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1990 Volume 1 Issue 2
1990, 1(2): 97-100
Abstract:
Three element triple exciplex formation has been observed first in the system of terephthalic dimethylester,1,4-dicyanzene and naphthalene by comparing its fluorescence spectra with those of the system of terephthalic dimethylester and naphthalene,and the system of 1,4-dicyanobsnzene and naphthalene at the same experimental conditions.
Three element triple exciplex formation has been observed first in the system of terephthalic dimethylester,1,4-dicyanzene and naphthalene by comparing its fluorescence spectra with those of the system of terephthalic dimethylester and naphthalene,and the system of 1,4-dicyanobsnzene and naphthalene at the same experimental conditions.
1990, 1(2): 101-104
Abstract:
The reaction mechanism of ammonia with formaldehyde was investigated by using the intrinsic reaction coordinate (IRC) method on the ab initio RHF/STO-3G basis set. our results indicate that the reaction proceeds in two stages:the first step yields the molecular complex and the second one is the rearrangement from molecular complex to the reaction proauct.
The reaction mechanism of ammonia with formaldehyde was investigated by using the intrinsic reaction coordinate (IRC) method on the ab initio RHF/STO-3G basis set. our results indicate that the reaction proceeds in two stages:the first step yields the molecular complex and the second one is the rearrangement from molecular complex to the reaction proauct.
1990, 1(2): 105-108
Abstract:
A new method for the determination of components in mixed acids has been developed.The mathematical model is obtained from samples of known composition and is then used to predict the concentrations of components in unknown sample.The practical utility of this method is demonstrated for simultaneous determination of two systems of ternary mixed acids and the results are satisfactory.
A new method for the determination of components in mixed acids has been developed.The mathematical model is obtained from samples of known composition and is then used to predict the concentrations of components in unknown sample.The practical utility of this method is demonstrated for simultaneous determination of two systems of ternary mixed acids and the results are satisfactory.
1990, 1(2): 109-112
Abstract:
Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the characteristic fragment ions were high in m/z,thereby the interpretation was facilitated.
Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the characteristic fragment ions were high in m/z,thereby the interpretation was facilitated.
1990, 1(2): 113-116
Abstract:
A carbon wire amperometric flow through detector is described which is easily constructed at low cost for application to flow injection analysis,continuous stream analysis and liquid chromatography.The theoretical limiting current of the detector is 2.14×106nCD2/3uf1/3 with 36% actual current efficiency.By use of flow injection analysis,thedetecting limits for Ag(I) and Cr(VI) had achieved 1 ppb and 0.4 ppb respectively with 1.2% (n=20) relative standard deviation after preliminary experiments.
A carbon wire amperometric flow through detector is described which is easily constructed at low cost for application to flow injection analysis,continuous stream analysis and liquid chromatography.The theoretical limiting current of the detector is 2.14×106nCD2/3uf1/3 with 36% actual current efficiency.By use of flow injection analysis,thedetecting limits for Ag(I) and Cr(VI) had achieved 1 ppb and 0.4 ppb respectively with 1.2% (n=20) relative standard deviation after preliminary experiments.
1990, 1(2): 117-118
Abstract:
The stability of the coordination compounds of the first transition series metal ions(Mn(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ) and Zn(Ⅱ)) with 2-mercaptopyridine-1-oxide is reported.A coordination compound CoL2 is synthesized and characterized for the first time.
The stability of the coordination compounds of the first transition series metal ions(Mn(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ) and Zn(Ⅱ)) with 2-mercaptopyridine-1-oxide is reported.A coordination compound CoL2 is synthesized and characterized for the first time.
1990, 1(2): 119-120
Abstract:
In this paper,complexes of rare earth nitrate with Schiff base derived from vanillin (3-methoxy-4-hydroxy-benzaldehyde) and p-toluidine [LnL2(NO3)2]NO3 (Ln=La-Eu except Pm,L=Schiff base ligand) have been prepared and characterized.
In this paper,complexes of rare earth nitrate with Schiff base derived from vanillin (3-methoxy-4-hydroxy-benzaldehyde) and p-toluidine [LnL2(NO3)2]NO3 (Ln=La-Eu except Pm,L=Schiff base ligand) have been prepared and characterized.
1990, 1(2): 121-122
Abstract:
A new trithiocarbonato Mo complex (Et4N)2 [(S2)MO2O2(μ-S)2(CS3)] was obtained from a system containing MoO42-,Sx2-,and CS2 and characterized by IR and X-ray structural analysis.The complex crystallizes in the monoclinic space group P21/c with a=9.539(3)Å,b=20.745(2)Å,c=15.452(2)Å,β=94.58(2)°,and Z=4.The structure was solved by direct and difference Fourier synthesis methods.Least squares refinement using 2910 reflections with I>3σ(I) converged to R=0.054.The CS32- ligand in the complex chelates to Mo atom and values of the C-S bond distances in the CS32- ligend indicate a substantial contribution of three resonance forms.
A new trithiocarbonato Mo complex (Et4N)2 [(S2)MO2O2(μ-S)2(CS3)] was obtained from a system containing MoO42-,Sx2-,and CS2 and characterized by IR and X-ray structural analysis.The complex crystallizes in the monoclinic space group P21/c with a=9.539(3)Å,b=20.745(2)Å,c=15.452(2)Å,β=94.58(2)°,and Z=4.The structure was solved by direct and difference Fourier synthesis methods.Least squares refinement using 2910 reflections with I>3σ(I) converged to R=0.054.The CS32- ligand in the complex chelates to Mo atom and values of the C-S bond distances in the CS32- ligend indicate a substantial contribution of three resonance forms.
1990, 1(2): 123-124
Abstract:
The synthesis,crystal structure and properties of the first Mn(Ⅲ)-disulfide complex (Et4N) [Mn(mp-mp)2] were reported with the Mn(Ⅲ) ion in a S2O4 octahedron distorted due to Jahn-Teller effect.Spectroscopic data revealed its paramagnetic properties.
The synthesis,crystal structure and properties of the first Mn(Ⅲ)-disulfide complex (Et4N) [Mn(mp-mp)2] were reported with the Mn(Ⅲ) ion in a S2O4 octahedron distorted due to Jahn-Teller effect.Spectroscopic data revealed its paramagnetic properties.
1990, 1(2): 125-126
Abstract:
A precursor 2 of cembrene-A (a termite trail pheromone) was prepared from geraniol through 7 steps.
A precursor 2 of cembrene-A (a termite trail pheromone) was prepared from geraniol through 7 steps.
1990, 1(2): 127-130
Abstract:
The replaced site of Eu2+ ion is dependent on the electronegativity difference of the cations in complex fluorides.In the mixed fluoride KMgF3:Eu2+,Eu2+ ion occupies K+ site,its emission spectrum is a sharp line and its valence-state is stable.
The replaced site of Eu2+ ion is dependent on the electronegativity difference of the cations in complex fluorides.In the mixed fluoride KMgF3:Eu2+,Eu2+ ion occupies K+ site,its emission spectrum is a sharp line and its valence-state is stable.
1990, 1(2): 131-132
Abstract:
In pH 2.0-3.0 medium,niobium(v) forms molybdoniobic acid with sodium molybdate.A spectrophotometric method has been developed for the determination of niobium based on the formation of ion-associate compound of molybdoniobate with butyl Rhodamine B in aqueous solution in the presence of polyvinyl alcohol and 0.4-0.7 mol/L H2SO4.The molar absorptivity is 7.5×105 L.mol-1.cm-1 for niobium at 585 nm.
In pH 2.0-3.0 medium,niobium(v) forms molybdoniobic acid with sodium molybdate.A spectrophotometric method has been developed for the determination of niobium based on the formation of ion-associate compound of molybdoniobate with butyl Rhodamine B in aqueous solution in the presence of polyvinyl alcohol and 0.4-0.7 mol/L H2SO4.The molar absorptivity is 7.5×105 L.mol-1.cm-1 for niobium at 585 nm.
1990, 1(2): 133-134
Abstract:
α-bromocarbonyl compounds can be debrominated with dibutyl telluride in the presence of triethylamine in high yields.
α-bromocarbonyl compounds can be debrominated with dibutyl telluride in the presence of triethylamine in high yields.
1990, 1(2): 135-138
Abstract:
Based on six thermodynamic equilibria,a unified retention model of solute in liquid chromatography(LC) is first proposed.The unified model was tested and proved to be valid for a LC system with mobile phase consisting of a complete range of multiple,ternary or binary components and each kind of LC except size exclusion chromatography.In addition,so long as making some assumptions and mathematical conversions,the expressions of various popular models in LC can be derived by using the unified model.
Based on six thermodynamic equilibria,a unified retention model of solute in liquid chromatography(LC) is first proposed.The unified model was tested and proved to be valid for a LC system with mobile phase consisting of a complete range of multiple,ternary or binary components and each kind of LC except size exclusion chromatography.In addition,so long as making some assumptions and mathematical conversions,the expressions of various popular models in LC can be derived by using the unified model.
1990, 1(2): 139-142
Abstract:
The present paper reports a novel chemiluminescence,i.e,isopropyl alcohol-C10--H2O2 system.The chemiluminescence intensity is proportionalto the concentration of C10- within certain range.Based on this fact,a new chemiluminescence method for the determination of micro amount of C10- has been developed.The detection limit is 2.6 x 10-8g/ml C10- and the dynamic linear range is 2.6 x 10-8g/ml to 2.3 x 10-5g/ml C10-.The method has good selectivlty and reproducibility.
The present paper reports a novel chemiluminescence,i.e,isopropyl alcohol-C10--H2O2 system.The chemiluminescence intensity is proportionalto the concentration of C10- within certain range.Based on this fact,a new chemiluminescence method for the determination of micro amount of C10- has been developed.The detection limit is 2.6 x 10-8g/ml C10- and the dynamic linear range is 2.6 x 10-8g/ml to 2.3 x 10-5g/ml C10-.The method has good selectivlty and reproducibility.
1990, 1(2): 143-146
Abstract:
A new GC/MS method for detection and identification of 19 anabolic steroids in human urine is presented.The procedure involves adsorption and isolation on a macroporous XAD-2 resin,enzymatic hydrolysis,alkaline extraction,derivatization,GC separation and MS detection.Gas chromatographic-mass spectrometric data illustrate artifacts arising from enzymatic hydrolysis of steroid glucuronides and the structural characterization of their metabolites.Using this method,metabolic studies of these steroids in human urine were made after their ingestion by normal and healthy male volunteers.This method was proven to be suitable for large-scale routine analysis of anabolic steroids and was used successfully in passing the doping control test held by the Medical Commission of the International Olympic Committee.
A new GC/MS method for detection and identification of 19 anabolic steroids in human urine is presented.The procedure involves adsorption and isolation on a macroporous XAD-2 resin,enzymatic hydrolysis,alkaline extraction,derivatization,GC separation and MS detection.Gas chromatographic-mass spectrometric data illustrate artifacts arising from enzymatic hydrolysis of steroid glucuronides and the structural characterization of their metabolites.Using this method,metabolic studies of these steroids in human urine were made after their ingestion by normal and healthy male volunteers.This method was proven to be suitable for large-scale routine analysis of anabolic steroids and was used successfully in passing the doping control test held by the Medical Commission of the International Olympic Committee.
1990, 1(2): 147-148
Abstract:
A facile method for removing copper from guanyl-0-alkylisourea copper complex was found by using electrolysis.The complex was electrolyzed at a copper cathode in dilute hydrochloric or nitric acid to give guanyl-O-alkylisourea salt in high yield and current efficiency.
A facile method for removing copper from guanyl-0-alkylisourea copper complex was found by using electrolysis.The complex was electrolyzed at a copper cathode in dilute hydrochloric or nitric acid to give guanyl-O-alkylisourea salt in high yield and current efficiency.
1990, 1(2): 149-152
Abstract:
The speculation that a flat molecule without a side-chain might not readily undergo the hydrophobicity-driven process of aggregation has been shown to be a plausible proposition by the fact that pyrene molecules do not form excimers even in a supersaturated solution with relatively high solvent aggregating power (SAgP).
The speculation that a flat molecule without a side-chain might not readily undergo the hydrophobicity-driven process of aggregation has been shown to be a plausible proposition by the fact that pyrene molecules do not form excimers even in a supersaturated solution with relatively high solvent aggregating power (SAgP).
1990, 1(2): 153-154
Abstract:
perfluoroalkyl iodides reacted with alkenes in acetonitrile solu-tion containing catalytic amount of organophosphine under mild condition to give the corresponding adducts in moderate to good yields.Reaction was shown to involve a free radical mechanism.
perfluoroalkyl iodides reacted with alkenes in acetonitrile solu-tion containing catalytic amount of organophosphine under mild condition to give the corresponding adducts in moderate to good yields.Reaction was shown to involve a free radical mechanism.
1990, 1(2): 155-156
Abstract:
The efficiency of TFMSA as a cleaving reagent for peptidyl resin(I-VⅢ) was evaluated by quantitative ninhydrin test of peptide substitution degree (SD) on resin.Under different conditions,such as variation of C-terminal residue,resin linkage,the temperature and reaction time etc.,TFMSA can be used very conveniently instead of HF in many cases.
The efficiency of TFMSA as a cleaving reagent for peptidyl resin(I-VⅢ) was evaluated by quantitative ninhydrin test of peptide substitution degree (SD) on resin.Under different conditions,such as variation of C-terminal residue,resin linkage,the temperature and reaction time etc.,TFMSA can be used very conveniently instead of HF in many cases.
1990, 1(2): 157-160
Abstract:
The performance of gas diffusion porous electrode starved of electrolyte solution can be significantly increased by decreasing the thickness of uneven liquid film covering the catalyst agglomerates.
The performance of gas diffusion porous electrode starved of electrolyte solution can be significantly increased by decreasing the thickness of uneven liquid film covering the catalyst agglomerates.
1990, 1(2): 161-164
Abstract:
Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor-bornadiene derivatives (Ⅰa,Ⅰb,Ⅰc) gave their corresponding isomers of quadri-cyclane (Ⅱa,Ⅱb,Ⅱc) operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.
Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor-bornadiene derivatives (Ⅰa,Ⅰb,Ⅰc) gave their corresponding isomers of quadri-cyclane (Ⅱa,Ⅱb,Ⅱc) operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.
PERFLUOROALKANESULFONYL IODIDE GENERATED FROM THE REACTION OF PERFLUOROALKANESULFINATE SALT WITH IC1
1990, 1(2): 165-166
Abstract:
The reaction between perfluoroalkanesulfinate salts (1) [RfSO2MRf=a,Cl(CF2)4;b,Cl(CF2)6;c,Cl(CF2)8;d,n-C6F13;e,n-C8F17;M-Na;K;Hg(I)] and iodine monochloride in dichloromethane at low temperature(e.g.-30- -50℃) resulted in the formation of the corresponding perfluoroalkane-sulfonyl iodides (2),which were identified by their 19F NMR spectra.The perfluoroalkanesulfonyl iodides generated in situ reacted smoothly with olefins to forum 1:1 adducts with good yields.Thus,these reactions provide another method for the synthesis of the very unstable perfluoroalkanesulfonyl iodide.
The reaction between perfluoroalkanesulfinate salts (1) [RfSO2MRf=a,Cl(CF2)4;b,Cl(CF2)6;c,Cl(CF2)8;d,n-C6F13;e,n-C8F17;M-Na;K;Hg(I)] and iodine monochloride in dichloromethane at low temperature(e.g.-30- -50℃) resulted in the formation of the corresponding perfluoroalkane-sulfonyl iodides (2),which were identified by their 19F NMR spectra.The perfluoroalkanesulfonyl iodides generated in situ reacted smoothly with olefins to forum 1:1 adducts with good yields.Thus,these reactions provide another method for the synthesis of the very unstable perfluoroalkanesulfonyl iodide.
1990, 1(2): 167-170
Abstract:
Benzoxazoline ring substituted ketene N,O-acetals 3 were synthesized by the reaction of ketene S,S-acetals 2 with 2-aminophenol.The tautomeric equilibrium of some 3 was also observed.
Benzoxazoline ring substituted ketene N,O-acetals 3 were synthesized by the reaction of ketene S,S-acetals 2 with 2-aminophenol.The tautomeric equilibrium of some 3 was also observed.
1990, 1(2): 171-172
Abstract:
Sodium bisulfite could add to the central methine bridge of biliver-din in methanol,and give sodium bilirubin-10-sulfonate,however no bilirubin was formed.
Sodium bisulfite could add to the central methine bridge of biliver-din in methanol,and give sodium bilirubin-10-sulfonate,however no bilirubin was formed.
1990, 1(2): 173-174
Abstract:
A new protoilludane sesquiterpenoid aromatic ester,named armillarizin (1) has been isolated from the artificially cultured mycelium of Armillaria me-llea(Vahl.ex Fr)Quel.(Tricholomataceae).Its structure was deduced on the ba-sis of spectral analyses.The relative configuration was established from thenuclear Overhauser effects and from the values of 1H-1H coupling constants.
A new protoilludane sesquiterpenoid aromatic ester,named armillarizin (1) has been isolated from the artificially cultured mycelium of Armillaria me-llea(Vahl.ex Fr)Quel.(Tricholomataceae).Its structure was deduced on the ba-sis of spectral analyses.The relative configuration was established from thenuclear Overhauser effects and from the values of 1H-1H coupling constants.
1990, 1(2): 175-178
Abstract:
A method is developed for the simultaneous determination of ephedrine,pseudoephedrine,norephedrine,norpseudoephedrine and methylephedrine in urine on a capillary column using nitrogen-phosphorus detector.Diphenylamine is used as the internal standard.Calibration graphs are linear down to 1.30ug/ml urine.
A method is developed for the simultaneous determination of ephedrine,pseudoephedrine,norephedrine,norpseudoephedrine and methylephedrine in urine on a capillary column using nitrogen-phosphorus detector.Diphenylamine is used as the internal standard.Calibration graphs are linear down to 1.30ug/ml urine.
1990, 1(2): 179-182
Abstract:
A simple,manual solid-phase synthesis of RNA fragments using 2'-(p-methoxyben-zyl) nucleosides and phosphoramidite chemistry is described.
A simple,manual solid-phase synthesis of RNA fragments using 2'-(p-methoxyben-zyl) nucleosides and phosphoramidite chemistry is described.
1990, 1(2): 183-184
Abstract:
The configuration of [PdCl2(C2H4OH)]- has been studied by pseudopotential ab initio method.A cis isomer was found to be the reaction intermediate in the Wacker process.
The configuration of [PdCl2(C2H4OH)]- has been studied by pseudopotential ab initio method.A cis isomer was found to be the reaction intermediate in the Wacker process.
1990, 1(2): 185-186
Abstract:
Recent years,many novel complexes have been prepared by using hetero-bidentate ligands.However,complexes with such ligands as 4-vinylpyridine which has two different coordinating sites have not been reported,and only a few complexes of Cu(I) have been published1-3.The title complex Cu2(C5H4N·CH=CH2)3Cl was prepared and characterized by elemental analyses,ICP,IR,and electronic spectra.Its conductivity,oxidation potential and reduction potential were measured.
Recent years,many novel complexes have been prepared by using hetero-bidentate ligands.However,complexes with such ligands as 4-vinylpyridine which has two different coordinating sites have not been reported,and only a few complexes of Cu(I) have been published1-3.The title complex Cu2(C5H4N·CH=CH2)3Cl was prepared and characterized by elemental analyses,ICP,IR,and electronic spectra.Its conductivity,oxidation potential and reduction potential were measured.
1990, 1(2): 187-190
Abstract:
A new method for determining volatile phenols in Chinese liquors is proposed.Phenols are sorbed on a macroporous anion-exchange resin after the liquors were brought to a pH value of 12.5,then eluted with HCl-acetone,extracted with methylene dichloride and concentrated to a suitable concentration for derivatization with pentafluorobenzyl bromide (PFB).The PFB derivatives of phenols were successfully separated by gas chromatography on a 30 m SE-54 elastic glass capillary column and detected with Ni-63 electron capture detec-tor.The characteristics of this method are:high sensitivity,low interference and 95% average recovery of phenols.The method was used successfully in the determination of vola-tile phenols in eight kinds of Chinese liquors.
A new method for determining volatile phenols in Chinese liquors is proposed.Phenols are sorbed on a macroporous anion-exchange resin after the liquors were brought to a pH value of 12.5,then eluted with HCl-acetone,extracted with methylene dichloride and concentrated to a suitable concentration for derivatization with pentafluorobenzyl bromide (PFB).The PFB derivatives of phenols were successfully separated by gas chromatography on a 30 m SE-54 elastic glass capillary column and detected with Ni-63 electron capture detec-tor.The characteristics of this method are:high sensitivity,low interference and 95% average recovery of phenols.The method was used successfully in the determination of vola-tile phenols in eight kinds of Chinese liquors.
