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Zhang Huaihao Ma Chi Hu Yongfeng Maclennan Aimee Hu Bin Zhao Jing Wang Tianyi Cheng Changjing 《Journal of Solid State Electrochemistry》2016,20(12):3437-3445
Journal of Solid State Electrochemistry - Analog sulfur-containing precursors (ASCPs) were employed to prepare activated carbon (AC) for supercapacitor by potassium hydroxide (KOH) chemical... 相似文献
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Aimee S. A. Johnson 《Israel Journal of Mathematics》1992,77(1-2):211-240
LetS be a nonlacunary subsemigroup of the natural numbers and letμ be anS-invariant and ergodic measure. Using entropy arguments on a symbolic representation of the inverse limit of this action,
we show that if any element inS has positive entropy with respect toμ, thenμ is Lebesgue. 相似文献
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Canoy WL Cooley BE Corona JA Lovelace TC Millar A Weber AM Xie S Zhang Y 《Organic letters》2008,10(6):1103-1106
A one-step diastereoselective (up to 98:2) synthesis of the bis-furan alcohol of Darunavir and other HIV drug candidates has been achieved utilizing the novel cyclization of glycolaldehyde and 2,3-dihydrofuran. The cycloaddition was catalyzed by a variety of catalysts including those formed from tin(II) triflate and common chiral ligands such as BINAP and Evans's box ligands. An efficient and unique enzymatic process enhanced the enantiomeric purity to provide the target in optically pure form. 相似文献
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The complexes M(II){N(H)Ar(Pr(i)(6))}(2) (M = Co, 1 or Ni, 2; Ar(Pr(i)(6)) = C(6)H(3)-2,6(C(6)H(2)-2,4,6-Pr(i)(3))(2)), which have rigorously linear, N-M-N = 180°, metal coordination, and M(II){N(H)Ar(Me(6))}(2) (M = Co, 3 or Ni, 4; Ar(Me(6)) = C(6)H(3)-2,6(C(6)H(2)-2,4,6-Me(3))(2)), which have bent, N-Co-N = 144.1(4)°, and N-Ni-N = 154.60(14)°, metal coordination, were synthesized and characterized to study the effects of the metal coordination geometries on their magnetic properties. The magnetometry studies show that the linear cobalt(II) species 1 has a very high ambient temperature moment of about 6.2 μ(B) (cf. spin only value = 3.87 μ(B)) whereas the bent cobalt species 3 had a lower μ(B) value of about 4.7 μ(B). In contrast, both the linear and the bent nickel complexes 2 and 4 have magnetic moments near 3.0 μ(B) at ambient temperatures, which is close to the spin only value of 2.83 μ(B). The studies suggest that in the linear cobalt species 1 there is a very strong enhanced spin orbital coupling which leads to magnetic moments that broach the free ion value of 6.63 μ(B) probably as a result of the relatively weak ligand field and its rigorously linear coordination. For the linear nickel species 2, however, the expected strong first order orbital angular momentum contribution does not occur (cf. free ion value 5.6 μ(B)) possibly because of π bonding effects involving the nitrogen p orbitals and the d(xz) and d(yz) orbitals (whose degeneracy is lifted in the C(2h) local symmetry of the Ni{N(H)C(ipso)}(2) array) which quench the orbital angular momentum. 相似文献
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We present a general strategy for obtaining large sulfur-containing polycyclic aromatics from thienyl precursors through iron(III) chloride mediated oxidative cyclizations. By placing thienyl moieties in close proximity to adjacent arenes, we have directed the oxidized intermediates into controlled cyclization pathways, effectively suppressing polymer formation. Utilizing these cyclized compounds and their thienyl precursors, we have studied cyclization/polymerization pathways of polymers such as poly(2). The unsubstituted positions alpha to the sulfur atoms within these aromatic cores allowed for efficient halogenation and further functionalization. As a demonstration, we prepared a series of arylene-ethynylene polymers with varying degrees of chromophore aromatization and used them to probe the effects of synthetically imposed rigidity on polymer photophysical behavior. The symmetries and effective conjugation pathways within the monomers play a key role in determining photophysical properties. We observed that rigid, aromatized chromophores generally led to increased excited-state lifetimes by decreasing radiative rates of fluorescence decay. 相似文献
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Medium-sized rings have much promise in medicinal chemistry, but are difficult to make using direct cyclisation methods. In this minireview, we highlight the value of ring expansion strategies to address this long-standing synthetic challenge. We have drawn on recent progress (post 2013) to highlight the key reaction design features that enable successful ‘normal-to-medium’ ring expansion for the synthesis of these medicinally important molecular frameworks, that are currently under-represented in compound screening collections and marketed drugs in view of their challenging syntheses.Ring expansion strategies are ideally suited to make synthetically challenging, medium-sized rings with much potential in medicinal chemistry. 相似文献
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A "ring expansion-annulation strategy" for the synthesis of substituted azulenes is described based on the reaction of beta'-bromo-alpha-diazo ketones with rhodium carboxylates. The key transformation involves an intramolecular Buchner reaction followed by beta-elimination of bromide, tautomerization, and in situ trapping of the resulting 1-hydroxyazulene as a carboxylate or triflate ester. Further synthetic elaboration of the azulenyl halide and sulfonate annulation products can be achieved by employing Heck, Negishi, Stille, and Suzuki coupling reactions. Reaction of the azulenyl triflate 84 with pinacolborane provides access to the azulenylboronate 91, which participates in Suzuki coupling reactions with alkenyl and aryl iodides. The application of these coupling reactions to the synthesis of biazulenes, terazulene 101, and related oligoazulenes is described, as well as the preparation of the azulenyl amino acid derivative 110. 相似文献
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Geert A. Daudey Mengjie Shen Ankush Singhal Patrick van der Est G. J. Agur Sevink Aimee L. Boyle Alexander Kros 《Chemical science》2021,12(41):13782
Biological membrane fusion is a highly specific and coordinated process as a multitude of vesicular fusion events proceed simultaneously in a complex environment with minimal off-target delivery. In this study, we develop a liposomal fusion model system with specific recognition using lipidated derivatives of a set of four de novo designed heterodimeric coiled coil (CC) peptide pairs. Content mixing was only obtained between liposomes functionalized with complementary peptides, demonstrating both fusogenic activity of CC peptides and the specificity of this model system. The diverse peptide fusogens revealed important relationships between the fusogenic efficacy and the peptide characteristics. The fusion efficiency increased from 20% to 70% as affinity between complementary peptides decreased, (from KF ≈ 108 to 104 M−1), and fusion efficiency also increased due to more pronounced asymmetric role-playing of membrane interacting ‘K’ peptides and homodimer-forming ‘E’ peptides. Furthermore, a new and highly fusogenic CC pair (E3/P1K) was discovered, providing an orthogonal peptide triad with the fusogenic CC pairs P2E/P2K and P3E/P3K. This E3/P1k pair was revealed, via molecular dynamics simulations, to have a shifted heptad repeat that can accommodate mismatched asparagine residues. These results will have broad implications not only for the fundamental understanding of CC design and how asparagine residues can be accommodated within the hydrophobic core, but also for drug delivery systems by revealing the necessary interplay of efficient peptide fusogens and enabling the targeted delivery of different carrier vesicles at various peptide-functionalized locations.We developed a liposomal fusion model system with specific recognition using a set of heterodimeric coiled coil peptide pairs. This study unravels important structure–fusogenic efficacy relationships of peptide fusogens. 相似文献