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181.
Simon J. Coles Christopher W. Hall Michael B. Hursthouse 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):o29-o31
The two title calix[4]arene compounds, C34H32O8, (I), and C36H36O8·CH3Cl, (II), respectively, which differ only in the size of the alkyl function on the pendant ester group, are compared. Compound (I) forms a novel supramolecular array, whilst (II) fails to do so due to accommodating a chloroform guest molecule in the lower‐rim cavity. 相似文献
182.
Mixtures of a fluorescent liquid crystalline side chain polyacrylate and its corresponding ferroelectric monomer were studied by optical microscopy, DSC, X-ray and electro-optic techniques. For some of these mixtures we surprisingly found the emergence of the ferroelectric S*x phase, which is not exhibited by the single components. The crystalline phase of the monomer is completely suppressed by polymer concentrations above 25 per cent. The 50 per cent polymer-containing mixture shows a clear eutectic effect for the tilted phases and allows electro-optic switching close to room temperature, more than 40 K below the melting point of the monomer. 相似文献
183.
Coloured ferroelectric liquid-crystalline side chain copolymers containing 5 per cent and 15 per cent of an azo dye were synthesized and characterized by DSC, GPC and optical microscopy. Order parameters, S, of the azo compound exceeding 0·8 were measured in the frozen smectic phase for the 5 per cent copolymer. The copolymers exhibit fast electrooptic switching in the range of a few hundred microseconds to milliseconds in the Sc* phase. Both linear (i.e. electroclinic-like) and ferroelectric switching have been observed. Tilt angles of ∼19° and spontaneous polarization of ∼300nC cm-2 have been recorded in the Sc* phase. 相似文献
184.
Cycloheptatriene-rhodium(I) acetylacetonate has been prepared; the d7 analogue undergoes deuterium scrambling at 60°. 相似文献
185.
Bi−P Bond Homolysis as a Route to Reduced Bismuth Compounds and Reversible Activation of P4
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Ryan J. Schwamm Dr. Matthias Lein Dr. Martyn P. Coles Dr. Christopher M. Fitchett 《Angewandte Chemie (International ed. in English)》2016,55(47):14798-14801
Bismuth diphenylphosphanides Bi(NONR)(PPh2) (NONR=[O(SiMe2NR)2], R=tBu, 2,6‐iPr2C6H3, Aryl) undergo facile decomposition via single‐electron processes to form reduced Bi and P species. The corresponding derivatives Bi(NONR)(PCy2) are stable. Reaction of the isolated BiII radical .Bi(NONAr) with white phosphorus (P4) proceeds with the reversible and selective activation of a single P?P bond to afford the bimetallic μ,η1:1‐bicyclo[1.1.0]tetraphosphabutane compound. 相似文献
186.
187.
Kylander ME Weiss DJ Jeffries TE Kober B Dolgopolova A Garcia-Sanchez R Coles BJ 《Analytica chimica acta》2007,582(1):116-124
An analytical protocol for rapid and reliable laser ablation-quadrupole (LA-Q)- and multi-collector (MC-) inductively coupled plasma-mass spectrometry (ICP-MS) analysis of Pb isotope ratios (207Pb/206Pb and 208Pb/206Pb) in peats and lichens is developed. This technique is applicable to source tracing atmospheric Pb deposition in biomonitoring studies and sample screening. Reference materials and environmental samples were dry ashed and pressed into pellets for introduction by laser ablation. No binder was used to reduce contamination. LA-MC-ICP-MS internal and external precisions were <1.1% and <0.3%, respectively, on both 207Pb/206Pb and 208Pb/206Pb ratios. LA-Q-ICP-MS internal precisions on 207Pb/206Pb and 208Pb/206Pb ratios were lower with values for the different sample sets <14.3% while external precisions were <2.9%. The level of external precision acquired in this study is high enough to distinguish between most modern Pb sources. LA-MC-ICP-MS measurements differed from thermal ionisation mass spectrometry (TIMS) values by 1% or less while the accuracy obtained using LA-Q-ICP-MS compared to solution MC-ICP-MS was 3.1% or better using a run bracketing (RB) mass bias correction method. Sample heterogeneity and detector switching when measuring 208Pb by Q-ICP-MS are identified as sources of reduced analytical performance. 相似文献
188.
Giacomo Picci Jessica Milia Maria Carla Aragoni Massimiliano Arca Simon J. Coles Alessandra Garau Vito Lippolis Riccardo Montis James B. Orton Claudia Caltagirone 《Molecules (Basel, Switzerland)》2021,26(5)
The new symmetric acyclic N,N’-bis(1-pyrenyl) squaramide (H2L) functionalized with the pyrene moiety as a fluorogenic fragment has been designed and its ability to selectively detect specific anions and metals investigated. H2L selectively binds Cl− both in solution (DMSO 0.5% H2O and MeCN) and in the solid state, and allows to selectively detect Cu2+ in MeCN with the formation of a 2:1 metal-receptor complex, with a green intense emission appreciable by naked eye under the UV lamp. The H2L copper complex preserves its emission properties in the presence of Cl−. The addition of basic anions (OH−, CN−, and F−) up to 10 equivalents caused the deprotonation of the squaramide NHs and a dramatic change of the emission properties of the H2L copper complex. 相似文献
189.
Formation and Structural Characterization of Metal Complexes derived from Thiosalicylic Acid
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Minu G. Bhowon Sabina Jhaumeer‐Laulloo Salma Moosun Lisa Humphreys Simon Coles Roshni Fowdram Evena Mungra 《无机化学与普通化学杂志》2017,643(18):1167-1172
The formation and structural aspects of some metal complexes of thiosalicylic acid (TSA) were studied. The μ‐bridging tetra‐coordinated Ru complex, [Ru(C6H4(CO2)(μ‐S)(H2O)]2 ( 1 ) was formed by hydrothermal reaction of TSA with RuCl3. The complexes [M(dtdb)(phen)(H2O)]n ( 2 – 4 ) (M = ZnII, CoII, NiII, dtdb = 2,2′‐dithiodibenzoate anion, phen = 1,10‐phenanthroline) were obtained by the slow diffusion technique and the in situ S–S bond formation was confirmed by elemental, spectral and X‐ray analysis. Reaction of TSA with CuCl2 and 2,2′‐bipyridine (bipy) under the slow diffusion technique yielded the dimer [Cu(tdb)(bipy)] ( 5 ) (tdb = thiodibenzoic acid), where the in situ generation of 2,2′‐thiodibenzoic acid was observed. 相似文献
190.
Beşli S Coles SJ Davies DB Hursthouse MB Kiliç A Shaw RA 《Dalton transactions (Cambridge, England : 2003)》2007,(26):2792-2801
Nucleophilic substitution reactions of cyclotriphosphazene derivatives having five-membered spiro rings, N(3)P(3)Cl(4)[O(CH(2))(2)X] (X = NH or O) with alkoxides (of tetraethylene glycol and some mono-functional alcohols) give unexpected rearrangements to form stable seven-membered ring ansa compounds, even though crystallographic evidence shows ring distortion and compression of the cyclophosphazene ring. With weaker nucleophiles such as sodium phenoxide and pyrrolidine substitution at a PCl2 group is preferred and no rearrangement takes place. In contrast, reactions of the analogous phosphazenes containing six-membered spiro rings, N(3)P(3)Cl(4)[O(CH(2))(3)X], with all of the above reagents give only normal substitution reactions at the PCl2 moieties and no rearrangement products. The spiro to ansa rearrangements in cyclophosphazenes are remarkable as the reported primary reaction products with the same difunctional reagents HO(CH(2))(2)XH are predominantly spiro, with some dangling and bridging derivatives, but no ansa compounds. 相似文献