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Katrina A. Jolliffe Mercedes Crego Calama Roel Fokkens Nico M. M. Nibbering Peter Timmerman David N. Reinhoudt 《Angewandte Chemie (International ed. in English)》1998,37(9):1247-1251
The high affinity of Ag + ions for aromatic π donors and cyano groups is exploited in a novel MALDI-TOF mass spectrometric method for the identification of hydrogen-bonded assemblies. The interaction with the Ag+ ions—which, for example, can be complexed by two phenyl groups in a sandwich-type manner (see drawing on the right)—provides positively charged assemblies in a nondestructive way. 相似文献
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Katrina A. Jolliffe Peter Timmerman David N. Reinhoudt 《Angewandte Chemie (International ed. in English)》1999,38(7):933-937
A total of 72 hydrogen bonds are formed in the spontaneous association of calix[4]arene tetramelamine and barbituric acid derivatives to give nanosized assemblies of the type represented in the picture. These consist of 15 components that assemble in a completely diastereoselective sense: of the eight possible diastereomers only the all-staggered diastereoisomer is obtained. 相似文献
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The anion binding ability of a family of bis(ZnII‐Dpa) functionalized cyclic peptides has been investigated using displacement assays with a fluorescent coumarin indicator in water, saline solution, and Krebs buffer. Non‐binding side‐chain steric bulk, the relative position of binding sites, and the scaffold size were all found to affect the ability of these receptors to discriminate between polyphosphate ions. Most receptors showed some selectivity for pyrophosphate over ATP and ADP in water and saline, and this selectivity was significantly enhanced in the biologically relevant Krebs buffer giving chemosensing ensembles capable of selective recognition of pyrophosphate in the presence of excess ATP. 相似文献
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McDonough MJ Reynolds AJ Lee WY Jolliffe KA 《Chemical communications (Cambridge, England)》2006,(28):2971-2973
A cyclic peptide based receptor, bearing two dipicolylamino arms complexed to zinc(II) ions, binds pyrophosphate ions with high affinity and selectivity in aqueous solution as determined using an indicator displacement assay. 相似文献
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(-)-3-Dehydroshikimic acid (3-DHS, 4), a C(7)-building block now available in large quantity from corn syrup, has been converted into the sialic acid (-)-KDN (3) as well as its C-7- and C-8-epimers. (-)-Quinic acid can be used for the same purpose. [structure: see text] 相似文献
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KA Saeed FO Ayorinde BE Eribo M Gordon L Collier 《Rapid communications in mass spectrometry : RCM》1999,13(19):1951-1957
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used for the characterization of a partially transesterified poly(beta-hydroxyalkanoate), PHA, polymer produced by the bacterial strain Alcaligenes eutrophus using saponified vegetable oils as the sole carbon sources. The transesterification was carried out separately under acidic and basic conditions to obtain PHA oligomers weighing less than 10 kDa. The intact oligomers were detected in their cationized [M + Na](+) and [M + K](+) forms by MALDI-TOFMS. A composition analysis, using the MALDI-TOF spectra, indicate that the oligomers obtained via acid catalysis were terminated with a methyl 3-hydroxybutyrate end group, and those obtained by base catalysis had a methyl crotonate (olefinic) termination. In addition to HB (hydroxy butyrate), the oligomers were found to contain a small percentage of HV (hydroxy valerate). This was independently confirmed using gas chromatography/mass spectrometry (GC/MS). In comparison, the analysis of a commercial PHA polymer, transesterified under identical conditions, only showed the presence of HB, i.e. a pure PHB homopolymer. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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A simple amplifier tube has been designed which, when used with already well-developed, stable single-frequency CO2 laser oscillators, produces a cw power output of up to 40 W suitable for pumping far infra-red lasers. 相似文献