Quantitative Design of Bright Fluorophores and AIEgens by the Accurate Prediction of Twisted Intramolecular Charge Transfer (TICT)

Inhibition of TICT can significantly increase the brightness of fluorescent materials. Accurate prediction of TICT is thus critical for the quantitative design of high‐performance fluorophores and AIEgens. TICT of 14 types of popular organic fluorophores were modeled with time‐dependent density functional theory (TD‐DFT). A reliable and generalizable computational approach for modeling TICT formations was established. To demonstrate the prediction power of our approach, we quantitatively designed a boron dipyrromethene (BODIPY)‐based AIEgen which exhibits (almost) barrierless TICT rotations in monomers. Subsequent experiments validated our molecular design and showed that the aggregation of this compound turns on bright emissions with ca. 27‐fold fluorescence enhancement, as TICT formation is inhibited in molecular aggregates.     

A Diffusion‐‐Reaction Competition Mechanism to Tailor Lithium Deposition for Lithium‐Metal Batteries

Lithium metal is recognized as one of the most promising anode materials owing to its ultrahigh theoretical specific capacity and low electrochemical potential. Nonetheless, dendritic Li growth has dramatically hindered the practical applications of Li metal anodes. Realizing spherical Li deposition is an effective approach to avoid Li dendrite growth, but the mechanism of spherical deposition is unknown. Herein, a diffusion‐reaction competition mechanism is proposed to reveal the rationale of different Li deposition morphologies. By controlling the rate‐determining step (diffusion or reaction) of Li deposition, various Li deposition scenarios are realized, in which the diffusion‐controlled process tends to lead to dendritic Li deposition while the reaction‐controlled process leads to spherical Li deposition. This study sheds fresh light on the dendrite‐free Li metal anode and guides to achieve safe batteries to benefit future wireless and fossil‐fuel‐free world.     

Enantioselective Catalytic Aldehyde α‐Alkylation/Semipinacol Rearrangement: Construction of α‐Quaternary‐δ‐Carbonyl Cycloketones and Total Synthesis of (+)‐Cerapicol

An enantioselective aldehyde α‐alkylation/semipinacol rearrangement was achieved through organo‐SOMO catalysis. The catalytically generated enamine radical cation serves as a carbon radical electrophile that can stereoselectively add to the alkene of an allylic alcohol and initiate ensuing ring‐expansion of cyclopropanol or cyclobutanol. This tandem reaction enables the production of a wide range of nonracemic functionalizable α‐quaternary‐δ‐carbonyl cycloketones in high yields and excellent enantioselectivity from simple aldehydes and allylic alcohols. As a key step, the intramolecular reaction was also successfully applied in the asymmetric total synthesis of (+)‐cerapicol.     

Structure Determination of Alkynyl‐Protected Gold Nanocluster Au22(tBuC≡C)18 and Its Thermochromic Luminescence

An alkynyl‐protected gold nanocluster, Au₂₂(^tBuC≡C)₁₈ ( 1 ), has been synthesized and its structure has been determined by single‐crystal X‐ray diffraction. The molecular structure consists of a Au₁₃ cuboctahedron kernel and three [Au₃(^tBuC≡C)₄] trimeric staples. The cluster 1 has strong luminescence in the solid state with a 15 % quantum yield, and it displays interesting thermochromic luminescence as revealed by temperature‐dependent emission spectra. The enhanced room‐temperature emission is characterized as thermally activated delayed fluorescence.     

Molecular‐Sieving Membrane by Partitioning the Channels in Ultrafiltration Membrane by In Situ Polymerization

Commercial ultrafiltration membranes have proliferated globally for water treatment. However, their pore sizes are too large to sieve gases. Conjugated microporous polymers (CMPs) feature well‐developed microporosity yet are difficult to be fabricated into membranes. Herein, we report a strategy to prepare molecular‐sieving membranes by partitioning the mesoscopic channels in water ultrafiltration membrane (PSU) into ultra‐micropores by space‐confined polymerization of multi‐functionalized rigid building units. Nine CMP@PSU membranes were obtained, and their separation performance for H₂/CO₂, H₂/N₂, and H₂/CH₄ pairs surpass the Robeson upper bound and rival against the best of those reported membranes. Furthermore, highly crosslinked skeletons inside the channels result in the structural robustness and transfer into the excellent aging resistance of the CMP@PSU. This strategy may shed light on the design and fabrication of high‐performance polymeric gas separation membranes.     

Formyl-selective deuteration of aldehydes with D2O via synergistic organic and photoredox catalysis

Formyl-selective deuteration of aldehydes is of high interest for labeling purposes and for optimizing properties of drug candidates. Herein, we report a mild general method for formyl-selective deuterium labeling of aldehydes with D₂O, an inexpensive deuterium source, via a synergistic combination of light-driven, polyoxometalate-facilitated hydrogen atom transfer and thiol catalysis. This highly efficient, scalable reaction showed excellent deuterium incorporation, a broad substrate scope, and excellent functional group tolerance and selectivity and is therefore a practical method for late-stage modification of synthetic intermediates in medicinal chemistry and for generating libraries of deuterated compounds.

Formyl-selective deuteration of aldehydes with D₂O mediated by the synergistic combination of light-driven, polyoxometalate-facilitated HAT and thiol catalysis is reported.     

Two New Sterols from Amoora yunnanensis

ThegenusAmooracomprisingabout25-3ospeciesisdistributedinIndiaandtheMalayPeninsula.SixspeciesaredistributedinYunnanprovince.Amoorayunnanensis(H.L.Li)C.YWu,ismainlydistributedintheSouthofYunnanl.AccordingtoPenningtonandStyles',Amooracannotbeconsideredasavalidgenus.UptonoWchemicalconstituentsforthisgenushavenotbeenreportedyet.lnourchemicalstudyonAmoorayunnanensis,tetTanortfiterPenoidsorprotolimonoidsthatwereconsideredaschemotaxonomicmarkersofthefamilyMeliaceae,werenotisolated.lnthispaper…     

(HAINH)_n(n=1～6)簇的结构、红外光谱和热力学性质的研究

用自洽场理论(HF)和密度泛函理论(DET)的B3LYP方法,在6-31G~μ水平上研究了HAINH的低聚物(HAINH)_n(n=1～6)簇的几何构型、电子结构、红外光谱和化学热力学性质,并比较了(HAINH)_n和(CIAINH)_n两种低聚物对应结构中化学键强弱,分析了引起(AIN)_n骨架结构发生变化的原因.结果表明,(HAINH)_n簇的基态结构为C_8(n=1),D_(2h)(n=2),D_(3h)(n=3),T_d(n=4),C_s(n=5)和D_(3d)(n=6)对称点群.HAINH基态结构中,AI-N键是三重键.在D_(2h)(n=2)和D_(3h)(n=3)结构中,所有AI-N键均为二重键.在Td(n=4)和D_(3d)(n=6)中,AI-N键为正常单键,而在C_s(n=5)结构中含有三种AI-N键:单键、双键和混合键.振动频率计算表明,结构a～f均为基态稳定结构.热力学计算给出的稳定性顺序为:f>d>e>c>b>a.     

酪氨酸在活性炭/水界面上的吸附

研究了不同pH值介质中酪氨酸在活性炭上的吸附行为.结果表明,pH值4.2～6.1时吸附量较大,在酪氨酸的等电点时吸附量最大;酪氨酸被吸附的主要形式是兼性离子;酪氨酸离子靠VanderWaals力吸附在活性炭/水界面上.用介质pH值对酪氨酸溶解度的影响和活性炭的表面性质解释了实验结果     

新型水溶性硫杂蒽酮类光引发剂的光引发性能研究

利用红外光谱技术对六种新型水溶性硫杂蒽酮类光引发剂在紫外光聚合反应中的引发性能进行了测试,用相对峰面积法计算了聚合反应的转化率,并据此对引发剂结构与光化学性能之间的关系做了一定的探讨。结果表明该类光引发剂具有很高的光化学活性,而引发剂的结构直接影响引发性能。研究发现硫杂蒽酮母体上甲基的引入使引发剂的引发效率增大,而引发剂侧链上羟基的引入,则由于降低了质量转移的有效性并有可能使引发剂分子缔合,致命引