鑽石舞台

Covalent organic frameworks with high quantum efficiency in sacrificial photocatalytic hydrogen evolutionNature Communications，Pub Date:2022-04-29,

DOI:10.1038/s41467-022-30035-xChunzhi Li, Jiali Liu, He Li, Kaifeng Wu, Junhui Wang, Qihua Yang

Organic semiconductors offer a tunable platform for photocatalysis, yet the more difficult exciton dissociation, compared to that in inorganic semiconductors, lowers their photocatalytic activities. In this work, we report that the charge carrier lifetime is dramatically prolonged by incorporating a suitable donor-acceptor (β-ketene-cyano) pair into a covalent organic framework nanosheet. These nanosheets show an apparent quantum efficiency up to 82.6% at 450 nm using platinum as co-catalyst for photocatalytic H2evolution. Charge carrier kinetic analysis and femtosecond transient absorption spectroscopy characterizations verify that these modified covalent organic framework nanosheets have intrinsically lower exciton binding energies and longer-lived charge carriers than the corresponding nanosheets without the donor-acceptor unit. This work provides a model for gaining insight into the nature of short-lived active species in polymeric organic photocatalysts.

https://www.nature.com/articles/s41467-022-30035-x

Super Mg2+ Conductivity around 10–3 S cm–1 Observed in a Porous Metal–Organic FrameworkJournal of the American Chemical Society，Pub Date:2022-05-04,

DOI:10.1021/jacs.2c01612Yuto Yoshida, Teppei Yamada, Yuan Jing, Takashi Toyao, Ken-ichi Shimizu, Masaaki Sadakiyo

We first report a solid-state crystalline 「Mg2+conductor」 showing a superionic conductivity of around 10–3S cm–1at ambient temperature, which was obtained using the pores of a metal–organic framework (MOF), MIL-101, as ion-conducting pathways. The MOF, MIL-101⊃{Mg(TFSI)2}1.6(TFSI–= bis(trifluoromethanesulfonyl)imide), containing Mg2+inside its pores, showed a superionic conductivity of 1.9 × 10–3S cm–1at room temperature (RT) (25 °C) under the optimal guest vapor (MeCN), which is the highest value among all Mg2+-containing crystalline compounds. The Mg2+conductivity in the MOF was estimated to be 0.8 × 10–3S cm–1at RT, by determining the transport number of Mg2+(tMg2+= 0.41), which is the level as high as practical use for secondary battery. Measurements of adsorption isotherms, pressure dependence of ionic conductivity, and in situ Fourier transform infrared measurements revealed that the 「super Mg2+conductivity」 is caused by the efficient migration of the Mg2+carrier with the help of adsorbed guest molecules.

https://pubs.acs.org/doi/abs/10.1021/jacs.2c01612

Delicate and Fast Photochemical Surface Modification of 2D Photoresponsive Organosilicon Metal‒Organic FrameworksAngewandte Chemie International Edition，Pub Date:2022-05-04,

DOI:10.1002/anie.202204568Baoling Yuan, Gaozhang Gou, Tao Fan, Mingxian Liu, Yunsheng Ma, Ryotaro Matsuda, Liangchun Li

Photoresponsive arylsilanes have been fascinating molecules for decades because of their unique photophysical characteristics and surface chemistry. Here we report the synthesis and fabrication of a crystalline two-dimensional trisilyl metal‒organic framework (TSiMOF) orderly installed with the classical photoresponsive hexamethyltrisilane groups on the surface. Irradiated by UV light under air in minutes the fluorescence of the TSiMOF is turned on simultaneously with an intriguing surface transformation from superhydrophobic to hydrophilic. Thus, multifarious luminescent and hydrophilic patterns including logos, characters and Quick Response codes, etc. with good resolution are readily generated on the facilely fabricated TSiMOF film. The mechanism of this transformation is revealed by control experiments that the superficial trimethylsilyl groups suffering photochemical oxidation have been converted to hydroxyl groups.

https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.202204568

Redox-Active Covalent Organic Frameworks with Nickel–Bis(dithiolene) Units as Guiding Layers for High-Performance Lithium Metal BatteriesJournal of the American Chemical Society，Pub Date:2022-04-28,

DOI:10.1021/jacs.2c01996Si-Wen Ke, Yaoda Wang, Jian Su, Kang Liao, Sen Lv, Xinmei Song, Tianrui Ma, Shuai Yuan, Zhong Jin, Jing-Lin Zuo

Combining the chemistry of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) can bring new opportunities for the design of advanced materials with enhanced tunability and functionality. Herein, we constructed two COFs based on Ni–bis(dithiolene) units and imine bonds, representing a bridge between traditional MOFs and COFs. The Ni–bis(dithiolene)tetrabenzaldehyde as the 4-connected linker was initially synthesized, which was further linked by 4-connected tetra(aminophenyl)pyrene (TAP) or 3-connected tris(aminophenyl)amine (TAA) linkers into two COFs, namely, Ni-TAP and Ni-TAA. Ni-TAP shows a two-dimensional sql network, while TAA is a twofold interpenetrated framework with an ffc topology. They both exhibit a high Brunauer–Emmett–Teller surface area (324 and 689 m2g–1for Ni-TAP and Ni-TAA, respectively), a fairly good conductivity (1.57 × 10–6and 9.75 × 10–5S m–1for Ni-TAP and Ni-TAA, respectively), and high chemical stability (a stable pH window of 1–14 for Ni-TAA). When applied in lithium metal batteries as an intermediate layer for guiding the uniform Li electrodeposition, Ni-TAP and Ni-TAA displayed impressive lithiophilicity and high Li-ion conductivity, enabling the achievement of smooth and dense Li deposition with a clear columnar morphology and stable Li plating/stripping behaviors with high Li utilization, which is anticipated to pave the way to upgrade Li metal anodes for application in high-energy-density battery systems.

https://pubs.acs.org/doi/abs/10.1021/jacs.2c01996