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1. A General Strategy for Visible-Light Decaging Based on the Quinone Trimethyl Lock

Author:
Walton, David P.; Dougherty, Dennis A.
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4655-4658
ISSN:
1520-5126
Subject:
absorption; amines; byproducts; hydroquinone; models
Abstract:
... Visible-light triggered quinone trimethyl locks are reported as a general design for long-wavelength photoremovable protecting groups for alcohols and amines. Intramolecular photoreduction unmasks a reactive phenol that undergoes fast lactonization to release alcohols and amines. Model substrates are released in quantitative yield along with well-defined, colorless hydroquinone byproducts. Substit ...
DOI:
10.1021/jacs.7b01548

2. A Metallo-molecular Cage That Can Close the Apertures with Coordination Bonds

Author:
Akine, Shigehisa; Miyashita, Masato; Nabeshima, Tatsuya
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4631-4634
ISSN:
1520-5126
Subject:
chemical bonding; ligands
Abstract:
... We designed a novel tricobalt(III) metallo-molecular cage in which its apertures can be closed with bifunctional ligands via coordination bonds. A closed-cage complex was easily formed by ligand exchange of its open-cage analogue. Guest uptake/release by the open-cage complex was sufficiently fast to quickly reach guest-binding equilibrium, while that by the closed-cage complex was extremely slow ...
DOI:
10.1021/jacs.7b00840

3. An All-Organic Proton Battery

Author:
Emanuelsson, Rikard; Sterby, Mia; Strømme, Maria; Sjödin, Martin
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4828-4834
ISSN:
1520-5126
Subject:
additives; anodes; anthraquinones; batteries; cathodes; electrolytes; hydroquinone; lithium; organic matter; pyridines; redox reactions; slurries; sodium
Abstract:
... Rechargeable batteries that use organic matter as the capacity-carrying material have previously been considered a technology for the future. Earlier batteries in which both the anode and cathode consisted of organic material required significant amounts of conductive additives and were often based on metal-ion electrolytes containing Li⁺ or Na⁺. However, we have used conducting poly(3,4-ethylened ...
DOI:
10.1021/jacs.7b00159

4. A Study of the Mechanism of the Hydrogen Evolution Reaction on Nickel by Surface Interrogation Scanning Electrochemical Microscopy

Author:
Liang, Zhenxing; Ahn, Hyun S.; Bard, Allen J.
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4854-4858
ISSN:
1520-5126
Subject:
adsorption; electrochemistry; hydrogen; hydrogen production; microscopy; nickel
Abstract:
... The hydrogen evolution reaction (HER) on Ni in alkaline media was investigated by scanning electrochemical microscopy under two operating modes. First, the substrate generation/tip collection mode was employed to extract the “true” cathodic current associated with the HER from the total current in the polarization curve. Compared to metallic Ni, the electrocatalytic activity of the HER is improved ...
DOI:
10.1021/jacs.7b00279

5. Controlled Sol–Gel Transitions by Actuating Molecular Machine Based Supramolecular Polymers

Author:
Goujon, Antoine; Mariani, Giacomo; Lang, Thomas; Moulin, Emilie; Rawiso, Michel; Buhler, Eric; Giuseppone, Nicolas
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4923-4928
ISSN:
1520-5126
Subject:
chemists; muscles; pH; polymers
Abstract:
... The implementation of artificial molecular machines in polymer science is an important objective that challenges chemists and physicists in order to access an entirely new class of smart materials. To design such systems, the amplification of a mechanical actuation from the nanoscale up to a macroscopic response in the bulk material is a central issue. In this article we show that bistable [c2]dai ...
DOI:
10.1021/jacs.7b00983

6. Copper(I)-Catalyzed Enantioselective Addition of Enynes to Ketones

Author:
Wei, Xiao-Feng; Xie, Xiao-Wei; Shimizu, Yohei; Kanai, Motomu
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4647-4650
ISSN:
1520-5126
Subject:
alcohols; catalysts; copper; enantiomers; ketones; ligands
Abstract:
... A copper(I)-catalyzed enantioselective addition of enynes to ketones was developed. The method allows facile construction of enantiomerically enriched tertiary alcohols using skipped enynes as stable hydrocarbon pronucleophiles. The combination of a soft copper(I)-conjugated Brønsted base catalyst with a chiral diphosphine ligand, (S,S)-Ph-BPE, enabled chemoselective deprotonation of the skipped e ...
DOI:
10.1021/jacs.7b01254

7. CO2-Selective Absorbents in Air: Reverse Lipid Bilayer Structure Forming Neutral Carbamic Acid in Water without Hydration

Author:
Inagaki, Fuyuhiko; Matsumoto, Chiaki; Iwata, Takashi; Mukai, Chisato
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4639-4642
ISSN:
1520-5126
Subject:
absorbents; absorption; air; carbon dioxide; carboxylic acids; energy; heat; hydrophobicity; lipid bilayers
Abstract:
... Emission gas and air contain not only CO₂ but also plentiful moisture, making it difficult to achieve selective CO₂ absorption without hydration. To generate absorbed CO₂ (wet CO₂) under heating, the need for external energy to release the absorbed water has been among the most serious problems in the fields of carbon dioxide capture and storage (CCS) and direct air capture (DAC). We found that th ...
DOI:
10.1021/jacs.7b01049

8. Defect-Induced Near-Infrared Photoluminescence of Single-Walled Carbon Nanotubes Treated with Polyunsaturated Fatty Acids

Author:
Chiu, Cheuk Fai; Saidi, Wissam A.; Kagan, Valerian E.; Star, Alexander
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4859-4865
ISSN:
1520-5126
Subject:
DNA; biocompatibility; carbon nanotubes; drugs; hydroperoxides; hydrophobicity; image analysis; lipid peroxidation; photoluminescence; photooxidation; polymers; polyunsaturated fatty acids; proteins; surfactants; therapeutics
Abstract:
... Single-walled carbon nanotubes (SWCNTs) have been incorporated in many emerging applications in the biomedical field including chemical sensing, biological imaging, drug delivery, and photothermal therapy. To overcome inherent hydrophobicity and improve their biocompatibility, pristine SWCNTs are often coated with surfactants, polymers, DNA, proteins, or lipids. In this paper, we report the effect ...
DOI:
10.1021/jacs.7b00390
PubMed:
28288512
PubMed Central:
PMC6540762

9. Determining Band-Edge Energies and Morphology-Dependent Stability of Formamidinium Lead Perovskite Films Using Spectroelectrochemistry and Photoelectron Spectroscopy

Author:
Shallcross, R. Clayton; Zheng, Yilong; Saavedra, S. Scott; Armstrong, Neal R.
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4866-4878
ISSN:
1520-5126
Subject:
X-ray photoelectron spectroscopy; absorbance; electrochemistry; electrodes; electrolytes; energy; indium tin oxide; photovoltaic cells; stoichiometry; titanium dioxide
Abstract:
... We show for the first time that the frontier orbital energetics (conduction band minimum (CBM) and valence band maximum (VBM)) of device-relevant, methylammonium bromide (MABr)-doped, formamidinium lead trihalide perovskite (FA-PVSK) thin films can be characterized using UV–vis spectroelectrochemistry, which provides an additional and straightforward experimental technique for determining energy b ...
DOI:
10.1021/jacs.7b00516

10. α-Dicationic Chelating Phosphines: Synthesis and Application to the Hydroarylation of Dienes

Author:
Gu, Lianghu; Wolf, Lawrence M.; Zieliński, Adam; Thiel, Walter; Alcarazo, Manuel
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4948-4953
ISSN:
1520-5126
Subject:
acidity; catalysts; chelates; ligands; metals; methodology
Abstract:
... A series of new P^P-chelating ligands constituted by a dicationic −[P(H₂Im)₂]⁺² unit (H₂Im = 1,3-dimethyl-4,5-dihydroimidazol-2-ylidene) and a −PPh₂ group connected through structurally different backbones have been synthesized. Evaluation of their reactivity toward different metal centers provides evidence that the dicationic fragment, otherwise reluctant to coordinate metals, readily participate ...
DOI:
10.1021/jacs.7b01441

11. Doubly Diastereoconvergent Preparation and Microsolvation-Controlled Properties of (Z)- and (E)-1′-Lithio-1′-(2,6-dimethylphenyl)propenes

Author:
Knorr, Rudolf; Behringer, Claudia; Knittl, Monika; von Roman, Ulrich; Lattke, Ernst
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4690-4703
ISSN:
1520-5126
Subject:
ambient temperature; nuclear magnetic resonance spectroscopy; propylene; solvents
Abstract:
... A doubly diastereoconvergent reaction can ad libitum generate either one or the other of two diastereomeric products with complete consumption of the diastereomeric precorsors or their mixtures. Thus, the preparation of configurationally pure (Z)-1′-lithio-1′-(2,6-dimethylphenyl)propene [(Z)-1] from any Z,E mixture of the corresponding bromoalkenes with n-butyllithium succeeded by means of a user- ...
DOI:
10.1021/jacs.6b11003

12. Electrochemically Assisted Self-Assembly Technique for the Fabrication of Mesoporous Metal–Organic Framework Thin Films: Composition of 3D Hexagonally Packed Crystals with 2D Honeycomb-like Mesopores

Author:
Alizadeh, Saber; Nematollahi, Davood
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4753-4761
ISSN:
1520-5126
Subject:
crystals; electrochemistry; electrodes; electron transfer; mass transfer; porous media
Abstract:
... In this work, we introduce a novel and general strategy for the environmentally friendly fabrication of mesoporous metal–organic framework (mMOF) thin films via the electrochemically assisted self-assembly (EASA) technique. Implementation of this procedure as a one-step, additive-free, and versatile protocol leads to the in situ simultaneous synthesis and deposition of mesoporous architectures of ...
DOI:
10.1021/jacs.6b12564

13. Enantioselective Ring-Opening Polymerization of rac-Lactide Dictated by Densely Substituted Amino Acids

Author:
Sanchez-Sanchez, Ana; Rivilla, Ivan; Agirre, Maddalen; Basterretxea, Andere; Etxeberria, Agustin; Veloso, Antonio; Sardon, Haritz; Mecerreyes, David; Cossío, Fernando P.
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4805-4814
ISSN:
1520-5126
Subject:
ambient temperature; amino acids; catalysts; diastereomers; enantiomers; methodology; polylactic acid; polymerization; stereochemistry; stereoisomerism
Abstract:
... Organocatalysis is becoming an important tool in polymer science because of its versatility and specificity. To date a limited number of organic catalysts have demonstrated the ability to promote stereocontrolled polymerizations. In this work we report one of the first examples of chirality transfer from a catalyst to a polymer in the organocatalyzed ring-opening polymerization (ROP) of rac-lactid ...
DOI:
10.1021/jacs.6b13080

14. Energy Storage during Compression of Metal–Organic Frameworks

Author:
Miao, Yu-Run; Su, Zhi; Suslick, Kenneth S.
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4667-4670
ISSN:
1520-5126
Subject:
absorption; coordination polymers; deformation; energy; mechanical properties; nanocrystals; transmission electron microscopes; trinitrotoluene
Abstract:
... Practical applications of metal–organic framework (MOF) materials require an in-depth understanding of their mechanical properties. We have investigated the mechanical properties and energy absorption behavior of single crystals of four isostructural UiO-type MOFs under uniaxial compression. In situ nanocompression experiments were used to measure the mechanical behavior of individual MOF nanocrys ...
DOI:
10.1021/jacs.7b01593

15. Engineered Split-TET2 Enzyme for Inducible Epigenetic Remodeling

Author:
Lee, Minjung; Li, Jia; Liang, Yi; Ma, Guolin; Zhang, Jixiang; He, Lian; Liu, Yuliang; Li, Qian; Li, Minyong; Sun, Deqiang; Zhou, Yubin; Huang, Yun
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4659-4662
ISSN:
1520-5126
Subject:
DNA; chromatin; epigenetics; genetic code; genome; mammals; oxidation
Abstract:
... The Ten-eleven translocation (TET) family of 5-methylcytosine (5mC) dioxygenases catalyze the conversion of 5mC into 5-hydroxymethylcytosine (5hmC) and further oxidized species to promote active DNA demethylation. Here we engineered a split-TET2 enzyme to enable temporal control of 5mC oxidation and subsequent remodeling of epigenetic states in mammalian cells. We further demonstrate the use of th ...
DOI:
10.1021/jacs.7b01459
PubMed:
28294608
PubMed Central:
PMC5385525

16. Enhanced Binding Affinity for an i-Motif DNA Substrate Exhibited by a Protein Containing Nucleobase Amino Acids

Author:
Bai, Xiaoguang; Talukder, Poulami; Daskalova, Sasha M.; Roy, Basab; Chen, Shengxi; Li, Zhongxian; Dedkova, Larisa M.; Hecht, Sidney M.
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4611-4614
ISSN:
1520-5126
Subject:
DNA; amino acids; binding capacity; molecular models; transcription factors; uracil
Abstract:
... Several variants of a nucleic acid binding motif (RRM1) of putative transcription factor hnRNP LL containing nucleobase amino acids at specific positions have been prepared and used to study binding affinity for the BCL2 i-motif DNA. Molecular modeling suggested a number of amino acids in RRM1 likely to be involved in interaction with the i-motif DNA, and His24 and Arg26 were chosen for modificati ...
DOI:
10.1021/jacs.6b11825
PubMed:
28263595
PubMed Central:
PMC5901667

17. Enhanced Superconductivity in Restacked TaS2 Nanosheets

Author:
Pan, Jie; Guo, Chenguang; Song, Changsheng; Lai, Xiaofang; Li, Hui; Zhao, Wei; Zhang, Hui; Mu, Gang; Bu, Kejun; Lin, Tianquan; Xie, Xiaoming; Chen, Mingwei; Huang, Fuqiang
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4623-4626
ISSN:
1520-5126
Subject:
crystals; heat; methodology; nanosheets; specific heat
Abstract:
... Since interface superconductivity was discovered at the interface between two insulating layers LaAlO₃ and SrTiO₃, such interface-induced superconducting systems have been a research hotspot in superconductivity. Here, we report homogeneous interfaces formed by stacking chemically exfoliated monolayer TaS₂ nanosheets randomly. Enhanced superconductivity of Tc = 3 K is observed, compared with 0.8 K ...
DOI:
10.1021/jacs.7b00216

18. Expanded Rosarin: A Versatile Fullerene (C60) Receptor

Author:
Ke, Xian-Sheng; Kim, Taeyeon; Brewster, James T.; Lynch, Vincent M.; Kim, Dongho; Sessler, Jonathan L.
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4627-4630
ISSN:
1520-5126
Subject:
X-ray diffraction; benzaldehyde; fullerene; nuclear magnetic resonance spectroscopy; oxidation; pyridines; solubility; stoichiometry; toluene
Abstract:
... An expanded rosarian (P₃P₆) with a bowl-like conformation has been prepared and characterized in a one-pot procedure that involves condensing a bispyrrole pyridine precursor (P₁P₂) with benzaldehyde, followed by oxidation. Single crystal X-ray diffraction analysis reveals a bowl-like conformation in the solid state with an upper rim diameter defined by the meso-phenyl substituents of ca. 13.5 Å an ...
DOI:
10.1021/jacs.7b00735

19. Exploring Oxygen Activity in the High Energy P2-Type Na0.78Ni0.23Mn0.69O2 Cathode Material for Na-Ion Batteries

Author:
Ma, Chuze; Alvarado, Judith; Xu, Jing; Clément, Raphaële J.; Kodur, Moses; Tong, Wei; Grey, Clare P.; Meng, Ying Shirley
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4835-4845
ISSN:
1520-5126
Subject:
manganese; phase transition; research and development; energy; renewable energy sources; cathodes; X-ray absorption spectroscopy; ambient temperature; electrochemistry; sodium; nickel; oxidation; oxides; metal ions; oxygen; batteries
Abstract:
... Large-scale electric energy storage is fundamental to the use of renewable energy. Recently, research and development efforts on room-temperature sodium-ion batteries (NIBs) have been revitalized, as NIBs are considered promising, low-cost alternatives to the current Li-ion battery technology for large-scale applications. Herein, we introduce a novel layered oxide cathode material, Na₀.₇₈Ni₀.₂₃Mn₀ ...
DOI:
10.1021/jacs.7b00164

20. Giant Electron–Hole Interactions in Confined Layered Structures for Molecular Oxygen Activation

Author:
Wang, Hui; Chen, Shichuan; Yong, Dingyu; Zhang, Xiaodong; Li, Shuang; Shao, Wei; Sun, Xianshun; Pan, Bicai; Xie, Yi
Source:
Journal of the American Chemical Society 2017 v.139 no.13 pp. 4737-4742
ISSN:
1520-5126
Subject:
bismuth; electrons; energy transfer; oxygen; photocatalysts; singlet oxygen
Abstract:
... Numerous efforts have been devoted to understanding the excitation processes of photocatalysts, whereas the potential Coulomb interactions between photogenerated electrons and holes have been long ignored. Once these interactions are considered, excitonic effects will arise that undoubtedly influence the sunlight-driven catalytic processes. Herein, by taking bismuth oxyhalide as examples, we propo ...
DOI:
10.1021/jacs.6b12273