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81.
The hydrothermal syntheses of a family of new alkali-metal/ammonium vanadium(V) methylphosphonates, M(VO(2))(3)(PO(3)CH(3))(2) (M = K, NH(4), Rb, Tl), are described. The crystal structures of K(VO(2))(3)(PO(3)CH(3))(2) and NH(4)(VO(2))(3)(PO(3)CH(3))(2) have been determined from single-crystal X-ray data. Crystal data: K(VO(2))(3)(PO(3)CH(3))(2), M(r) = 475.93, trigonal, R32 (No. 155), a = 7.139(3) ?, c = 19.109(5) ?, Z = 3; NH(4)(VO(2))(3)(PO(3)CH(3))(2), M(r) = 454.87, trigonal, R32 (No. 155), a = 7.150(3) ?, c = 19.459(5) ?, Z = 3. These isostructural, noncentrosymmetric phases are built up from hexagonal tungsten oxide (HTO) like sheets of vertex-sharing VO(6) octahedra, capped on both sides of the V/O sheets by PCH(3) entities (as [PO(3)CH(3)](2-) methylphosphonate groups). In both phases, the vanadium octahedra display a distinctive two short + two intermediate + two long V-O bond distance distribution within the VO(6) unit. Interlayer potassium or ammonium cations provide charge balance for the anionic (VO(2))(3)(PO(3)CH(3))(2) sheets. Powder X-ray, TGA, IR, and Raman data for these phases are reported and discussed. The structures of K(VO(2))(3)(PO(3)CH(3))(2) and NH(4)(VO(2))(3)(PO(3)CH(3))(2) are compared and contrasted with related layered phases based on the HTO motif. 相似文献
82.
Allan C. Baxter James H. Cameron Alexander McAuley Fiona M. McLaren John M. Winfield 《Journal of fluorine chemistry》1977,10(4):289-298
Copper(II) fluorine reacts with the pentafluorides, TaF5, PF5, and AsF5, in acetonitrile to give solvated CuII, hexafluoroanion salts. These react with copper metal to give the corresponding CuI compounds. Similar reactions occur between AsF5 and silver(I) or thallium(I) fluorides, but silver(II) fluoride reacts with MeCN, and AgI hexafluoroarsenate is formed. PF5 oxidises Cu slowly in MeCN to give CuI hexafluorophosphate, but AsF5 has no oxidising ability towards metals in MeCN. Spectroscopic data for Cu(MF6)2·5MeCN and Cu(MF6)·4MeCN (M = Ta or P) are discussed. 相似文献
83.
PHOTOSENSITIZATION OF MURINE TUMOR, VASCULATURE and SKIN BY 5-AMINOLEVULINIC ACID-INDUCED PORPHYRIN 总被引:2,自引:0,他引:2
Barbara W. Henderson Lurink Vaughan David A. Bellnier Henricus van Leengoed Patricia G. Johnson Allan R. Oseroff 《Photochemistry and photobiology》1995,62(4):780-789
Abstract— The effects of topical and systemic administration of 5-aminolevulinic acid (ALA) were examined in several murine tumor systems with regard to porphyrin accumulation kinetics in tumor, skin and blood, vascular and tumor cell photosensitization and tumor response after light exposure. Marked, transient increases in porphyrin levels were observed in tumor and skin after systemic and topical ALA. Rapid, transient, dose-dependent porphyrin increases were also observed in blood; these were pronounced after systemic ALA injection and mild after topical application. They were highest within 1 h after ALA injection, thereafter declining rapidly. This matched the clearing kinetics of injected exogenous protoporphyrin IX (PpIX). Initially, vascular photosensitivity changed inversely to blood porphyrin levels, increasing gradually up to 5 h post-ALA, as porphyrin was clearing from the bloodstream. This pattern was again matched by injected, exogenous PpIX. After therapeutic tumor treatment vascular disruption of the tumor bed, while observed, was incomplete, especially at the tumor base. Minimal direct tumor cell kill was found at low photodynamic therapy (PDT) doses (250 mg/kg ALA, 135 J/cm2 light). Significant, but limited (<1 log) direct photodynamic tumor cell kill was obtained when the PDT dose was raised to 500 mg/kg systemic ALA, followed 3 h later by 270 J/cm2 , a dose that was however toxic to the animals. The further reduction of clonogenic tumor cells over 24 h following treatment was moderate and probably limited by the incomplete disruption of the vasculature. Tumor responses were highest when light treatment was carried out at the time of highest tumor porphyrin content rather than at the time of highest vascular photosensitivity. Tumor destruction did not reach the tumor base, regardless of treatment conditions. 相似文献
84.
Avelina Arnanz Consuelo Moreno Allan J. Lough Salomé Delgado 《Journal of organometallic chemistry》2004,689(20):3218-3231
The reaction between 2,5-bis(trimethylsilylethynyl)thiophene and Co2(CO)8 or Co2(CO)6(X), (X = dppa, dppm), gave rise to the formation of substituted ethynylcobalt complexes containing one or two Co2(CO)6 or Co2(CO)4(X) units, 2-[Co2(CO)4(X){μ2-η2-(SiMe3)C2}]-5-(Me3SiCC)C4H2S (X = 2CO (1), dppa (3) or dppm (4)) and 2,5-[Co2(CO)4(X){μ2-η2-SiMe3C2}]2C4H2S (X = 2CO (2), dppa (5) or dppm (6)). Desilylation of the non-metallated and metallated alkynes in 3, 4 and 6 occurred on treatment with KOH and tetrabutylammonium fluoride to give 2-[Co2(CO)4(μ-X){μ2-η2-SiMe3C2}]-5-(CCH)C4H2S (X = dppa (7), dppm (8)) and 2,5-[Co2(CO)4(μ-dppm){μ2-η2-HC2}]2C4H2S (9), respectively. Crystals of 6 suitable for single-crystal X-ray diffraction were grown and the molecular structure of this compound is discussed. A comparative electrochemical study of all these complexes is presented by means of the cyclic and square-wave voltammetry techniques. 相似文献
85.
James O. Alben Allan A. Croteau Frank G. Fiamingo Craig F. Hemann Virginia A. Molleran Sungjo Park Kimerly A. Powell 《Mikrochimica acta》1988,94(1-6):335-338
Biological applications of infrared spectroscopy have pressed for ever greater instrumental capabilities in terms of spectral sensitivity and quantitative exactness. Improved instrumentation has provided measurement of many vibrational modes in biological samples that previously were lost in noise. With highly optimized sampling conditions, useful measurements have been made with a peak-to-peak noise level less than 5 microabsorbance (5×10–6 absorbance), at 0.5 cm–1 resolution. However, optical and instrumental instabilities often result in sine waves that are not totally removed by the ratio of sample to reference. These often limit effective spectral sensitivity to 50 or 100 microabsorbance, peak-to-peak, and constitute a non-random noise. Non-atmospheric absorptions, especially one at 1959 cm–1 with 0.8 cm–1 band width (FWHM) are reported. The latter is due to a trace impurity in the KBr beam splitter substrate and compensator plate. Improvements in instrumentation and sampling conditions are expected to yield measurements of absorption bands as small as 50 microabsorbance with excellent signal/noise. 相似文献
86.
Pettinari C Pettinari R Fianchini M Marchetti F Skelton BW White AH 《Inorganic chemistry》2005,44(22):7933-7942
New [CpM(Q)Cl] complexes (M = Rh or Ir, Cp = pentamethylcyclopentadienyl, HQ = 1-phenyl-3-methyl-4R(C=O)-pyrazol-5-one in general, in detail HQ(Me), R = CH(3); HQ(Et), R = CH(2)CH(3); HQ(Piv), R = CH(2)-C(CH(3))(3); HQ(Bn), R = CH(2)-(C(6)H(5)); HQ(S), R = CH-(C(6)H(5))(2)) have been synthesized from the reaction of [CpMCl(2)](2) with the sodium salt, NaQ, of the appropriate HQ proligand. Crystal structure determinations for a representative selection of these [CpM(Q)Cl] compounds show a pseudo-octahedral metal environment with the Q ligand bonded in the O,O'-chelating form. In each case, two enantiomers (S(M)) and (R(M)) arise, differing only in the metal chirality. The reaction of [CpRh(Q(Bn))Cl] with MgCH(3)Br produces only halide exchange with the formation of [CpRh(Q(Bn))Br]. The [CpRh(Q)Cl] complexes react with PPh(3) in dichloromethane yielding the adducts CpRh(Q)Cl/PPh(3) (1:1) which exist in solution in two different isomeric forms. The interaction of [CpRh(Q(Me))Cl] with AgNO(3) in MeCN allows generation of [CpRh(Q(Me))(MeCN)]NO(3).3H(2)O, whereas the reaction of [CpRh(Q(Me))Cl] with AgClO(4) in the same solvent yields both [CpRh(Q(Me))(H(2)O)]ClO(4) and [CpRh(Cl)(H(2)O)(2)]ClO(4); the H(2)O molecules derive from the not-rigorously anhydrous solvents or silver salts. 相似文献
87.
Christopher S. Griffith George A. Koutsantonis Brian W. Skelton Allan H. White 《Journal of organometallic chemistry》2003,670(1-2):198-204
The acid–base chemistry of some ruthenium ethyne-1,2-diyl complexes, [{Ru(CO)2(η-C5H4R)}2(μ2-CC)] (R=H, Me) has been investigated. Initial protonation of [{Ru(CO)2{η-C5H4R}}2(μ2-CC)] gave the unexpected complex cation, crystallised as the BF4 salt, [{Ru(CO)2(η-C5H4R}}3(μ3-CC)][BF4] (R=Me structurally characterised). This synthesis proved to be unreliable but subsequent, careful protonation experiments gave excellent yields of the protonated ethyne-1,2-diyl complexes, [{Ru(CO)2{η-C5H4R)}2(μ2-η1:η2-CCH)](BF4) (R=Me structurally characterised) which could be deprotonated in high yield to return the starting ethyne-1,2-diyl complexes. 相似文献
88.
Michael I. Bruce Benjamin G. Ellis Allan H. White 《Journal of organometallic chemistry》2005,690(3):792-801
Whereas {Ru(dppm)Cp*}2(μ-CCCC) (2) is the only product formed by deprotonation of [{Ru(dppm)Cp*}2{μ(CCHCHC)}]+ with dbu, a mixture of 2 with Ru{CCCHCH(PPh2)2[RuCp*]}(dppm)Cp* (3) and {Cp*Ru(PPh2CHCCH-)}2 (4) is obtained with KOBut. A similar reaction with [{Ru(dppm)Cp*}2{μ(CCMeCMeC)}]+ (5) gave Ru{CCCMeCH(PPh2)2[RuCp*]}(dppm)Cp* (6). X-ray structures of 4, 5 and 6 confirm the presence of the 1-ruthena-2,4-diphosphabicyclo[1.1.1]pentane moiety, which is likely formed by an intramolecular attack of the deprotonated dppm ligand on C(1) of the vinylidene ligand. Protonation of {Ru(dppe)Cp*}2(μ-CCCC) (8-Ru) regenerates its precursor [{Ru(dppe)Cp*}2{μ(CCHCHC)}]2+ (7-Ru). Ready oxidation of the bis(vinylidene) complex affords the cationic carbonyl [Ru(CO)(dppe)Cp*]PF6 (9) (X-ray structure). 相似文献
89.
Richard M. Kettler Donald A. Palmer David J. Wesolowski 《Journal of solution chemistry》1995,24(1):65-87
The first and second molal dissociation quotients of succinic acid were measured potentiometrically with a hydrogen-electrode, concentration cell. These measurements were carried out from 0 to 225°C over 25° intervals at five ionic strengths ranging from 0.1 to 5.0 molal (NaCl). The dissociation quotients from this and two other studies were combined and treated with empirical equations to yield the following thermodynamic quantities for the first acid dissociation equilibrium at 25°C: log K1a=–4.210±0.003; H
1a
0
=2.9±0.2 kJ-mol–1; S
1a
0
=–71±1 J-mol–1-K–1; and C
p1a
0
=–98±3 J-mol–1-K–1; and for the second acid dissociation equilibrium at 25°C: log K2a=–5.638±0.001; H
2a
0
= –0.5±0.1 kJ-mol–1; S
2a
0
=–109.7±0.4 J-mol–1-K–1; and C
p2a
0
= –215±8 J-mol–1-K–1. 相似文献
90.
Chris J. Adams Michael I. Bruce Brian W. Skelton Allan H. White 《Journal of Cluster Science》1994,5(3):419-441
The reactions between Ru5(
5-C2PPh2)(gm-PPh2(CO)13 (1) and cyclopentadienes afforded the hexanuclear clusters Ru6(
6-C)(
3-PPh2)2(CO)10(-C5
R
5) [R
5 = H5 (2), H4Me (3), Me5 (4)] which contain an encapsulated carbide and a face-capping
3-CH group, formed by cleavage of CC and CP bonds of the C2PPh2 moiety in1. In the reaction with cyclopentadiene, the unusual ligand C13H12O, formed by combination of C2, CO and two molecules of C5H6 (or one molecule of dicyclopentadien), was characterized in the complex Ru5(
4-PPh) (
4-C13H12O)(-PPh2(CO)11(-C5H5) (5). In the reaction with pentamethylcyclopentadiene, the vinylidene complex Ru5(
3-CCHPh)(
4-PPh)(
4-PPh) (-PPh2)(CO)9(-C5Me5) (6) was also formed. 相似文献