Microdetermination of Proteins by Enhanced Rayleigh Light Scattering Spectroscopy with Thorin

ＩｎｔｒｏｄｕｃｔｉｏｎＰｒｏｔｅｉｎｄｅｔｅｒｍｉｎａｔｉｏｎｉｓａｌｗａｙｓｉｍｐｏｒｔａｎｔｉｎｃｌｉｎｉｃａｌａｐｐｌｉｃａｔｉｏｎｓ .Ｎｅｗｍｅｔｈｏｄｓｉｎｃｌｕｄｉｎｇｓｐｃｅｔｒｏｐｈｏｔｏｍｅｔｒｙ ,1ｆｌｕｏｒｏｍｅｔｒｙ2 ａｎｄｃｈｅｍｉｌｕｍｉｎｉｃｅｎｃｅ3 ,4 ａｒｅｃｏｎｔｉｎｕｏｕｓｌｙｂｅ ｉｎｇｄｅｖｅｌｏｐｅｄ .Ｐａｓｔｅｒｎａｃｋｅｔａｌ.5,6ｄｅｖｅｌｏｐｅｄａｔｅｃｈ ｎｉｑｕｅｔｏｍｅａｓｕｒｅｔｈｅｉｎｔｅｎｓｉｔｙｏｆｓｃａｔｔｅｒｉｎｇｌｉｇｈｔｕｓｉ…     

N，N-二丁基辛酰胺从硝酸介质中萃取铀(Ⅵ)和钍(Ⅳ)

合成了N,N-二丁基辛酰胺(简称DBOA)。以甲苯为稀释剂研究了DBOA萃取硝酸的平衡,认为低酸度下形成HNO₃·DBOA,得到萃取平衡常数为0.2 mol^-2·L²;研究了水相酸度和萃取剂浓度对DBOA萃取硝酸铀酰平衡的影响,得到萃合物组成UO₂(NO₃)₂·(DBOA)₂,25℃下萃取平衡常数为4.93 mol^-4·L⁴;利用红外光谱分析并确定了萃合物的结构;考察温度对萃取平衡的影响,得到萃取反应热为-29.1 kJ·mol^-1。实验结果表明相同条件下DBOA萃取Th⁴⁺、 Fe³⁺的能力很弱,UO²⁺₂能与之有效地分离,表明DBOA在钍-铀分离方面具有应用前景。     

Kinetics and Mechanism of the Oxidation of Glycol by Dihydroxyditelluratoargentate(Ⅲ) with Spectrophotometry

The kinetics of the oxidation of glycol by dihydroxyditelluratoargentate (Ⅲ) complex(DDA) was studied in alkaline medium with spectrophotometry(in a temperature range of 16.6-40 ℃).The first-order rates with respect to glycol and Ag(Ⅲ) were all found.The rates increased with the increase in [OH-] and decreased with the increase in [TeO2-4].No effect was found with the addition of KNO3 and no free radical was detected.In view of this,the dihydroxymonotelluratoargentate(Ⅲ) species(DMA) is assumed to be the active species.A plausible mechanism involving a two-electron transfer is proposed,and the rate equation derived from the mechanism can explain all experimental observations.Activation parameters of the rate-determining step and constants are evaluated.     

阳离子交换树脂膜吸附-X荧光光谱法测定矿石中的钍

本文介绍了一种用阳离子交换树脂膜吸附X荧光光谱法测定矿石中钍的方法。在0～250微克/100毫升范围,钍的浓度与强度呈线性关系,当钍含量大于100ppm时,其变异系数为3.38%。     

Attempted Removal of Oxygen Function at 1-Position of 10-Deacetylbaccatin Ⅲ

PaclitaxelisapromisinganticancerdmgusedfortreatInentofbreastandovarycancer.lSARstUdieshaverevealedthatthefunctionalitiesatthes0uthemhemisphereofthemoleculeareimPortantf0rantitUmoractivity',butl-hydroXyisstillablackb0x.TwogrouPs"shaveindePendentlyremovedC-l0oxygenfunctionalityusingsamariumdiiodide,anelectrontransferlanthanidereagent,stedingfr0mbaccatinIIIorfr0mpaclitaxel.Wereasonedthatthel-OHofbaccatinlllmightberemovedbyfirstconvertingC-2benzoateint0aketone,whichwillreducethesterichindran…     

Extraction chromatographic study of aluminium(III) and mutual separation of aluminium(III), gallium(III), indium(III) and thallium(III) with N-n-octylaniline

A selective method has been developed for extraction chromatographic studies of aluminium(III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium(III) was quantitatively extracted with the 0.065 mol/L N-n-octylaninine from 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (KdAl(III)) versus N-n-octylaniline concentrationin 0.005 and 0.007 mol/L sodium succinate gave theslopes 0.5 and 0.7 respectively and showed theprobable composition of theextracted species was 1:1 (metal to amine ratio) and the nature of extracted species is [RR''NH2+ Al succinate2-] org. .The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium(III), indium(III), gallium(III) and thallium(III) has been developed by using suitable masking agents. The method is fast, accurate and precise.     

Effect of Cationic Micelles on the Kinetics of Interaction of [Cr（Ⅲ）-Gly-Gly]^2＋ with Ninhydrin

The effect of cationic micelles of cetyltrimethylammonium bromide (CTAB) on the interaction of chromium dipeptide complex ([Cr(Ⅲ)-Gly-Gly]2 ) with ninhydrin under varying conditions has been investigated. The rates of the reaction were determined in both water and surfactant micelles in the absence and presence of various organic and inorganic salts at 70 ℃ and pH 5.0. The reaction followed first- and fractional-order kinetics with respect to [Cr(Ⅲ)- Gly-Gly2 ] and [ninhydrin]. Increase in the total concentration of CTAB from 0 to 40×10-3 mol·dm-3 resulted in an increase in the pseudo-first-order rate constant (kψ) by a factor of ca 3. Quantitative kinetic analysis of kψ-[CTAB] data was performed on the basis of the pseudo-phase model of the micelles. As added salts induce structural changes in micellar systems that may modify the substrate-surfactant interactions, the effect of some inorganic (NaBr, NaCl, Na2SO4) and organic (NaBenz, NaSal, NaTos) salts on the rate was also explored. It was found that the tightly bound counterions (derived from organic salts) were the most effective.     

Solid Phase Extraction of Uranium by Naphthalene‐Methyltrioctylammonium Chloride and Arsenazo(III) Adsorbent and Subsequent Spectrophotometric Determination

A simple and effective method has been presented for the preconcentration of uranium by solid phase extraction. For this purpose arsenazo(III) supported on naphthalene‐methyltrioctylammonium chloride was used as an adsorbent and uranium solution at pH 3.5 with flow rate of 1 mL·min⁻¹ was passed through the column. Therefore, uranium‐arsenazo(III) complex was formed onto column. Uranium was quantitatively eluted with 5 mL of a 0.1% ammonium tetraphenylborate and determined by spectrophotometric method at 652 nm. Several parameters such as pH, amount of reagents, sample volume, etc. were investigated. The effect of diverse ions on the preconcentration has also been studied and the optimized conditions developed have been utilized for the trace determination of uranium. A preconcentration factor of 100 was achieved. The relative standard deviation (N=8) was 0.5% for 3 ng· mL⁻¹ of uranium. The three sigma detection limit (36) was 0.045 ng·mL⁻¹     

Resonance Rayleigh Scattering Spectra of Thorium(IV)-bisazo Dye of Chromotropic Acidprotein Systems and Their Analytical Applications

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｄｅｔｅｒｍｉｎａｔｉｏｎｏｆｐｒｏｔｅｉｎｓｉｓｉｍｐｏｒｔａｎｔｉｎｂｉｏｃｈｅｍｉｃａｌｓｔｕｄｙ ,ｃｌｉｎｉｃａｌｔｒｅａｔｍｅｎｔａｎｄｆｏｏｄａｎａｌｙｓｉｓ .Ａｓｉｔｉｓｋｎｏｗｎ ,ｔｈｅｃｏｍｍｏｎｍｅｔｈｏｄｓｕｓｅｄｔｏｄｅｔｅｒｍｉｎｅｔｈｅｐｒｏｔｅｉｎｑｕａｎｔｉｔａ ｔｉｖｅｌｙａｔｐｒｅｓｅｎｔａｒｅｓｐｅｃｔｒｏｐｈｏｔｏｍｅｔｒｙａｎｄｆｌｕｏｒｏｓｐｅｃ ｔｒｏｐｈｏｔｏｍｅｔｒｙ.1Ｒｅｃｅｎｔｌｙ ,ｒｅｓｏｎａｎｃｅＲａｙｌｅｉｇ…     

Ene Reaction with Pummerer‐type Reaction Intermediate of α‐(Methylthio)‐N‐methoxy‐N‐methyl Acetamide: A New Synthesis of N‐methoxy‐N‐methyl‐(E,E)‐2,4‐dienamides

Pummerer‐type reaction intermediate 2 of α‐(methylthio)‐N‐methoxy‐N‐methyl acetamide (1) has been found to react with 1‐alkenes to afford ene adducts 3 . N‐Methoxy‐N‐methyl‐(E,E)‐2,4‐dienamides were synthesized from the adducts 3b‐f .     

Spectroscopic and electrochemical study for evaluating DNA interaction activity of 4‐(3‐halophenyl)‐6‐(pyridin‐2‐yl)pyrimidin‐2‐amine based piano stool Cp* Rh (III) and Ir (III) complexes

Six novel organometallic half sandwich complexes [(η5‐C₅Me₅)M(L^1–3)Cl]Cl.2H₂O were synthesized using [{(η⁵‐C₅Me₅)M(μ‐Cl)Cl₂], where M = Ir (III)/Rh (III) and L^1–3 = three pyridyl pyrimidine based ligands; and characterized by NMR, Infra‐red spectroscopy, conductance, elemental and thermal analysis. The complex‐DNA binding mode and/or strength evaluated using absorption titration, electrochemical studies and hydrodynamic measurement proposed intercalative binding mode, which was also confirmed by molecular docking study. Differential pulse voltammetry and cyclic voltammetry studies indicated an alteration in oxidation and reduction potentials of complexes (M⁺⁴/M⁺³) in presence of CT‐DNA. The metal complexes can cleave plasmid DNA as proposed in gel electrophoretic analysis. The LC₅₀ values of complexes evaluated on brine shrimp suggested their potent cytotoxic nature.     

Luminescent Strategies for Label‐Free G‐Quadruplex‐Based Enzyme Activity Sensing

By catalyzing highly specific and tightly controlled chemical reactions, enzymes are essential to maintaining normal cellular physiology. However, aberrant enzymatic activity can be linked to the pathogenesis of various diseases. Therefore, the unusual activity of particular enzymes can represent testable biomarkers for the diagnosis or screening of certain diseases. In recent years, G‐quadruplex‐based platforms have attracted wide attention for the monitoring of enzymatic activities. In this Personal Account, we discuss our group's works on the development of G‐quadruplex‐based sensing system for enzyme activities by using mainly iridium(III) complexes as luminescent label‐free probes. These studies showcase the versatility of the G‐quadruplex for developing assays for a variety of different enzymes.     

Pictet‐Spengler Condensation of N,N‐Dimethylsulfamoyl‐β‐Phenethylamines with Methylthioacetic Acid Ethyl Ester. New Synthesis of Ethyl 1,2,3,4‐Tetrahydroisoquinoline‐1‐Carboxylates

The reaction of N,N‐dimethylsulfamoyl‐β‐phenethylamines with methylthioacetic acid ethyl ester using phenyliodine(III) bis(trifluoroacetate) gives moderate to good yields of the corresponding ethyl 1,2,3,4‐tetrahydroisoquinoline‐1‐carboxylates.     

Development of Pr(III) Selective Electrode Using 1,6,7,12‐Tetramine‐2,5,8,11‐tetraoxo‐1(12),6(7)‐di(biphenyl)‐dodecane (TATODBDD) as a Neutral Carrier

A polyvinyl chloride (PVC) membrane based Pr(III) selective electrode was constructed using 1,6,7,12‐tetramine‐2,5,8,11‐tetraoxo‐1(12),6(7)‐di(biphenyl)dodecane (TATODBDD) as a neutral carrier. The sensor exhibits a Nernstian response for Pr(III) ions, a wide concentration range of 3.9×10^?7?1.0×10^?1 mol/L with a detection limit of 5.0×10^?8 mol/L and slope of 19.5 mV/decade. The developed sensor revealed relatively good selectivity and high sensitivity for Pr(III) ions over the other lanthanide ions. The potentiometric response of the sensor is independent in the pH range 2.9–9.5. The advantages of sensor are low resistance, very fast response time (<10 s) with good selectivity. This sensor can be used up to 6 weeks without any divergences in potential response.     

Mesityl‐phenolato‐vanadium(III)‐Komplexe: Synthese,Struktur und Verhalten

Mesityl‐vanadium(III)‐phenolate Complexes: Synthesis, Structure, and Reactivity Protolysis reactions of [VMes₃(THF)] with ortho‐substituted phenols (2‐iso‐propyl‐(H–IPP), 2‐tert‐butyl(H–TBP), 2,4,6‐trimethylphenol (HOMes) and 2,2′biphenol (H₂–Biphen) yield the partially and fully phenolate substituted complexes [VMes(OAr)₂(THF)₂] (OAr = IPP ( 1 ), TBP ( 2 )), [VMes₂(OMes)(THF)] ( 4 ), [V(OAr)₃(THF)₂] (OAr = TBP ( 3 ), OMes ( 5 )), and [V₂(Biphen)₃(THF)₄] ( 6 ). Treatment of 6 with Li₂Biphen(Et₂O)₄ results in formation of [{Li(OEt₂)}₃V(Biphen)₃] ( 7 ) and with MesLi complexes [{Li(THF)₂}₂VMes(Biphen)₂] · THF ( 8 ) and [{Li(DME)}VMes₂(Biphen)] ( 9 ) are formed. Reacting [VCl₃(THF)₃] with LiOMes in 1 : 1 to 1 : 4 ratios yields the componds [VCl_3–n(OMes)_n(THF)₂] (n = 1 ( 5 b ), 2 ( 5 a ), 3 ( 5 )) and [{Li(DME)₂}V(OMes)₄] ( 5 c ), the latter showing thermochromism due to a complexation/decomplexation equilibrium of the solvated cation. The mixed ligand mesityl phenolate complexes [{Li(DME)_n}{VMes₂(OAr)₂}] (OAr = IPP ( 10 ), TBP ( 11 ), OMes ( 12 ) (n = 2 or 3) and [{Li(DME)₂}{VMes(OMes)₃}] ( 15 ) are obtained by reaction of 1 , 2 , 5 a and 5 with MesLi. With [{Li(DME)₂(THF)}{VMes₃(IPP)}] ( 13 ) a ligand exchange product of 10 was isolated. Addition of LiOMes to [VMes₃(THF)] forming [Li(THF)₄][VMes₃(OMes)] ( 14 ) completes the series of [Li(solv.)_x][VMes_4–n(OMes)_n] (n = 1 to 4) complexes which have been oxidised to their corresponding neutral [VMes_4–n(OMes)_n] derivatives 16 to 19 by reaction with p‐chloranile. They were investigated by epr spectroscopy. The molecular structures of 1 , 3 , 5 , 5 a , 5 a – Br , 7 , 10 and 13 have been determined by X‐ray analysis. In 1 (monoclinic, C2/c, a = 29.566(3) Å, b = 14.562(2) Å, c = 15.313(1) Å, β = 100.21(1)°, Z = 8), 3 (orthorhombic, Pbcn, a = 28.119(5) Å, b = 14.549(3) Å, c = 17.784(4) Å, β = 90.00°, Z = 8), ( 5 ) (triclinic, P1, a = 8.868(1) Å, b = 14.520(3) Å, c = 14.664(3) Å, α = 111.44(1)°, β = 96.33(1)°, γ = 102.86(1)°, Z = 2), 5 a (monoclinic, P2₁/c, a = 20.451(2) Å, b = 8.198(1) Å, c = 15.790(2) Å, β = 103.38(1)°, Z = 4) and 5 a – Br (monoclinic, P2₁/c, a = 21.264(3) Å, b = 8.242(4) Å, c = 15.950(2) Å, β = 109.14(1)°, Z = 4) the vanadium atoms are coordinated trigonal bipyramidal with the THF molecules in the axial positions. The central atom in 7 (trigonal, P3c1, a = 20.500(3) Å, b = 20.500(3) Å, c = 18.658(4) Å, Z = 6) has an octahedral environment. The three Li(OEt₂)⁺ fragments are bound bridging the biphenolate ligands. The structures of 10 (monoclinic, P2₁/c, a = 16.894(3) Å, b = 12.181(2) Å, c = 25.180(3) Å, β = 91.52(1)°, Z = 4) and 13 (orthorhombic, Pna2₁, a = 16.152(4) Å, b = 17.293(6) Å, c = 16.530(7) Å, Z = 4) are characterised by separated ions with tetrahedrally coordinated vanadate(III) anions and the lithium cations being the centres of octahedral and trigonal bipyramidal solvent environments, respectively.     

Synthesis,crystal structure and magnetic property of a two‐dimensional herringbone‐like network with praseodymium(III) nitrate and 1‐bromo‐ 3,5‐bis(imidazol‐1‐ylmethyl)benzene (bib)

A new complex [Pr(bib)₂(NO₃)₃] ( 1 ) was synthesized by reaction of bidentate imidazole‐containing ligand 1‐bromo‐3,5‐bis(imidazol‐1‐ylmethyl)benzene (bib) with Pr(NO₃)·6H₂O and characterized by X‐ray crystallography. Complex 1 has a two‐dimensional herringbone‐like structure with the ligand bib serving as a bridging ligand using its two imidazolyl nitrogen atoms. Ligand bib adopts cis and trans two different conformations, and the Pr(III) atoms are bridged by bib in two different ways. Thermogravimetric analysis for complex 1 was carried out and the result shows that the complex is stable up to 180 °C. Variable‐temperature magnetic susceptibility of complex 1 was measured between 1.8 and 300 K and the result shows that the χ_MT value decreases continuously over the whole temperature range. Copyright © 2005 John Wiley & Sons, Ltd.