Showing papers by "Wenting Wu published in 2020"
TL;DR: It is demonstrated that the optimal TTA-UC pair developed in this study can act as a highly effective light wavelength up-shifter to enable NIR light to drive a photoredox catalysis that otherwise requires visible light.
Abstract: Organic triplet-triplet annihilation upconversion (TTA-UC) materials have considerable promise in areas as broad as biology, solar energy harvesting, and photocatalysis. However, the development of highly efficient near-infrared (NIR) light activatable TTA-UC systems remains extremely challenging. In this work, we report on a method of systematically tailoring an annihilator to attain such outstanding systems. By chemical modifications of a commonly used perylene annihilator, we constructed a family of perylene derivatives that have simultaneously tailored triplet excited state energy (T1) and singlet excited state energy (S1), two key annihilator factors to determine TTA-UC performance. Via this method, we were able to tune the TTA-UC system from an endothermic type to an exothermic one, thus significantly elevating the upconversion performance of NIR light activatable TTA upconversion systems. In conjunction with the photosensitizer PdTNP (10 μM), the upconversion efficiency using the optimal annihilator (100 μM) identified in this study was measured to be 14.1% under the low-power density of NIR light (100 mW/cm2, 720 nm). Furthermore, using such a low concentration of perylene derivative, we demonstrated that the optimal TTA-UC pair developed in our study can act as a highly effective light wavelength up-shifter to enable NIR light to drive a photoredox catalysis that otherwise requires visible light. We found that such an NIR driven method is highly effective and can even surpass directly visible light driven photoredox catalysis. This method is important for photoredox catalysis as NIR light can penetrate much deeper in colored photoredox catalysis reaction solutions, especially when done in a large-scale manner. Furthermore, this TTA-UC mediated photoredox catalysis reaction is found to be outdoor sunlight operable. Thus, our study provides a solution to enhance NIR activatable organic upconversion and set the stage for a wide array of applications that have previously been limited by the suboptimal efficiency of the existing TTA upconversion materials.
55 citations
TL;DR: A gold-catalyzed dearomatization reaction of indole derivatives was realized in the presence of JohnPhosAuCl/AgOMs to afford a series of spiroindolenines in excellent yields and both reactions feature readily available substrates, mild conditions, and good functional group tolerance.
35 citations
TL;DR: This work provides a new research direction for engineering the electron transfer pathway between the photocatalyst and sacrificial agent (e.g., pollutant) in natural seawater.
Abstract: Photocatalytic H2 evolution (PHE) from extremely abundant seawater resources is an ideal way to secure sustainable H2 for humanity, but the saline in seawater easily competitively absorbs the active sites and poisons the catalyst. Herein, a series of low-cost alkali halide (NaI, KI, RbI, CsI, CsBr, and CsCl), analogous to the saline in natural seawater, was selected to modify carbon nitride (MX-CN) through one-step facile pyrolysis with the assistance of water. MX-CN possesses a large amount of negative charges, which could inhibit anion absorption, to some extent, preventing chloride corrosion. Importantly, it can greatly boost the electron transfer between MX-CN and triethanolamine (TEOA) (sacrificial agent) because the alkali cation in seawater can coordinate with TEOA, and easily come in contact with MX-CN through alkali-cation exchange and electrostatic attraction. Benefiting from it, the PHE performance in seawater is 200 times better than that of original CN in deionized water above, and the apparent quantum efficiency of MX-CN (CsI-CN) under 420 nm light irradiation comes to 72% in seawater, the highest value reported for seawater thus far. This work provides a new research direction for engineering the electron transfer pathway between the photocatalyst and sacrificial agent (e.g., pollutant) in natural seawater.
20 citations
TL;DR: A gold-catalyzed dearomatization reaction of β-naphthol derivatives via intramolecular hydroalkylation of alkynes is described, and various spironaphthalenones were obtained from α-tethered alkyne β- naphthols in good to excellent yields under open-flask conditions.
20 citations