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91.
C. K. Chang Brian Ward Richard Young Michail P. Kondylis 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(10-11):1307-1326
Heme reactivity in hemoproteins is governed by the microenvironment near the ligand binding site. In order to quantify polarity effects on heme ligand binding, the kinetics of O2 and CO binding have been measured for a series of synthetic heme models equipped with a range of groups of varying dipole moments positioned near the heme coordination site. For hemes with polar aprotic groups, both O2 on (k′) and off rates (k) are found to be dependent on the dipole moment. For model systems containing protic groups, the O2 off rate is substantially reduced due to hydrogen bonding with the coordinated O2. The hydrogen-bonding stabilization is estimated to be 0.7 and 1.6 kcal/mol for an alcohol and a secondary amide, respectively. CO binding displays little correlation with a polarity effect; instead it seems to depend upon the size and position of the polar group. 相似文献
92.
We report the synthesis of three new dipyrrinone imine analogues and the characterisation of their self-association properties. Based on vapour pressure osmometry and nuclear magnetic resonance studies, placing the imine functional group at C(9) of the dipyrrinone disrupts the native self-association of the dipyrrinone core in a manner that correlates with the conformational A-value of the imine N-substituent. 相似文献
93.
The syntheses, characterization and metal ion complexation and extraction capabilities of six new calix[4]arene Schiff base compounds, 5–10, are reported. The preparation of the compounds was achieved by the condensation of 5,17-diamino-11,23-di-tert-butyl-25,27-di-n-butoxy-26,28-dihydroxycalix[4]arene with the appropriate aldehyde (5-bromosalicylaldehyde for 5, 4-anisaldehyde for 6, 4-(dimethylamino)benzaldehyde for 7, 9-anthracenecarboxaldehyde for 8, 1-pyrenecarboxaldehyde for 9, and 9-fluorenecarboxaldehyde for 10) in refluxing ethanol. The compounds were characterized by 1H and 13C NMR spectroscopy, IR spectroscopy, high-resolution mass spectrometry and elemental analysis. The X-ray crystal structures of 7, 8 and 9 (as dichloromethane solvates) revealed that the calixarene molecules adopt H-bond stabilized, distorted-cone conformations and form centrosymmetric dimers in the solid state. Compounds 5–10 did not form host–guest complexes with NEt4[(bdt)MoO2(OSiPh3)] (bdt2–=benzene-1,2-dithiolate), a potential precursor for biologically relevant oxosulfido-Mo(VI/V) enzyme models; such host–guest complexes have the potential to stabilize these sought-after but highly reactive model compounds. In addition, the capabilities of 5–10 to extract selected metal ions (Ni2+, Co2+, Cu2+, Zn2+, Ag+, Pb2+, Cd2+ and Hg2+) from an aqueous into an organic phase have been assessed by picrate extraction experiments. Compound 5 displayed exceptional selectivity towards Ni2+, compound 7 exhibited enhanced extraction towards all of the metal ions tested and compounds 6, 9 and 10 showed very high selectivity towards Hg2+. On the other hand, compound 8 exhibited negligible capacity to extract any of the metal ions tested. 相似文献
94.
Gyula Dekany Karen Wright Peter Ward Istvan Toth 《Journal of carbohydrate chemistry》2013,32(4):383-398
Abstract Sialyl Lewis X (SLex) analogs 2a and 2b were synthesised, where the N-acetyl-D-glucose and the D-galactose units of SLex 1 were replaced with an alkyl and a heteroalkyl spacer. Sulphate ester 6i was also synthesised from alcohol 6b and chlorosulphonic acid. A novel promoter, silver mercaptoethanesulphonate, was used to synthesise α-sialosides 2c. 7b and 7c. 相似文献
95.
Santos Jovy Ann Simon Paulo Bernot Anthony R. Babasi Christopher Ward Patrick A. Hwang Son-Jong Zidan Ragaiy Teprovich Joseph A. 《Journal of Solid State Electrochemistry》2021,25(4):1441-1452
Journal of Solid State Electrochemistry - In this work, we evaluate the electrochemical properties of MBH4-C60 (M = Li+, Na+) nanocomposites for potential use as a solid-state electrolyte in... 相似文献
96.
HengYan Wang WenQiang Zheng NengKun Yu KeRen Li DaWei Lu Tao Xin Carson Li ZhengFeng Ji David Kribs Bei Zeng XinHua Peng JiangFeng Du 《中国科学:物理学 力学 天文学(英文版)》2016,59(10):100313
We investigate quantum state tomography(QST) for pure states and quantum process tomography(QPT) for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert space, we first propose an adaptive protocol where only 2d. 1 measurement outcomes are used to accomplish the QST for all pure states. This idea is then extended to study QPT for unitary channels, where an adaptive unitary process tomography(AUPT) protocol of d2+d.1measurement outcomes is constructed for any unitary channel. We experimentally implement the AUPT protocol in a 2-qubit nuclear magnetic resonance system. We examine the performance of the AUPT protocol when applied to Hadamard gate, T gate(/8 phase gate), and controlled-NOT gate,respectively, as these gates form the universal gate set for quantum information processing purpose. As a comparison, standard QPT is also implemented for each gate. Our experimental results show that the AUPT protocol that reconstructing unitary channels via adaptive measurements significantly reduce the number of experiments required by standard QPT without considerable loss of fidelity. 相似文献
97.
The correlation properties of speckle fields are studied for general paraxial systems. The previous studies on lateral and longitudinal speckle size for the case of free-space propagation (Fresnel transform) are generalized to the case of the linear canonical transform. These results have implications for the control of speckle size, through appropriate design of optical systems, with particular relevance for speckle interferometry. 相似文献
98.
An efficient approach for the synthesis of monosubstituted aromatic compounds relying on a ring-closing metathesis followed by spontaneous 1,2-elimination is presented. The efficiency for late-stage functionalization is highlighted in various solvents (up to 920 TON). This approach is compatible with strained cycles and other multiple bonds in the substrate. 相似文献
99.
Corrigendum: Combined Two‐Photon Excitation and d→f Energy Transfer in a Water‐Soluble IrIII/EuIII Dyad: Two Luminescence Components from One Molecule for Cellular Imaging
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100.
Solar Hydrogen from an Aqueous,Noble‐Metal‐Free Hybrid System in a Continuous‐Flow Sampling Reaction System
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Dr. Xiaobo Li Dr. Antony J. Ward Prof. Anthony F. Masters Prof. Thomas Maschmeyer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(24):7345-7350
We introduce the visible‐light photocatalytic H2 evolution reaction as catalyzed by a cobaloxime/carbon nitride (C3N4) noble‐metal‐free hybrid photosystem by using a continuous‐flow sampling reaction system. The photocatalytic H2 evolution rate is highly dependent on the structure of C3N4, in which porous C3N4 shows the best activity compared with bulk C3N4 (lamellar) and C3N4 nanosheets. When using porous C3N4, the system is neither affected by the solution pH, nor the C3N4 concentration, nor the structure of the cobaloxime complex. 相似文献