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191.
Martínez-Otero A Evangelio E Alibés R Bourdelande JL Ruiz-Molina D Busqué F Hernando J 《Langmuir : the ACS journal of surfaces and colloids》2008,24(7):2963-2966
In this letter, we report on the development of a surface molecular sensor for the detection of acidity. Lithographically controlled wetting deposition has been applied to form the nanostructure of a new fluorescent compound with three protonation states featuring different optical properties on a glass substrate. Atomic force microscopy demonstrates the functionalization of the surface with ordered arrays of the sensor molecules. The fluorescence properties of the resulting nanopattern at different pH values have been investigated by confocal fluorescene microsopy, thus revealing the fast, sensitive, reversible response of the prepared nanosensor to gas flows of varying acidity. 相似文献
192.
A general route is presented toward the template-directed preparation of self-assembled heteromultimetallic salen structures using noncovalent coordinative metal-ligand interactions. Various higher order assemblies have been studied in detail using a combination of NMR spectroscopy and X-ray crystallography. 相似文献
193.
Mayneris J Martínez R Hernando J Gray SK González M 《The Journal of chemical physics》2008,128(14):144302
Extensive quantum real wave packet calculations within the helicity decoupling approximation are used to analyze the influence of the HF vibrational excitation on the K+HF(v=0-2,j=0)-->KF+H reaction. Quantum reaction probabilities P and reaction cross sections sigma are compared with corresponding quasiclassical trajectory (QCT) results. Disregarding threshold regions for v=0 and 1 (v=2 has no threshold), both approaches lead to remarkably similar results, particularly for sigma, validating the use of the QCT method for this system. When moving from v=0 to v=1 there is a large increase in P and sigma, as expected for a late barrier system. For v=2 the reaction becomes exoergic and P approximately 0.95 (with the exception of large total angular momenta where centrifugal barriers play a role). While substantial vibrational enhancement of the reactivity is thus seen, it is still quite less than that inferred from experimental data in the intermediate and high collision energy ranges. The origin of this discrepancy is unclear. 相似文献
194.
The combination of the square-planar cis-protected [Pt(dppp)(O 3SCF 3) 2] (M) with the ditopic N, N'-bis(3,5-dimethyl-4-pyridinyl)-4-ethoxy-2,6-pyridinedicarboxamide ligand (L) leads both in solution and in the solid state to the quantitative self-assembly of a M 2L 2 metallocycle. We also report crystallographic evidence derived from the solid-state structure of the dinuclear metallocycle in support of the existence of anion-pi-pi interactions. 相似文献
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197.
As N-sulfenyl imines (e.g., RR'C=N-SAr) can be readily transformed to their N-sulfinyl imines (RR'C=N-SOAr), N-sulfonyl imines (RR'C=N-SO2Ar), and N-sulfonyl oxaziridines, the very mild procedure developed to convert ketoximes and secondary nitro derivatives to N-arenesulfenyl ketimines constitutes a new and efficient route to all these series of compounds. The configuration of the alpha-stereocenters is retained. 相似文献
198.
Worthington RJ O'Rourke AP Morral J Tan TH Micklefield J 《Organic & biomolecular chemistry》2007,5(2):249-259
Pyrrolidine-amide oligonucleotide mimics (POMs) exhibit promising properties for potential applications, including in vivo DNA and RNA targeting, diagnostics and bioanalysis. Before POMs can be evaluated in these applications it is first necessary to synthesise and establish the properties of fully modified oligomers, with biologically relevant mixed sequences. Accordingly, Boc-Z-protected thyminyl, adeninyl and cytosinyl POM monomers were prepared and used in the first successful solid phase synthesis of a mixed sequence POM, Lys-TCACAACTT-NH2. UV thermal denaturation studies revealed that the POM oligomer is capable of hybridising with sequence selectivity to both complementary parallel and antiparallel RNA and DNA strands. Whilst the duplex melting temperatures (Tm) were higher than the corresponding duplexes formed with isosequential PNA, DNA and RNA oligomers the rates of association/dissociation of the mixed sequence POM with DNA/RNA targets were noticeably slower. 相似文献
199.
Tan TH Worthington RJ Pritchard RG Morral J Micklefield J 《Organic & biomolecular chemistry》2007,5(2):239-248
By chemically modifying or replacing the backbone of oligonucleotides it is possible to modulate the DNA and RNA recognition properties and fine-tune the physiochemical properties of oligomers. This is important because it challenges our understanding of natural nucleic acid structural and recognition properties and can lead to nucleic acid mimics with a wide range of applications in nucleic acid targeting, analysis or diagnostics. In this paper we describe the solid phase synthesis of pyrrolidine-amide oligonucleotide mimics (POMs) using Fmoc-peptide chemistry. This required the synthesis of adeninyl, cytosinyl, thyminyl and guaninyl pyrrolidine monomers, with Fmoc- and standard acyl-protecting groups on the exocyclic amino groups and nucleobases respectively. These monomers were used to synthesise several thyminyl and adeninyl POM pentamers, with modest coupling efficiency. The pentamers were purified by RP-HPLC, characterised by mass spectrometry and their DNA and RNA binding properties were investigated using UV thermal denaturation/renaturation experiments. This revealed that all the pentamers exhibit strong affinity for complementary nucleic acids. The further evaluation of longer mixed-sequence POMs is described in a second accompanying paper (R. J. Worthington et al., Org. Biomol. Chem., 2006, DOI: 10.1039/b613386j). 相似文献
200.