Journal of the American Chemical Society (J AM CHEM SOC )

Publisher: American Chemical Society; American Chemical Society; Marian S. Carson Collection (Library of Congress), American Chemical Society

Description

The Journal of the American Chemical Society, founded in 1879, is the flagship journal of the American Chemical Society and a highly esteemed journal in the field. This periodical is devoted to the publication of research papers in all fields of chemistry and publishes approximately 13,000 pages of new chemistry a year. Published weekly, JACS provides research crucial to the field of chemistry. The Journal of the American Chemical Society publishes articles, communications to the Editor, book reviews, and computer software reviews.

  • Impact factor
    10.68
    Hide impact factor history
     
    Impact factor
  • 5-year impact
    10.24
  • Cited half-life
    7.70
  • Immediacy index
    2.16
  • Eigenfactor
    0.83
  • Article influence
    2.99
  • Website
    Journal of the American Chemical Society website
  • Other titles
    Journal of the American Chemical Society, Review of American chemical research
  • ISSN
    0002-7863
  • OCLC
    1226990
  • Material type
    Periodical, Internet resource
  • Document type
    Journal / Magazine / Newspaper, Internet Resource

Publisher details

American Chemical Society

  • Pre-print
    • Author cannot archive a pre-print version
  • Restrictions
    • Must obtain written permission from Editor
    • Must not violate ACS ethical Guidelines
  • Post-print
    • Author cannot archive a post-print version
  • Restrictions
    • If mandated by funding agency or employer/ institution
    • If mandated to deposit before 12 months, must obtain waiver from Institution/Funding agency or use AuthorChoice
    • 12 months embargo
  • Conditions
    • On author's personal website, pre-print servers, institutional website, institutional repositories or subject repositories
    • Non-Commercial
    • Must be accompanied by set statement (see policy)
    • Must link to publisher version
    • Publisher's version/PDF cannot be used
    • If mandated sooner than 12 months, must obtain waiver from Editors or use AuthorChoice
    • Reviewed on 07/08/2014
  • Classification
    ​ white

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: We have developed a Pd(II)-catalyzed oxidative tandem aminoalkylation via divergent C(sp3)-H functionalization, affording three- and five-membered-ring fused indolines in good yields under two optimized conditions, respectively. The mechanism studies have indicated that the benzylic C-H cleavage involved in the former transformation is the rate-determining step, while the cleavage of amide α-C-H in the latter is not. This is the first example of Pd-catalyzed tandem reaction involving C(sp3)-H activation without the employment of prefunctionalized reagents (e.g. halogenated and boron reagents) and directing groups, representing a green and economic protocol for construction of N-containing heterocycles.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: The Ln(3+) and Ln(2+) complexes, Cp'3Ln, 1, (Cp' = C5H4SiMe3) and [K(2.2.2-cryptand)][Cp'3Ln], 2, respectively, have been synthesized for the six lanthanides traditionally known in +2 oxidation states, i.e., Ln = Eu, Yb, Sm, Tm, Dy, and Nd, to allow direct structural and spectroscopic comparison with the recently discovered Ln(2+) ions of Ln = Pr, Gd, Tb, Ho, Y, Er, and Lu in 2. 2-La and 2-Ce were also prepared to allow the first comparison of all the lanthanides in the same coordination environment in both +2 and +3 oxidation states. 2-La and 2-Ce show the same unusual structural feature of the recently discovered +2 complexes, that the Ln-(Cp' ring centroid) distances are only about 0.03 Å longer than in the +3 analogs, 1. The Eu, Yb, Sm, Tm, Dy, and Nd complexes were expected to show much larger differences, but this was observed for only four of these traditional six lanthanides. 2-Dy and 2-Nd are like the new nine ions in this tris(cyclopentadienyl) coordination geometry. A DFT-based model explains the results and shows that a 4f (n)5d(1) electron configuration is appropriate not only for the nine recently discovered Ln(2+) ions in 2 but also for Dy(2+) and Nd(2+), which traditionally have 4f (n+1) electron configurations like Eu(2+), Yb(2+), Sm(2+), and Tm(2+). These results indicate that the ground state of a lanthanide ion in a molecule can be changed by the ligand set, a previously unknown option with these metals due to the limited radial extension of the 4f orbitals.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: V-shaped polyaromatic amphiphiles with phenanthrene or naphthalene rings spontaneously and quantitatively formed micelle-like nanocapsules in water at room temperature. In contrast to usual polyaromatic aggregates with weak fluorescent properties, the new capsules providing spherical polyaromatic shells with diameters of ∼2 nm show strong fluorescent emissions due to an aggregation-induced enhanced emission (AIEE) effect and moreover encapsulate a fluorescent coumarin dye to generate highly emissive host-guest composites.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: A zerovalent copper and cobalt-catalyzed direct coupling of sp3 α-carbon of alcohols with alkenes and hydroperoxides was developed in which the hydroperoxides acted as radical initiator cum coupling partner. 1,3-Enynes and vinylarenes underwent alkylation-peroxidation to give β-peroxy alcohols and β-hydroxyketones correspondingly with excellent functional group tolerance. The resulting β-peroxy alcohols could be further transformed into β-hydroxyynones and propargylic 1,3-diols.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: Non-classical nanotube endcaps have been constructed from strain-free heterocyclic precursors using a one-step synthetic procedure, involving multiple nickel-mediated Ullmann couplings. These systems consist of tubular macrocyclic sections that are tightly capped on one side with a bridging benzene ring, forming deep, chemically accessible cavities. The endcaps are characterized by exceptionally high internal strain energies reaching 144 kcal/mol. The optical absorption and emission properties of these molecules show a marked dependence on conjugation length and geometrical factors. The mechanism of endcap formation, investigated using DFT calculations, relies on precise timing of transmetallation and reductive elimination events.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: The unstable species dichlorosilylene was previously stabilized by carbene. The lone pair of electrons on the silicon atom of (carbene)SiCl2 can form a coordinate bond with metal-carbonyls. Herein we report that (carbene)SiCl2 can stabilize a phosphinidene (Ar-P, a carbone analogue) with the general formula carbene→SiCl2→P-Ar (carbene = cyclic alkyl(amino) carbene (cAAC; 2) and N-heterocyclic carbene (NHC; 3)). Compounds 2 and 3 are stable, isolable, and storable at 0 °C (2) to room temperature (3) under an inert atmosphere. The crystals of 2 and 3 are dark blue and red, respectively. The intense blue color of 2 arises due to the strong intramolecular charge transfer (ICT) transition from Si=P→*cAAC. The electronic structure and bonding of 2, 3 were studied by theoretical calculations. The HOMO of the molecule is located on the Si=P bond while the LUMO is located at the carbene moiety (cAAC or NHC). The dramatic change in color of these compounds from red (3, NHC) to blue (2, cAAC) is ascribed to the difference in energy of the LUMO within the carbenes (cAAC/NHC) due to a lower lying LUMO of cAAC.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: Flexible microdisk whispering-gallery-mode (WGM) resonators with high quality factors were achieved through the controlled assembly of organic materials with an emulsion-solvent-evaporation method. The high material compatibility of the assembled microdisks enabled us to realize low-threshold WGM lasers by doping with organic dyes as gain media. Furthermore, the emulsion assisted self-assembly provided a strategy for the one-step fabrication of microwire waveguide connected microdisk heterostructures, which can be utilized for the efficient output of the isotropic WGM lasers from the coupled waveguides. We hope that the results would pave an avenue to the construction of new-type flexible WGM-based components for photonic integrations.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: In this manuscript, structural characterization of synthetically useful gem-bis(iodozincio)methane species is described. Despite numerous studies on their synthetic application (methylenation of carbonyl compounds), crystallographic characterization of these useful reagents has remained elusive, presumably due to their tendency to decompose via a Schlenk equilibrium associated with their inherent high reactivity. In the current work, use of the sterically crowded bipyridine ligand provided the first example of the isolation and structural characterization of these species. As zinc atoms can be easily replaced with other transition metals by transmetallation, the current study will open up new perspectives on the design and development of synthetically useful gem-dimetallomethane species that are difficult to access by conventional protocols. In fact, gem-bis(halozincio)alkanes are included in the first step of the generation of titanium reagents for the total synthesis of Maitotoxin by K. C. Nicolaou (J. Am. Chem. Soc. 2011, 133, 220) and Brevenal by J. D. Rainier (J. Am. Chem. Soc. 2011, 133, 3208). We believe that the present work will attract a wide readership not only organometallic chemists but also synthetic organic chemists.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: We report the first example of a traceless directing group in a radical cascade. The chemo- and regioselectivity of the initial attack in skipped oligoalkynes is controlled by propargyl OR moiety. Radical translocations lead to the boomerang return of radical center to the site of initial attack where it assists to the elimination of the directing functionality via β-scission in the last step of the cascade. The Bu3Sn moiety allows further via facile reactions with electrophiles as well as Stille and Suzuki cross-coupling reactions. This selective radical transformation opens a new approach for the controlled transformation of skipped oligoalkynes into polycyclic ribbons of tunable dimensions.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: Upon exposure to neutral or cationic Rh(I)-catalyst systems, amino-substituted cyclopropanes undergo carbonylative cycloaddition with tethered alkenes to provide stereochemically complex N-heterocyclic scaffolds. These processes rely upon the generation and trapping of rhodacyclopentanone intermediates, which arise by regioselective, Cbz-directed insertion of Rh and CO into one of the two proximal aminocyclopropane C-C bonds. For cyclizations using cationic Rh(I)-systems, synthetic and mechanistic studies indicate that rhodacyclopentanone formation is reversible and that the alkene insertion step determines product diastereoselectivity. This regime facilitates high levels of stereocontrol with respect to substituents on the alkene tether. The option of generating rhodacyclopentanones dynamically provides a new facet to a growing area of catalysis and may find use as a (stereo)control strategy in other processes.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: Highly twisted π-conjugated molecules have been attractive but challenging targets. We report here an efficient synthesis of highly twisted diporphyrins with 126° and 136° twist angles that involves an oxidative fusion reaction of planar aminoporphyrin precursors at room temperature. Repeated amination-oxidative fusion sequences provides a unidirectionally twisted tetramer. The twisting angle of the tetramer is 298°.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: The complex Pt(SnBu(t)3)2(CNBu(t))2(H)2, 1, was obtained from the reaction of Pt(COD)2 and Bu(t)3SnH, followed by addition of CNBu(t). The two hydride ligands in 1 can be eliminated, both in solution and in the solid state, to yield Pt(SnBu(t)3)2(CNBu(t))2, 2. Addition of hydrogen to 2 at room temperature in solution and in the solid state regenerates 1. Complex 2 catalyzes H2-D2 exchange in solution to give HD. The proposed mechanism of exchange involves reductive elimination of Bu(t)3SnH from 1 to afford vacant sites on the Pt center, thus facilitating the exchange process. This is supported by isolation and characterization of Pt(SnMes3)(SnBu(t)3)(CNBu(t))2, 3, when the addition of H2 to 2 was carried out in the presence of free ligand Mes3SnH (Mes = 2,4,6-Me3C6H2). Complex Pt(SnMes3)2(CNBu(t))2, 5, can be prepared from the reaction of Pt(COD)2 with Mes3SnH and CNBu(t). The exchange reaction of 2 with Ph3SnH gave Pt(SnPh3)3(CNBu(t))2(H), 6, wherein both SnBu(t)3 ligands are replaced by SnPh3. Complex 6 decomposes in air to form square planar Pt(SnPh3)2(CNBu(t))2, 7. The complex Pt(SnPr(i)3)2(CNBu(t))2, 8, was also prepared. Out of the four analogous complexes Pt(SnR3)2(CNBu(t))2 (R = Bu(t), Mes, Ph, or Pr(i)), only the Bu(t) analogue does both H2 activation and H2-D2 exchange. This is due to steric effects imparted by the bulky Bu(t) groups that distort the geometry of the complex considerably from planarity. The reaction of Pt(COD)2 with Bu(t)3SnH and CO gas afforded trans-Pt(SnBu(t)3)2(CO)2, 9. Compound 9 can be converted to 2 by replacement of the CO ligands with CNBu(t) via the intermediate Pt(SnBu(t)3)2(CNBu(t))2(CO), 10.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: The discovery of n-type ferromagnetic semiconductors (n-FMSs) exhibiting high electrical conductivity and Curie temperature (Tc) above 300 K would dramatically improve semiconductor spintronics and pave the way for the fabrication of spin-based semiconducting devices. However, the realization of high-Tc n-FMSs and p-FMSs in conventional high-symmetry semiconductors has proven extremely difficult due to the strongly coupled and interacting magnetic and semiconducting sublattices. Here, we show that decoupling both functional sublattices in the low-symmetry semiconductor FeBi2Se4 enables unprecedented coexistence of high n-type electrical conduction and ferromagnetism with Tc~450 K. The structure of FeBi2Se4 consists of well-ordered magnetic sublattices built of [FenSe4n+2]∞ single-chain edge-sharing octahedra, coherently embedded within the three-dimensional Bi-rich semiconducting framework. Magnetotransport data reveal a negative magnetoresistance, indicating spin-polarization of itinerant conducting electrons. These findings demonstrate that decoupling magnetic and semiconducting sublattices allows access to high-Tc n-FMSs and p-FMSs as well as helps unveil the mechanism of carrier-mediated ferromagnetism in spintronic materials.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: We describe the facile synthesis of several two-dimensional covalent organic frameworks (2D COFs) as films by vapor-assisted conversion at room temperature. High-quality films of benzodithiophene-containing BDT-COF and COF-5 with tunable thickness were synthesized under different conditions on glass substrates. BDT-COF films of several micrometer thickness exhibit mesoporosity as well as textural porosity, whereas thinner BDT-COF films materialize as a cohesive dense layer. In addition, we studied the formation of COF-5 films with different solvent mixture compositions serving as vapor source. Room temperature vapor assisted conversion is an excellent path to form COF films of fragile precursors and on sensitive substrates.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: This work focuses on the control of the polymerisation process for melon ("graphitic carbon nitride"), with the aim of improving its photocatalytic activity intrinsically. We demonstrate here that reduction of the synthesis temperature leads to a mixture of the monomer melem and its higher condensates. We show that this mixture can be separated and provide evidence that the higher condensates are isolated oligomers of melem. On evaluating their photocatalytic activity for hydrogen evolution, the oligomers were found to be the most active species, having up to double the activity of the monomer/oligomer mixture of the as-synthesized material, which in turn has doubled the activity of the polymer melon, the literature benchmark. These results highlight the role of "defects", i.e. chain terminations, in increasing the catalytic activity of carbon nitrides and at the same time points to the ample potential of intrinsically improving the photocatalytic activity of "carbon nitride", especially through the selective synthesis of the active phase.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: Controlling the crystal structure of transparent metal oxides is essential for tailoring the properties of these polymorphic materials to specific applications. The structural control is usually done via solid state phase transformation at high temperature or pressure. Here, we report the kinetic study of in situ phase transformation of In2O3 nanocrystals from metastable rhombohedral phase to stable cubic phase during their colloidal synthesis. By examining the phase content as a function of time using the model fitting approach, we identified two distinct coexisting mechanisms - surface and interface nucleation. It is shown that the mechanism of phase transformation can be controlled systematically through modulation of temperature and precursor to solvent ratio. The increase in both of these parameters leads to gradual change from surface to interface nucleation, which is associated with the increased probability of nanocrystal contact formation in the solution phase. The activation energy for surface nucleation is found to be 144±30 kJ/mol, very similar to that for interface nucleation. In spite of the comparable activation energy, the interface nucleation dominates at higher temperatures due to increased nanocrystal interactions. The results of this work demonstrate enhanced control over polymorphic nanocrystal systems, and contribute to further understanding of the kinetic processes at the nanoscale, including nucleation, crystallization, and biomineralization.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: The pseudo-octahedral 16-electron molybdenum benzylidyne complex [TolC≡Mo(ONO)(OR)]•KOR (R = CCH3(CF3)2) 1 featuring a stabilizing ONO pincer ligand initiates the controlled living polymerization of strained dibenzocyclooctynes at T > 60 °C to give high molecular weight polymers with exceptionally low polydispersities, PDI ~ 1.02. Kinetic analyses reveal that the growing polymer chain at-tached to the propagating catalyst efficiently limits the rate of propagation with respect to the rate of initiation (kp/ki ~ 10-3). The reversible coordination of KOCCH3(CF3)2 to the propagating catalyst prevents undesired chain-termination and -transfer processes. The ring-opening alkyne metathesis polymerization with 1 has all the characteristics of a living polymerization and enables, for the first time, the controlled synthesis of amphiphilic block-copolymers via ROAMP.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: The photoreceptor protein cryptochrome is thought to host, upon light absorption, a radical pair which is sensitive to very weak magnetic fields, endowing migratory birds with a magnetic compass sense. The molecular mechanism which leads to formation of a stabilised, magnetic field sensitive radical pair has despite various theoretical and experimental efforts not been unambiguously identified yet. We challenge this unambiguity through a unique quantum mechanical molecular dynamics approach where we perform electron transfer dynamics simulations taking into account the motion of the protein upon the electron transfer. This approach allows us to follow the time evolution of the electron transfer in an unbiased fashion and to reveal the molecular driving force which ensures fast electron transfer in cryptochrome guaranteeing formation of a persistent radical pair suitable for magnetoreception. We argue that this unraveled molecular mechanism is a general principle inherent to all proteins of the cryptochrome/photolyase family and that cryptochromes are, therefore, tailored to potentially function as efficient chemical magnetoreceptors.
    Journal of the American Chemical Society 12/2014;
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    ABSTRACT: Biosynthesis of some polyether natural products involves a kinetically disfavored epoxide-opening cyclic ether formation, a reaction termed anti-Baldwin cyclization. One such example is the biosynthesis of lasalocid A, an ionophore antibiotic polyether. During lasalocid A biosynthesis, an epoxide hydrolase, Lsd19, converts the bisepoxy polyketide intermediate into the tetrahydro-furanyl-tetrahydropyran product. We report the crystal structure of Lsd19 in complex with lasalocid A. The struc-ture unambiguously shows that the C-terminal domain of Lsd19 catalyzes the intriguing anti-Baldwin cyclization. We propose a general mechanism for epoxide selection by ionophore polyether epoxide hydrolases.
    Journal of the American Chemical Society 12/2014;