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111.
Dr. Jens Atzrodt Dr. Volker Derdau Prof. Dr. William J. Kerr Dr. Marc Reid 《Angewandte Chemie (International ed. in English)》2018,57(12):3022-3047
The various applications of hydrogen isotopes (deuterium, D, and tritium, T) in the physical and life sciences demand a range of methods for their installation in an array of molecular architectures. In this Review, we describe recent advances in synthetic C?H functionalisation for hydrogen isotope exchange. 相似文献
112.
We describe configurations of a novel synchronously pumped femtosecond optical parametric oscillator based on the crystal RbTiOAsO(4) and operating with a signal-pulse-repetition frequency as high as 344 MHz. Average signal powers as high as 600 mW and pulse durations of 78 fs are demonstrated at a wavelength of 1.25 microm, and a characterization of the signal output using frequency-resolved optical gating implies asymmetric near-sech(2)(t) intensity-profile pulses with significant amounts of spectral cubic phase. 相似文献
113.
Broadly tunable infrared femtosecond optical parametric oscillator based on periodically poled RbTiOAsO(4) 总被引:1,自引:0,他引:1
Reid DT Penman Z Ebrahimzadeh M Sibbett W Karlsson H Laurell F 《Optics letters》1997,22(18):1397-1399
We present results from what we believe is the first reported example of an optical parametric oscillator based on periodically poled RbTiOAsO(4). The oscillator is pumped by a femtosecond self-mode-locked Ti:sapphire laser and, with a single-grating 2-mm-long crystal and one mirror set, a combination of pump and cavity-length tuning provided wavelength coverage from 1060 to 1225nm (signal) and 2.67 to 4.5 microm (idler). Average output powers were as much as 120mW in the signal and 105mW in the idler and interferometric autocorrelations recorded at signal and idler wavelengths of 1.1 and 3.26 microm, respectively, imply pulse durations of 125 and 115fs, respectively. 相似文献
114.
115.
Daniel A. Osborne W. Reid Dreher Jr. H. Ray Gore Jr. Andrew Stoddard Edward J. Valente 《Journal of chemical crystallography》2000,30(9):583-588
Racemic ethyl 2-acetamido-2-carboxy-5-oxohexanoate has been isolated by single hydrolysis of the corresponding diethyl ester and resolved essentially quantitatively by diastereomeric salt formation with (–)-quinine. The (+)-isomer was retrieved from the less-soluble quininium salt. Racemate crystals, (plusmn;)-1, are monoclinic, space group P21/c, a = 7.609(4)Å, b = 16.731(7)Å, c = 10.746(5) Å, = 99.83(4)° enantiomeric crystals, (+)-1, are monoclinic, space group P21, a = 5.857(2)Å, b = 15.282(4)Å, c = 7.618(2)Å, = 95.62(2)°. Molecular packing is similar in the two structures; the enantiomer has a 0.7% higher volume per molecule and the lower fusion temperatures by 3°C. In both structures, carboxylic acids donate hydrogen bonds to the amide carbonyls of adjacent molecules without reciprocation. Amides form three-centered hydrogen bonds to carboxy oxygen of an intramolecular carboxylic acid group and to oxygen of a ketone carbonyl in an adjacent molecule. 相似文献
116.
Jan C. A. Boeyens Leanne M. Cook Tak-ho Ngoi David H. Reid 《Journal of chemical crystallography》1996,26(3):215-218
The crystal structure of two isomeric oximes, C11N10N2OS have been studied by X-ray diffraction. The open-chain thiocyanato derivative is somewhat'less dense and crystallizes with the orthorhombic space group Pbcn;a,b,c=18.718(1), 10.601(3), 11.528(1) Å,Z=8. The heterocyclic isomer occurs as pseudo-orthorhombic (Cmma)twinned crystals of space group P21/n, a, b, c, =12.11(1), 7.46(1), 12.12(1) Å, 100.09(1)o,Z=4. Twinning occurs as a result of the near-equality of the monoclinica andc cell constants. 相似文献
117.
Reid Tingley Valerio Bertolasi Keith Vaughan 《Journal of chemical crystallography》2006,36(12):831-839
A new series of bis-triazenes, the 1-aryl-2-[3-(3-[2-aryl-1-diazenyl]-1,3-diazepan-1-ylmethyl)-1,3-diazepan-1-yl]-1-diazenes has been synthesized from the reaction of diazonium salts with a mixture of 1,4-diaminobutane and formaldehyde. The structures of 1-(p-bromophenyl)-2-[3-{3-[2-(p-bromophenyl)-1-diazenyl]-1,3-diazepan-1-ylmethyl}-1,3-diazepan-1-yl]-1-diazene(1), 1-(p-cyanophenyl)-2-[3-{3-[2-(p-cyanophenyl)-1-diazenyl]-1,3-di azepan-1-ylmethyl}-1,3-diazepan-1-yl]-1-diazene(2), and 1-(p-methoxyphenyl)-2-[3-{3-[2-(p-methoxy-phenyl)-1-diazenyl]-1,3-diazepan-1-ylmethyl}-1,3-diazepan-1-yl]-1 diazene(3) have been unequivocally determined by X-ray crystallography. The new bis-triazenes are important since the structure contains the novel saturated heterocycle, 1,3-diazepane. The general conclusion of this study is that alkanediamines with 3 or 4 carbon atoms in the spacer link between the nitrogen atoms give rise to the linear bicyclic molecules of type 5, in contrast to the case of ethylenediamine (spacer link 2 carbon atoms), which affords molecules of type 6, which exemplify the general cage structure of type 4. The crystal structures of 1, 2 and 3 are compared with the previously reported structure of the hexahydropyrimidine analogue 8a(X=CN); compounds 2 and 8a(X=CN) are homologous with respect to the alkane spacer moiety. The structures of 2 and 8a(X=CN) are very different in one respect; in 2 the aryldiazenyl-1,3-diazepanyl groups are in the s-trans orientation around the central methylene group whereas in 8a(X=CN) the arrangement of the aryldiazenyl-hexahydropyrimidinyl groups is the s-cis orientation.Crystal data: 1 C23H30N8Br2, triclinic, space group P-1, a=8.3979(2), b=10.7828(3), c=14.4692(5) ?, α=83.670(1), β=78.662(1), γ=78.758(1)°, V=1256.48(6) ?3, for Z=2. 2 C25H30N10, monoclinic, space group P2
1
/n, a=13.4046(6), b=9.4482(4), c=10.6913(4)?, β=103.239(2)°, V=2490.5(2) ?3, for Z=4. 3 C25H36N8O2, triclinic, space group P-1, a=8.5223(3), b=10.6913(4), c=14.4034(7)?, α=85.657(2), β=78.731(2), γ=80.153(1)°, V=1266.88(9) ?3, for Z=2. 相似文献
118.
Friscić T Fábián L Burley JC Reid DG Duer MJ Jones W 《Chemical communications (Cambridge, England)》2008,(14):1644-1646
Comparison of structure and hydration stability of pairs of chiral and racemic binary cocrystals indicates that the racemic solid is more stable than the chiral one; we illustrate that this difference might arise from intermolecular (crystal packing) factors in one case, while intramolecular (molecular conformation) factors are more significant in the other. 相似文献
119.
Davis MF Levason W Reid G Webster M 《Dalton transactions (Cambridge, England : 2003)》2008,(17):2261-2269
The first phosphane complexes of germanium(iv) fluoride, trans-[GeF(4)(PR(3))(2)] (R = Me or Ph) and cis-[GeF(4)(diphosphane)] (diphosphane = R(2)P(CH(2))(2)PR(2), R = Me, Et, Ph or Cy; o-C(6)H(4)(PR(2))(2), R = Me or Ph) have been prepared from [GeF(4)(MeCN)(2)] and the ligands in dry CH(2)Cl(2) and characterised by microanalysis, IR, Raman, (1)H, (19)F{(1)H} and (31)P{(1)H} NMR spectroscopy. The crystal structures of [GeF(4)(diphosphane)] (diphosphane = Ph(2)P(CH(2))(2)PPh(2) and o-C(6)H(4)(PMe(2))(2)) have been determined and show the expected cis octahedral geometries. In anhydrous CH(2)Cl(2) solution the complexes are slowly converted into the corresponding phosphane oxide adducts by dry O(2). The apparently contradictory literature on the reaction of GeCl(4) with phosphanes is clarified. The complexes trans-[GeCl(4)(AsR(3))(2)] (R = Me or Et) are obtained from GeCl(4) and AsR(3) either without solvent or in CH(2)Cl(2), and the structures of trans-[GeCl(4)(AsEt(3))(2)] and Et(3)AsCl(2) determined. Unexpectedly, the complexes of GeF(4) with arsane ligands are very unstable and have not been isolated in a pure state. The behaviour of the germanium(iv) halides towards phosphane and arsane ligands are compared with the corresponding silicon(iv) and tin(iv) systems. 相似文献
120.
Levkin PA Eeltink S Stratton TR Brennen R Robotti K Yin H Killeen K Svec F Fréchet JM 《Journal of chromatography. A》2008,1200(1):55-61
Poly(lauryl methacrylate-co-ethylene dimethacrylate) and poly(styrene-co-divinylbenzene) stationary phases in monolithic format have been prepared by thermally initiated free radical polymerization within polyimide chips featuring channels having a cross-section of 200micromx200microm and a length of 6.8cm. These chips were then used for the separation of a mixture of proteins including ribonuclease A, myoglobin, cytochrome c, and ovalbumin, as well as peptides. The separations were monitored by UV adsorption. Both the monolithic phases based on methacrylate and on styrene chemistries enabled the rapid baseline separation of most of the test mixtures. Best performance was achieved with the styrenic monolith leading to fast baseline separation of all four proteins in less than 2.5min. The in situ monolith preparation process affords microfluidic devices exhibiting good batch-to-batch and injection-to-injection repeatability. 相似文献