Significant efforts are devoted to developing artificial photosynthetic systems to produce fuels and chemicals in order to cope with the exacerbating energy and environmental crises in the world now. Nonetheless, the large-scale reactions that are the focus of the artificial photosynthesis community, such as water splitting, are thus far not economically viable, owing to the existing, cheaper alternatives to the gaseous hydrogen and oxygen products. As a potential substitute for water oxidation, here, a unique, visible light-driven oxygenation of carboncarbon bonds for the selective transformation of 32 unactivated alcohols, mediated by a vanadium photocatalyst under ambient, atmospheric conditions is presented. Furthermore, since the initial alcohol products remain as substrates, an unprecedented photodriven cascade carboncarbon bond cleavage of macromolecules can be performed. Accordingly, hydroxyl-terminated polymers such as polyethylene glycol, its block co-polymer with polycaprolactone, and even the non-biodegradable polyethylene can be repurposed into fuels and chemical feedstocks, such as formic acid and methyl formate. Thus, a distinctive approach is presented to integrate the benefits of photoredox catalysis into environmental remediation and artificial photosynthesis.

We report the generation of cationic N-radicals from Selectfluor® via energy transfer with anthraquinone as a photocatalyst for the fluorination of unactivated C-H bonds.

The annual production is still growing and is expected to continue, meaning that it is imperative for us to plan for a future that will have even more plastics.Yet, the ubiquity of plastics has been recognized to be a double-edged sword. It was estimated that 8300 Mt of virgin plastics were produced between 1950 to 2015, but 6300 Mt of them had become plastic waste with 79% accumulated in landfills or the natural environment such as the waterways and the ocean. [1a] In 2015 alone, around 302 Mt or 74% of the annual production had become waste, with only 14% recycled, 14% combusted, and the remainder exposed to the environment (Table 1). [2] Over 8 Mt of plastics are believed to be added to the aquatic ecosystems every year since 2010, [3] with samples being discovered in some of the remotest marine ecosystems like the Mariana trench, including some dating as far back as 1957. [4] The increase in ocean plastics has been especially dramatic since the 1990s. [4a] Besides being potentially toxic by compromising the immune system in different organisms, plastics have also been found to disrupt global biogeochemical cycles such as nitrification and denitrification. [5] Furthermore, the enormous volumes of plastics being produced, converted, and disposed have been estimated to contribute almost 1800 Mt of CO 2 -equivalents (CO 2 e) in greenhouse gas (GHG) emissions in 2015, with the majority (61% or 1085 Mt) generated at the production stage, 30% or 535 Mt during conversion, and the remaining 9% or 161 Mt from the end of life disposal (Table 2). [6] Alarmingly, the current trajectory in growth of plastics consumption suggests that around 6500 Mt of CO 2 e in GHG emissions (15% of the global carbon budget) is expected by 2050. [6] In 2020, owing to the COVID-19 pandemic, even more plastic wastes are being generated due to increases in the use of food and other packaging materials, as well as the proliferation of single use disposal face masks. This has resulted in a surge in criminal recycling scams where plastic wastes from Europe and North America are being illegally exported to Asian countries to artificially inflate the recycling rates in the countries of origin. [7] Patently, more sustainable approaches are needed to manage the entire life cycle of plastics from production to end of life.To manage the inexorable growth of plastics production and waste, one strategy can be to adopt a zero waste hierarchy that was proposed by the European Commission's Waste Plastics are now indispensable in daily lives. However, the pollution from plastics is also increasingly becoming a serious environmental issue. Recent years have seen more sustainable approaches and technologies, commonly known as upcycling, to transform plastics into value-added materials and chemical feedstocks. In this review, the latest research on upcycling is presented, with a greater focus on the use of renewable energy as well as the more selective methods to repurpose synthetic polymers. First, thermal upcycling approaches are briefly introduced, inc...

Here, we report dicyanopyrazine (DPZ)-derived push–pull chromophores, easily prepared and tunable organic compounds, as new kinds of photoredox catalysts.

The first enantioselective tungstate-catalyzed oxidation reaction is presented. High enantioselectivities were achieved for a variety of drug-like phenyl and heterocyclic sulfides under mild conditions with H2 O2 , a cheap and environmentally friendly oxidant. Synthetic utility was demonstrated through the preparation of (S)-Lansoprazole, a commercial proton-pump inhibitor. The active ion-pair catalyst was identified to be bisguanidinium diphosphatobisperoxotungstate using Raman spectroscopy and computational studies.

Photoelectrochemical cells have been used as one of the most common artificial photosynthetic approaches to mimic natural photosynthetic water splitting reactions. However, despite the tremendous advances made to improve the affordability and efficiency of photoelectrochemical water splitting, it is still not an economically feasible method to produce solar fuels currently since only the H 2 evolving reduction half-reaction generates valuable fuels. Therefore, in this review, we intend to highlight other underexplored substrates and reactions for producing solar fuels in photo-electrochemical cells, as well as alternative architectures including temporally independent and biohybrid systems. We show that besides water oxidation, electrocatalytic or photoredox reactions for pollutant degradation, biomass valorization, and organic chemical synthesis can be or have been successfully adapted for photoelectrochemical cells, thus offering a virtually infinite number of possibilities for artificial photosynthetic applications which generate valuable products in both the reduction and oxidation half reactions.

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A pentanidium-catalyzed highly enantioselective conjugate addition of 3-alkyloxindoles to phenyl vinyl sulfone has been demonstrated. This approach allows the construction of 3,3-dialkyl-substituted oxindole frameworks with high yield and excellent enantioselectivity (up to 99%) under simple phase-transfer conditions. A variety of oxindoles bearing all-carbon quaternary stereogenic centers were obtained in the presence of 0.25 mol% pentanidium. Meanwhile, practicality was illustrated by a gram-scale asymmetric synthesis of two 3,3-dialkyl-substituted oxindoles. The resulting adduct can be smoothly transformed to the natural product analogue in a short synthetic route.