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61.
Dr. Rüdiger W. Seidel Richard Goddard Constantin Hoch Iris M. Oppel 《无机化学与普通化学杂志》2011,637(11):1545-1554
Attempts to crystal engineer metallosupramolecularcomplexes from Cu(phen)2+ building blocks and the prototypical,rod‐like, exo‐bidentate ligand 4,4′‐bipyridine (4,4′‐bipy) by layering techniques are described. Reactions of Cu(phen)2+ (phen = 1,10‐phenanthroline) with 4,4′‐bipy in the presence of NO3– counterions yielded two distinct, discrete, dinuclear, Ci symmetric, dumbbell‐typecomplexes, [{Cu(NO3)2(phen)}2(4,4′‐bipy)] ( 1 ) and [{Cu(NO3)(phen)(H2O)}2(4,4′‐bipy)](NO3)2 ( 2 ), depending upon the mixture of solvents used for crystallization. In compound 1 , a mono‐ and a bidentate nitrato group coordinate to Cu2+, whereas in 2 the monodentate nitrato groups are replaced by aqua ligands, which introduce additional hydrogen‐bond donor functionality to the molecule. The crystal structure of 1 was determined by single‐crystal X‐ray analysis at 296 and 110 K. Upon cooling, a disorder‐order transition occurs, with retention of the space group symmetry. The crystal structure of 2 at room temperature was reported previously [Z.‐X. Du, J.‐X. Li, Acta Cryst. 2007 , E63, m2282]. We have redetermined the crystal structure of 2 at 100 K. A phase transition is not observed for 2 , but the low temperature single‐crystal structure determination is of significantly higher precision than the room temperature study. Both 1 and 2 are obtained phase‐pure, as proven by powder X‐ray diffraction of the bulk materials. Crystals of [Cu(phen)(CF3SO3)2(4,4′‐bipy) · 0.5H2O]n ( 3 ), a one‐dimensional coordination polymer, were obtained from [Cu(CF3SO3)2(phen)(H2O)2] and 4,4′‐bipy. In 3 , Cu(phen)2+ corner units are joined by 4,4′‐bipy via the two vacant cis sites to form polymeric zig‐zag chains, which are tightly packed in the crystal. Compounds 1 – 3 were further studied by infrared spectroscopy. 相似文献
62.
Gupta R Baldock SJ Carreras P Fielden PR Goddard NJ Mohr S Razavi BS Brown BJ 《Lab on a chip》2011,11(23):4052-4056
The primary requirement for a mixing operation in droplet-based microfluidic devices is an accurate pairing of droplets of reaction fluids over an extended period of time. In this paper, a novel device for self-synchronous production of droplets has been demonstrated. The device uses a change in impedance across a pair of electrodes introduced due to the passage of a pre-formed droplet to generate a second droplet at a second pair of electrodes. The device was characterised using image analysis. Droplets with a volume of ~23.5 ± 3.1 nl (i.e.~93% of the volume of pre-formed droplets) were produced on applying a voltage of 500 V. The synchronisation efficiency of the device was 83%. As the device enables self-synchronised production of droplets, it has a potential to increase the reliability and robustness of mixing operations in droplet-based microfluidic devices. 相似文献
63.
P. Goddard W. Nahm D. Olive A. Schwimmer 《Communications in Mathematical Physics》1986,107(2):179-212
A vertex operator construction is given for the level one representations of the affine Kac-Moody algebras associated with non-simply-laced finite-dimensional Lie algebras, using free boson and interacting fermion fields. The fermion fields are constructed explicitly and a detailed discussion is given of the theory of the cocycles necessary for this and other vertex operator constructions. The construction is related in detail to the folding of Dynkin diagrams and a generalisation of it yields Freudenthal's magic square.On leave from the Weizmann Institute, Israel 相似文献
64.
E. Bonvin R. Bopp L. J. Carroll A. J. Cass S. U. Chung M. Donnat P. A. Dorsaz M. E. Feliks L. Fluri J. N. Jackson M. N. Kienzle-Focacci J. G. Lynch M. Martin L. Mathys P. J. Negus L. Perini R. Poultney W. H. Range L. Rosselet S. W. Snow A. S. Thompson R. M. Turnbull M. Werlen WA -Collaboration 《Zeitschrift fur Physik C Particles and Fields》1989,41(4):591-598
A search for pairs of highp T prompt photons produced in hydrogen by a 280 GeV/c incidentπ - beam has been carried out using a fine-grained electromagnetic calorimeter and the Omega spectrometer at the CERN SPS. Clear evidence for the existence of such events is found with a six standard deviation signal forp T >3.0 GeV/c. The cross-sections are consistent with beyond leading order QCD calculations. A discussion on the determination of α s is also presented. 相似文献
65.
The First Crystal Structure of a Reactive Dirhodium Carbene Complex and a Versatile Method for the Preparation of Gold Carbenes by Rhodium‐to‐Gold Transmetalation 下载免费PDF全文
Dr. Christophe Werlé Dr. Richard Goddard Prof. Alois Fürstner 《Angewandte Chemie (International ed. in English)》2015,54(51):15452-15456
The dirhodium carbene derived from bis(4‐methoxyphenyl)diazomethane and [Rh(tpa)4]?CH2Cl2 (tpa=triphenylacetate) was characterized by UV, IR, and NMR spectroscopy, HRMS, as well as by X‐ray diffraction. The isolated complex exhibits prototypical rhodium carbene reactivity in that it cyclopropanates 4‐methoxystyrene at low temperature. Experimental structural information on this important type of reactive intermediate is extremely scarce and thus serves as a reference point for mechanistic discussions of rhodium catalysis in general. Moreover, dirhodium carbenes are shown to undergo remarkably facile carbene transfer on treatment with [LAuNTf2] (L=phosphine). This formal transmetalation opens a valuable new entry into gold carbene complexes that cannot easily be made otherwise; three fully characterized representatives illustrate this aspect. 相似文献
66.
Baum A Scully PJ Basanta M Thomas CL Fielden PR Goddard NJ Perrie W Chalker PR 《Optics letters》2007,32(2):190-192
Femtosecond, subablation threshold photomodification of poly(methyl methacrylate) (PMMA) at 387 nm is explored to enable fabrication of optical components. Volatile fragment analysis (thermal desorption gas chromatography-mass spectrometry) and molecular weight distribution monitoring (size exclusion chromatography) suggest photochemical modification, involving direct cleavage of the polymer backbone and propagation via chain unzipping under formation of monomers, similar to the pyrolytic degradation of PMMA. Waveguides were produced in undoped, clinical-grade PMMA, showing an increased refractive index in the laser focal region (Dnmax=4x10(-3)). 相似文献
67.
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69.
Prest JE Baldock SJ Beardah MS Doyle SP Fielden PR Goddard NJ Treves Brown BJ 《The Analyst》2011,136(15):3170-3176
A new method has been developed to improve the determination of thiocyanate using isotachophoresis. This method uses complexation with copper(II) as a mechanism for improving the separation of thiocyanate from chlorate and perchlorate. By using a pH of 3.25 the method can also be used to analyse nitrite. Separations were carried out using a miniaturised poly(methyl methacrylate) (PMMA) separation device. Linearity was observed from 1.25 to 75 mg dm(-3) with a correlation coefficient of 0.998 for both thiocyanate and nitrite. Limits of detection for these two species were calculated to be 0.8 mg dm(-3) and 0.9 mg dm(-3) respectively. The method was successfully applied to the analysis of these anions in a range of samples including explosive residues. 相似文献
70.
Cammidge AN Goddard VH Schubert CP Gopee H Hughes DL Gonzalez-Lucas D 《Organic letters》2011,13(22):6034-6037
An intriguing class of quinones that efficiently catalyze the air oxidation (overall hydroxylation) of arylboronic acids to the corresponding phenol is reported. Autocatalysis in the parent system is particularly efficient and leads to rapid, quantitative synthesis of quinones such as 4 from boronic acid 1 at room temperature using air as stoichiometric oxidant. The efficiency results from a balance between two-stage conjugate addition and migration with each step driven by aromatization of a naphthalene fragment. 相似文献