An Amine–Borane System Featuring Room‐Temperature Dehydrogenation and Regeneration

An Amine–Borane System Featuring Room‐Temperature Dehydrogenation and Regeneration

An amine–borane system has been discovered to deliver a reversible dehydrogenation/regeneration at room temperature. It provides a new way for hydrogen storage under mild conditions.

Abstract

Amine–borane complexes have been extensively studied as hydrogen storage materials. Herein, we report a new amine–borane system featuring a reversible dehydrogenation and regeneration at room temperature. In addition to high purity H2, the reaction between ethylenediamine bisborane (EDAB) and ethylenediamine (ED) leads to unique boron–carbon–nitrogen 5‐membered rings in the dehydrogenation product where one boron is tricoordinated by three nitrogen atoms. Owing to the unique cyclic structure, the dehydrogenation product can be efficiently converted back to EDAB by NaBH4 and H2O at room temperature. This finding could lead to the discovery of new amine boranes with potential usage as hydrogen storage materials.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Guojin Zhang, Daniel Morrison, Guochen Bao, Haibo Yu, Chang Won Yoon, Taekyong Song, Jihye Lee, Alison T. Ung, Zhenguo Huang
onlinelibrary.wiley.com/doi/10.1002/anie.202017302

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A Molecular Transformer: A π‐Conjugated Macrocycle as an Adaptable Host

A Molecular Transformer: A π‐Conjugated Macrocycle as an Adaptable Host

Molecular Transformer: A flexible π‐conjugated, all carbon‐based “figure‐eight” macrocycle (3) without a meso bridge was synthesized in one step. The supramolecular assembly behavior of 3 was investigated in this work; compared to the rigid conformation of dimer 1, the structure of tetramer 3 is more flexible due to its larger ring size, which endows it with the ability to adjust its conformation according to changes in the external environment.

Abstract

Here, we report a facile method to synthesize a series of macrocycles with different conformations. The planar macrocycle dimer (1), twisted macrocycle trimer (2) and “figure‐eight” tetramer (3) are clearly elucidated by X‐ray single‐crystal analysis, in which the electron‐rich phenanthrene units offer the possibility of supramolecular assembly. As expected, in the solid state, 1 and 3 assemble into a columnar stack and an interlocking dimer, respectively, via π–π interactions between the phenanthrene units. Compared to the rigid conformation of dimer 1, the structure of tetramer 3 is more flexible due to its enlarged ring size. 3 can deform from a figure‐eight into a boat‐shaped geometry to host a planar electron‐deficient guest using its electron‐rich phenanthrene units. When assembled with spherical electron‐deficient C60, interestingly, 3 further undergoes a conformational transformation from a figure‐eight to a belt shape in order to host C60. These supramolecular assembly behaviors of 3 demonstrate that it is an adaptable macrocyclic host for both planar molecules and fullerenes.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Junting Wang, Yang‐Yang Ju, Kam‐Hung Low, Yuan‐Zhi Tan, Junzhi Liu
onlinelibrary.wiley.com/doi/10.1002/anie.202102637

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Potential‐Induced Spin Changes in Fe/N/C Electrocatalysts Assessed by In Situ X‐ray Emission Spectroscopy

Potential‐Induced Spin Changes in Fe/N/C Electrocatalysts Assessed by In Situ X‐ray Emission Spectroscopy

The needed improvements in the activity and stability of Fe/N/C‐based electrocatalysts for the reduction of oxygen or carbon dioxide require a better understanding of their active sites’ structure and electronic properties. To this end, herein we have applied ex situ and in situ X‐ray emission spectroscopy to track the potential‐induced changes in the average spin state of these materials’ molecular Fe‐Nx sites.

Abstract

The commercial success of the electrochemical energy conversion technologies required for the decarbonization of the energy sector requires the replacement of the noble metal‐based electrocatalysts currently used in (co‐)electrolyzers and fuel cells with inexpensive, platinum‐group metal‐free analogs. Among these, Fe/N/C‐type catalysts display promising performances for the reduction of O2 or CO2, but their insufficient activity and stability jeopardize their implementation in such devices. To circumvent these issues, a better understanding of the local geometric and electronic structure of their catalytic active sites under reaction conditions is needed. Herein we shed light on the electronic structure of the molecular sites in two Fe/N/C catalysts by probing their average spin state with X‐ray emission spectroscopy (XES). Chiefly, our in situ XES measurements reveal for the first time the existence of reversible, potential‐induced spin state changes in these materials.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Viktoriia A. Saveleva, Kathrin Ebner, Lingmei Ni, Grigory Smolentsev, Daniel Klose, Andrea Zitolo, Elena Marelli, Jingkun Li, Marisa Medarde, Olga V. Safonova, Maarten Nachtegaal, Frédéric Jaouen, Ulrike I. Kramm, Thomas J. Schmidt, Juan Herranz
onlinelibrary.wiley.com/doi/10.1002/anie.202016951

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Redefining the Mechanistic Scenario of Carbon−Sulfur Nucleophilic Coupling via High‐Valent Cp*CoIV Species

Redefining the Mechanistic Scenario of Carbon−Sulfur Nucleophilic Coupling via High‐Valent Cp*CoIV Species

The joint application of experimental and computational approaches discloses unprecedented mechanistic intricacies associated to Cp*Co‐catalyzed C−H functionalization reactions when using nucleophilic coupling partners. The use of trifluoromethylthiolation reveals an exceptional reductive elimination event from high‐valent Cp*CoIV that can be promoted by either chemical oxidants or electrochemical methods.

Abstract

The potential access to CoIV species for promoting transformations that are particularly challenging at CoIII still remains underexploited in the context of Cp*Co‐catalyzed C−H functionalization reactions. Herein, we disclose a combined experimental and computational strategy for uncovering the participation of Cp*CoIV species in a Cp*Co‐mediated C−S bond‐reductive elimination. These studies support the intermediacy of high‐valent Cp*Co species in C−H functionalization reactions, under oxidative conditions, when involving nucleophilic coupling partners.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Sara López‐Resano, Sara Martínez de Salinas, Felipe A. Garcés‐Pineda, Andrea Moneo‐Corcuera, José Ramón Galán‐Mascarós, Feliu Maseras, Mónica H. Pérez‐Temprano
onlinelibrary.wiley.com/doi/10.1002/anie.202101390

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Solvent‐Switched Oxidation Selectivities with O2: Controlled Synthesis of α‐Difluoro(thio)methylated Alcohols and Ketones

Solvent‐Switched Oxidation Selectivities with O2: Controlled Synthesis of α‐Difluoro(thio)methylated Alcohols and Ketones

The solvent‐switched hydroxylation and oxygenation of α‐difluoro(thio)methylated carbanions with molecular oxygen under mild conditions are reported, delivering various useful α‐difluoro(thio)methylated alcohols and ketones in high yields. The solvent‐bonding effect tames the redox reactions of the hydroperoxy difluoromethylsulfide intermediates, and alters their reactivity and switches the oxidation selectivities.

Abstract

The solvent‐switched hydroxylation and oxygenation of α‐difluoro(thio)methylated carbanions with molecular oxygen under mild conditions are reported. This strategy tames the redox reactions of the in situ generated hydroperoxy difluoromethylsulfides, in which solvent‐bonding can alter their reactivity and switch the oxidation selectivities. These controllable three‐component reactions of gem‐difluoroalkenes, thiols and molecular oxygen afford various useful α‐difluoro(thio)methylated alcohols and ketones in high yields. Significantly, this protocol has been applied in the synthesis different bioactive molecules. Mechanism studies enable the detection of the hydroperoxy difluoromethylsulfide intermediates and exclude the thiol‐based radical pathway.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Chi Liu, Chuanle Zhu, Yingying Cai, Huanfeng Jiang
onlinelibrary.wiley.com/doi/10.1002/anie.202017271

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sp3 Bis‐Organometallic Reagents via Catalytic 1,1‐Difunctionalization of Unactivated Olefins

sp3 Bis‐Organometallic Reagents via Catalytic 1,1‐Difunctionalization of Unactivated Olefins

A highly modular, site‐selective 1,1‐difunctionalization of unactivated olefins en route to versatile bis‐organometallic B,B(Si)‐reagents was developed by nickel catalyzed chain‐walking events. This protocol is characterized by exceptional reaction rates, mild conditions, broad scope, excellent chemo‐ and regioselectivity, thus unlocking a new technique for preparing densely functionalized 1,2‐bisorganometallic reagents from simple distinct, yet widely available, electrophilic partners.

Abstract

A catalytic 1,1‐difunctionalization of unactivated olefins en route to sp3bis‐organometallic B,B(Si)‐reagents is described. The protocol is characterized by exceptional reaction rates, mild conditions, wide scope, and exquisite selectivity pattern, constituting a new platform to access sp3bis‐organometallics.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Shang‐Zheng Sun, Laura Talavera, Philipp Spieß, Craig S. Day, Ruben Martin
onlinelibrary.wiley.com/doi/10.1002/anie.202100810

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Large‐Scale Rapid Positioning of Hierarchical Assemblies of Conjugated Polymers via Meniscus‐Assisted Self‐Assembly

Large‐Scale Rapid Positioning of Hierarchical Assemblies of Conjugated Polymers via Meniscus‐Assisted Self‐Assembly

A convenient, rapid and robust meniscus‐assisted self‐assembly (MASA) strategy, which combines a deliberately designed upper plate with a moving substrate, prints microscopically conjugated polymer (PFOs) patterns of different shapes within which the β‐phase PFOs self‐assemble at the nanometer scale.

Abstract

Rapid and deliberate patterning of nanomaterials over a large area is desirable for device manufacturing. We report a method for meniscus‐assisted self‐assembly (MASA)‐enabled rapid positioning of hierarchically assembled dots and stripes composed of luminescent conjugated polymer over two length scales. Periodically arranged conjugated poly(9,9‐dioctylfluorene) (PFO) polymers, yield dots, punch‐holes and stripes at microscopic scale via MASA. Concurrent self‐assembly of PFOs into two‐dimensional lenticular crystals within each dot, punch‐hole and stripe is realized at nanoscopic scale. Hierarchical assembly is achieved by constraining the evaporation of the PFOs solution in two approximately parallel plates via a MASA process. The three‐phase contact line (TCL) of the liquid meniscus of the PFOs was printed using the upper plate, yielding an array of curved stripes. Rapid creation of hierarchical assemblies via MASA opens up possibilities for large‐scale organization of a wide range of soft matters and nanomaterials.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Shuang Pan, Juan Peng, Zhiqun Lin
onlinelibrary.wiley.com/doi/10.1002/anie.202101272

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Reactions on a 1,2‐Dicarbonyl Moiety of a Fullerene Skeleton

Reactions on a 1,2‐Dicarbonyl Moiety of a Fullerene Skeleton

The chemical transformation of a 1,2‐dicarbonyl moiety embedded in a cage‐opened fullerene C60 derivative was examined to produce β‐oxo‐phosphorus ylide, α‐methylene carbonyl, and acid anhydride compounds. The former two showed a significantly supressed encapsulation/escape dynamics of a water molecule as well as electrochemical properties largely different from the last one.

Abstract

A 1,2‐dicarbonyl moiety on a cage‐opened fullerene skeleton is one of suitable building blocks for the further derivatization. Herein, we discuss the chemical transformation of a 1,2‐dicarbonyl compound into β‐oxo‐phosphorus ylide, acid anhydride, and α‐methylene carbonyl derivatives. Despite possessing a sterically small methylene unit in the last one, the release of an encapsulated water molecule was significantly supressed whereas the β‐oxo‐phosphorus ylide bearing three bulky p‐tolyl groups on the P‐atom enabled the faster insertion/release dynamics, implying the flexibility of the phosphonium substituent. The replacement of the carbonyl group with phosphorus ylide and methylene units largely varied electrochemical properties of the fullerene skeleton, likely arising from the anionic charge delocalized over the entire molecule and removal of an electron‐withdrawable carbonyl group, respectively.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Yoshifumi Hashikawa, Jiayue Li, Shu Okamoto, Yasujiro Murata
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202100640

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Double‐Network Heparin Dynamic Hydrogels: Dynagels as Anti‐bacterial 3D Cell Culture Scaffolds

Double‐Network Heparin Dynamic Hydrogels: Dynagels as Anti‐bacterial 3D Cell Culture Scaffolds

Multicomponent dynagels for heparin encapsulation: Dynamic covalently cross‐linked dynamers with high mechanical strength, biocompatibility and self‐healing behaviors have been used for biomedical applications.

Abstract

Double cross‐linked dynamic hydrogels, dynagels, have been prepared through reversible imine bonds and supramolecular interactions, which showed good pH responsiveness, injectability, self‐healing property and biocompatibility. With the further encapsulation of heparin, the obtained hydrogels exhibited good anti‐bacterial activity and promotion effects for 3D cell culture.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Han Cui, Qimeng Wang, Ye Zhang, Mihail Barboiu, Yan Zhang, Jinghua Chen
chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/chem.202005376

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Self‐Assembly of Nanographenes

Self‐Assembly of Nanographenes

Suitably decorated small aromatic systems can organize one‐dimensionally stacked structures. We found that nanographenes carrying long alkyl chains behaved similarly. The experiments demonstrated that the nanographenes underwent aggregation and disaggregation regulated by concentration, solvent polarity, temperature, and sonication.

Abstract

Suitably decorated small aromatic systems can organize stacked structures that display interesting properties arising from their unique morphologies. Although nanographenes produced by top‐down methods have graphitic domains and can in principle be applied for such supramolecular systems, to our knowledge, no such example has been reported thus far. This is partly because of their limited solubility in organic solvents and partly because of their wide lateral size distribution. To realize nanographene‐based supramolecular aggregates, nanographenes carrying alkyl chains with narrow lateral size distributions are employed. We find that the nanographenes undergo self‐assembly and that self‐assembly is regulated by concentration, solvent polarity, temperature, and sonication. Optical measurements and AFM images indicate that stacked structures are possible candidates for aggregates. A molecular mechanics calculation models the interactions in the aggregates. The nanographenes showed concentration‐dependent morphologies on mica, stacked structures at low concentrations and polymer‐like network structures on mica at higher concentrations.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Ikuya Matsumoto, Ryo Sekiya, Takeharu Haino
onlinelibrary.wiley.com/doi/10.1002/anie.202101992

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In Vitro-Evolved Peptides Bind Monomeric Actin and Mimic Actin-Binding Protein Thymosin-β4

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ACS Chemical Biology

ACS Chemical Biology: Latest Articles (ACS Publications)
Authors: Raphael J. Gübeli, Davide Bertoldo, Kenji Shimada, Christian B. Gerhold, Verena Hurst, Yuichiro Takahashi, Kai Harada, Ganesh K. Mothukuri, Jonas Wilbs, Masahiko Harata, Susan M. Gasser, and Christian Heinis
feedproxy.google.com/~r/acs/acbcct/~3/JtnvAFO4wgU/acschembio.0c00825

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Dramatic Effect of γ-Heteroatom Dienolate Substituents on Counterion Assisted Asymmetric Anionic Amino-Cope Reaction Cascades

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Journal of the American Chemical Society

Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Pradipta Das, Michael D. Delost, Munaum H. Qureshi, Jianhua Bao, Jason S. Fell, Kendall N. Houk, and Jon T. Njardarson
feedproxy.google.com/~r/acs/jacsat/~3/C3ed_gzs_aI/jacs.1c00745

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Machine-Learning-Guided Discovery and Optimization of Additives in Preparing Cu Catalysts for CO2 Reduction

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Journal of the American Chemical Society

Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Ying Guo, Xinru He, Yuming Su, Yiheng Dai, Mingcan Xie, Shuangli Yang, Jiawei Chen, Kun Wang, Da Zhou, and Cheng Wang
feedproxy.google.com/~r/acs/jacsat/~3/5cs9lsBMwXk/jacs.1c00339

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Bridging Interparticle Li+ Conduction in a Soft Ceramic Oxide Electrolyte

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Journal of the American Chemical Society

Journal of the American Chemical Society: Latest Articles (ACS Publications)
Authors: Wan-Ping Chen, Hui Duan, Ji-Lei Shi, Yumin Qian, Jing Wan, Xu-Dong Zhang, Hang Sheng, Bo Guan, Rui Wen, Ya-Xia Yin, Sen Xin, Yu-Guo Guo, and Li-Jun Wan
feedproxy.google.com/~r/acs/jacsat/~3/bohCNeeW5HY/jacs.0c12965

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Synthesis of the Potent, Selective, and Efficacious β-Secretase (BACE1) Inhibitor NB-360

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Journal of Medicinal Chemistry

Journal of Medicinal Chemistry: Latest Articles (ACS Publications)
Authors: Heinrich Rueeger, Rainer Lueoend, Rainer Machauer, Siem J. Veenstra, Philipp Holzer, Konstanze Hurth, Markus Voegtle, Mathias Frederiksen, Jean-Michel Rondeau, Marina Tintelnot-Blomley, Laura H. Jacobson, Matthias Staufenbiel, Grit Laue, and Ulf Neumann
feedproxy.google.com/~r/acs/jmcmar/~3/XHjtpRB4XzM/acs.jmedchem.0c02143

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Three-Dimensional Proteome-Wide Scale Screening for the 5-Alpha Reductase Inhibitor Finasteride: Identification of a Novel Off-Target

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Journal of Medicinal Chemistry

Journal of Medicinal Chemistry: Latest Articles (ACS Publications)
Authors: Silvia Giatti, Alessandro Di Domizio, Silvia Diviccaro, Eva Falvo, Donatella Caruso, Alessandro Contini, and Roberto Cosimo Melcangi
feedproxy.google.com/~r/acs/jmcmar/~3/r463G4-LZgw/acs.jmedchem.0c02039

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