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1.
Complexes of La(Ⅲ),Nd(Ⅲ),Sm(Ⅲ),Eu(Ⅲ),Gd(Ⅲ),Dy(Ⅲ),Er(Ⅲ),Yb(Ⅲ)and Y(Ⅲ)with piperonal isonicotinoyl hydrazone(HPIN)have been synthesized in DMF and EtOH.The complexes have been characte-rized by elemental analysis,molar conductance,i.r.,UV and~1H n.m.r.spectra,magnetic measurements,X-ray powder diffraction and DTA.  相似文献   

2.
Therearemanykindsofhairdyeswithdifferentformulae.Thekindwedeterminedcontainsthefollowingfiveconstituentsfl,4-phenylenediamine(P-PDA),4-aminophenol(P-APO),3-aminophenol(m-APO),1,3-benzendiol(m-BDO)and2,6-diaminopyridine(DAP).Withreversed-phasehigh-performanceliquidchromatography(RP-HPLC),someotherkindsofhairdyeshadbeendetermined"',butnotourkind.lnthispaperwedescribeaRP-HPLCmethodsuitabIefortheseparationandquantitativedeterminationofallthosefiveconstituentsinhairdyes.Analyseswereperf…  相似文献   

3.
Honorary Members:Kenichi Fukui,Martin Karplus,C.S.Lin,S.H.Lin,Keiji Morokuma,S.Peyerimhoff,Bernard PullmanCha Quan-xing(Cha Chuan-sin),Chen Rong-ti(Y.T.Chen),Liu You-cheng,Jiang Ming-qian(Chiang Ming-chien),Kao Chen-heng,Qian Bao-gong(Pao-kcing Chien),Tang Au-chin,Tang You-chi(You-chi Tang)  相似文献   

4.
INTRODUCTIONAsanimportantfunctionalresin,theiminocarboxylicchelatingresin,suchasD401(China),DowexA--1(U.S.A),DiaionCR--10(Japan),KT--1(USSR)hasalreadybecomecommodityinChinaandothercountries.Theresincaneasilyformchelatingcomplexwithdivalentmetallicions.Thesyntheticmethodsofthisresinhavebeenreportedanddeeperresearchesarestillcarried..[l--sj.Theuseofchelatingresin,however,hasdisadvantagethattheadsorptionrateisverylowandthetreatmentofsuchresinsisdifficult.In'Postgraduate(1992)ordertoe…  相似文献   

5.
Compoundl,whitepowder,gaveamolecularformulaofC,,H.,O,,basedonitsEI-MS(m/z284M ofaglycone),positiveMALDI-TOF-HRMS(M linjz839.2610,cafed.ForC,,H.,O,,,839.2604),IHNMRand13CNMRspectra.TheUV(MeOH)bandsat268,328urnsuggestedaflavonoidskeleton.ItsiR(KBr)spectrumshowedabsorptionat3440(OH),2950(saturatedCH),1735(esterC=O),1650(aAunsaturatedC=O),1615(C=C),1590,1515,1500cm-1(aromaticsystem).FiBurc1.Keyinteractionsof1initsHMBCspectrumInitsiHNMR(500MHz,DMSO-d,),thearomaticproton…  相似文献   

6.
InapreviouspaPer,wehadrcyortedonanew~enod,lungshengeninAl11(3),thefirstenhaUrendforidinwhichtherarebeOxy~sontheA-ring,isedfr0InIsodOnIhagSengensisC.Y.WuetH.W.LLapereInhalhdeofthcLabfor~,whichisdistriedinhagtwcountyoftheboZhUangAutonOInOUSheandisusedasanagatforthetreatIneIItofhrpandsinlocalfOlkmwhcine.theinvestighonofthisplantledtOtheisohaonoftW0newditmpenOdsnamcdaslungsh~B-C(l-2),ThispaPerdealsedthotStrUcturalclucidation.LUngshengedB(l),coloresscubescrystallizedfromcyclohexane,…  相似文献   

7.
ThereactionsofLuwithhydrogenperoxidecatalysedbymetalionsandalsoreactionofLuwithorganicreductantssuchasglucoseandascorbicacidhavebeenreported"=.OurrecentstudiesshowedthatsomeinorganicreductantssuchasMo(Ill),V(11),U(ill),W(ill),Cr(II),Ti(ill)andFe(11)etc.canreactwithLuinstrongalkalinemediumtogenerateCL.Inthispaper,theCLreactionbetweenLuandMo(ill)producedbyaJonesreductor3hasbeenstudiedindetailforthefirsttime,andtheCLreactionhasbeensuccessfullyappliedtodeterminemolybdenumwithexcellentsensi…  相似文献   

8.
InthePreviouspaPed'],werePOrtedthebioactivditerPeedds,namedasgeSnerofdinAC,wereisolatedfromtlhaPlan.theinveedgationOfthisPlanlettoisolationofthreenewditerPenuldswiasgeSnerofdinsD-F(l-3).AspapewhdealwiththednddridationFigUrel.The1H-13Clong-rangeCOSYoflGesneroidinD(l),~lizedfromaeeone,mPl29.5-l3o.5"C,HRMS(5l8.2477,calc.5l8.25l6)SUggestedtheformulaCasH38O9.EIMS(7oeV)wt(rel.int.%)f5l8mp+(lO),458(3O),4l6(35),356(85),296(1oo).DuetotheabsencesofthecharaCteristicallsorptioninUVandIR…  相似文献   

9.
曾正志  邓汝温  吴集贵  陈江 《化学学报》1984,42(10):1100-1102
氯灭酸[N-(间氯苯基)-邻氨基苯甲酸]是我国首先合成并筛选出来的解热消炎镇痛药,临床效果较好,但有不少副作用.近年来的无机药物研究表明,金属配合物与人体的关系十分密切.我们曾制出十六种氯灭酸的稀土盐,其毒性比相应的氯化物小.其他金属的氯灭酸盐尚未见报道.本文在水中以氯灭酸钠(以NaA表示)与Mg(Ⅱ),Ca(Ⅱ),Sr(Ⅱ),Ba(Ⅱ),In(Ⅱ),Tl(I),Mn(Ⅱ),Fe(Ⅲ),Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ),Zn(Ⅱ),Ag(Ⅰ),Cd(Ⅱ),Pb(Ⅱ)等金属离子制备出十五种氯灭酸金属盐,测定了它们的化学组成,UV,IR,摩尔电导率及热谱,其结果汇总于表1及表2.  相似文献   

10.
蔡进华  陈昌能 《结构化学》1989,8(3):220-224
<正> Fe6S5 (u-SPh) (P-n-Bu3)A (SPh )2, Mr = 1632. 21 , triclinic, P1, a = 11.877(3), b=14. 302(3), c= 24. 920(2) A ,a= 94. 84 (2), B = 96. 59 (2), y = 100. 44(2),V= 4111.7(13)A3,Z=2,Dx==1. 32gcm3,MoKa(0. 71069A),u=13.4 cm-1,F(000) = 1726,T=293K,R(Ru) = 0. 077(0. 060) for 6042 observed (I>3o(I)) reflections.  相似文献   

11.
The voltammetry of Cu underpotential deposition (UPD) onto Pt dendrimer-encapsulated nanoparticles (DENs) containing an average of 147 Pt atoms (Pt(147)) is correlated to density functional theory (DFT) calculations. Specifically, the voltammetric peak positions are in good agreement with the calculated energies for Cu deposition and stripping on the Pt(100) and Pt(111) facets of the DENs. Partial Cu shells on Pt(147) are more stable on the Pt(100) facets, compared to the Pt(111) facets, and therefore, Cu UPD occurs on the 4-fold hollow sites of Pt(100) first. Finally, the structures of Pt DENs having full and partial monolayers of Cu were characterized in situ by X-ray absorption spectroscopy (XAS). The results of XAS studies are also in good agreement with the DFT-optimized models.  相似文献   

12.
Designing highly active catalysts at an atomic scale is required to drive the hydrogen evolution reaction (HER). Copper–platinum (Cu‐Pt) dual sites were alloyed with palladium nanorings (Pd NRs) containing 1.5 atom % Pt, using atomically dispersed Cu on ultrathin Pd NRs as seeds. The ultrafine structure of atomically dispersed Cu‐Pt dual sites was confirmed with X‐ray absorption fine structure (XAFS) measurements. The Pd/Cu‐Pt NRs exhibit excellent HER properties in acidic solution with an overpotential of only 22.8 mV at a current density of 10 mA cm−2 and a high mass current density of 3002 A g−1(Pd+Pt) at a −0.05 V potential.  相似文献   

13.
应用电化学去合金法制备了表面覆盖有Pt(Pd)原子层的Pt(Pd)-Cu合金催化剂.研究该催化剂在0.1mol.L-1HClO4酸性溶液中对氧气电化学还原的催化活性,并采用同步辐射反常X-射线衍射法(Anomalous X-ray Diffraction,AXRD)和表面X-射线散射法(Surface X-ray Scattering,SXS)从原子尺度研究了去合金化后催化剂的结构.分析对比纳米颗粒、薄膜和单晶3种不同形式的去合金化Pt-Cu的结构和催化活性以及Pt-Cu和Pd-Cu两种不同合金薄膜的结构和催化活性.结果表明,表面应力是影响催化剂催化活性的关键因素,而应力大小则与去合金化后所形成的表面Pt(Pd)层的厚度相关,材料尺寸和组成元素等都影响表面Pt(Pd)层的厚度.提出可利用调控材料表面的应力来设计高催化活性的催化剂.  相似文献   

14.
Voltammetric dealloying of bimetallic platinum-copper (Pt-Cu) alloys has been shown to be an effective strategy to modify the surface electrocatalytic reactivity of Pt bimetallic nanoparticles (S. Koh and P. Strasser, J. Am. Chem. Soc., 2007, 129, 12624). Using cyclic voltammetry and structural XRD studies, we systematically characterize the Pt-Cu precursor compounds as well as the early stages of the selective Cu surface dissolution (dealloying) process for Pt(25)Cu(75), Pt(50)Cu(50), and Pt(75)Cu(25) alloy nanoparticles annealed at both low and high temperature. We also assess the impact of the synthesis conditions on the electrocatalytic reactivity for the oxygen reduction reaction (ORR). To gain atomistic insight into the observed voltammetric profiles, we compare our experimental results with periodic DFT calculations of trends in the thermodynamics of surface Cu dissolution potentials from highly stepped and kinked Pt(854) single crystal surfaces. The modeling suggests a dependence of the electrochemical Cu dissolution potentials on the detailed atomic environment (coordination number, nature of coordinating atoms) of the bimetallic Pt-Cu surfaces. The DFT-predicted shifts in electrochemical Cu dissolution potentials are shown to qualitatively account for the observed voltammetric profiles during Cu dealloying. Our study suggests that metal-specific energetics have to be taken into account to explain the detailed dealloying behavior of bimetallic surfaces.  相似文献   

15.
Mastery over the structure of materials at nanoscale can effectively tailor and control their catalytic properties, enabling enhancement in both activity and durability. We report a size‐controlled synthesis of novel Pt–Cu hierarchical trigonal bipyramid nanoframes (HTBNFs). The obtained nanocrystals looked like a trigonal bipyramid on the whole, composed of similar ordered frame structural units. By varying the amount of KI involved in the reaction, HTBNFs with variable sizes from 110 to 250 nm could be obtained. In addition, the structure of HTBNFs could be preserved only in a limited range of the Pt/Cu feeding ratio. Relative to the commercial Pt/C, these Pt–Cu HTBNFs with different Pt/Cu ratio exhibited enhanced electrocatalytic activity toward formic acid oxidation reaction as much as 5.5 times in specific activity and 2.1 times in mass activity. The excellent electrocatalytic activity and better durability are due to the unique structure of HTBNFs and probably synergetic effects between Pt and Cu.  相似文献   

16.
The formation of a Pt(Cu) bimetallic catalyst on the carbon support by galvanic displacement of copper electrodeposits with platinum (PtCl 6 2? as the displacing agent) is systematically studied. Composition, structure, and electrocatalytic properties of samples corresponding to different stages of copper displacement are analyzed. For substantially long displacement times, the formation of stable Pt(Cu)st particles with the atomic ratio Pt: Cu ≈ 7: 3 is observed. The Pt(Cu)st/C electrodes are shown to be close to the Pt/C electrode as regards the adsorption of hydrogen and copper atoms and the specific activity in methanol oxidation (with 0.5 M H2SO4 as the supporting electrolyte). Such electrocatalytic behavior of Pt(Cu)st particles makes it possible to infer the formation of the “core(Pt, Cu)-shell(Pt)” structure, as confirmed by the XPS data.  相似文献   

17.
The primary route to hydrogen production from fossil fuels involves the water-gas shift (WGS) reaction, and an improvement in the efficiency of WGS catalysts could therefore lead to a major leap forward in the realization of hydrogen economy. On the basis of a combination of high-resolution scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory (DFT) calculations, we suggest the existence of a new thermodynamically stable Cu/Pt near-surface alloy (NSA). Temperature-programmed desorption and DFT reveal that this Cu/Pt NSA binds CO significantly more weakly than does Pt alone, thereby implying a considerable reduction in the potential for CO poisoning of the Cu/Pt NSA surface as compared to that of pure Pt. In addition, DFT calculations show that this Cu/Pt NSA is able to activate H2O easily, which is the rate-determining step for the WGS on several metal surfaces, and, at the same time, to bind the products of that reaction and formate intermediates rather weakly, thus avoiding possible poisoning of the catalyst surface. The Cu/Pt NSA is thus a promising candidate for an improved WGS catalyst.  相似文献   

18.
Pt? Cu alloy octahedral nanocrystals (NCs) have been synthesized successfully by using N,N‐dimethylformamide as both the solvent and the reducing agent in the presence of cetyltrimethylammonium chloride. Cu underpotential deposition (UPD) is found to play a key role in the formation of the Pt? Cu alloy NCs. The composition in the Pt? Cu alloy can be tuned by adjusting the ratio of metal precursors in solution. However, the Cu content in the Pt? Cu alloy NCs cannot exceed 50 %. Due to the fact that Cu precursor cannot be reduced to metallic copper and the Cu content cannot exceed 50 %, we achieved the formation of the Pt? Cu alloy by using Cu UPD on the Pt surface. In addition, the catalytic activities of Pt? Cu alloy NCs with different composition were investigated in electrocatalytic oxidation of formic acid. The results reveal that the catalytic performance is strongly dependent on Pt? Cu alloy composition. The sample of Pt50Cu50 exhibits excellent activity in electrocatalytic oxidation of formic acid.  相似文献   

19.
Heterobimetallic CuPd and CuPt bis(mu-oxo) complexes have been prepared by the reaction of (PPh3)2MO2 (M=Pd, Pt) with LCu(I) precursors (L=beta-diketiminate and di- and triamine ligands) and characterized by low-temperature UV-vis, resonance Raman, and 1H and 31P[1H] NMR spectroscopy in conjunction with DFT calculations. The complexes decompose upon warming to yield OPPh3, and in one case this was shown to occur by an intramolecular process through crossover experiments using double-labeling (oxo and phosphine). The reactivity of one of the complexes, LMe2Cu(mu-O)2Pt(PPh3)2 (LMe2 = beta-diketiminate), with a variety of reagents including CO2, 2,4-di-tert-butylphenol, 2,4-di-tert-butylphenolate, [NH4][PF6], and dihydroanthracene, was compared to that of homometallic Pt2 and Cu2 counterparts. Unlike typical [Cu2(mu-O)2]2+ cores which have electrophilic oxo groups, the oxo groups in the [Cu(mu-O)2Pt]+ core behave as bases and nucleophiles, similar to previously described Pt2 compounds. In addition, however, the [Cu(mu-O)2Pt]+ core is capable of oxidatively coupling 2,4-di-tert-butylphenol and 2,4-di-tert-butylphenolate. Theoretical evaluation of the electron affinities, basicities, and H-atom transfer kinetics and thermodynamics of the Cu2 and CuM (M=Pd, Pt) cores showed that the latter are more basic and form stronger O-H bonds.  相似文献   

20.
Self-assembly between Pt(phen)(edt) (phen=phenanthroline, edt=1,2-ethanedithiolate) and [Cu(PPh3)2(MeCN)2](ClO4) (PPh3=triphenylphosphine) gave rise to formation of heterohexanuclear complex [Pt4Cu2(edt)4(PPh3)6](ClO4)2(4H2O) (1). The complex was characterized by elemental analyses, ES-MS, UV-Vis, IR, 31P NMR spectroscopy and X-ray crystallography. The molecule consists of two [Pt2Cu(edt)2(PPh3)3] units which has a centrosymmmetric inversion to give a cyclic heterohexanuclear skeleton. The Pt and Cu center adopt square-planar and trigonal coordination modes, respectively. The compound shows intense emission at 632 nm in the solid state and at 678 nm in frozen dichloromethane glass at 77 K.  相似文献   

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