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- Author:
- Pan, Xiaobo; Wang, Xingyong; Zhao, Yue; Sui, Yunxia; Wang, Xinping
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9834-9837
- ISSN:
- 1520-5126
- Subject:
- X-ray diffraction; anions; chemical bonding; electron paramagnetic resonance spectroscopy; free radicals; phosphorus; salts; ultraviolet-visible spectroscopy
- Abstract:
- ... Salts containing phosphaalkene radical anions have been isolated and characterized by electron paramagnetic resonance (EPR) spectroscopy, UV–vis absorption spectroscopy, and single-crystal X-ray diffraction. The radical anions feature elongated P–C bonds and an aromatization of fulvene compared to the neutral phosphaalkene. Their EPR spectra and theoretical calculations indicate the spin density o ...
- DOI:
- 10.1021/ja504001x
-
http://dx.doi.org/10.1021%2Fja504001x
- Author:
- Langseth, Eirin; Nova, Ainara; Tråseth, Eline
Aa.; Rise, Frode; Øien, Sigurd; Heyn, Richard H.; Tilset, Mats
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10104-10115
- ISSN:
- 1520-5126
- Subject:
- X-ray diffraction; ambient temperature; dissociation; ethylene; gold; isomers; ligands; methylene chloride; nuclear magnetic resonance spectroscopy; olefin; thermodynamics
- Abstract:
- ... The Au(III) complex Au(OAcF)₂(tpy) (1, OAcF = OCOCF₃; tpy = 2-p-tolylpyridine) undergoes reversible dissociation of the OAcF ligand trans to C, as seen by ¹⁹F NMR. In dichloromethane or trifluoroacetic acid (TFA), the reaction between 1 and ethylene produces Au(OAcF)(CH₂CH₂OAcF)(tpy) (2). The reaction is a formal insertion of the olefin into the Au–O bond trans to N. In TFA this reaction occurs in ...
- DOI:
- 10.1021/ja504554u
-
http://dx.doi.org/10.1021%2Fja504554u
- Author:
- Konnick, Michael
M.; Bischof, Steven M.; Yousufuddin, Muhammed; Hashiguchi, Brian G.; Ess, Daniel H.; Periana, Roy A.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10085-10094
- ISSN:
- 1520-5126
- Subject:
- catalysts; energy; ethane; ethanol; ethylene; methane; oxidation; platinum; shale; solvents; sulfuric acid; temperature
- Abstract:
- ... The selective, oxidative functionalization of ethane, a significant component of shale gas, to products such as ethylene or ethanol at low temperatures and pressures remains a significant challenge. Herein we report that ethane is efficiently and selectively functionalized to the ethanol ester of H₂SO₄, ethyl bisulfate (EtOSO₃H) as the initial product, with the Ptᴵᴵ “Periana-Catalytica” catalyst i ...
- DOI:
- 10.1021/ja504368r
-
http://dx.doi.org/10.1021%2Fja504368r
- Author:
- Awakawa, Takayoshi; Zhang, Lihan; Wakimoto, Toshiyuki; Hoshino, Shotaro; Mori, Takahiro; Ito, Takuya; Ishikawa, Jun; Tanner, Martin
E.; Abe, Ikuro
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9910-9913
- ISSN:
- 1520-5126
- Subject:
- Streptomyces; biosynthesis; cations; chemical structure; chromosomes; genes; heterologous gene expression; methylation; methyltransferases; protein kinase C; terpenoids; transcription (genetics)
- Abstract:
- ... Teleocidin B is an indole terpenoid isolated from Streptomyces. Due to its unique chemical structure and ability to activate protein kinase C, it has attracted interest in the areas of organic chemistry and cell biology. Here, we report the identification of genes encoding enzymes for teleocidin B biosynthesis, including nonribosomal peptide synthetase (tleA), P-450 monooxygenase (tleB), prenyltra ...
- DOI:
- 10.1021/ja505224r
-
http://dx.doi.org/10.1021%2Fja505224r
- Author:
- Shie, Jiun-Jie; Liu, Ying-Chih; Lee, Yu-Ming; Lim, Carmay; Fang, Jim-Min; Wong, Chi-Huey
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9953-9961
- ISSN:
- 1520-5126
- Subject:
- alkynes; copper; cycloaddition reactions; fluorescence; gel electrophoresis; glycoproteins; glycosylation; image analysis; triazoles; wavelengths
- Abstract:
- ... We have designed a low fluorescent azido-BODIPY-based probe AzBOCEt (Az10) that undergoes copper(I)-catalyzed 1,3-dipolar cycloadditions with alkynes to yield strongly fluorescent triazole derivatives. The fluorescent quantum yield of a triazole product T10 is enhanced by 52-fold as compared to AzBOCEt upon excitation at a wavelength above 500 nm. Quantum mechanical calculations indicate that the ...
- DOI:
- 10.1021/ja5010174
-
http://dx.doi.org/10.1021%2Fja5010174
- Author:
- Lian, Wenlong; Jiang, Bisheng; Qian, Ziqing; Pei, Dehua
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9830-9833
- ISSN:
- 1520-5126
- Subject:
- cell membranes; cyclic peptides; peptidylprolyl isomerase; protein-tyrosine-phosphatase; proteins
- Abstract:
- ... Cyclic peptides have great potential as therapeutic agents and research tools but are generally impermeable to the cell membrane. Fusion of cyclic peptides with a cyclic cell-penetrating peptide produces bicyclic peptides that are cell-permeable and retain the ability to recognize specific intracellular targets. Application of this strategy to protein tyrosine phosphatase 1B and a peptidyl-prolyl ...
- DOI:
- 10.1021/ja503710n
- PubMed:
- 24972263
- PubMed Central:
- PMC4227718
-
http://dx.doi.org/10.1021%2Fja503710n
- Author:
- Beaumont, Simon
K.; Alayoglu, Selim; Specht, Colin; Michalak, William D.; Pushkarev, Vladimir
V.; Guo, Jinghua; Kruse, Norbert; Somorjai, Gabor A.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9898-9901
- ISSN:
- 1520-5126
- Subject:
- X-ray absorption spectroscopy; carbon dioxide; catalysts; catalytic activity; cobalt; hydrogen; hydrogenation; nanoparticles; platinum; synthetic fuels; temperature
- Abstract:
- ... The mechanistic role of platinum and precious metals in promoting cobalt hydrogenation catalysts of the type used in reactions such as Fischer–Tropsch synthesis is highly debated. Here we use well-defined monometallic Pt and Co nanoparticles (NPs) and CO₂ methanation as a probe reaction to show that Pt NPs deposited near Co NPs can enhance the CO₂ methanation rate by up to a factor of 6 per Co sur ...
- DOI:
- 10.1021/ja505286j
-
http://dx.doi.org/10.1021%2Fja505286j
- Author:
- Islam, Zahidul; Strutzenberg, Timothy S.; Gurevic, Ilya; Kohen, Amnon
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9850-9853
- ISSN:
- 1520-5126
- Subject:
- DNA; active sites; antibiotics; arginine; biomimetics; catalysts; catalytic activity; cysteine; drug therapy; drugs; hydrides; isotopes; mutagenesis; thymidylate synthase
- Abstract:
- ... Thymidylate synthase (TSase) catalyzes the intracellular de novo formation of thymidylate (a DNA building block) in most living organisms, making it a common target for chemotherapeutic and antibiotic drugs. Two mechanisms have been proposed for the rate-limiting hydride transfer step in TSase catalysis: a stepwise mechanism in which the hydride transfer precedes the cleavage of the covalent bond ...
- DOI:
- 10.1021/ja504341g
- PubMed:
- 24949852
- PubMed Central:
- PMC4105062
-
http://dx.doi.org/10.1021%2Fja504341g
- Author:
- Suzuki, Takuya; Yamamoto, Takuya; Tezuka, Yasuyuki
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10148-10155
- ISSN:
- 1520-5126
- Subject:
- hydrodynamics; isomers; polymers
- Abstract:
- ... A triply fused tetracyclic macromolecular K₃,₃ graph has been constructed through electrostatic self-assembly of a uniformly sized dendritic polymer precursor having six cyclic ammonium salt end groups carrying two units of a trifunctional carboxylate counteranions, and subsequent covalent conversion by the ring-opening reaction of cyclic ammonium salt groups at an elevated temperature under dilut ...
- DOI:
- 10.1021/ja504891x
-
http://dx.doi.org/10.1021%2Fja504891x
- Author:
- Fañanás-Mastral, Martín; Feringa, Ben L.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9894-9897
- ISSN:
- 1520-5126
- Subject:
- catalysts; chemical reactions; copper; oxygen; phosphonates; salts
- Abstract:
- ... Copper-catalysis allows the direct oxygen-arylation of dialkyl phosphonates with diaryliodonium salts. This novel methodology proceeds with a wide range of phosphonates and phosphoramidates under mild conditions and gives straightforward access to valuable mixed alkyl aryl phosphonates in very good yields and near perfect selectivity. ...
- DOI:
- 10.1021/ja505281v
-
http://dx.doi.org/10.1021%2Fja505281v
- Author:
- Lee, Sai-Ho; Chan, Chris
Tsz-Leung; Wong, Keith Man-Chung; Lam, Wai Han; Kwok, Wai-Ming; Yam, Vivian Wing-Wah
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10041-10052
- ISSN:
- 1520-5126
- Subject:
- absorption; electrochemistry; electron transfer; energy transfer; fullerene; methylene chloride; models; platinum; spectroscopy
- Abstract:
- ... Donor–chromophore–acceptor triads, (PTZ)₂-Pt(bpy)-C₆₀ and (ᵗBuPTZ)₂-Pt(bpy)-C₆₀, along with their model compound, (Ph)₂-Pt(bpy)-C₆₀, have been synthesized and characterized; their photophysical and electrochemical properties have been studied, and the origin of the absorption and emission properties has been supported by computational studies. The photoinduced electron transfer reactions have been ...
- DOI:
- 10.1021/ja5040073
-
http://dx.doi.org/10.1021%2Fja5040073
- Author:
- Plummer, Christopher
W.; Wei, Carolyn S.; Yozwiak, Carrie E.; Soheili, Arash; Smithback, Sara O.; Leighton, James L.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9878-9881
- ISSN:
- 1520-5126
- Subject:
- biosynthesis; chemical reactions; chemical structure; fungal proteins; temperature
- Abstract:
- ... An approach to the synthesis of the (iso)cyclocitrinol core structure is described. The key step is a tandem Ireland Claisen/Cope rearrangement sequence, wherein the Ireland Claisen rearrangement effects ring contraction to a strained 10-membered ring, and that strain in turn drives the Cope rearrangement under unusually mild thermal conditions. A major side product was identified as resulting fro ...
- DOI:
- 10.1021/ja505131v
-
http://dx.doi.org/10.1021%2Fja505131v
- Author:
- Chen, Kai; Xu, Jing; Luft, J. Christopher; Tian, Shaomin; Raval, Jay S.; DeSimone, Joseph M.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9947-9952
- ISSN:
- 1520-5126
- Subject:
- amines; crosslinking; electrolytes; hydrogels; nucleic acids; oxygen; polymers
- Abstract:
- ... Lowering the modulus of hydrogel particles could enable them to bypass in vivo physical barriers that would otherwise filter particles with similar size but higher modulus. Incorporation of electrolyte moieties into the polymer network of hydrogel particles to increase the swelling ratio is a straightforward and quite efficient way to decrease the modulus. In addition, charged groups in hydrogel p ...
- DOI:
- 10.1021/ja503939n
- PubMed:
- 24941029
- PubMed Central:
- PMC4227716
-
http://dx.doi.org/10.1021%2Fja503939n
- Author:
- Wang, Qianqian; Xu, Bo; Sun, Jian; Liu, Hanyu; Zhao, Zhisheng; Yu, Dongli; Fan, Changzeng; He, Julong
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9826-9829
- ISSN:
- 1520-5126
- Subject:
- clean energy; electric power; optical properties; photovoltaic cells; silicon; solar collectors; solar energy
- Abstract:
- ... Elemental silicon has a large impact on the economy of the modern world and is of fundamental importance in the technological field, particularly in solar cell industry. The great demand of society for new clean energy and the shortcomings of the current silicon solar cells are calling for new materials that can make full use of the solar power. In this paper, six metastable allotropes of silicon ...
- DOI:
- 10.1021/ja5035792
-
http://dx.doi.org/10.1021%2Fja5035792
- Author:
- Fishovitz, Jennifer; Rojas-Altuve, Alzoray; Otero, Lisandro
H.; Dawley, Matthew; Carrasco-López, Cesar; Chang, Mayland; Hermoso, Juan A.; Mobashery, Shahriar
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9814-9817
- ISSN:
- 1520-5126
- Subject:
- X-radiation; active sites; antibiotic resistance; biosynthesis; death; methicillin; methicillin-resistant Staphylococcus aureus; mutants
- Abstract:
- ... Ceftaroline, a recently approved β-lactam antibiotic for treatment of infections by methicillin-resistant Staphylococcus aureus (MRSA), is able to inhibit penicillin-binding protein 2a (PBP2a) by triggering an allosteric conformational change that leads to the opening of the active site. The opened active site is now vulnerable to inhibition by a second molecule of ceftaroline, an event that impai ...
- DOI:
- 10.1021/ja5030657
-
http://dx.doi.org/10.1021%2Fja5030657
- Author:
- Buchsbaum, Steven
F.; Nguyen, Gael; Howorka, Stefan; Siwy, Zuzanna S.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9902-9905
- ISSN:
- 1520-5126
- Subject:
- DNA; cell membranes; drugs; membrane potential; nanopores; pH; polymers
- Abstract:
- ... Biological channels embedded in cell membranes regulate ionic transport by responding to external stimuli such as pH, voltage, and molecular binding. Mimicking the gating properties of these biological structures would be instrumental in the preparation of smart membranes used in biosensing, drug delivery, and ionic circuit construction. Here we present a new concept for building synthetic nanopor ...
- DOI:
- 10.1021/ja505302q
-
http://dx.doi.org/10.1021%2Fja505302q
- Author:
- Goldman, Lawrence
M.; Amyes, Tina L.; Goryanova, Bogdana; Gerlt, John A.; Richard, John P.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10156-10165
- ISSN:
- 1520-5126
- Subject:
- amides; catalysts; decarboxylation; energy; hydrogen bonding; mutants; mutation; orotic acid; thermodynamics
- Abstract:
- ... The mechanism for activation of orotidine 5′-monophosphate decarboxylase (OMPDC) by interactions of side chains from Gln215 and Try217 at a gripper loop and R235, adjacent to this loop, with the phosphodianion of OMP was probed by determining the kinetic parameters kcₐₜ and Kₘ for all combinations of single, double, and triple Q215A, Y217F, and R235A mutations. The 12 kcal/mol intrinsic binding en ...
- DOI:
- 10.1021/ja505037v
- PubMed:
- 24958125
- PubMed Central:
- PMC4227808
-
http://dx.doi.org/10.1021%2Fja505037v
- Author:
- Keane, Andrew
J.; Yonke, Brendan L.; Hirotsu, Masakazu; Zavalij, Peter Y.; Sita, Lawrence R.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9906-9909
- ISSN:
- 1520-5126
- Subject:
- Gibbs free energy; energy; isomerization; nitrogen
- Abstract:
- ... Experimental data support a mechanism for NN bond cleavage within a series of group 5 bimetallic dinitrogen complexes of general formula, {Cp*M[N(ⁱPr)C(R)N(ⁱPr)]}₂(μ-N₂) (Cp* = η⁵-C₅Me₅) (M = Nb, Ta), that proceeds in solution through an intramolecular “end-on-bridged” (μ-η¹:η¹-N₂) to “side-on-bridged” (μ-η²:η²-N₂) isomerization process to quantitatively provide the corresponding bimetallic bis(μ ...
- DOI:
- 10.1021/ja505309j
-
http://dx.doi.org/10.1021%2Fja505309j
- Author:
- Li, Wei-Peng; Liao, Pei-Yi; Su, Chia-Hao; Yeh, Chen-Sheng
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10062-10075
- ISSN:
- 1520-5126
- Subject:
- drug therapy; drugs; gold; iron oxides; magnetic materials; magnetic resonance imaging; magnetism; nanocarriers; nanogold; nanoparticles; neoplasms; oligonucleotides; porous media; silica
- Abstract:
- ... A new multifunctional nanoparticle to perform a near-infrared (NIR)-responsive remote control drug release behavior was designed for applications in the biomedical field. Different from the previous studies in formation of Fe₃O₄-Au core–shell nanoparticles resulting in a spherical morphology, the heterostructure with polyhedral core and shell was presented with the truncated octahedral Fe₃O₄ nanop ...
- DOI:
- 10.1021/ja504118q
-
http://dx.doi.org/10.1021%2Fja504118q
- Author:
- Kazem Shiroodi, Roohollah; Soltani, Mohammad; Gevorgyan, Vladimir
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9882-9885
- ISSN:
- 1520-5126
- Subject:
- chemical bonding; electronics; gold; stereochemistry; thermodynamics
- Abstract:
- ... An efficient, regioselective gold-catalyzed 1,3-transposition reaction of ynones and diynones has been developed. It was found that stereoelectronic (interrupted conjugation) and electronic (extended conjugation) factors could efficiently govern the regioselectivity of this thermodynamically controlled transformation. The produced conjugated diynones were efficiently transformed into diverse alkyn ...
- DOI:
- 10.1021/ja504892c
- PubMed:
- 24971528
- PubMed Central:
- PMC4206192
-
http://dx.doi.org/10.1021%2Fja504892c
- Author:
- Wang, Xiaorui; Hu, Jinming; Zhang, Guoying; Liu, Shiyong
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9890-9893
- ISSN:
- 1520-5126
- Subject:
- antigens; biosensors; crosslinking; enzymatic reactions; enzyme-linked immunosorbent assay; fluorescence; glucose; humans; hydrogen peroxide; peroxidase; tyrosine
- Abstract:
- ... The development of a highly selective and fast responsive fluorogenic biosensor for diverse analytes ranging from bioactive small molecules to specific antigens is highly desirable but remains a considerable challenge. We herein propose a new approach by integrating substrate-selective enzymatic reactions with fluorogens exhibiting aggregation-induced emission feature. Tyrosine-functionalized tetr ...
- DOI:
- 10.1021/ja505278w
-
http://dx.doi.org/10.1021%2Fja505278w
- Author:
- Faber, Matthew
S.; Dziedzic, Rafal; Lukowski, Mark A.; Kaiser, Nicholas S.; Ding, Qi; Jin, Song
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10053-10061
- ISSN:
- 1520-5126
- Subject:
- catalysts; catalytic activity; electrodes; geometry; hydrogen; hydrogen production; metals; nanowires; photovoltaic cells; pyrite; surface area
- Abstract:
- ... The development of efficient and robust earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) is an ongoing challenge. We report metallic cobalt pyrite (cobalt disulfide, CoS₂) as one such high-activity candidate material and demonstrate that its specific morphologyfilm, microwire, or nanowire, made available through controlled synthesisplays a crucial role in determining its ...
- DOI:
- 10.1021/ja504099w
-
http://dx.doi.org/10.1021%2Fja504099w
- Author:
- Qi, Dianyu; Lu, Liujia; Wang, Lingzhi; Zhang, Jinlong
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9886-9889
- ISSN:
- 1520-5126
- Subject:
- Raman spectroscopy; irradiation; light scattering; lighting; microarray technology; photonics; titanium dioxide; wavelengths
- Abstract:
- ... Highly sensitive surface-enhanced Raman scattering (SERS) detection was achieved on plasmon-free TiO₂ photonic artificial microarray, which can be quickly recovered under simulated solar light irradiation and repeatedly used. The sensitive detection performance is attributed to the enhanced matter-light interaction through repeated and multiple light scattering in photonic microarray. Moreover, th ...
- DOI:
- 10.1021/ja5052632
-
http://dx.doi.org/10.1021%2Fja5052632
- Author:
- Gros, Corey
R.; Peprah, Marcus K.; Hosterman, Brian D.; Brinzari, Tatiana V.; Quintero, Pedro A.; Sendova, Mariana; Meisel, Mark W.; Talham, Daniel R.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9846-9849
- ISSN:
- 1520-5126
- Subject:
- Raman spectroscopy; coordination polymers; iron
- Abstract:
- ... Coordination polymer thin film heterostructures of the Prussian blue analogue Niᴵᴵb[Crᴵᴵᴵ(CN)₆]₀.₇·nH₂O (NiCr-PBA) and the 3D Hofmann-like spin crossover compound Fe(azpy)[Pt(CN)₄]·xH₂O {azpy = 4,4′-azopyridine} have been developed, and spin transition properties have been characterized via SQUID magnetometry and Raman spectroscopy. The magnetic response of the ferromagnetic NiCr-PBA layer (Tc ≈ 7 ...
- DOI:
- 10.1021/ja504289p
-
http://dx.doi.org/10.1021%2Fja504289p
- Author:
- Banga, Resham
J.; Chernyak, Natalia; Narayan, Suguna P.; Nguyen, SonBinh T.; Mirkin, Chad A.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9866-9869
- ISSN:
- 1520-5126
- Subject:
- DNA; genes; hydrophobic bonding; nanomaterials; phospholipids
- Abstract:
- ... A novel class of metal-free spherical nucleic acid nanostructures was synthesized from readily available starting components. These particles consist of 30 nm liposomal cores, composed of an FDA-approved 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) lipid monomer. The surface of the liposomes was functionalized with DNA strands modified with a tocopherol tail that intercalates into the phospholi ...
- DOI:
- 10.1021/ja504845f
- PubMed:
- 24983505
- PubMed Central:
- PMC4280063
-
http://dx.doi.org/10.1021%2Fja504845f
- Author:
- Fromm, Andreas; van Wüllen, Christoph; Hackenberger, Dagmar; Gooßen, Lukas J.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10007-10023
- ISSN:
- 1520-5126
- Subject:
- Gibbs free energy; activation energy; benzoates; bromine; catalysts; copper; decarboxylation; halides; ligands; palladium; prediction; temperature
- Abstract:
- ... The reaction mechanism of decarboxylative cross-couplings of benzoates with aryl halides to give biaryls, which is cooperatively catalyzed by copper/palladium systems, was investigated with DFT methods. The geometries and energies of all starting materials, products, intermediates, and transition states of the catalytic cycle were calculated for the two model reactions of potassium 2- and 4-fluoro ...
- DOI:
- 10.1021/ja503295x
-
http://dx.doi.org/10.1021%2Fja503295x
- Author:
- Lee, Jung Yoon; Peterson, Ryan L.; Ohkubo, Kei; Garcia-Bosch, Isaac; Himes, Richard A.; Woertink, Julia; Moore, Cathy D.; Solomon, Edward I.; Fukuzumi, Shunichi; Karlin, Kenneth D.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9925-9937
- ISSN:
- 1520-5126
- Subject:
- copper; deuterium; electron paramagnetic resonance spectroscopy; electron transfer; hydrogen peroxide; hydrolysis; isotopes; oxidation; phenols; superoxide anion
- Abstract:
- ... To obtain mechanistic insights into the inherent reactivity patterns for copper(I)–O₂ adducts, a new cupric–superoxo complex [(DMM-tmpa)Cuᴵᴵ(O₂•–)]⁺ (2) [DMM-tmpa = tris((4-methoxy-3,5-dimethylpyridin-2-yl)methyl)amine] has been synthesized and studied in phenol oxidation–oxygenation reactions. Compound 2 is characterized by UV–vis, resonance Raman, and EPR spectroscopies. Its reactions with a ser ...
- DOI:
- 10.1021/ja503105b
-
http://dx.doi.org/10.1021%2Fja503105b
- Author:
- Li, Zhengqiu; Wang, Danyang; Li, Lin; Pan, Sijun; Na, Zhenkun; Tan, Chelsea Y. J.; Yao, Shao Q.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9990-9998
- ISSN:
- 1520-5126
- Subject:
- bioactive compounds; biomedical research; chemical reactions; drugs; enzymes; epigenetics; image analysis; mammals; monitoring; photoaffinity labeling; proteins; proteome; proteomics; solubility
- Abstract:
- ... Target identification of bioactive compounds within the native cellular environment is important in biomedical research and drug discovery, but it has traditionally been carried out in vitro. Information about how such molecules interact with their endogenous targets (on and off) is currently highly limited. An ideal strategy would be one that recapitulates protein–small molecule interactions in s ...
- DOI:
- 10.1021/ja502780z
-
http://dx.doi.org/10.1021%2Fja502780z
- Author:
- Zhou, Liyi; Zhang, Xiaobing; Wang, Qianqian; Lv, Yifan; Mao, Guojiang; Luo, Aili; Wu, Yongxiang; Wu, Yuan; Zhang, Jing; Tan, Weihong
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9838-9841
- ISSN:
- 1520-5126
- Subject:
- energy transfer; engineering; environmental factors; fluorescence; fluorescent dyes; image analysis; microscopy; naphthalene; tissues
- Abstract:
- ... In contrast to one-photon microscopy, two-photon probe-based fluorescent imaging can provide improved three-dimensional spatial localization and increased imaging depth. Consequently, it has become one of the most attractive techniques for studying biological events in living cells and tissues. However, the quantitation of these probes is primarily based on single-emission intensity change, which ...
- DOI:
- 10.1021/ja504015t
-
http://dx.doi.org/10.1021%2Fja504015t
- Author:
- Wang, Dian; Izawa, Yusuke; Stahl, Shannon S.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9914-9917
- ISSN:
- 1520-5126
- Subject:
- acetates; catalysts; isotopes; xylene
- Abstract:
- ... Pd-catalyzed aerobic oxidative coupling of arenes provides efficient access to biaryl compounds. The biaryl product forms via C–H activation of two arenes to afford a PdᴵᴵArAr′ intermediate, which then undergoes C–C reductive elimination. The key PdᴵᴵArAr′ intermediate could form via a “monometallic” pathway involving sequential C–H activation at a single Pdᴵᴵ center, or via a “bimetallic” pathway ...
- DOI:
- 10.1021/ja505405u
- PubMed:
- 24965384
- PubMed Central:
- PMC4161672
-
http://dx.doi.org/10.1021%2Fja505405u
- Author:
- Torres, Olga; Procacci, Barbara; Halse, Meghan E.; Adams, Ralph W.; Blazina, Damir; Duckett, Simon B.; Eguillor, Beatriz; Green, Richard A.; Perutz, Robin N.; Williamson, David C.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10124-10131
- ISSN:
- 1520-5126
- Subject:
- hydrides; hydrogen; image analysis; irradiation; magnetic fields; nuclear magnetic resonance spectroscopy; phosphorus; radio waves; stable isotopes
- Abstract:
- ... We report pump–probe experiments employing laser-synchronized reactions of para-hydrogen (para-H₂) with transition metal dihydride complexes in conjunction with nuclear magnetic resonance (NMR) detection. The pump–probe experiment consists of a single nanosecond laser pump pulse followed, after a precisely defined delay, by a single radio frequency (rf) probe pulse. Laser irradiation eliminates H₂ ...
- DOI:
- 10.1021/ja504732u
-
http://dx.doi.org/10.1021%2Fja504732u
- Author:
- Chen, Long; Furukawa, Ko; Gao, Jia; Nagai, Atsushi; Nakamura, Toshikazu; Dong, Yuping; Jiang, Donglin
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9806-9809
- ISSN:
- 1520-5126
- Subject:
- electron transfer; fullerene; topology
- Abstract:
- ... Ordered one-dimensional open channels represent the typical porous structure of two-dimensional covalent organic frameworks (COFs). Here we report a general synthetic strategy for converting these open lattice structures into ordered donor–acceptor heterojunctions. A three-component topological design scheme was explored to prepare electron-donating intermediate COFs, which upon click reaction wer ...
- DOI:
- 10.1021/ja502692w
-
http://dx.doi.org/10.1021%2Fja502692w
- Author:
- Barskaya, Irina
Yu.; Tretyakov, Evgeny V.; Sagdeev, Renad Z.; Ovcharenko, Victor
I.; Bagryanskaya, Elena G.; Maryunina, Kseniya Yu.; Takui, Takeji; Sato, Kazunobu; Fedin, Matvey V.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10132-10138
- ISSN:
- 1520-5126
- Subject:
- copper; electron paramagnetic resonance spectroscopy; magnetic materials; temperature
- Abstract:
- ... Most photoswitchable molecular magnets exhibit thermally induced switching, as is typical of spin crossover (SCO), valence tautomerism and SCO-like phenomena. We report a rare case of a copper-nitroxide based molecular magnet Cu(hfac)₂Lⁱ⁻ᴾʳ that does not exhibit quantitative SCO-like behavior in the temperature range of its chemical stability (2–350 K); however, it can be switched to a metastable ...
- DOI:
- 10.1021/ja504774q
-
http://dx.doi.org/10.1021%2Fja504774q
- Author:
- Shevelev, Georgiy
Yu.; Krumkacheva, Olesya
A.; Lomzov, Alexander
A.; Kuzhelev, Andrey A.; Rogozhnikova, Olga Yu.; Trukhin, Dmitry V.; Troitskaya, Tatiana I.; Tormyshev, Victor M.; Fedin, Matvey V.; Pyshnyi, Dmitrii V.; Bagryanskaya, Elena G.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9874-9877
- ISSN:
- 1520-5126
- Subject:
- DNA; electron paramagnetic resonance spectroscopy; free radicals; models; sorbents; temperature
- Abstract:
- ... Resolving the nanometer-scale structure of biomolecules in natural conditions still remains a challenging task. We report the first distance measurement in nucleic acid at physiological temperature using electron paramagnetic resonance (EPR). The model 10-mer DNA duplex has been labeled with reactive forms of triarylmethyl radicals and then immobilized on a sorbent in water solution and investigat ...
- DOI:
- 10.1021/ja505122n
-
http://dx.doi.org/10.1021%2Fja505122n
- Author:
- Fan, Bo; Trant, John F.; Wong, Andrew
D.; Gillies, Elizabeth R.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10116-10123
- ISSN:
- 1520-5126
- Subject:
- aqueous solutions; composite polymers; depolymerization; ethanol; glyoxylic acid; humans; irradiation; maleic acid; micelles; polymerization; toxicity; ultraviolet radiation
- Abstract:
- ... Self-immolative polymers, which degrade by an end-to-end depolymerization mechanism in response to the cleavage of a stabilizing end-cap from the polymer terminus, are of increasing interest for a wide variety of applications ranging from sensors to controlled release. However, the preparation of these materials often requires expensive, multistep monomer syntheses, and the degradation products su ...
- DOI:
- 10.1021/ja504727u
-
http://dx.doi.org/10.1021%2Fja504727u
- Author:
- McAtee, Jesse
R.; Yap, Glenn P. A.; Watson, Donald A.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10166-10172
- ISSN:
- 1520-5126
- Subject:
- X-ray diffraction; catalysts; catalytic activity; isomerization; ligands; oxidation; palladium; phosphine
- Abstract:
- ... Using rational ligand design, we have developed of a second-generation ligand, bis(3,5-di-tert-butylphenyl)(tert-butyl)phosphine, for the preparation of allylsilanes using the palladium-catalyzed silyl-Heck reaction. This new ligand provides nearly complete suppression of starting material alkene isomerization that was observed with our first-generation catalyst, providing vastly improved yields o ...
- DOI:
- 10.1021/ja505446y
- PubMed:
- 25003502
- PubMed Central:
- PMC4105080
-
http://dx.doi.org/10.1021%2Fja505446y
- Author:
- Pinkowicz, Dawid; Southerland, Heather; Wang, Xin-Yi; Dunbar, Kim R.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9922-9924
- ISSN:
- 1520-5126
- Subject:
- cyanides; ferrimagnetic materials
- Abstract:
- ... The pentanuclear compound [Vᴵᴵ(tmphen)₂]₃[Moᴵᴵᴵ(CN)₆]₂ (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline) exhibits a record antiferromagnetic exchange coupling constant of JV–Mₒ = −114 cm–¹. This is the first example of a heterobimetallic cyanide compound with such strong magnetic coupling. ...
- DOI:
- 10.1021/ja5044352
-
http://dx.doi.org/10.1021%2Fja5044352
- Author:
- Skomski, Daniel; Tempas, Christopher D.; Smith, Kevin
A.; Tait, Steven L.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9862-9865
- ISSN:
- 1520-5126
- Subject:
- X-ray photoelectron spectroscopy; binding sites; catalysts; catalytic activity; geometry; gold; ligands; oxidation; platinum; scanning probe microscopy
- Abstract:
- ... The formation and stabilization of well-defined transition-metal single sites at surfaces may open new routes to achieve higher selectivity in heterogeneous catalysts. Organic ligand coordination to produce a well-defined oxidation state in weakly reducing metal sites at surfaces, desirable for selective catalysis, has not been achieved. Here, we address this using metallic platinum interacting wi ...
- DOI:
- 10.1021/ja504850f
-
http://dx.doi.org/10.1021%2Fja504850f
- Author:
- Guo, Zhi; Lee, Doyun; Schaller, Richard D.; Zuo, Xiaobing; Lee, Byeongdu; Luo, TengFei; Gao, Haifeng; Huang, Libai
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10024-10032
- ISSN:
- 1520-5126
- Subject:
- composite polymers; crystal structure; energy; photovoltaic cells; spectroscopy
- Abstract:
- ... We present a systematic study of the roles of crystallinity, interchain interaction, and exciton delocalization on ultrafast charge separation pathways in donor–acceptor copoloymer blends. We characterize the energy levels, excited state structures, and dynamics of the interchain species by combined ultrafast spectroscopy and computational quantum chemistry approaches. The alkyl side chain of a hi ...
- DOI:
- 10.1021/ja503465s
-
http://dx.doi.org/10.1021%2Fja503465s
- Author:
- Horch, Marius; Schoknecht, Janna; Mroginski, Maria Andrea; Lenz, Oliver; Hildebrandt, Peter; Zebger, Ingo
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9870-9873
- ISSN:
- 1520-5126
- Subject:
- Raman spectroscopy; active sites; energy conversion; ferredoxin hydrogenase; hydrogen; iron; models; monitoring; nickel
- Abstract:
- ... [NiFe] hydrogenases catalyze the reversible cleavage of hydrogen and, thus, represent model systems for the investigation and exploitation of emission-free energy conversion processes. Valuable information on the underlying molecular mechanisms can be obtained by spectroscopic techniques that monitor individual catalytic intermediates. Here, we employed resonance Raman spectroscopy and extended it ...
- DOI:
- 10.1021/ja505119q
-
http://dx.doi.org/10.1021%2Fja505119q
- Author:
- Kuo, Ting-Fang; Mao, Di; Hirata, Nao; Khambu, Bilon; Kimura, Yasuhisa; Kawase, Eihachiro; Shimogawa, Hiroki; Ojika, Makoto; Nakatsuji, Norio; Ueda, Kazumitsu; Uesugi, Motonari
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9798-9801
- ISSN:
- 1520-5126
- Subject:
- ABC transporters; cytotoxicity; death; embryonic stem cells; humans; okadaic acid; screening; therapeutics
- Abstract:
- ... One of the current obstacles to stem cell therapy is the tumorigenic potential of residual undifferentiated stem cells. The present study reports rediscovery of a synthetic derivative of okadaic acid, a marine polyether toxin, as a reagent that selectively induces the death of human pluripotent stem cells. Cell-based screening of 333 cytotoxic compounds identified methyl 27-deoxy-27-oxookadaate (m ...
- DOI:
- 10.1021/ja501795c
-
http://dx.doi.org/10.1021%2Fja501795c
- Author:
- Tu, Fuquan; Lee, Daeyeon
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9999-10006
- ISSN:
- 1520-5126
- Subject:
- acrylic acid; colloids; droplets; emulsifying; emulsions; environmental factors; hydrophilicity; hydrophobicity; pH; polymerization; separation; styrene; surfactants; wettability
- Abstract:
- ... Janus particles are biphasic colloids that have two sides with distinct chemistry and wettability. Because of their amphiphilicity, Janus particles present a unique opportunity for stabilizing multiphasic fluid mixtures such as emulsions. Our work is motivated by one class of molecular amphiphiles that change their surfactant properties in response to environmental stimuli. Depending on the enviro ...
- DOI:
- 10.1021/ja503189r
-
http://dx.doi.org/10.1021%2Fja503189r
- Author:
- Carlred, Louise; Gunnarsson, Anders; Solé-Domènech, Santiago; Johansson, Björn; Vukojević, Vladana; Terenius, Lars; Codita, Alina; Winblad, Bengt; Schalling, Martin; Höök, Fredrik; Sjövall, Peter
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9973-9981
- ISSN:
- 1520-5126
- Subject:
- Alzheimer disease; antibodies; brain; cholesterol; fluorescence microscopy; genetically modified organisms; image analysis; immunohistochemistry; mass spectrometry; mice; neurodegenerative diseases; phospholipids; salts; scanning electron microscopy
- Abstract:
- ... The spatial localization of amyloid-β peptide deposits, the major component of senile plaques in Alzheimer’s disease (AD), was mapped in transgenic AD mouse brains using time-of-flight secondary ion mass spectrometry (ToF-SIMS), simultaneously with several endogenous molecules that cannot be mapped using conventional immunohistochemistry imaging, including phospholipids, cholesterol and sulfatides ...
- DOI:
- 10.1021/ja5019145
-
http://dx.doi.org/10.1021%2Fja5019145
- Author:
- Ku, Kang Hee; Shin, Jae Man; Kim, Minsoo
P.; Lee, Chun-Ho; Seo, Min-Kyo; Yi, Gi-Ra; Jang, Se Gyu; Kim, Bumjoon J.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9982-9989
- ISSN:
- 1520-5126
- Subject:
- composite polymers; gold; image analysis; light scattering; nanogold; neutralization; surfactants
- Abstract:
- ... The tuning of interfacial properties at selective and desired locations on the particles is of great importance to create the novel structured particles by breaking the symmetry of their surface property. Herein, a dramatic transition of both the external shape and internal morphology of the particles of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) was induced by precise positioning of size-con ...
- DOI:
- 10.1021/ja502075f
-
http://dx.doi.org/10.1021%2Fja502075f
- Author:
- Seamon, Kyle J.; Hansen, Erik C.; Kadina, Anastasia
P.; Kashemirov, Boris A.; McKenna, Charles E.; Bumpus, Namandjé N.; Stivers, James T.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9822-9825
- ISSN:
- 1520-5126
- Subject:
- CD4-positive T-lymphocytes; Human immunodeficiency virus 1; carbon; macrophages; phosphates
- Abstract:
- ... SAMHD1 is a GTP-activated nonspecific dNTP triphosphohydrolase that depletes dNTP pools in resting CD4+ T cells and macrophages and effectively restricts infection by HIV-1. We have designed a nonsubstrate dUTP analogue with a methylene bridge connecting the α phosphate and 5′ carbon that potently inhibits SAMHD1. Although pppCH₂dU shows apparent competitive inhibition, it acts by a surprising all ...
- DOI:
- 10.1021/ja5035717
- PubMed:
- 24983818
- PubMed Central:
- PMC4105058
-
http://dx.doi.org/10.1021%2Fja5035717
- Author:
- Nagata, Yuuya; Takagi, Keisuke; Suginome, Michinori
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9858-9861
- ISSN:
- 1520-5126
- Subject:
- ambient temperature; annealing; chloroform; ethylene dichloride; films (materials); polymers; vapors
- Abstract:
- ... Poly(quinoxaline-2,3-diyl)s bearing (S)-2-methylbutyl, n-butyl, and 8-chlorooctyl groups as side chains were synthesized to fabricate dry solid polymer thin films. These films exhibited selective reflection of right-handed circular polarized light (CPL) in the visible region after annealing in CHCl₃ vapor at room temperature. The handedness of reflected CPL was inverted to the left after annealing ...
- DOI:
- 10.1021/ja504808r
-
http://dx.doi.org/10.1021%2Fja504808r
- Author:
- Ye, Heng-Yun; Li, Shen-Hui; Zhang, Yi; Zhou, Lei; Deng, Feng; Xiong, Ren-Gen
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10033-10040
- ISSN:
- 1520-5126
- Subject:
- molecular dynamics; nuclear magnetic resonance spectroscopy; phase transition
- Abstract:
- ... Many order–disorder-type phase transitions in molecule-based ferroelectrics are related to changes of molecular dynamics. If the molecular motions do not involve reorientations of dipole moments, their ordering fails to contribute directly to spontaneous electric polarization. For understanding ferroelectric mechanisms in these systems, it is important to clarify how such molecular dynamics change ...
- DOI:
- 10.1021/ja503344b
-
http://dx.doi.org/10.1021%2Fja503344b
- Author:
- Fox, Daniel
A.; Larsson, Per; Lo, Ryan H.; Kroncke, Brett M.; Kasson, Peter M.; Columbus, Linda
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9938-9946
- ISSN:
- 1520-5126
- Subject:
- Neisseria gonorrhoeae; Neisseria meningitidis; humans; molecular dynamics; nuclear magnetic resonance spectroscopy; outer membrane proteins; pathogenesis; receptors
- Abstract:
- ... The structure and dynamics of Opa proteins, which we report herein, are responsible for the receptor-mediated engulfment of Neisseria gonorrheae or Neisseria meningitidis by human cells and can offer deep understanding into the molecular recognition of pathogen–host receptor interactions. Such interactions are vital to understanding bacterial pathogenesis as well as the mechanism of foreign body e ...
- DOI:
- 10.1021/ja503093y
-
http://dx.doi.org/10.1021%2Fja503093y
- Author:
- Qian, Kun; Sweeny, Brendan
C.; Johnston-Peck, Aaron C.; Niu, Wenxin; Graham, Jeremy O.; DuChene, Joseph S.; Qiu, Jingjing; Wang, Yi-Chung; Engelhard, Mark H.; Su, Dong; Stach, Eric A.; Wei, Wei David
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9842-9845
- ISSN:
- 1520-5126
- Subject:
- electron transfer; energy conversion; gold; nanogold; photocatalysis; photocatalysts; titanium dioxide
- Abstract:
- ... Water reduction under two different visible-light ranges (λ > 400 nm and λ > 435 nm) was investigated in gold-loaded titanium dioxide (Au-TiO₂) heterostructures with different sizes of Au nanoparticles (NPs). Our study clearly demonstrates the essential role played by Au NP size in plasmon-driven H₂O reduction and reveals two distinct mechanisms to clarify visible-light photocatalytic activity und ...
- DOI:
- 10.1021/ja504097v
-
http://dx.doi.org/10.1021%2Fja504097v
- Author:
- Fier, Patrick
S.; Hartwig, John F.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10139-10147
- ISSN:
- 1520-5126
- Subject:
- carbon; chemical reactions; fluorides; nitrogen; oxygen; pyridines; sulfur
- Abstract:
- ... We report the late-stage functionalization of multisubstituted pyridines and diazines at the position α to nitrogen. By this process, a series of functional groups and substituents bound to the ring through nitrogen, oxygen, sulfur, or carbon are installed. This functionalization is accomplished by a combination of fluorination and nucleophilic aromatic substitution of the installed fluoride. A di ...
- DOI:
- 10.1021/ja5049303
- PubMed:
- 24918484
- PubMed Central:
- PMC4227713
-
http://dx.doi.org/10.1021%2Fja5049303
- Author:
- Braun, Anthony
R.; Lacy, Michael M.; Ducas, Vanessa C.; Rhoades, Elizabeth; Sachs, Jonathan N.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9962-9972
- ISSN:
- 1520-5126
- Subject:
- binding capacity; energy; fluorescence; hydrophobicity; molecular dynamics; spectroscopy
- Abstract:
- ... We have investigated the membrane remodeling capacity of the N-terminal membrane-binding domain of α-synuclein (α-Syn₁₀₀). Using fluorescence correlation spectroscopy and vesicle clearance assays, we show that α-Syn₁₀₀ fully tubulates POPG vesicles, the first demonstration that the amphipathic helix on its own is capable of this effect. We also show that at equal density of membrane-bound protein, ...
- DOI:
- 10.1021/ja5016958
-
http://dx.doi.org/10.1021%2Fja5016958
- Author:
- Choi, Jin; Park, Hoyoon; Yoo, Hyun Jung; Kim, Sinae; Sorensen, Erik J.; Lee, Chulbom
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9918-9921
- ISSN:
- 1520-5126
- Subject:
- acids; cycloaddition reactions; cyclohexenes; extrusion; sulfur dioxide
- Abstract:
- ... A pericyclic approach for the synthesis of six-membered ring structures is described. The method employs 1,3-dienes with a 1-sulfur substituent in a tandem sequence of Diels–Alder and retro-ene reactions. In this pairing of [4 + 2] cycloaddition and 1,5-sigmatropic rearrangement, 1-sulfenyl-1,3-dienes engage in Diels–Alder reactions with electron-deficient dienophiles. Subsequently, the sulfenyl g ...
- DOI:
- 10.1021/ja505721v
-
http://dx.doi.org/10.1021%2Fja505721v
- Author:
- Linder, Douglas
P.; Silvernail, Nathan J.; Barabanschikov, Alexander; Zhao, Jiyong; Alp, E. Ercan; Sturhahn, Wolfgang; Sage, J. Timothy; Scheidt, W. Robert; Rodgers, Kenton R.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9818-9821
- ISSN:
- 1520-5126
- Subject:
- crystals; heme; iron; proteins
- Abstract:
- ... Heme-carbonyl complexes are widely exploited for the insight they provide into the structural basis of function in heme-based proteins, by revealing the nature of their bonded and nonbonded interactions with the protein. This report presents two novel results which clearly establish a FeCO vibrational signature for crystallographically verified pentacoordination. First, anisotropy in the NRVS dens ...
- DOI:
- 10.1021/ja503191z
- PubMed:
- 24950373
- PubMed Central:
- PMC4120987
-
http://dx.doi.org/10.1021%2Fja503191z
- Author:
- Vennekate, Hendrik; Schwarzer, Dirk; Torres-Alacan, Joel; Vöhringer, Peter
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10095-10103
- ISSN:
- 1520-5126
- Subject:
- Fourier transform infrared spectroscopy; ambient temperature; anions; cations; chemical bonding; dissociation; energy; free radicals; iron; nitrides; photolysis; photons; photooxidation; ultraviolet radiation
- Abstract:
- ... Recently, the complex cation [(cyclam-ac)Feᴵᴵᴵ(N₃)]⁺ has been used in solid matrices under cryogenic conditions as a photochemical precursor for an octahedral iron nitride containing the metal at the remarkably high oxidation state +5. Here, we study the photochemical primary events of this complex cation in liquid solution at room temperature using femtosecond time-resolved mid-infrared (fs-MIR) ...
- DOI:
- 10.1021/ja5045133
-
http://dx.doi.org/10.1021%2Fja5045133
- Author:
- Wang, Xiao-Na; Krenske, Elizabeth H.; Johnston, Ryne C.; Houk, K. N.; Hsung, Richard P.
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9802-9805
- ISSN:
- 1520-5126
- Subject:
- cis-trans isomers; macrocyclic compounds; thermodynamics
- Abstract:
- ... Electrocyclic ring opening of 4,6-fused cyclobutenamides 1 under thermal conditions leads to cis,trans-cyclooctadienones 2-E,E as transient intermediates, en route to 5,5-bicyclic products 3. Theoretical calculations predict that 4,5-fused cyclobutenamides should likewise undergo thermal ring opening, giving cis,trans-cycloheptadienones, but in this case conversion to 5,4-bicyclic products is ther ...
- DOI:
- 10.1021/ja502252t
- PubMed:
- 24992255
- PubMed Central:
- PMC4353010
-
http://dx.doi.org/10.1021%2Fja502252t
- Author:
- Xuan, Feng; Hsing, I-Ming
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9810-9813
- ISSN:
- 1520-5126
- Subject:
- DNA; chemical structure; fluorescence; fluorescence emission spectroscopy; growth models; hybridization chain reaction; image analysis; nanomaterials; polyacrylamide gel electrophoresis
- Abstract:
- ... We present a nonlinear hybridization chain reaction (HCR) system in which a trigger DNA initiates self-sustained assembly of quenched double-stranded substrates into fluorescent dendritic nanostructures. During the process, an increasing number of originally sequestered trigger sequences labeled with fluorescent reporters are freed up from quenched substrates, leading to chain-branching growth of ...
- DOI:
- 10.1021/ja502904s
-
http://dx.doi.org/10.1021%2Fja502904s
- Author:
- Pendlebury, Stephanie R; Wang, Xiuli; Le Formal, Florian; Cornuz, Maurin; Kafizas, Andreas; Tilley, S. David; Grätzel, Michael; Durrant, James R
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 9854-9857
- ISSN:
- 1520-5126
- Subject:
- hematite; oxidation; spectroscopy; titanium dioxide
- Abstract:
- ... Transient absorption spectroscopy on subpicosecond to second time scales is used to investigate photogenerated charge carrier recombination in Si-doped nanostructured hematite (α-Fe₂O₃) photoanodes as a function of applied bias. For unbiased hematite, this recombination exhibits a 50% decay time of ∼6 ps, ∼10³ times faster than that of TiO₂ under comparable conditions. Anodic bias significantly re ...
- DOI:
- 10.1021/ja504473e
- PubMed:
- 24950057
- PubMed Central:
- PMC4210134
-
http://dx.doi.org/10.1021%2Fja504473e
- Author:
- Hall, Eleanor
R.; Pollock, Christopher J.; Bendix, Jesper; Collins, Terrence J.; Glatzel, Pieter; DeBeer, Serena
- Source:
- Journal of the American Chemical Society 2014 v.136 no.28 pp. 10076-10084
- ISSN:
- 1520-5126
- Subject:
- X-radiation; X-ray absorption spectroscopy; active sites; catalysts; fluorescence; geometry; ionization; ligands; manganese; metalloproteins; models; monitoring
- Abstract:
- ... X-ray absorption spectroscopy (XAS) can provide detailed insight into the electronic and geometric structures of transition-metal active sites in metalloproteins and chemical catalysts. However, standard XAS spectra inherently represent an average contribution from the entire coordination environment with limited ligand selectivity. To address this limitation, we have investigated the enhancement ...
- DOI:
- 10.1021/ja504206y
-
http://dx.doi.org/10.1021%2Fja504206y