, β-hydroxy, β-dimethoxymethoxy, and β-formyloxy alkanoates, could be facilely accessed with high functional group tolerance and high efficiency. Moreover, the mechanism study revealed that β-hydroxy alkanoates were generated by a selective decomposition of orthoformates promoted by the N-alkoxyazinium salt.