We first describe a photoinduced decatungstate-catalyzed direct coupling of cycloalkanes and cyclic aldimines.The desired products were generated in moderate to good yields with wide substrate scope under mild reaction conditions.The mechanistic study revealed a radical process.In addition,the usefulness of the reaction in organic synthesis was proved by the scale-up synthesis as well as the late-stage modification of drug-like molecules.
Wide-bandgap(WB)mixed-halide perovskite solar cells(PSCs)play a crucial role in perovskite-based tandem solar cells(TSCs),enabling them to exceed the Shockley-Queisser limits of single-junction solar cells.Nonetheless,the lack of stability in WB perovskite films due to photoinduced phase segregation undermines the stability of WB PSCs and their TSCs,thus impeding the commercialization of perovskite-based TSCs.Many efforts have been made to suppress photoinduced phase segregation in WB perovskite films and significant progresses have been obtained.In this review,we elaborate the mechanisms behind photoinduced phase segregation and its impact on the photovoltaic performance and stability of devices.The importance role of advanced characterization techniques in confirming the photoinduced phase segregation are comprehensively summarized.Beyond that,the effective strategies to alleviate photoinduced phase segregation in WB mixed halide PSCs are systematically assessed.Finally,the prospects for developing highly efficient and stable WB PSCs in tandem application are also presented.
Dynamic photoresponsive molecular crystals are promising candidates for making intelligent devices and materials in the future.Here,we synthesized a new photoactive molecule(E)-2,2-dimethyl-5-[3-(naphthalen-1-yl)allylide]-1,3-dioxane-4,6-dione[(E)-DNADD]that undergoes an E-to-Z photoisomerization in both liquid solution and solids when exposed to visible light(405 nm).Compared to the bulk crystals,the photoresponsive behavior in microcrystals was profoundly improved.Highly crystalline(E)-DNADD microplate crystals exhibit robust motions,including bending,curling,and coiling under light irradiation.The photoproduct conversion of the photochemical reaction in the microplate is no more than 20%,while the large bending curvature of the coiled illuminated samples was estimated at approximately 150–300 mm−1,comparable to some photoactive nanowires.Our results indicate that shrinking crystal dimensions can boost the photoresponses in molecular crystals and provide a facile strategy for developing dynamic molecular crystals at the microscopic scale.
Tryptophan(Trp)carries a unique heteroaromatic indole side chain and plays a critical role in peptide or protein modification.Herein,we have reported a metal-free photoinduced N-H alkylation strategy using N-aryl glycines for specific modification of tryptophan-containing peptides.The robustness of our approach is demonstrated by its wide substrate scope,excellent isolated yields,as well as almost unobservable side effects.Using this highly efficiently metal-free condition,alkylated Trp-containing peptides can be smoothly assembled.This study provides a reliable and practical tool for the chemo-selective modification of various tryptophan containing oligopeptides.
Jianhui YinWenjing HuangChangyong GuoChao LiuFei GaoHonggang Hu
An atom economicβ-C(sp^(3))−H chlorination of amide derivatives has been developed.This mild protocol employs CuCl_(2) instead of palladium catalysts with atom-economic HCl as chlorine sources and enables the late-stage functionalization of medicine derivatives.Mechanism studies suggest a plausible visible light triggered ligand-to-metal charge transfer(LMCT)/1,4-hydrogen atom transfer(HAT)cascade.
Photoinduced ligand-to-metal charge transfer(LMCT) has emerged as an effective strategy for synthesizing organic molecules in a sustainable manner. However, the majority of existing reports on selective C(sp^(3))–H bond functionalization via photoinduced LMCT focus on the use of late transition metals or rare-earth metals for radical additions or cross-couplings. In contrast, the utilization of photoinduced LMCT with 3d early transition metals poses a significant challenge. Herein, we describe an unprecedented approach to allylic C(sp^(3))–H addition to aldehydes, employing chromium(Cr) complexes as catalysts through visible-light-induced LMCT. By investigating the reaction pathway through various mechanistic studies, including radical trapping, kinetic isotope effect(KIE) analysis, and transient absorption spectroscopy, valuable insights have been gained. The proposed mechanism suggests the intermediacy of bromine radicals through homolysis of the Cr–Br bond. Notably, this protocol expands our understanding of the photochemical properties of earth-abundant Cr complexes.
Xianrong ZengFeng-Hua ZhangRunchen LaiXiaoyu LinZhaobin Wang
Two distinctive rearranged 19-nor-7,8-seco-labdane diterpenoids(1 and 2)with a novel tetracyclo[5.2.1.0^(2,5.)0^(4,10)]decane skeleton,a derivative of the open tetrahydrofuran ring(7),three dimeric compounds(8-10),and four revised homologs(3-6)were obtained from Chinese liverwort Pallavicinia ambigua.Their structures were identified via combined analysis of their spectroscopic data,single-crystal X-ray diffraction patterns,and ECD calculations.The light-driven conversion of compound 5 to compounds 1-4 demonstrated that photochemically induced postmodification involved in biosynthesis is an important way to diversify natural structures.A preliminary cytotoxicity assay revealed that compound 5 showed significant inhibition in the human prostate cancer(PC-3)cell line via an apoptotic pathway.
Photoinduced electron transfer(PET)is a critical process in many functional materials,underpinning various technological applications(i.e.,fluorescent probes and photocatalysts).Despite its signifi-cance,the detailed structural dynamics of PET,particularly during the excited state,remain poorly understood.This study investigates the mechanisms of conformational folding and their implications for activating PET in molecular systems characterized by a fluorophore-spacer-receptor configuration.We demonstrate that traditional computational models,primarily based on frontier molecular orbitals,often fall short in capturing these conformational dynamics,leading to inadequate explanations of PET phenomena.With the incorporation of conformational folding,our computational model has achieved excellent agreement with experimental data,thereby resolving several long-standing debates on PET mechanisms.This mechanistic advancement not only deepens our understanding of PET but also opens new avenues for designing advanced functional materials.We have thus successfully demonstrated the imaging of lysosomes in live cells using a PET probe.
Shiqing HuangSyed Ali Abbas AbediZhifeng LiRongrong HuangXiaoyu YanMohammad IzadyarQinglong QiaoYu FangZhaochao XuXiaogang Liu
In correlated oxides,collaborative manipulation on light intensity,wavelength,pulse duration and polarization has yielded many exotic discoveries,such as phase transitions and novel quantum states.In view of potential optoelectronic applications,tailoring long-lived static properties by light-induced effects is highly desirable.So far,the polarization state of light has rarely been reported as a control parameter for this purpose.Here,we report polarization-dependent metal-to-insulator transition(MIT)in phaseseparated manganite thin films,introducing a new degree of freedom to control static MIT.Specifically,we observed giant photoinduced resistance jumps with striking features:(1)a single resistance jump occurs upon a linearly polarized light incident with a chosen polarization angle,and a second resistance jump occurs when the polarization angle changes;(2)the amplitude of the second resistance jump depends sensitively on the actual change of the polarization angles.Linear transmittance measurements reveal that the origin of the above phenomena is closely related to the coexistence of anisotropic micro-domains.Our results represent a first step to utilize light polarization as an active knob to manipulate static phase transitions,pointing towards new pathways for nonvolatile optoelectronic devices and sensors.
In this paper,the difunctionalizative perfluoroalkyloximation of alkenes has been developed for the first time.This photochemical method allows for the synthesis of various perfluoroalkyl ethanone oximes with excellent regioselectivity and good functional group tolerance.Our method employs the most common perfluoroalkyl source,perfluoroalkyl iodides,as Rf reagents.Besides long-chain perfluoroalkyl groups,this approach could be extended to incorporating additional groups,including trifluoromethyl,difluoromethyl,sulfonyl,and malonate,selectively into olefins,resulting in a range ofβ-substituted ethanone oximes.Notably,the potential of this method in the Fukuyama indole synthesis,generating novel 2-perfluoroalkylated 3-(α-oximidobenzyl)indoles via a radical cascade mechanism with 2-vinylphenylacryloyl isocyanate as the radical acceptor,presents a compelling avenue for drug synthesis.The protocol is efficient,scalable,and useful for late-stage modification of bioactive molecules.
Wei LiZhongji LiDeliang ZhongNianxing WangHuaifeng Li
