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- 2016 (3)
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- Photocatalysis (2)
- Air purification (1)
- Carbon nitride (1)
- TiO2 (1)
- VOC degradation (1)
- Water reduction (1)
- Water splitting (1)
- cascade reaction (1)
- enatioselective (1)
- organocatalysis (1)
The photocatalytic degradation of three indoor air relevant volatile organic compounds (VOC), namely toluene, butylacetate (BuAc) and limonene was investigated both under UV and visible light using modified TiO2 as photcatalyst. The new materials feature a high reactivity under UV light and, compared to pure TiO2, a significantly enhanced reactivity under blue light irradiation for the decomposition of BuAc (up to 39% degradation).
A heptazine-based polymer network (HMP-3) with a donor–acceptor (D–A) structure was prepared and tested as catalyst for photocatalytic hydrogen evolution from water. Compared to other heptazine-based materials, which are typically prepared at high temperatures and have recently received much interest as metal-free photocatalysts, the low-temperature protocol applied here allows the defined introduction of organic functional groups within the polymer backbone. The structure of HMP-3 contains alternating heptazine and benzothiadiazole moieties as electron acceptors connected by aminobenzene bridges as electron donors. The resulting material leads to enhanced hydrogen evolution compared to graphitic carbon nitride materials prepared at high temperatures (>500 8C) most probably because of the stabilization of photogenerated charge carriers in the D–A structure.
An unprecedented organocatalytic enantioselective vinylogous Michael addition/Henry cyclization cascade is presented for the synthesis of highly substituted tetrahydrofluoren-9-ones 3 employing novel 1,3-indandionederived pronucleophiles 1a−g and nitroalkenes 2. Following a very simple protocol, a wide range of products were obtained in good to excellent yields and with excellent enantioinduction (43−98% yield, up to 98% ee). The reaction proceeded with excellent diastereocontrol despite the simultaneous generation of four stereogenic centers. Surprisingly, when 2-(1-phenylethylidene)-1H-indandione (1h) was used as a pronucleophile, no cyclization was observed, and only Michael addition adducts 4a−x were furnished in very good yields and excellent enantioselectivities.