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A convenient methodology for introducing single functional groups to the lower rim of resorcinarenes is described. The methodology allows for very convenient differential protection or derivatisation of the upper and lower rims, and a wide range of functional groups (alcohol, carboxylic acid, thiol, amine, carbamate, alkyl halide) can be incorporated as a single unit at the lower rim, opening up the way to further modification at this point and generally widening the scope for further utilising resorcinarenes. Furthermore, our approach has enabled us to link two resorcinarenes together to form novel resorcinarene dimers. 相似文献
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A cobalt porphyrin equipped with two different but geometrically complementary pyridine ligands self-assembles to form an unusually stable complex with approximately 12 porphyrin monomers arranged in a macrocyclic array. 相似文献
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CLAUDIA L. PARKER OSCAR N. VENTURA STAN K. BURT RAÚL E. CACHAU 《Molecular physics》2013,111(17):2659-2668
We present a general purpose QM-MM-MD engine (DYNGA) designed to test alternative hybrid Hamiltonians geared towards the treatment of problems of interest in structural biology including the use of experimental data constraints. In this first presentation we use DYNGA to explore the behaviour of a traditional QM-MM approach in the treatment of the water—water interaction. We find the potential energy hypersurface for the water dimer computed with the HF 4–31G*/TIP3P hybrid Hamiltonian tends to be too flat. We also explore the effect of using traditional QM-MM techniques on proton wires and conclude there is a need for improvement, possibly addressed by using polarizable force fields. 相似文献
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Nathan Hollingsworth Graeme A. Horley Muhammed Mazhar Mary F. Mahon Kieran C. Molloy Peter W. Haycock Christopher P. Myers Gary W. Critchlow 《应用有机金属化学》2006,20(10):687-695
Tin(II) methoxide reacts with N,N′‐dimethylaminoethanol (dmaeH) to yield Sn(dmae)2 ( 1 ) along with small amounts of the hydrolysis product Sn6(O)4(dmae)4 ( 2 ). The geometrically more regular iso‐structural cage Sn6(O)4(OEt)4 ( 3 ) was obtained as the only tractable product isolated from reaction of 2 and Sb(OEt)3, while 1 reacted with CdX2 (X = acac, I) to afford Sn(dmae)2Cd(acac)2 ( 4 ) and Sn(dmae)2CdI2 ( 5 ). The X‐ray structures of 2, 3 and 4 are reported. Decomposition of 4 under aerosol‐assisted chemical vapour deposition conditions leads to amorphous tin oxide films with no detectable cadmium (i.e. ca < 2% cadmium), rather than a stoichiometric Sn:Cd oxide. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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Atomically resolved non-contact fm mode atomic force microscopy images have been obtained from TiO2(100) surfaces. The 1×1 surface is observed, as well as the 1×3 phase previously imaged with STM. The morphology of the latter reconstruction consists of (110) microfacets. An additional reconstruction with 1×3 symmetry is observed, which is assigned to a phase intermediate between the 1×1 and 1×3-microfacet terminations. 相似文献
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Abstract We analyze the efficiency of the international management of the Bay of Biscay anchovy. While a sharing agreement between France and Spain has been in place since 1992, the fish stock collapsed in 2005 and the fishery closed from 2005 to spring 2010. We consider differences in production technologies between both countries and calibrate our model using data from 1987 to 2009. Our results suggest two sources of rent dissipation under the existing sharing agreement: inefficient quota allocation and production inefficiencies due to inflexible national regulations. We discuss several alternatives to improve management. 相似文献
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J. B. Lampart A. Müller G. Fromme und J. Haycock 《Fresenius' Journal of Analytical Chemistry》1916,55(7):364-366
Ohne Zusammenfassung 相似文献
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A newly developed interface coupling a CHN combustion device (elemental analyser 'EA') to an isotope ratio mass spectrometer is described and evaluated. The purpose of the device is to extend the dynamic range of delta(13)C and delta(15)N analysis from less than 2 orders of magnitude to more than 3 orders of magnitude. Carbon isotope ratio measurements of atropine as a model compound have been performed analysing between 1 μg to 5 mg C with acceptable to excellent precision (0.6 to 0.06 per thousand, delta-notation). The correction due to the blank signal is critical for sample amounts smaller than 4 μg C. The maximum sample weight is determined by the combustion capacity of the EA. Larger sample amounts are measured using dilution of a small part of the EA effluent with helium. The dilution mechanism works virtually free of isotope fractionation. Copyright 1999 John Wiley & Sons, Ltd. 相似文献
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