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951.
Hyun Ook Seo Dae Han Kim Kwang-Dae Kim Eun Ji Park Chae Won Sim Young Dok Kim 《Adsorption》2013,19(6):1181-1187
Adsorption and desorption of toluene on bare and TiO2-coated silica with a mean pore size of 15 nm under dry and humid conditions were studied using toluene breakthrough curves and temperature programmed desorption (TPD) of toluene and CO2. Two TiO2/silica samples (either partially or fully covered with TiO2) were prepared with 50 and 200 cycles of TiO2 atomic layer deposition (ALD), respectively. The capacity of silica to adsorb toluene improved significantly with TiO2-thin film coating under dry conditions. However, toluene desorption from the surface due to displacement by water was more pronounced for TiO2-coated samples than bare samples under humid conditions. In TPD experiments, silica with a thinner TiO2 film (50-ALD cycled) had the highest reactivity for toluene oxidation to CO2 both in the absence and presence of water. Toluene adsorption and oxidation reactivity of silica can be controlled by modifying the silica surface with small amount of TiO2 using ALD. 相似文献
952.
Gadolinium(III)‐Hydroxy Ladders Trapped in Succinate Frameworks with Optimized Magnetocaloric Effect
Yan‐Cong Chen Fu‐Sheng Guo Prof. Dr. Yan‐Zhen Zheng Jun‐Liang Liu Ji‐Dong Leng Róbert Tarasenko Prof. Dr. Martin Orendáč Dr. Jan Prokleška Prof. Dr. Vladimír Sechovský Prof. Dr. Ming‐Liang Tong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(40):13504-13510
Two kinds of inorganic gadolinium(III)‐hydroxy “ladders”, [2×n] and [3×n], were successfully trapped in succinate (suc) coordination polymers, [Gd2(OH)2(suc)2(H2O)]n ? 2n H2O ( 1 ) and [Gd6(OH)8(suc)5(H2O)2]n ? 4n H2O ( 2 ), respectively. Such coordination polymers could be regarded as alternating inorganic–organic hybrid materials with relatively high density. Magnetic and heat capacity studies reveal a large cryogenic magnetocaloric effect (MCE) in both compounds, namely (ΔH=70 kG) 42.8 J kg?1 K?1 for complex 1 and 48.0 J kg?1 K?1 for complex 2 . The effect of the high density is evident, which gives very large volumetric MCEs up to 120 and 144 mJ cm?3 K?1 for complexes 1 and 2 , respectively. 相似文献
953.
Tao Wang Shuai Shi Dr. Mie Højer Vilhelmsen Tuo Zhang Dr. Matthias Rudolph Prof. Dr. A. Stephen K. Hashmi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(37):12512-12516
New and chemoselective gold(I)‐catalyzed transformations of 1‐(arylethynyl)‐7‐oxabicyclo[4.1.0]‐ heptan‐2‐ones were developed. Two completely different products—6,7‐dihydrobenzofuran‐4(5H)‐ones and benzofurans—could be obtained from the same starting material. The selectivity is determined by the ligand of the gold catalyst: triphenylphosphine delivers 6,7‐dihydrobenzofuran‐4(5H)‐ones, and 1,3‐bis(diisopropylphenyl)imidazol‐2‐ylidene leads to benzofurans. Eleven examples of each case are provided. The mechanistic suggestions for the pathways to both product types are supported by isotope labeling experiments. 相似文献
954.
Dr. Zhao‐Yang Fei Bo Sun Liang Zhao Prof. Wei‐Jie Ji Prof. Chak‐Tong Au 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(20):6480-6487
Gold nanoparticles (3–4 nm) were deposited on Mn3O4 nanocrystallites with three distinct morphologies (cubic, hexagonal, and octahedral). The resulting structures were characterized, and their activities for benzene combustion were evaluated. The dominant exposed facets for the three kinds of Mn3O4 polyhedrons show the activity order: (103)≈(200)>(101). A similar activity order was derived for the interfaces between the Au and the Mn3O4 facet: Au/(200)≈Au/(103)>Au/(101). The metal–support interactions between the Au nanoclusters and specific facets of the Mn3O4 polyhedrons lead to a unique interfacial synergism in which the electronic modification of the Au nanoparticles and the morphology of the Mn3O4 substrate have a joint effect that is responsible for a significant enhancement in the catalytic activity of the Au/Mn3O4 system. 相似文献
955.
956.
Hui‐Jun Yun Yun‐Ji Lee Seung‐Jin Yoo Prof. Dae Sung Chung Prof. Yun‐Hi Kim Prof. Soon‐Ki Kwon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(39):13242-13248
We describe herein the synthesis of novel donor–acceptor conjugated polymers with dithienobenzodithiophenes (DTBDT) as the electron donor and 2,1,3‐benzothiadiazole as the electron acceptor for high‐performance organic photovoltaics (OPVs). We studied the effects of strategically inserting thiophene into the DTBDT as a substituent on the skeletal structure on the opto‐electronic performances of fabricated devices. From UV/Vis absorption, electrochemical, and field‐effect transistor analyses, we found that the thiophene‐containing DTBDT derivative can substantially increase the orbital overlap area between adjacent conjugated chains and thus dramatically enhance charge‐carrier mobility up to 0.55 cm2 V?1 s?1. The outstanding charge‐transport characteristics of this polymer allowed the realization of high‐performance organic solar cells with a power conversion efficiency (PCE) of 5.1 %. Detailed studies on the morphological factors that enable the maximum PCE of the polymer solar cells are discussed along with a hole/electron mobility analysis based on the space‐charge‐limited current model. 相似文献
957.
Ying‐Lu Cui Ji‐Long Zhang Prof. Qing‐Chuan Zheng Rui‐Juan Niu Yu Xu Prof. Hong‐Xing Zhang Chia‐Chung Sun 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(2):549-557
Cytochrome P450 (CYP) 7B1 is a steroid cytochrome P450 7α‐hydroxylase that has been linked directly with bile salt synthesis and hereditary spastic paraplegia type 5 (SPG5). The enzyme provides the primary metabolic route for neurosteroids dehydroepiandrosterone (DHEA), cholesterol derivatives 25‐hydroxycholesterol (25‐HOChol), and other steroids such as 5α‐androstane‐3β,17β‐diol (anediol), and 5α‐androstene‐3β,17β‐diol (enediol). A series of investigations including homology modeling, molecular dynamics (MD), and automatic docking, combined with the results of previous experimental site‐directed mutagenesis studies and access channels analysis, have identified the structural features relevant to the substrate selectivity of CYP7B1. The results clearly identify the dominant access channels and critical residues responsible for ligand binding. Both binding free energy analysis and total interaction energy analysis are consistent with the experimental conclusion that 25‐HOChol is the best substrate. According to 20 ns MD simulations, the Phe cluster residues that lie above the active site, particularly Phe489, are proposed to merge the active site with the adjacent channel to the surface and accommodate substrate binding in a reasonable orientation. The investigation of CYP7B1–substrate binding modes provides detailed insights into the poorly understood structural features of human CYP7B1 at the atomic level, and will be valuable information for drug development and protein engineering. 相似文献
958.
Dr. Qingsong Dong Prof. Xiao‐Juan Yang Shida Gong Dr. Qiong Luo Prof. Qian‐Shu Li Prof. Ji‐Hu Su Dr. Yanxia Zhao Prof. Biao Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(45):15240-15247
A nickel? nickel‐bonded complex, [{Ni(μ‐L.?)}2] ( 1 ; L=[(2,6‐iPr2C6H3)NC(Me)]2), was synthesized from reduction of the LNiBr2 precursor by sodium metal. Further controllable reduction of 1 with 1.0, 2.0 and 3.0 equiv of Na, respectively, afforded the singly, doubly, and triply reduced compounds [Na(DME)3] ? [{Ni(μ‐L.?)}2] ( 2 ; DME=1,2‐dimethoxyethane), [Na(Et2O)]Na[(L.?)Ni? NiL2?] ( 3 ), and [Na(Et2O)]2Na[L2?Ni? NiL2?] ( 4 ). Here L represents the neutral ligand, L.? denotes its radical monoanion, and L2? is the dianion. All of the four compounds feature a short Ni? Ni bond from 2.2957(6) to 2.4649(8) Å. Interestingly, they display two different structures: the perpendicular ( 1 and 2 ) and the coaxial ( 3 and 4 ) structure, in which the metal? metal bond axis is perpendicular to or collinear with the axes of the α‐diimine ligands, respectively. The electronic structures, Ni? Ni bonding nature, and energetic comparisons of the two structure types were investigated by DFT computations. 相似文献
959.
Tao Yang Prof. Dr. Xiang Zhao Prof. Dr. Shigeru Nagase 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(8):2649-2654
Like C60, C70 is one of the most representative fullerenes in fullerene science. Even though there are 8149 C70 isomers, only two of them have been found before: the conventional D5h and an isolated pentagon rule (IPR)‐violating C2v(7854). Through the use of quantum chemical methods, we report a new unconventional C70 isomer, C2(7892), which survives in the form of dimetallic sulfide endohedral fullerene Sc2S@C70. Compared with the IPR‐obeying C70 and the C2v(7854) fullerene with three pairs of pentagon adjacencies, the C2(7892) cage violates the isolated pentagon rule and has two pairs of pentagon adjacencies. In Sc2S@C2(7892)‐C70, two scandium atoms coordinate with two pentalene motifs, respectively, presenting two equivalent Sc? S bonds. The strong coordination interaction, along with the electron transfer from the Sc2S cluster to the fullerene cage, results in the stabilization of the non‐IPR endohedral fullerene. The electronic structure of Sc2S@C70 can be formally described as [Sc2S]4+@[C70]4?; however, a substantial overlap between the metallic orbitals and cage orbitals has also been found. Electrochemical properties and electronic absorption, infrared, and 13C NMR spectra of Sc2S@C70 have been calculated theoretically. 相似文献
960.
Cotton fabrics with antibacterial properties were prepared by the treatment with 3,3′4,4′-benzophenone tetracarboxylic dianhydride (BPTCD) in a combined process of shaking immersion in dyeing machine and pad-dry-cure. Environmentally-benign choline chloride (ChCl)-based deep eutectic solvents (DESs) were mainly examined as treatment media instead of using organic solvent. The results revealed that cotton fabrics treated with BPTCD in urea-ChCl DES showed a strong ester carbonyl peak in fourier transform infrared (FTIR) analysis, indicating fixation of BPTCD on cotton cellulose. Detailed characterizations of the BPTCD-treated cotton were carried out by FTIR, thermogravimetric analysis, scanning electron microscopy, dye staining, and evaluation of hydrophilicity and strength. The treated fabrics demonstrated a high level of antibacterial characteristics before and after UV irradiation. This indicated that addition of ChCl could enhance antibacterial activity of cotton before UV irradiation. Therefore, use of ChCl-based DES along with BPTCD incorporation provided environmentally-acceptable and economically-feasible treatment process for preparation of novel antibacterial cotton. 相似文献