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2002 Volume 13 Issue 7
2002, 13(7): 589-592
Abstract:
Catalyzed by zinc bromide, tetrahydrofuran ring can be opened with acyloxyphos-phonium bromide gcneratcd in situ to afford 4-bromobutyl csters under mild conditions in good to cxccllcnt yields.
Catalyzed by zinc bromide, tetrahydrofuran ring can be opened with acyloxyphos-phonium bromide gcneratcd in situ to afford 4-bromobutyl csters under mild conditions in good to cxccllcnt yields.
2002, 13(7): 593-596
Abstract:
Several isoxazoline compounds were obtained by the 1,3-dipolar cycloaddition of benzonitrile oxide to 5-(R)-(l-menthyloxy)-2(5H)-furanone. The reaction condition was investigated preliminarily, the structures of these compounds have been establishcd via the analysis of NMR data (involved NOEID or HMBC) and the reaction seems occurred regioselectively.
Several isoxazoline compounds were obtained by the 1,3-dipolar cycloaddition of benzonitrile oxide to 5-(R)-(l-menthyloxy)-2(5H)-furanone. The reaction condition was investigated preliminarily, the structures of these compounds have been establishcd via the analysis of NMR data (involved NOEID or HMBC) and the reaction seems occurred regioselectively.
2002, 13(7): 597-600
Abstract:
Pyridinium ylids 4 were generated as reaction intermediates from the decarboxylation of pyridinium bctaincs 3, which were preparcd from the reactions of α-amino acid ester hydrochlorides with 2,4,6-triphenylpyrylium tetrafluoroborate. Protonation, addition and substitution reactions of 4 with electrophiles werc studied in this paper.
Pyridinium ylids 4 were generated as reaction intermediates from the decarboxylation of pyridinium bctaincs 3, which were preparcd from the reactions of α-amino acid ester hydrochlorides with 2,4,6-triphenylpyrylium tetrafluoroborate. Protonation, addition and substitution reactions of 4 with electrophiles werc studied in this paper.
2002, 13(7): 601-604
Abstract:
Some oligopeptidcs and peptoids were synthesized by applying the organophosphorus compound DEPBT as a coupling rcagent. D-Biotin-OOBt was obtained unexpcctcdly. A proposed reaction mechanism for DEPBT-mediated coupling was proved.
Some oligopeptidcs and peptoids were synthesized by applying the organophosphorus compound DEPBT as a coupling rcagent. D-Biotin-OOBt was obtained unexpcctcdly. A proposed reaction mechanism for DEPBT-mediated coupling was proved.
2002, 13(7): 605-606
Abstract:
Four pyrylium salts, (2,6-diphenyl-4-arylpyrylium tetrafluoroborate, aryl=C6H5, 4-MeO C6H4, 4-Me2NC6H4, 4-NO2C6H4) were synthesized efficiently and economically from acctophenone and substituted chalcones in the presence of borontrifluoride.
Four pyrylium salts, (2,6-diphenyl-4-arylpyrylium tetrafluoroborate, aryl=C6H5, 4-MeO C6H4, 4-Me2NC6H4, 4-NO2C6H4) were synthesized efficiently and economically from acctophenone and substituted chalcones in the presence of borontrifluoride.
2002, 13(7): 607-608
Abstract:
High molecular weight copoly(ether ketone)s (PEK) based on 4-(4-hydroxyphenyl)-l-phthalazinone (DHPZ)/4,4'-thiobisphenol (TBP)/4,4'-diflourodiphenylketone (DFK) were prepared by nuclcophilic substitution polycondcnsation. The copolymers were characterized by FT-IR and 1H-NMR. Thermal properties and solubility of copolymers were studied.
High molecular weight copoly(ether ketone)s (PEK) based on 4-(4-hydroxyphenyl)-l-phthalazinone (DHPZ)/4,4'-thiobisphenol (TBP)/4,4'-diflourodiphenylketone (DFK) were prepared by nuclcophilic substitution polycondcnsation. The copolymers were characterized by FT-IR and 1H-NMR. Thermal properties and solubility of copolymers were studied.
2002, 13(7): 609-612
Abstract:
Synthesis of the third-order nonlinear materials:bis (l,4-dihydroxynaphthalene) tetrathiafulvalene and bis (1,4-dialkoxylnaphthalene) tetrathiafulvalene has been achieved in four steps, starting from 2,3-dichloro-l,4-naphthaquinone. The matcrials exhibit larger third-order nonlinear optical susceptibilities χ(3).
Synthesis of the third-order nonlinear materials:bis (l,4-dihydroxynaphthalene) tetrathiafulvalene and bis (1,4-dialkoxylnaphthalene) tetrathiafulvalene has been achieved in four steps, starting from 2,3-dichloro-l,4-naphthaquinone. The matcrials exhibit larger third-order nonlinear optical susceptibilities χ(3).
2002, 13(7): 613-616
Abstract:
A series of pyrazolo[3,4-d] pyrimidin-4-one derivatives were synthesized and tested for vasodilatory activities. All of them were new compounds and their structures were confirmed by IR, 1H NMR, MS and elemental analysis.
A series of pyrazolo[3,4-d] pyrimidin-4-one derivatives were synthesized and tested for vasodilatory activities. All of them were new compounds and their structures were confirmed by IR, 1H NMR, MS and elemental analysis.
2002, 13(7): 617-619
Abstract:
(-)-Menthol reacts with phosphorus trichloride to afford menthyl phosphorodichloridite 2,which further reacts with racemic 1, 1'-binaphthalene-2, 2'-diol to give phosphite (±)-3 in the presence of triethylamine. (±)-3 can be easily separated by fractional crystallization to form the crystal (+)-(S)-3 and the mother liquor (-)-(R)-3. Then both the crystal and the mother liquor are treated with AcOH-H20 to obtain enantiomeric pure (-)-(S)-1 and (+)-(R)-1 respectively, with enantiomeric excess up to 99.7%.
(-)-Menthol reacts with phosphorus trichloride to afford menthyl phosphorodichloridite 2,which further reacts with racemic 1, 1'-binaphthalene-2, 2'-diol to give phosphite (±)-3 in the presence of triethylamine. (±)-3 can be easily separated by fractional crystallization to form the crystal (+)-(S)-3 and the mother liquor (-)-(R)-3. Then both the crystal and the mother liquor are treated with AcOH-H20 to obtain enantiomeric pure (-)-(S)-1 and (+)-(R)-1 respectively, with enantiomeric excess up to 99.7%.
2002, 13(7): 620-622
Abstract:
Two new dibenzofurans, 7,8-dimethoxy-4-methyldibenzofuran-l-carboxaldehyde,named ligumedial (1) and 7,8-dimethoxy-4-methyldibenzofuran-l-carboxylic acid, named ligumcdiaoic acid (2), have been isolated from the underground parts of Ligularia intermedia.Their structures were clucidated by spectroscopic methods.
Two new dibenzofurans, 7,8-dimethoxy-4-methyldibenzofuran-l-carboxaldehyde,named ligumedial (1) and 7,8-dimethoxy-4-methyldibenzofuran-l-carboxylic acid, named ligumcdiaoic acid (2), have been isolated from the underground parts of Ligularia intermedia.Their structures were clucidated by spectroscopic methods.
2002, 13(7): 623-624
Abstract:
A new xanthone, 1,2-dihydro-3,6,8-trihydroxy-1,l-bis (3-methylbut-2-enyl)-5-(l,1-dimcthylprop-2-enyl)-xanthen-2,9-dione (1), has been isolated from the aerial part of Hypericum erectum.
A new xanthone, 1,2-dihydro-3,6,8-trihydroxy-1,l-bis (3-methylbut-2-enyl)-5-(l,1-dimcthylprop-2-enyl)-xanthen-2,9-dione (1), has been isolated from the aerial part of Hypericum erectum.
2002, 13(7): 625-628
Abstract:
An aqucous acidic polysaccharide, named rhamnogalacturonan (designated as TTP-D2)was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 was estimated to be 26 KDa by gel filtration. TTP-D2 is composed of galacturonic acid, rhamnose, arabinose, galactose, fucose, mannosc, xylose and glucose in a ratio of 71.4:13.5:5.6:4.9:3.1:1.9:1.9:1.0. The main chain structure of TTP-D2 was elucidated as an acidic hetero-polysaccharidc with the connection of α-(l-4) galacturonic acid with α-(1-3) rhamnose by GC analysis of partially hydrolyzed products and the determination of 1H, 13C-NMR spectra.
An aqucous acidic polysaccharide, named rhamnogalacturonan (designated as TTP-D2)was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 was estimated to be 26 KDa by gel filtration. TTP-D2 is composed of galacturonic acid, rhamnose, arabinose, galactose, fucose, mannosc, xylose and glucose in a ratio of 71.4:13.5:5.6:4.9:3.1:1.9:1.9:1.0. The main chain structure of TTP-D2 was elucidated as an acidic hetero-polysaccharidc with the connection of α-(l-4) galacturonic acid with α-(1-3) rhamnose by GC analysis of partially hydrolyzed products and the determination of 1H, 13C-NMR spectra.
2002, 13(7): 629-632
Abstract:
Two new spirostanol glycosides named agamenoside A and B, were isolated from the fcrmcnted leaves of Agave americana. Their structures were elucidated as (23S, 25R)-5α-spirostan-3β, 6α, 23-triol 3-O-α-L-rhamnopyranosyl-(1→3)-β-D-glucopyranosyl-(l→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyranosyl-(l→4)-β-D-galactopyranoside (1) and (25R)-5α-spiro stan-3β, 6α-diol 3-O-β-D-glucopyranosyl-(l→2)-[β-D-xylopyranosyl-(l→3)]-β-D-glucopyra nosyl-(1→4)-β-D-galactopyranoside (2) by a combination of chemical and spectral methods.
Two new spirostanol glycosides named agamenoside A and B, were isolated from the fcrmcnted leaves of Agave americana. Their structures were elucidated as (23S, 25R)-5α-spirostan-3β, 6α, 23-triol 3-O-α-L-rhamnopyranosyl-(1→3)-β-D-glucopyranosyl-(l→2)-[β-D-xylopyranosyl-(1→3)]-β-D-glucopyranosyl-(l→4)-β-D-galactopyranoside (1) and (25R)-5α-spiro stan-3β, 6α-diol 3-O-β-D-glucopyranosyl-(l→2)-[β-D-xylopyranosyl-(l→3)]-β-D-glucopyra nosyl-(1→4)-β-D-galactopyranoside (2) by a combination of chemical and spectral methods.
2002, 13(7): 633-636
Abstract:
Two new C27 steroidal glycosides, named taccaoside A (1) and B (2), were isolated from the traditional Chinese herb Tacca plantaginea. The spectroscopic and chemical evidences revealed their structures to be 26-O-β-D-glucopyranosyl-(25R)-3β,26-dihydroxy furost-5,20-diene-3-O-[α-L-rhamnopyranosyl(l→2)]-[α-L-rhamnopyranosyl(1→3)]-β-D-glucopyranoside (1) and 26-O-β-D-glucopyranosyl-(25R)-3β,26-dihydroxy furost-5,20-diene-3-O-[α-L-rhamnopyranosyl (1→2)]-[β-D-gl ucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→3)]-β-D-gl ucopyranoside (2), res pectively.
Two new C27 steroidal glycosides, named taccaoside A (1) and B (2), were isolated from the traditional Chinese herb Tacca plantaginea. The spectroscopic and chemical evidences revealed their structures to be 26-O-β-D-glucopyranosyl-(25R)-3β,26-dihydroxy furost-5,20-diene-3-O-[α-L-rhamnopyranosyl(l→2)]-[α-L-rhamnopyranosyl(1→3)]-β-D-glucopyranoside (1) and 26-O-β-D-glucopyranosyl-(25R)-3β,26-dihydroxy furost-5,20-diene-3-O-[α-L-rhamnopyranosyl (1→2)]-[β-D-gl ucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→3)]-β-D-gl ucopyranoside (2), res pectively.
2002, 13(7): 637-640
Abstract:
A new triterpenoid saponin was isolated by bioactivity-guided isolation from "Gualou-xiebai-baijiu-tang" consisting of Fructus trichosanthisi and Bulbus allii macrostemi. Its structure was determined as 3-O-β-D-galactopyranosyl-hederagenin 28-O-β-D-xylopyranosyl (1→6)-β-D-galactopyranosyl ester by means of chemical evidences and spectral analysis.
A new triterpenoid saponin was isolated by bioactivity-guided isolation from "Gualou-xiebai-baijiu-tang" consisting of Fructus trichosanthisi and Bulbus allii macrostemi. Its structure was determined as 3-O-β-D-galactopyranosyl-hederagenin 28-O-β-D-xylopyranosyl (1→6)-β-D-galactopyranosyl ester by means of chemical evidences and spectral analysis.
2002, 13(7): 641-644
Abstract:
A new diterpenoid was isolated from the ethanolic extract of the dried root bark of Tripterygium wilfordii Hook.f. It is the first example of abietane diterpenoid glycoside isolated from Tripterygium wilfordii Hook.f. Its structure was identified to be 11-O-β-D-glucopyranosyl neotriptophenolide based on spectral methods.
A new diterpenoid was isolated from the ethanolic extract of the dried root bark of Tripterygium wilfordii Hook.f. It is the first example of abietane diterpenoid glycoside isolated from Tripterygium wilfordii Hook.f. Its structure was identified to be 11-O-β-D-glucopyranosyl neotriptophenolide based on spectral methods.
2002, 13(7): 645-648
Abstract:
By means of variable temperature NMR spectra, conformation of 8-C-glucosyl prunetin,isolated from the leaves of Dalbergia hainanensis (Leguminosae), was studied. The restricted rotation around the C (sp3)-C (sp2) bond in the C-glucosides isoflavonoid results in two main conformers (syn and anti). With the help of MM calculation, the preferred conformation A has H-I" gauche to the 7-OCH3. The barrier to rotation was 18.1 kcal/mol. This result agrees with the calculated value 16.2 kcal/mol of free energy of activation for the interconversion between the conformers.
By means of variable temperature NMR spectra, conformation of 8-C-glucosyl prunetin,isolated from the leaves of Dalbergia hainanensis (Leguminosae), was studied. The restricted rotation around the C (sp3)-C (sp2) bond in the C-glucosides isoflavonoid results in two main conformers (syn and anti). With the help of MM calculation, the preferred conformation A has H-I" gauche to the 7-OCH3. The barrier to rotation was 18.1 kcal/mol. This result agrees with the calculated value 16.2 kcal/mol of free energy of activation for the interconversion between the conformers.
2002, 13(7): 649-652
Abstract:
A new method for the preparation of an organic-inorganic composite fihm of the heteropolyanion has been developed by modifying P(Mo2O7)6-7 to the indium tin oxide (ITO) electrode surface. The modified electrode displayed a strong catalytic activity towards the reduction of IO3-. In the range of 1.0×l0-6~5×l0-4mol/L, the catalytic current was linear proportional to the IO3- concentration.
A new method for the preparation of an organic-inorganic composite fihm of the heteropolyanion has been developed by modifying P(Mo2O7)6-7 to the indium tin oxide (ITO) electrode surface. The modified electrode displayed a strong catalytic activity towards the reduction of IO3-. In the range of 1.0×l0-6~5×l0-4mol/L, the catalytic current was linear proportional to the IO3- concentration.
2002, 13(7): 653-654
Abstract:
Electrochemistry of nitrate reductases (NR) incorporated into 2-aminoethanethiol self-assembled on the gold electrode and polyacrylamide east on the pyrolytic graphite electrode was cxamined. NR on chemical modified electrode showed electrochcmical cyclic voltammetric responses in phosphate buffers.
Electrochemistry of nitrate reductases (NR) incorporated into 2-aminoethanethiol self-assembled on the gold electrode and polyacrylamide east on the pyrolytic graphite electrode was cxamined. NR on chemical modified electrode showed electrochcmical cyclic voltammetric responses in phosphate buffers.
2002, 13(7): 655-657
Abstract:
A novel method for detcrmination of amino acids in individual human red blood cells has been dcveloped. In this method, the derivatization reagents (NDA and CN-) are introduced into living cells by clcctroporation. After completion of derivatization, the amino acids in a single cell is determined by capillary zone electrophoresis with end-column ampcrometric detection.
A novel method for detcrmination of amino acids in individual human red blood cells has been dcveloped. In this method, the derivatization reagents (NDA and CN-) are introduced into living cells by clcctroporation. After completion of derivatization, the amino acids in a single cell is determined by capillary zone electrophoresis with end-column ampcrometric detection.
2002, 13(7): 658-659
Abstract:
A multi-phase model of Pr(Ⅲ) speciation in human interstitial fluid was constructed and insoluble Pr(Ⅲ) speciation was studied. When the total concentration of Pr(Ⅲ) is below 8.401E-10 mol/L, soluble Pr(Ⅲ) species are main species. With rising the total concentration of Pr(Ⅲ), Pr(Ⅲ) is firstly bound to phosphate to form precipitate of PrPO4, then bound to carbonate and another precipitate of Pr2(CO3)3 was obtained. When the total concentration is between 1.583E-9 mol/L and 4.000E-3 mol/L, the insoluble species are predominant Pr(Ⅲ) species.
A multi-phase model of Pr(Ⅲ) speciation in human interstitial fluid was constructed and insoluble Pr(Ⅲ) speciation was studied. When the total concentration of Pr(Ⅲ) is below 8.401E-10 mol/L, soluble Pr(Ⅲ) species are main species. With rising the total concentration of Pr(Ⅲ), Pr(Ⅲ) is firstly bound to phosphate to form precipitate of PrPO4, then bound to carbonate and another precipitate of Pr2(CO3)3 was obtained. When the total concentration is between 1.583E-9 mol/L and 4.000E-3 mol/L, the insoluble species are predominant Pr(Ⅲ) species.
2002, 13(7): 660-661
Abstract:
Diphenylcarbazine citrate was synthesized and a high-speed color reaction of the new reagent with Cr (VI) was developed and used to determine trace Cr (VI) in elcctroplating water.In acid medium, diphenylcarbazine citrate reacted with Cr (VI) to form a magenta-colored complex.The molar absorptivity of the complex is 3.32×104 L·mol-1·cm-1 at 540 nm. Beer's law is obeyed for Cr (VI) in the range of 0.03~2.00 mg/L. Contents of Cr (VI) in electroplating waste water was determined in-situ and satisfactory results were obtained.
Diphenylcarbazine citrate was synthesized and a high-speed color reaction of the new reagent with Cr (VI) was developed and used to determine trace Cr (VI) in elcctroplating water.In acid medium, diphenylcarbazine citrate reacted with Cr (VI) to form a magenta-colored complex.The molar absorptivity of the complex is 3.32×104 L·mol-1·cm-1 at 540 nm. Beer's law is obeyed for Cr (VI) in the range of 0.03~2.00 mg/L. Contents of Cr (VI) in electroplating waste water was determined in-situ and satisfactory results were obtained.
2002, 13(7): 662-665
Abstract:
The hydrogen abstraction reaction of O (3P) with Si2H6 has been studied theoretically.Two transition states of 3A" and 3A' symmetries have been located for this abstraction reaction.Geometries have been optimized at the UMP2 level with 6-311G+(d) basis set. G3MP2 has been used for the final single-point energy calculation. The rate constants have been calculated over a wide temperature range of 200~3000 K using canonical variational transition-state theory (CVT) with small curvature tunneling effect (SCT). The calculated CVT/SCT rate constants match well with the experimental value.
The hydrogen abstraction reaction of O (3P) with Si2H6 has been studied theoretically.Two transition states of 3A" and 3A' symmetries have been located for this abstraction reaction.Geometries have been optimized at the UMP2 level with 6-311G+(d) basis set. G3MP2 has been used for the final single-point energy calculation. The rate constants have been calculated over a wide temperature range of 200~3000 K using canonical variational transition-state theory (CVT) with small curvature tunneling effect (SCT). The calculated CVT/SCT rate constants match well with the experimental value.
2002, 13(7): 666-669
Abstract:
The reduction ofperfluorodecalin was studied by the method of electrochemistry. The results indicated that the electrochemical reduction of perfluorodecalin was a multi-step reaction.The mechanism of the first consecutive reaction showed that it is to diffusion controlling step.
The reduction ofperfluorodecalin was studied by the method of electrochemistry. The results indicated that the electrochemical reduction of perfluorodecalin was a multi-step reaction.The mechanism of the first consecutive reaction showed that it is to diffusion controlling step.
2002, 13(7): 670-673
Abstract:
The air-solution equilibrium tension γe and dynamic surface tension γt, of nonionic surfactant alkyl polyglucoside have been studied. γe was measured by the Wilhelmy method with Krüss K12 tensiometer. The CMC and the surface excesses l' were determined from the surface tension vs. concentration curve. The γt decays were measured in the range 0.2~20 s using a maximum bubble pressure instrument and analyzed with the Ward and Tordai cquation.
The air-solution equilibrium tension γe and dynamic surface tension γt, of nonionic surfactant alkyl polyglucoside have been studied. γe was measured by the Wilhelmy method with Krüss K12 tensiometer. The CMC and the surface excesses l' were determined from the surface tension vs. concentration curve. The γt decays were measured in the range 0.2~20 s using a maximum bubble pressure instrument and analyzed with the Ward and Tordai cquation.
2002, 13(7): 674-677
Abstract:
A novel blue luminescent polymer bearing coumarin pendants was prepared. Its luminescent properties were determined indicating that it had strong blue fluorescent properties and good film formation ability. This novel polymer can be used as a blue organic electroluminescent material (OELM) in organic electroluminescent devices.
A novel blue luminescent polymer bearing coumarin pendants was prepared. Its luminescent properties were determined indicating that it had strong blue fluorescent properties and good film formation ability. This novel polymer can be used as a blue organic electroluminescent material (OELM) in organic electroluminescent devices.
2002, 13(7): 678-680
Abstract:
In this paper, the helix-sense-selective polymerization of N,N-diphenyl acrylamide (DPAA) and N,N-diphenyl methacrylamide (DPMAA) were studied with living helix prepolymer as anionic initiator, and the chiral optical properties of the obtained polymers were investigated too.It was shown that optically active polymers of DPAA and DPMAA could be obtained under the experimental condition, and exhibited the same screw sense as that of the prepolymer.
In this paper, the helix-sense-selective polymerization of N,N-diphenyl acrylamide (DPAA) and N,N-diphenyl methacrylamide (DPMAA) were studied with living helix prepolymer as anionic initiator, and the chiral optical properties of the obtained polymers were investigated too.It was shown that optically active polymers of DPAA and DPMAA could be obtained under the experimental condition, and exhibited the same screw sense as that of the prepolymer.
2002, 13(7): 681-682
Abstract:
Polymerization of 4-vinylpyridine was carried out with the lanthanide coordination catalyst. The influence of the component in catalytic system and solvents had been examined.The molecular weight of poly(4-vinylpyridinc) obtained in CH2Cl2 with Ln(P204)3/Al(i-Bu)3 is more than 20×104.
Polymerization of 4-vinylpyridine was carried out with the lanthanide coordination catalyst. The influence of the component in catalytic system and solvents had been examined.The molecular weight of poly(4-vinylpyridinc) obtained in CH2Cl2 with Ln(P204)3/Al(i-Bu)3 is more than 20×104.
2002, 13(7): 683-684
Abstract:
The heterogeneous free-radical polymerization of methyl methylacrylatc (MMA) and divinylbenzene (DVB) as cross-linker within supercritical carbon dioxide-swollen silicon rubber (SR) has been studied as an approach to preparing semi-interpenetrating polymer network (semi-IPN) of SR and poly(methyl methylacrylate) (PMMA). The SR/PMMA semi-IPNs were characterized by scanning electron microscopy (SEM) and dynamic mechanical analyzer (DMA).
The heterogeneous free-radical polymerization of methyl methylacrylatc (MMA) and divinylbenzene (DVB) as cross-linker within supercritical carbon dioxide-swollen silicon rubber (SR) has been studied as an approach to preparing semi-interpenetrating polymer network (semi-IPN) of SR and poly(methyl methylacrylate) (PMMA). The SR/PMMA semi-IPNs were characterized by scanning electron microscopy (SEM) and dynamic mechanical analyzer (DMA).
2002, 13(7): 685-686
Abstract:
Copolymerization of styrene (St) with N-phenylmaleimide (NPMI) was studied with rare earth coordination catalyst Nd(naph)3-AlEt3 in toluene. Characterization of the copolymers showed that the copolymers possess an alternating structure.
Copolymerization of styrene (St) with N-phenylmaleimide (NPMI) was studied with rare earth coordination catalyst Nd(naph)3-AlEt3 in toluene. Characterization of the copolymers showed that the copolymers possess an alternating structure.
2002, 13(7): 687-688
Abstract:
A new activation method has been developed for electroless copper plating on silicon wafer based on palladium chemisorption on SAMs of APTS without SnCl2 sensitization and roughening condition. A closely packed electroless copper film with strong adhesion is successfully fonned by AFM observation. XPS study indicates that palladium chemisorption occurred via palladium chloride bonding to the pendant amino group of the SAMs.
A new activation method has been developed for electroless copper plating on silicon wafer based on palladium chemisorption on SAMs of APTS without SnCl2 sensitization and roughening condition. A closely packed electroless copper film with strong adhesion is successfully fonned by AFM observation. XPS study indicates that palladium chemisorption occurred via palladium chloride bonding to the pendant amino group of the SAMs.
2002, 13(7): 689-692
Abstract:
Self-ordering of the cell arrangement of the anodic porous alumina was prepared in oxalic acid solution at a constant potential of 40V and at a temperature of 20℃. The honeycomb structure made by one step anodization method and two step anodization method is different.Pores in the alumina film prepared by two step anodization method were more ordered than those by one step anodization method.
Self-ordering of the cell arrangement of the anodic porous alumina was prepared in oxalic acid solution at a constant potential of 40V and at a temperature of 20℃. The honeycomb structure made by one step anodization method and two step anodization method is different.Pores in the alumina film prepared by two step anodization method were more ordered than those by one step anodization method.
2002, 13(7): 693-694
Abstract:
The absorption spectra of the neodymium, holmium and erbium complexes with 1-cyclopropyl-6-fluoro-l,4-dihydro-7-(4-ethyl-l-piperazinyl)-4-oxo-3-quinoline carboxylic acid hydrochloride in the presence of TX-100 have been shown. The characteristic absorption bands of the 4f electron transitions of the complexes are enhanced markedly.
The absorption spectra of the neodymium, holmium and erbium complexes with 1-cyclopropyl-6-fluoro-l,4-dihydro-7-(4-ethyl-l-piperazinyl)-4-oxo-3-quinoline carboxylic acid hydrochloride in the presence of TX-100 have been shown. The characteristic absorption bands of the 4f electron transitions of the complexes are enhanced markedly.
2002, 13(7): 695-698
Abstract:
A novel complex of monomeric thallium(Ⅲ) with the nitrogen donor ligand phenanthroline (phen) has been prepared and characterized by multinuclear NMR (1H, 13C, 205Tl).The three complexes exist in equilibria in DMSO and acetonitrile solution, which was proved by the 205Tl NMR spectra. The 1H and 13C NMR spectra of tris-phen Tl(Ⅲ) complex have been measured, where the spin-spin coupling between Tl (l=1/2) and 13C or 1H signals were observed with the 1H and 13C NMR spectroscopy in acetonitrile. The coupling constants are presented and the chemical shifts of complexes are discussed in detail.
A novel complex of monomeric thallium(Ⅲ) with the nitrogen donor ligand phenanthroline (phen) has been prepared and characterized by multinuclear NMR (1H, 13C, 205Tl).The three complexes exist in equilibria in DMSO and acetonitrile solution, which was proved by the 205Tl NMR spectra. The 1H and 13C NMR spectra of tris-phen Tl(Ⅲ) complex have been measured, where the spin-spin coupling between Tl (l=1/2) and 13C or 1H signals were observed with the 1H and 13C NMR spectroscopy in acetonitrile. The coupling constants are presented and the chemical shifts of complexes are discussed in detail.
