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1.
Summary Several new neutral and cationic di- and tri-nuclear cyano-bridged bis(dioximato)cobalt(III) complexes have been synthesized and characterized (dioximato = dimethylglyoximato or diphenylglyoximato). These compounds are obtained through substitution of labile axial ligands by the nitrogen of the cyano-group in [Co(dioximato)2(CN)2]– or [LCo(dioximato)2(CN)] (L = H2O, NH3, or py). In the first case, the existence of only one band in the CN-stretching region of the i.r. spectrum at 2190–2200 cm–1 is indicative of a trinuclear compound, while the presence of a second band at 2140 cm–1 attributable to a terminal cyano-group indicates a dinuclear structure. In the presence of water, aquation of axial positions may take place at the same time as bridge formation, whereas the use of a non-aqueous solvent allows the preparation of complexes with pyridine or NH3. 相似文献
2.
Frontispiece: A Multicomponent Conjugation Strategy to Unique N‐Steroidal Peptides: First Evidence of the Steroidal Nucleus as a β‐Turn Inducer in Acyclic Peptides 下载免费PDF全文
3.
Molecularly imprinted capillary electrochromatography for selective determination of thiabendazole in citrus samples 总被引:3,自引:0,他引:3
In this work, the suitability of the combination of molecular imprinting and capillary electrochromatography (MIP-CEC) to be used as powerful tool in environmental or food analysis has been for the first time studied and successfully demonstrated. A molecularly imprinted monolith (MIM) has been synthesised and evaluated as stationary phase for the selective determination of the fungicide thiabendazole (TBZ) in citrus samples by non-aqueous capillary electrochromatography. The influence of the mobile phase composition, the voltage of the power supply and the separation temperature on the recognition of TBZ by the imprinted polymer has been evaluated, and the imprint effect in the MIM was clearly demonstrated. Once optimum recognition conditions were established, other variables affecting mechanical properties and chromatographic performance of MIM were adjusted using computational approach. The high selectivity achieved by the MIP-CEC developed procedure allowed unambiguous detection and quantification of TBZ in citrus samples by direct injection of the crude sample extracts, without any previous clean-up, in less than 6 min. The developed method was properly validated and the calculated detection limits were below the established maximum residue limits (MRLs), clearly demonstrating the suitability of the method to be used for the control of the selected fungicide. 相似文献
4.
Febles M Pérez-Hernandez N Pérez C Rodríguez ML Foces-Foces C Roux MV Morales EQ Buntkowsky G Limbach HH Martín JD 《Journal of the American Chemical Society》2006,128(31):10008-10009
Water molecules confined inside narrow pores are of great importance in understanding the structure, stability, and function of water channels. Here we report that besides the H-bonding water that structures the pore, the permanent presence of a significant, fast-moving fraction of incompletely H-bonded water molecules inside the pore should control the free entry and exit of water. This is achieved by means of complementary DSC and solid-state NMR studies. We also present compelling evidence from X-ray diffraction data that the cluster formed by six water molecules in the most stable cage-like structure is sufficiently hydrophobic to be stably adsorbed in a nonpolar environment. 相似文献
5.
del Puerto E Sánchez-Cortés S García-Ramos JV Domingo C 《Chemical communications (Cambridge, England)》2011,47(6):1854-1856
A possibility of getting SERS spectra of insoluble aromatic compounds in colloidal silver solutions is described. The method tested for the organic pigment quinacridone quinone consists of dispersing it in calix[n]arenes. The potentials of such cavitands, both as dispersing and as silver functionalization agents, is reported as a function of the substitution in their lower rim and their cavity size. 相似文献
6.
Esther Domínguez Concepción Laborra Aranzazu Linaza Ana Madoz Issa A. Katime 《Monatshefte für Chemie / Chemical Monthly》1989,120(8-9):743-748
Summary A series of mono and diesters of itaconic acid containing alkoxy and sulfide side chains of variable lengths has been synthesized. Their structures have been established on the basis of their spectral data.
Eine Serie von Mono- und Diestern von Itaconsäure: Synthese und Strukturbestimmung
Zusammenfassung Es wurde eine Serie von Mono- und Diestern von Itaconsäure mit Alkoxy- und Sulfidseitenketten variabler Länge synthetisiert. Die Strukturaufklärung erfolgte mittels spektroskopischer Daten.相似文献
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8.
Vera L.M. Silva Artur M.S. Silva Rosa M. Claramunt Concepción López Dionisia Sanz Lourdes Infantes Ángela Martínez López Felipe Reviriego Ibon Alkorta José Elguero 《Tetrahedron》2019,75(48):130690
Tetrakis(1H-pyrazol-1-yl)methanes are very rare compounds of which only two are known: the unsubstituted 1 obtained classically by Hückel in 1937 from carbon tetrachloride and prepared again several times and the 3,5-dimethyl substituted 2 obtained serendipitously by Pombeiro in 2009. We have now extended this group to include four new derivatives 8, 9, 11 and 12 bearing methyl groups. The X-ray crystal structure of the four compounds has been determined. They have been studied by NMR both in solution (1H, 13C, 15N) and in the solid state (13C and 15N). DFT calculations of the six compounds (geometries, energies and absolute shieldings) have been used to discuss the experimental observations. 相似文献
9.
López C Caubet A Pérez S Solans X Font-Bardía M 《Chemical communications (Cambridge, England)》2004,(5):540-541
The synthesis of the first examples of diastereomerically pure platinacycles having simultaneously a chiral carbon and a sigma[Pt-C(sp(2), ferrocene)] bond is described. 相似文献
10.