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991.
Jie Shao Hai Lin Xue-Fang Shang Hua-Mei Chen Hua-Kuan Lin 《Journal of inclusion phenomena and macrocyclic chemistry》2007,59(3-4):371-375
A new urea-based receptor was designed to selectively recognize H2PO4− among other anions (such as F-, Cl-, Br-, I-, OH-, AcO-) in organic solvent (DMSO) through intermolecular hydrogen bonding. Addition of anions to the receptor caused changes in
UV–vis spectrum which provided the first indication of its anion binding ability.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
992.
本文提出平行催化体系的对位叠式循环方波伏安法,并对共作了系统的研究,推导了这一方法的催化电流理论方程,并用验验证这理论的正确性,得到其各脉冲电流皆为同方向,对位叠式循环催化电流相当于将电流叠加4次,而波形不受方波幅度大小的影响,因而灵敏度和分辨率有较大提高,优于其它方波伏安法。 相似文献
993.
R. Picorel M. Bakhtiari T. Lu T. M. Cotton M. Seibert 《Photochemistry and photobiology》1992,56(2):263-270
Strong resonance Raman (RR) and surface-enhanced resonance Raman scattering (SERRS) signals from carotenoids were detected from thylakoid (stromal-side out) vesicles and inside-out (lumenal-side out) vesicles isolated from spinach chloroplasts. The intensity of the signals from both types of membranes was comparable, indicating that plant carotenoids are exposed on or close to both surfaces or sides of the thylakoid membrane. This is in contrast to previous studies with bacterial photosynthetic membranes (Picorel et al., 1988, J. Biol. Chem. 263 , 4374–4380; and 1990, Biochemistry 29 , 707–712) that show carotenoids selectively located on the cytoplasmic side. In addition; strong RR and SERRS signals were detected from stacked and unstacked photosystem-II-enriched membrane fragments, demonstrating that carotenoids are also exposed on both surfaces of the appressed region of the thylakoid membrane. Antibodies against the photosystem (PS) II extrinsic proteins blocked SERRS signals from stacked PS II membrane fragments, but only partially affected the SERRS signals from unstacked membranes. The results indicate that these antibodies, which preferentially cover the surface of the original lumenalside of the appressed region, act as spacers between the membrane and SERRS electrode surfaces. The original stromal-side of the appressed region is unaffected. These findings verify the distance sensitivity of the SERRS technique and underscore the above conclusion about the location of carotenoids in the appressed regions. Finally, SERRS signals are sensitive to membrane aging and storage temperature; caution is suggested to those applying SERRS spectroscopy to intact membrane systems. 相似文献
994.
Arylvinylidenecyclopropanes undergo a novel reaction upon heating at 150 °C with diaryl diselenide to give the corresponding 1,2-diarylselenocyclopentene derivatives in good to high yields within 1.5 h. The further transformation of 1,2-diarylselenocyclopentene derivatives has been disclosed. 相似文献
995.
Molecular dynamics simulation of a reverse micelle self assembly in supercritical CO2 总被引:1,自引:0,他引:1
In this communication we report on molecular dynamics computer simulations of self-assembly of reverse micelles in supercritical carbon dioxide. The reverse micelles contain perfluoropolyether ammonium carboxylate surfactants and an aqueous core. We observed a quick self-assembly of these micelles over time periods of approximately 5 ns, irrespective of initial conditions. In most cases, the self-assembled perfluorinated reverse micelles have a nice spherical shape and properties consistent with experiments. When the fluorinated surfactant is replaced by its hydrogenated analogue, the assembled aggregate contains a region of direct contact between water and carbon dioxide, indicating that hydrogenated surfactant is not a good agent for creation of microemulsions in water/carbon dioxide mixtures. 相似文献
996.
Synthesis and photochemistry of several title compounds 1-3 containing multiple chromophoric systems are described. The Diels-Alder reactions of 2,6,6-trimethylcyclohexa-2,4-dienone (5) with acetylenes 6a-d provided the adducts 7a-d, which upon hydrolysis furnished the desired bicyclo[2.2.2]octenediones 1a-d. Oximes 2a-d were prepared from diones 1a-d by treatment with hydroxylamine hydrochloride in pyridine. 5-Methylenebicyclo[2.2.2]oct-7-en-2-ones 3a-d were obtained via chemoselective Wittig reaction of the corresponding diones 1a-d. Bicyclo[2.2.2]octenediones 1a-c underwent chemoselective oxa-di-pi-methane rearrangement under sensitized conditions and suffered formal ketene extrusion upon direct irradiation. Direct irradiation of 1d afforded 11d via formal ketene extrusion but under sensitization it remained unchanged. Oximes 2a-d suffered ketene extrusion upon direct irradiation and E/Z isomerization under sensitized conditions. On the other hand, 5-methylenebicyclo[2.2.2]oct-7-en-2-ones 3a-d generally underwent 1,3-acyl shift. The plausible courses of all these photochemical processes are discussed. 相似文献
997.
Fan J Gan L Kawaguchi H Sun WY Yu KB Tang WX 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(16):3965-3973
Six noninterpenetrating organic-inorganic hybridized coordination complexes, [Mn(3)(2)(H(2)O)(2)](ClO(4))(2).2 H(2)O (5), [Mn(3)(2)(H(2)O)(2)](NO(3))(2) (6), [Mn(3)(2)(N(3))(2)].2 H(2)O (7), [Cu(3)(2)(H(2)O)(2)](ClO(4))(2) (8), [Mn(4)(2)(H(2)O)(SO(4))].CH(3)OH.5 H(2)O (9) and [Mn(4)(2)](ClO(4))(2) (10) were obtained through self-assembly of novel tripodal ligands, 1,3,5-tris(1-imidazolyl)benzene (3) and 1,3-bis(1-imidazolyl)-5-(imidazol-1-ylmethyl)benzene (4) with the corresponding metal salts, respectively. Their structures were determined by X-ray crystallography. The results of structural analysis of complexes 5, 6, 7, and 8 with rigid ligand 3 indicate that their structures are mainly dependant on the nature of the organic ligand and geometric need of the metal ions, but not influenced greatly by the anions and metal ions. While in complexes 9 and 10, which contain the flexible ligand 4, the counteranion plays an important role in the formation of the frameworks. Entirely different structures of complexes 5 and 10 indicate that the organic ligands greatly affect the structures of assemblies. Furthermore, in complexes 5 and 6, the counteranions located between the cationic layers can be exchanged by other anions. Reversible anion exchanges between complexes 5 and 6 without destruction of the frameworks demonstrate that 5 and 6 can act as cationic layered materials for anion exchange, as determined by IR spectroscopy, elemental analyses, and X-ray powder diffraction. 相似文献
998.
SynthesisandCrystalStructureofDinuclearCopperClusterCompound[Cu(dtp)PPh_3]_2ChenQiu-Hua;LuShao-Fang;HuangXiao-Ying(StatekeyLab... 相似文献
999.
Changyuan Lu Side Yao Wenfeng Wang Yongpeng Tong Weizhen Lin Tingwen Rong Nianyun Lin 《中国科学B辑(英文版)》1998,41(3):259-265
Fullerols of C60 and of C70 [C60(OH)n, C70(OH)m], water-soluble fullerene derivatives, unlike some other fullerene derivatives (such as C60 (C4H6O), C60 (C3H7N) and C60 [C(COOEt)2]x), do not result in excited triplet state but in ionization via monophotonic process in aqueous solutions with 248 nm laser.
The quantum yields of formation of hydrated electron (Φe
−) are determined to be 0.08 and 0.11 for fullerols of C60 and of C70 respectively at room temperature (ca. 15°C) with KI solution used as reference. By laser flash photolysis and oxidation of
sulfate radical anion SO4
−, the fullerol radical cation or neutral radical of C60 is confirmed to be existent and the transient absorption spectra of fullerol radical cation of C70 are observed for the first time.
Project supported by the National Natural Science Foundation of China 相似文献
1000.
We report a convenient method for quantitative non-covalent functionalization of single-walled carbon nanotubes (SWNT) with phthalocyanine (Pc) compounds, in which a surface coverage of 49% was achieved. The effect of several process parameters on the functionalization process was elucidated. Firstly, as-produced SWNT gave the largest extent of functionalization compared with purified SWNT and as-produced multi-walled carbon nanotubes (MWNT). Secondly, the extent of functionalization was sensitive to the specific molecular structures of the Pc compounds. Finally, in terms of solvent selection, dimethylformamide (DMF) was found to give the largest extent of functionalization, which is then followed by chloroform (CHCl3) and 1,2-dichlorobenzene (ODCB). The method reported in this paper provides new insights on the interactions between Pc molecules and carbon nanotubes and paves the way for rational control of the degree of functionalization, which is an important step from the perspective of carbon nanotube applications.
Electronic supplementary material Supplementary material for this article is avilable at and is accessible for authorised users. 相似文献