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991.
本文将研究贝叶斯法则视角下的空间自相关误差自相关模型(Spatial Autoregressive Model with Autoregressive Disturbances,SARAR模型)变量选择问题。通过将基于BIC准则的子集选择法推广到空间模型,实现SARAR模型的变量选择,并证明在一定条件下,对于SARAR模型的变量选择BIC准则具有良好的渐近性质。同时本文还将利用Monte Carlo模拟验证BIC准则能够很好的实现SARAR模型的变量选择。最后以股票收益率为例,在验证股票收益率具有空间效应的前提下,利用BIC准则对影响股票收益率的众多财务指标进行变量选择。 相似文献
992.
Dr. Ruofei Cheng Prof. Dr. Chao-Jun Li 《Angewandte Chemie (International ed. in English)》2023,62(20):e202301730
A novel method for the formation of Csp3−PIII bonds via the nickel-catalyzed cross-coupling of Umpolung carbonyls and phosphine chlorides is reported herein. This process leads to a series of alkylphosphines, which are characterized as sulfides or borane-phosphine complexes after undergoing further transformation with moderate to good yields. Invaluable free alkylphosphines can be easily obtained by desulfurization or deboration of the products. A possible mechanistic pathway is also discussed. This report represents the first example of using renewable carbonyls as latent organometallic reagent surrogates for cross-coupling with heteroatom electrophiles. 相似文献
993.
Runtian Zheng Yuhang Li Dr. Haoxiang Yu Xikun Zhang Dr. Ding Yang Dr. Lei Yan Prof. Yu Li Prof. Jie Shu Prof. Bao-Lian Su 《Angewandte Chemie (International ed. in English)》2023,62(23):e202301629
Ammonium-ion batteries (AIBs) have recently attracted increasing attention in the field of aqueous batteries owing to their high safety and fast diffusion kinetics. The NH4+ storage mechanism is quite different from that of spherical metal ions (e.g. Li+, Na+, K+, Mg2+, and Zn2+) because of the formation of hydrogen bonds between NH4+ and host materials. Although many materials have been proposed as electrode materials for AIBs, their performances hardly meet the requirement of future electrochemical energy storage devices. It is thus urgent to design and exploit advanced materials for AIBs. This review highlights the state-of-the-art research on AIBs. The insights into the basic configuration, operating mechanism and recent progress of electrode materials and corresponding electrolytes for AIBs have been comprehensively outlined. The electrode materials are classified and compared according to different NH4+ storage behaviour in the structure. The challenges, design strategies and perspectives are also discussed for the future development of AIBs. 相似文献
994.
Jared C. Paris Dr. Sha Hu Aiwen Wen Dr. Andrew C. Weitz Dr. Ronghai Cheng Dr. Leland B. Gee Dr. Yijie Tang Hyomin Kim Prof. Arturo Vegas Prof. Wei-chen Chang Prof. Sean J. Elliott Prof. Pinghua Liu Prof. Yisong Guo 《Angewandte Chemie (International ed. in English)》2023,62(43):e202309362
Ergothioneine (ESH) and ovothiol A (OSHA) are two natural thiol-histidine derivatives. ESH has been implicated as a longevity vitamin and OSHA inhibits the proliferation of hepatocarcinoma. The key biosynthetic step of ESH and OSHA in the aerobic pathways is the O2-dependent C−S bond formation catalyzed by non-heme iron enzymes (e.g., OvoA in ovothiol biosynthesis), but due to the lack of identification of key reactive intermediate the mechanism of this novel reaction is unresolved. In this study, we report the identification and characterization of a kinetically competent S=1 iron(IV) intermediate supported by a four-histidine ligand environment (three from the protein residues and one from the substrate) in enabling C−S bond formation in OvoA from Methyloversatilis thermotoleran, which represents the first experimentally observed intermediate spin iron(IV) species in non-heme iron enzymes. Results reported in this study thus set the stage to further dissect the mechanism of enzymatic oxidative C−S bond formation in the OSHA biosynthesis pathway. They also afford new opportunities to study the structure-function relationship of high-valent iron intermediates supported by a histidine rich ligand environment. 相似文献
995.
Dr. Peiying Li Shuya Wang Jinjin Hao Xiang Wang Prof. Shu-Meng Hao Yuhao Lu Prof. Hong Li Prof. Weidong Zhou Dr. Yuliang Li 《Angewandte Chemie (International ed. in English)》2023,62(38):e202309613
In situ polymerization of liquid electrolytes is currently the most feasible way for constructing solid-state batteries, which, however, is affected by various interfering factors of reactions and so the electrochemical performance of cells. To disclose the effects from polymerization conditions, two types of generally used in situ polymerizing reactions of ring-opening polymerization (ROP) and double bond radical polymerization (DBRP) were investigated on the aspects of monomer conversion and electrochemical properties (Li+-conductivity and interfacial stability). The ROP generated poly-ester and poly-carbonate show a high monomer conversion of ≈90 %, but suffer a poor Li+-conductivity of lower than 2×10−5 S cm−1 at room temperature (RT). Additionally, the terminal alkoxy anion derived from the ROP is not resistant to high-voltage cathodes. While, the DBRP produced poly-VEC(vinyl ethylene carbonate) and poly-VC(vinylene carbonate) show lower monomer conversions of 50–80 %, delivering relatively higher Li+-conductivities of 2×10−4 S cm−1 at RT. Compared two polymerizing reactions and four monomers, the VEC-based F-containing copolymer possesses advantages in Li+-conductivity and antioxidant capacity, which also shows simultaneous stability towards Li-metal with the help of LiF-based passivating layer, allowing a long-term stable cycling of high-voltage quasi solid-state cells. 相似文献
996.
Ming-Yu Qi Prof. Dr. Yi-Jun Xu 《Angewandte Chemie (International ed. in English)》2023,62(41):e202311731
Solar-driven CO2 reduction integrated with C−C/C−X bond-forming organic synthesis represents a substantially untapped opportunity to simultaneously tackle carbon neutrality and create an atom-/redox-economical chemical synthesis. Herein, we demonstrate the first cooperative photoredox catalysis of efficient and tunable CO2 reduction to syngas, paired with direct alkylation/arylation of unactivated allylic sp3 C−H bonds for accessing allylic C−C products, over SiO2-supported single Ni atoms-decorated CdS quantum dots (QDs). Our protocol not only bypasses additional oxidant/reductant and pre-functionalization of organic substrates, affording a broad of allylic C−C products with moderate to excellent yields, but also produces syngas with tunable CO/H2 ratios (1 : 2–5 : 1). Such win-win coupling catalysis highlights the high atom-, step- and redox-economy, and good durability, illuminating the tantalizing possibility of a renewable sunlight-driven chemical feedstocks manufacturing industry. 相似文献
997.
Dr. Xiaoming Jie Dr. Chaohuang Chen Dr. Constantin G. Daniliuc Dr. Gerald Kehr Prof. Gerhard Erker 《Angewandte Chemie (International ed. in English)》2023,62(4):e202214700
Hydroboration of styrene or vinylcyclohexane with the IMes(C6F5)BH+ cation followed by deprotonation provided a convenient synthetic entry to the [B]=CHCH2R boraalkenes 9 a and 9 b . The in situ generated IMes(SCN)BH+ system reacted similarly with 1,1-diphenylethene followed by deprotonation to give the isothiocyanato substituted boraalkene 9 c . The boraalkenes underwent [2+2] cycloaddition reactions with a small series of heterocumulenes to give the respective four-membered heterocycles. The [B]=CHCH2R+CO2 cycloadducts 13 a and 13 b added the borane HB(C6F5)2 with cleavage of the central B−C σ-bond. CS2 underwent an unusual reaction with the boraalkenes, namely insertion into the B=C bond with formation of the borylated dithioketene acetal under complete rupture of the strong B=C double bond. The intermediate dithiobora-β-lactone type intermediate was isolated in the case of the isothiocyanato-boraalkene reaction and characterized by X-ray diffraction. 相似文献
998.
Dr. Hongfei Wang Wuquan Ye Bowen Yin Kexin Wang Dr. Muhammad Sohail Riaz Dr. Bin-Bin Xie Prof. Yijun Zhong Prof. Yong Hu 《Angewandte Chemie (International ed. in English)》2023,62(10):e202218872
Highly reversible plating/stripping in aqueous electrolytes is one of the critical processes determining the performance of Zn-ion batteries, but it is severely impeded by the parasitic side reaction and dendrite growth. Herein, a novel electrolyte engineering strategy is first proposed based on the usage of 100 mM xylitol additive, which inhibits hydrogen evolution reaction and accelerates cations migration by expelling active H2O molecules and weakening electrostatic interaction through oriented reconstruction of hydrogen bonds. Concomitantly, xylitol molecules are preferentially adsorbed by Zn surface, which provides a shielding buffer layer to retard the sedimentation and suppress the planar diffusion of Zn2+ ions. Zn2+ transference number and cycling lifespan of Zn ∥ Zn cells have been significantly elevated, overwhelmingly larger than bare ZnSO4. The cell coupled with a NaV3O8 cathode still behaves much better than the additive-free device in terms of capacity retention. 相似文献
999.
Saber Mehrparvar Christoph Wölper Gebhard Haberhauer 《Angewandte Chemie (International ed. in English)》2023,62(29):e202304202
As a rule, helical structures at the molecular level are formed by non-planar units. This makes the design of helices, starting from planar building blocks via self-assembly, even more fascinating. Until now, however, this has only been achieved in rare cases, where hydrogen and halogen bonds were involved. Here, we show that the carbonyl-tellurium interaction motif is suitable to assemble even small planar units into helical structures in solid phase. We found two different types of helices: both single and double helices, depending on the substitution pattern. In the double helix, the strands are connected by additional Te⋅⋅⋅Te chalcogen bonds. In the case of the single helix, a spontaneous enantiomeric resolution occurs in the crystal. This underlines the potential of the carbonyl-tellurium chalcogen bond to generate complex three-dimensional patterns. 相似文献
1000.
Jian Zhou Dr. Ling Meng Dr. Shujuan Lin Baohua Cai Prof. Jun Wang 《Angewandte Chemie (International ed. in English)》2023,62(26):e202303727
Transition metal-catalyzed hydrofunctionalization of methylenecyclopropanes (MCPs) has presented a considerable challenge due to the difficult manipulation of regioselectivity and complicated reaction patterns. Herein, we report a straightforward Pd-catalyzed ring-opening hydrophosphinylation reaction of MCPs via highly selective C−C bond cleavage. This method allows for rapid and efficient access to a wide range of chiral allylic phosphine oxides in good yields and high enantioselectivities. Additionally, density functional theory (DFT) calculations were performed to elucidate the reaction mechanism and the origin of enantioselectivity. 相似文献