Recognition and sensing of anions through synergistic effects using simple benzimidazolium-urea receptors

Benzimidazolium-based receptors 1-3 were designed and synthesized. On the basis of fluorescence, UV-Vis, and 1H NMR spectroscopic studies, and X-ray single crystal structure analysis, it was confirmed that the receptor 1 displays strong (C-H)+···X, N-H···X hydrogen bonds and charge-charge interactions with anions. More importantly, these investigations demonstrated that the charged (C-H)+ benzimidazolium and urea moieties play a synergistic role in anion recognition.     

Ionic liquids containing the urea moiety for recognition of halides and complex anions

A series of novel imidazolium based ionic liquids containing the urea moiety were designed and synthesized for anion recognition. 1-Ethylurea-3-methylimidazolium acetate ([Eumim]OAc) was used as the receptor for the halides and complex anions (BF4-, PF6-, BPh4-). 1H NMR spectra showed that the urea protons and imidazolium C(2) proton of the receptor ([Eumim]OAc) moved upfield on addition of various anions. A Job plot showed that the [Eumim]OAc receptor formed a 1:1 complex with BPh4-. X-ray diffraction analysis and the molecular modeling study revealed that the conformations of [Eumim]OAc and [Eumim]BPh4 were different. The conformational change of the cation was caused by anion exchange, and may provide an alternative to current methods for recognition of anions.     

Studies on the interaction of DNA and Ru (1,10-phenanthroline)2− (dipyrido[3,2−a:2′,3′−c]phenazine)2+

The interaction of Ru(phen)₂(dppz)²⁺(phen=1,10-phenanthroline,dppz=dipyrido[3,2−1:2′,3′−c]phenazine) and the calfthymus DNA were studied with fluorescence and ultraviolet visible absorption spectroscopy. The ultraviolet visible absorption spectrum of Ru(phen)₂(dppz)²⁺ calfthymus DNA, and their interaction demonstrated that Ru(phen)₂(dppz)²⁺ intercalated into the double helix of DNA via the ligand dppz. Fe(CN)₆ ⁴⁻ and NaCl can not quench the fluorescence of Ru(phen)₂(dppz)²⁺-DNA, which was in agreement with the intercalation mode. Foundation item: Supported by National Natural Science Foundation of China Biography: LING Lian-sheng (1972-), male, PhD, candidate.     

Characterization of Anabaena cylindrica Solution System Using Synchronous-Scan Fluorescence Spectroscopy

The characterization of the algaeAnabaena cylindrica solution with Fe (III) was investigated using fluorescence emission and synchronous-scan spectroscopy. The ranges of concentrations of algae and Fe (III) in aqueous solutions were 5.0×10⁸ 2.5×10⁸ cell/L and 1060 μmol/L. respectively. The effective characterization method used was synchronous-scan fluorescence spectroscopy (SFS). The wavelength difference (Δλ) of 90 nm, was maintained between excitation wavelength (λen) and emission wavelength (λen). The peak was observed at about (λex) (λem) 326 nm for synchronous scan fluorescence spectroscopy. The fluorescence quenching in system of algae Fe(III)-HA was studied using synchronous-scan spectroscopy for the first time, Fe(III) was clearly the effective quencher. The relationship betweenI I (quenching efficiency) andc (concentration of Fe (III) added) was, a linear correlation for the algae solution with Fe(III). Also, Aldrich humie acid (HA) was found to be an effective quencher. Foundation item: Supported by the National Natural Science Foundation of China (20177017) and the Scientific Research Foundation of Wuhan Environmental Protection Bureau Biography: LIU Xian li(1965), male. Ph.D. Associate professor, research direction: environmental chemistry.     

Fluorescence Determination of Artemisinin Using Hemoglobin as Catalyst and Pyronine B as Substrate

0 IntroductionMaalnadria siusb atr ompajicosr .he aAltrthe pmrisoibnlienmi (n qtihneghtraoopsiucs,QHS,Fig.1) is a sesquiterpene endoperoxide isola-ted fromArtemisia annuaL., an ancient Chineseherbal medicine usedfor treatment of fever and ma-laria.Studies of the structure and activity relation-ship have shownthat endoperoxide groupis essentialfor anti malarial activity of QHS and absence of thismoiety lead to completely loss in activity of thedrug. Many techniques have been developed to de…     

A Novel Degradation Pathway of Zn（dmid） （ phen）2 in Pyridine

The light-oxidation degradation processes of Zn(dmid)(phen)2(dmid = 4, 5-dimercapto-1,3-dithiole-2 one, phen = 1,10-phenanthroaline) in pyridine solvent has been monitored, h has been found under the light, dmid^2- of Zn(dmid)(phen)2 in pyridine solution could generate NCS^- and NCS^-replaces dmid^2- to form Zn(NCS)2 (phen)2 simultaneously. The crystal structure of Zn(NCS)2 (phen)2 has been determined. In the crystal of Zn(NCS)2 (phen)2. two NCS^- ligands are arranged in syn-configuration, and there is strong π-π interaction between the two adjacent parallel phen.     

Formation of the inclusion complex of Orange II with β-Cyclodextrin and its photostability

Inclusion complex of Orange II with β-Cyclodextrin (β-CD) and the anti-photolysis effect under UV-light were investigated. The molar ratio of inclusion complex of β-Cyclodextrin and Orange II is 1∶1. The formation constantK = 1.236×10³ L/mol was determined by the UV and Fluorescence spectra respectively, which was quite in accordance with the calculation with a modified Benesi-Hildbrand equation. The inclusion complex was characterized by the IR spectra and the molar ratio of inclusion complex is 1∶1 too. The formation constantK = 1.266×10³ L/mol was determined by¹H NMR analysis and was nearly the same by UV and fluorescence spectra. The photocatalytic decolorization rate of Orange II solutions containing β-CD and TiO₂ was smaller by 51.9% than that of the Orange II solutions only containing TiO₂, while in the case of direct photolysis of Orange II solutions, β-CD can lower the photolysis rate by 48.1% under UV-light. This result indicates β-CD can inhibit the photolysis and photocatalytic decolorization of Orange II under UV-light. The β-CD inclusion complex was found to be persistent to UV-light photolysis. Foundation item: Supported by the National Natural Science Foundation of China (20177017) Biography: Lu Ping (1958), male. Associate professor, research direction: environmental photochemistry.     

Application of an Optical Biosensor to Study the Interaction between Porphyrins and Wheat Germ Agglutinin

0Introduction Porphyrinderivativeshavebeenusedasphotosensitizersinphotodynamictherapy(PDT),anewapproachdevel opedforthetreatmentofcancer[1].Cationwater solublepor phyrinsareofconsiderableinterestowingtotheirpossiblebio medicalapplications[2].Inwhich,theinhibiteffectonthe growthmetabolismofE.coliandcancercellHL60ofmeso tetra(4N ethylacetatepyridyl)porphyrin(H2NEAE pp)and itsZn(Ⅱ)complexform(ZnNEAE pp)havebeenrecentlyin vestigated[3,4].Toenhancetumor locationandanticancerac tivitiesofdr…     

Application of Nanometer-Size Titanium Dioxide in Extreme-Trace V（Ⅴ） Analysis

0Introduction Vanadiumplaysanimportantroleinmodernindustry,es peciallyinsteelandchemicalindustry.Forinstance,itscompoundsarewidelyappliedintheproceduresofvitrioland petroleumchemicalmanufactureascatalyzers[14].Vanadium hasseveralvalences,butgenerallyitslowvalencesturnintohighoneseasilyinenvironment[5].BecauseV(Ⅴ)isthemost stableandpoisonousone,weoftenlayemphasisonitinenvi ronmentalpollutioncontrol.Vanadiumexistsinenvironmentalwaterwithextremelylowconcentration.Inseawateritscontentislessthan…     

Spectrofluorimetric method for the determination of triamcinolone acetonide

0　IntroductionTriamcinoloneAcetonide,9 fluoro 11β,2 1 dihydroxy 16α,17[(1 methylethylidene)bis (oxy) ] pregn 1,4 diene 3,2 0 dione,Mris 4 34.4 8(abr.TA ) .Itbelongstoaclassofadrenalcortexhormonedrug ,whosefunctionsareaffectionofsugarmetabolism ,anti inflammationandresistancehypersusceptibilityetc.TAcanbesuitabletorheumatoidarthritisanddermatosissuchashypersusceptibilityandneuropathicdermatitis .ThefunctionsofTAisstrongerandlongerthantriamcinolone[1 ,2 ] .ThecommonmethodsofdetectingTAm…     

Sensitive Determination of DNA by RLS Enhancement of Metal Ions

0　IntroductionThequantitativeanalysisofnucleicacids,especiallythemi cro determinationofnucleicacids,isbecomingmoreandmoreimportantinmanybiologicalstudies.Recently ,apromisingspectraltechnique ,whichwasbasedonthemeasurementofen hancedresonancelightscattering (RLS) [1 ,2 ] ,hasgivenrisetostronginterestbyanalystsandbiochemistsfornucleicacidsandproteinassay[3 9] .Uptonow ,manykindscompoundshavebeenfoundRLSenhancementwhilebindingtoDNA ,andallthesecompoundsarecharacterizedofpositivechargewhicha…     

An explanation to the high efficiency ofm-THPC (temporfin) used in photodynamic therapy

Meso-tetrahydroxylphenyl chlorin (m-THPC) is one of the most efficient prospective sensitizers used in photodynamic therapy (PDT). ESR spectroscopy, fluorescence quenching experiments and cyclic voltammogram measurement were used to study its redox properties. The results showed that the ability of m-THPC generating superoxide radical anions was very strong, and the rate constant of m-THPC fluorescence quenching by oxygen k_q (O₂)=1.46×10¹⁰ mol^-1·s^-1. The values of fluorescence quen- ching rate constant of m-THPC by some other electron acceptors, such as methyl viologen (MV²⁺) and anthraquinone (An), were also measured. And they were k_q (MV²⁺)=5.51×10⁹ mol^-1·s^-1, k_q (An)=7.81×10⁹ mol^-1·s^-1. The oxidation potential of m-THPC was examined to be +0.62 V (vs. NHE) in acetonitrile. All these suggested that m-THPC should be a much stronger electron donor than photofrin, the currently used in clinical photodrug, and may react easily through electron transfer with biological matter to yield various radicals. So it seemed reasonable that the type Ⅰ reaction may play an important role in the high activity of m-THPC-PDT.     

Synergistic interaction and gelation in cationic guar gum-sodium alginate system

The synergistic interaction between the cationic guar gum (the ammonium hydroxy-propyl-trimethyl chloride of guar gum) and sodium algirmte has been studied. The effects of the mass ratio of them, mixed temperature, balk salt ion concentration, incubation time and pH value on gelation were investigated. It has been observed that there was a gel strength maximum when the mass ratio was 0. 6, the mixed temperature was 70 ~C, the balk salt ion concentration was 1.0 mol ~ L-1 , the incubation time was 30 rain and the pH value was 8. Interaction between molecules of these two polysaccharides was investigated by FT-IR spectrometry.     

Photodegradation of 17α-Ethynylestradiol in Aqueous Solution with Nitzschia hantzschiana or Chlorella vulgaris and Fe^3＋

0　IntroductionTherehasbeenincreasingconcernabouttheenvironmentaleffectsofoestrogensandxenoestrogens[1 ] .17α ethynylestradiol(EE2 ) (Fig .1)isasyntheticestrogenicsteroidthathastherapeuticuses (e.g .Oralcontraception) .Syntheticestrogensaregenerallymorestableinwaterthannaturalestrogensandhavegreaterpotency.Theyaredifficulttobeabsolutelyremovedfromwastewatersbyprimaryandsecondarytreatment.Thedegradationchemistryofthiscom poundhasnotbeenextensivelystudied .Therearefewpublishedarticlesstudying…     

Investigation of Ru （ phen ）3^2＋-Hydrazine-Ce（Ⅳ） Chemiluminescence System and Its Analytical Application

0 IntroductionThbiep ycroidmipnlee)xru ctahteinoinu mof(Ⅱ r)u t(he Rniuu(mbip,y m)3ai2n +ly) atrnids- t(r2is -,(21’ -,10-phenanthroline)ruthenium(Ⅱ) (Ru(phen)32 +) ,is a kindof sensitive analytical reagent for electrogenerated chemilumi-nescence(ECL) and chemiluminescence(CL) ,on which a par-ticular review has been presented[1]. The earliest publicationon the synthesis of Ru(bipy)32 +appeared in 1936[2], andduringthefollowing30 years ,theinvestigations relatedtothissubstance were only in…     

Synthesis and Characterization of Polyamide-Containing 2, 6- （Substituded） pyridine Derivatives

0 IntroductionPayrriodminaetiics hoenteer oofc ythcleics m .os tC oambupnoduanndts a cnodn tbaeisntin kgno twhnepyridine ring are widely distributedin nature,principally asenzymes and alkaloids . Pyridine enzymes have been foundintissues of all plants and ani mals examined thus far ,andare derivedfromeither nicotinic acid or Vitamin B6[1].Pyr-idine derivatives are also the building block of many phar-maceuticals with a wide range of functionalities that includeantitubercular compounds ,antivi…     

Myoglobin as Mimetic Enzyme and Its Analytical Application in Determination of H2O2

0 IntroductionSltougdiiceasl csoynstceermnsin gharveeac btieveen o txhyeg ei nm psopretcaienst ( oRbjOecSt) iinn bbiioo--medicine and analytical chemistry in recent years[1-4]. Manyi mportant life phenomena and diseases are relatedtotheinter-mediates of ROS[5-7].ROS have beeni mplicated as ani mpor-tant causative factor in cell damage,including apoptosis andnecrosis . Their proposed actions comprise lipid peroxidation,DNAdamage,the mitochondrial respiratory chain destructionand protein mo…     

Synthesis and X-ray crystal structure of a new manganese 18-metallacrown-6

0　IntroductionThemetalionsinmetallamacrocylesformedbysupramolecularself assemblycantaketrigonal,square planar,andtetrahe dralconfiguration[1 ,2 ] .Metallacrownisaspecialclassofmetalla macrocyle,theyareanalogoustocrownethersinbothstructureandfunctionexceptthatthemetalionsarenowtakingthepositionsofcoordinationatomsincrownether[3,4] .Themetallacrownswithdifferentnumberof [M—N—O]repeatunithavedifferentcavitysizes,suchas 9 MC 3[5 7] ,12 MC 4 [4,8 1 4 ] and 15 MC 5 [1 5] .Thereportedazameta…     

Investigation of performances and mechanism of fluoride removal by Fe (III)-loaded ligand exchange cotton cellulose adsorbent

Novel adsorbent, Fe(III)-loaded ligand exchange cotton cellulose adsorbent [Fe(III)LECCA], was used to investigate the adsorption performances and mechanism of fluoride removal from aqueous solutions. The adsorbent was found to adsorb fluoride rapidly and effectively. The fluoride removal was influenced by pH. Adsorption model followed first-order reaction at different temperature, theapparent adsorption activated energyE, was 6.37 kJ·mol⁻¹, and adsorption enthalpy ΔH was 5.35 kJ·mol⁻¹. The adsorption capacity of fluoride on adsorbent was 3.2 mmol·g⁻¹ (dry weight). The maximal integer coordination ratio of fluoride with Fe(III) LECCA was 3∶1. The ligand exchange mechanism of adsorption was elucidated through chemical methods and IR spectral analysis. Foundation item: Supported by the National Natural Science Foundation of China (29977010) and Shanghai Priority Academic Discipline Biography: ZHAO Ya-ping (1974-), female, Ph.D., research direction: water and wastewater treatment.     

Determination of ammonium ion in lake water by voltammetry

0　IntroductionDetectionofammoniumionisveryimportantinmanyfields,suchashealthcare,agriculture ,cultivationandenviron mentalpollutioncontrol.Severalanalyticalmethodshavebeende velopedforammoniumdeterminationincludingionchromatography ,spectrophotometry,fluorimetryandchemiluminescence .MostofthemarebasedonspectrophotometryusingtheBerthelot reactionbetweenammonium ,phenol,andhypochloriteleadingtothefor mationofanindophenoldye[1 ] .Thereactiontimeisaboutanhour,andsomedissolvedorganicnitrogencompo…