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71.
Lin Bo Gong Shu Ling Gong Qin Zheng Xiong Li Yuan Yin Chen 《中国化学快报》2007,18(4):435-436
The reaction of 1,3-dipropyn-2-yloxycalix[4]arene with mercury(II)acetate could give mercury-containing alkynyl calixarenepolymer.The extraction behavior of 1,3-dipropyn-2-yl-oxycalix[4]arene towards mercury(II)ion was examined.When the moleratio of Hg~(2 )/calixarene was 1:1,the extractive percent can reach to 99.1%,and the extraction capacity was up to 431 mg/g.It couldalso decrease the Hg~(2 )concentration from 5 to 0.85 mg/L,which was only 17%of the national standard of effluent and satisfied thenational standard of drinking water.The extraction process included chemical reaction. 相似文献
72.
采用共沉淀并加法制备了B位掺杂烧绿石型稀土复合氧化物纳米微晶Y2Sn2-xFexO7-δ(x=00~10)。制备的纳米微晶属于立方晶系,Fd3m,晶胞参数与掺杂量呈线性关系。通过Msbauer、TGDTA,气相色谱和γ射线辐照等技术研究了纳米微晶对CO的催化选择性能。结果表明,纳米微晶对CO的催化选择性明显高于一般粉料对CO的选择性;纳米微晶对CO的选择性与掺杂量有关;未辐照的纳米微晶,当掺杂量x=06时,其对CO的选择性为最高,辐照后的纳米微晶,当掺杂量x=04时,其对CO的选择性为最高 相似文献
73.
The chiral separation of simendan enantiomers using capillary electrophoresis was studied with beta-cyclodextrin (beta-CD) as chiral selector. The influences of the concentration and pH of borate buffer solution, beta-CD concentration and methanol content in the background electrolyte were investigated. These factors were compared with those in an HPLC with beta-CD as chiral mobile phase additive (CMPA-HPLC). The quantification properties of the developed CE method were examined. A baseline separation of simendan enantiomers was achieved in the background electrolyte of 20 mmol/L borate buffer (pH 11.0) containing 12 mmol/L beta-CD-methanol (50:50 in volume ratio). The CE method is comparable with CMPA-HPLC in chiral resolution, although the optimal pH in CE (11.0) is much higher than that (6.0) in CMPA-HPLC. This chiral CE method is applicable to the quantitative ananlysis and enantiomeric excess value determination of L-simendan. 相似文献
74.
Sulfur diisocyanate is generated from a heterogeneous reaction of gaseous sulfur dichloride with silver cyanate and studied for the first time in the gas phase. Combined with quantum chemical calculations, the electronic structure is characterized by photoelectron spectroscopy (PES). Simultaneously, an investigation of the possible ionization and dissociation processes for the molecular cation is presented based on experimental soft ionization mass spectrometry. From the calculated bond-dissociation energies, the dissociation pathway is determined. S(NCO)2+ undergoes 1,3-sigmatropic rearrangement with a smaller barrier height (9.9 kcal mol(-1)) than the neutral counterpart. Thus, the 1,3-sigmatropic rearrangement is preferred for the molecular cation, and OCNCO+ and NS+ is produced by subsequent dissociation of the rearrangement product. The analysis agrees very well with the experimental mass spectrum. 相似文献
75.
We report on a photoluminescence observation of robust excitonic polarons due to resonant coupling of exciton and longitudinal optical (LO) phonon as well as Fano-type interference in high quality ZnO crystal. At low enough temperatures, resonant coupling of excitons and LO phonons leads to not only traditional Stokes lines (SLs) but also up to second-order anti-Stokes lines (ASLs) besides the zero-phonon line (ZPL). The SLs and ASLs are found to be not mirror symmetric with respect to the ZPL, strongly suggesting that they are from different coupling states of exciton and phonons. Besides these spectral features showing the quasiparticle properties of exciton-phonon coupling system, the first-order SL is found to exhibit characteristic Fano lineshape, caused by quantum interference between the LO components of excitonic polarons and the continuous phonon bath. These findings lead to a new insight into fundamental effects of exciton-phonon interactions. 相似文献
76.
The reaction of Cu(I)(CH(3)CN)(4)BF(4) with 4-pyridylacrylic acid (4-HPYA) affords an unprecedented 8-fold interpenetrating diamondoid-like coordination polymer network [Cu(I)(3)(4-PYA)(2)(H(2)O)(BF(4)) ] (1) with a Cu(+)(4)(CO(2))(4) cluster as connecting node. The interpenetration in metal coordination polymers is the highest degree ever found within diamondoid nets containing a cluster as connecting note. Its fluorescent property was also reported. 相似文献
77.
Abstract -Adaptation processes enable phototropism and other blue light responses of Phycomyces to operate over a 10-decade range of Ruencc rate. Phototropic latency, used routinely to monitor the kinetics of sensitivity recovery after a step down in fluence rate, can be shortened by application of dim light for 35 min during the early part of the latency period. This light is termed subliminal , because it does not elicit phototropism under these experimental conditions; rather, it exerts its influence on the underlying adaptation kinetics. Fluence rate-response data for this latency reduction, obtained at 17 wavelengths of subliminal light from 347 to 742 nm, showed a variety of shapes that could be fit by zero, one, or two sigmoidal components, plus a constant term. At most wavelengths, the fluence-rate threshold for latency reduction by subliminal light tended to be well below the absolute threshold for phototropism, indicating that this effect is highly sensitive. An action spectrum for the sensitivity of the subliminal light effect, derived from the fluence rate-response curves, shows major peaks around 400 and 500 nm and a broad band from 570 to 670 nm, followed by a steep absorption edge. The sensitivity in the near ultraviolet region is relatively very low. The magnitude of the latency reduction also depends strongly on wavelength with a maximum at about 450 nm. The Huence-rate response data and the action spectrum–which is markedly different from that for phototropism and other blue-light responses of Phycornyces – indicate the participation of multiple pigments, or pigment states, in the photocontrol of adaptation. 相似文献
78.
Nathaniel L SegravesSuzette Lopez Tyler A JohnsonSadri A Said Xiong FuFrancis J Schmitz Halina PietraszkiewiczFrederick A Valeriote Phillip Crews 《Tetrahedron letters》2003,44(17):3471-3475
The structural variations and bioactivity properties of the alkaloids in the fascaplysin (1) and the reticulatine (3) families were examined. Four organisms were analyzed consisting of two collections of the sponge Fascaplysinopsis reticulata and two collections of the tunicate Didemnum sp. Reported are the isolation of three new compounds: 3-bromofascaplysin (2), 14-bromoreticulatine (4), and 14-bromoreticulatate (6) along with reticulatate (5) previously known as a semi-synthetic product of 1. Compounds 1 and 5 showed selectivity in a cell based cytotoxicity assay. 相似文献
79.
3-苯氧甲基-6-(2,4-二氟苯基)-7H-1,2,4-三唑并[3,4-b][1,3,4]噻二嗪的合成与晶体结构研究 总被引:2,自引:0,他引:2
由苯氧乙酸出发,经多步反应,制得3-苯氧甲基-4-氨基-5-巯基-1,2, 4-三唑,它与2-氯-2',4'-二氟苯乙酮进行环化反应,生成3-苯氧甲基-6-( 2,4-二氟苯基)-7H-1,2,4-三唑并[3,4-b][1,3,4]噻二嗪,通过元素分析、红外 光谱、核磁共振氢谱与碳谱、质谱进行表征,并利用单晶X射线衍射法测定其结构 。晶体属单斜晶系、P2_(1/c)空间群,a = 1.339(3) nm, b = 1.4683(4) nm, c = 0.8606(2) nm, β = 108.49(2)°, Z = 4, F(000) = 736, R_1 = 0.0509。还 对均三唑并噻二唑两类稠杂环的晶体结构作了比较。 相似文献
80.
Sheng‐Xiong Huang Xun Liao Quan‐Jiang Nie Li‐Sheng Ding Shu‐Lin Peng 《Helvetica chimica acta》2004,87(3):598-604
Three new phenyl glycosides, scrophenoside A ( 1 ), B ( 2 ), and C ( 3 ), and two new phenylethyl glycosides, scroside D ( 4 ) and scroside E ( 5 ), were isolated from the stem of Picrorhiza scrophulariiflora Pennell (Scrophularlaceae), besides five known compounds. On the basis of spectroscopic evidence, the structures of the new compounds were elucidated as 4‐acetyl‐2‐methoxyphenyl 6‐O‐[4‐(β‐D ‐glucopyranosyloxy)vanilloyl]‐β‐D ‐glucopyranoside ( 1 ), 4‐acetylphenyl 6‐O‐[(E)‐p‐coumaroyl]‐β‐D ‐glucopyranoside ( 2 ), 4‐[(1R)‐ and (1S)‐1‐hydroxyethyl]‐2‐methoxyphenyl β‐D ‐glucopyranoside ( 3a and 3b , resp.), 2‐(3,4‐dihydroxyphenyl)ethyl O‐β‐D ‐glucopyranosyl‐(1→3)‐4‐O‐[(E)‐feruloyl]‐β‐D ‐glucopyranoside ( 4 ), and 2‐(3,4‐dihydroxyphenyl)ethyl O‐β‐D ‐glucopyranosyl‐(1→3)‐6‐O‐[(E)‐feruloyl]‐β‐D ‐glucopyranoside ( 5 ). 相似文献