Login In
2008 Volume 19 Issue 4
2008, 19(4): 379-382
doi: 10.1016/j.cclet.2008.01.032
Abstract:
A series of 2, 4, 5-triaryl substituted 1H-pyrazol-3(2H)-ones, as ALK5 inhibitors, were desigened, synthesized and evaluated in vitro.Most compounds exhibited noticeable ALK5 inhibition activities at 1 μmol/L and displayed no significant cytotoxicities at 30 μmol/L.
A series of 2, 4, 5-triaryl substituted 1H-pyrazol-3(2H)-ones, as ALK5 inhibitors, were desigened, synthesized and evaluated in vitro.Most compounds exhibited noticeable ALK5 inhibition activities at 1 μmol/L and displayed no significant cytotoxicities at 30 μmol/L.
2008, 19(4): 383-386
doi: 10.1016/j.cclet.2008.01.025
Abstract:
Two species of N-arylpyrazoles containing active amino group were synthesized.And formylations of N-arylpyazoles containing amino in different position of pyrazole rings using Vilsmeier-Hacck reaction gave a series of useful pyrazole intermediates.The important features of this protocol were cheap materials, easy process, mild reaction conditions and good yield of products.
Two species of N-arylpyrazoles containing active amino group were synthesized.And formylations of N-arylpyazoles containing amino in different position of pyrazole rings using Vilsmeier-Hacck reaction gave a series of useful pyrazole intermediates.The important features of this protocol were cheap materials, easy process, mild reaction conditions and good yield of products.
2008, 19(4): 387-389
doi: 10.1016/j.cclet.2008.01.024
Abstract:
Five new C-8 Mannich base derivatives of irisolidone 2a-2e were synthesized and their nitric oxide (NO) production inhibitory activity was evaluated.Compounds 2a, 2b, 2c and 2e displayed stronger activities in vitro than the parent compound irisolidone.
Five new C-8 Mannich base derivatives of irisolidone 2a-2e were synthesized and their nitric oxide (NO) production inhibitory activity was evaluated.Compounds 2a, 2b, 2c and 2e displayed stronger activities in vitro than the parent compound irisolidone.
2008, 19(4): 390-394
doi: 10.1016/j.cclet.2008.01.033
Abstract:
2, 6-Diisopropylnaphthalene (2, 6-DIPN), as the precursor of important monomer 2, 6-naphthalene dicarboxylic acid, was prepared by hydroisopropylation of refined naphthalene with propene over shape-selective catalyst.Naphthalene conversion of 92% and 2, 6-DIPN selectivity of 64% were obtained.Static melt crystallization was applied to separate and purify 2, 6-DIPN from its isomers, resulted in a product purity of ≥99%.The other isomers were converted into monoisopropylnaphthalene, which also reacted with propcne to form 2, 6-DIPN.A recycled process including hydroisopropylation, separation and transalkylation was established, the yield of 2, 6-DIPN based on naphthalene could be doubled by one cycle operation.
2, 6-Diisopropylnaphthalene (2, 6-DIPN), as the precursor of important monomer 2, 6-naphthalene dicarboxylic acid, was prepared by hydroisopropylation of refined naphthalene with propene over shape-selective catalyst.Naphthalene conversion of 92% and 2, 6-DIPN selectivity of 64% were obtained.Static melt crystallization was applied to separate and purify 2, 6-DIPN from its isomers, resulted in a product purity of ≥99%.The other isomers were converted into monoisopropylnaphthalene, which also reacted with propcne to form 2, 6-DIPN.A recycled process including hydroisopropylation, separation and transalkylation was established, the yield of 2, 6-DIPN based on naphthalene could be doubled by one cycle operation.
2008, 19(4): 395-398
doi: 10.1016/j.cclet.2007.12.024
Abstract:
In this paper, aliphatic amidediol was synthesized and mixed with glycerol used as a plasticizer for preparing thermoplastic starch (AGPTPS).The yield of aliphatic amidediol was 91%.FT-IR expressed that the mixture of aliphatic amidediol and glycerol formed stronger and stable hydrogen bond with starch molecules compared to the native cornstarch.By scanning electron microscope (SEM) native cornstarch granules were proved to transfer to a homogeneous continuous system.After being stored for a period time at room temperature, the mechanical properties of AGPTPS were also studied.As a mixed plasticizer, aliphatic amidediol and glycerol would be practical to extend TPS application scopes.
In this paper, aliphatic amidediol was synthesized and mixed with glycerol used as a plasticizer for preparing thermoplastic starch (AGPTPS).The yield of aliphatic amidediol was 91%.FT-IR expressed that the mixture of aliphatic amidediol and glycerol formed stronger and stable hydrogen bond with starch molecules compared to the native cornstarch.By scanning electron microscope (SEM) native cornstarch granules were proved to transfer to a homogeneous continuous system.After being stored for a period time at room temperature, the mechanical properties of AGPTPS were also studied.As a mixed plasticizer, aliphatic amidediol and glycerol would be practical to extend TPS application scopes.
2008, 19(4): 399-402
doi: 10.1016/j.cclet.2008.01.034
Abstract:
A new and practical method of the D301 resin, a weak basic anion exchange resin with secondary amine functionality (Grade Matrix Structure:Styrene-DVB D301R), used as base to Heck reactions catalyzed by palladium reagent without phosphine compound as ligand is described.It was found that the D301 resin used as base is an efficient and reusable base and can be regenerated and recycled in the reaction.The olefination of heteroaryl halides prepared the corresponding products in good yields using D301 resin as base.
A new and practical method of the D301 resin, a weak basic anion exchange resin with secondary amine functionality (Grade Matrix Structure:Styrene-DVB D301R), used as base to Heck reactions catalyzed by palladium reagent without phosphine compound as ligand is described.It was found that the D301 resin used as base is an efficient and reusable base and can be regenerated and recycled in the reaction.The olefination of heteroaryl halides prepared the corresponding products in good yields using D301 resin as base.
2008, 19(4): 403-405
doi: 10.1016/j.cclet.2008.01.039
Abstract:
Two representative macrocyclic lactones with methoxysulfonyl side chain (5a and 5b) were synthesized employing Michael addition with acrolein and ring enlargement as the key steps, starting from potassium α-oxocycloalkylsulfonates (1) in total yields of 45 and 57%, respectively.
Two representative macrocyclic lactones with methoxysulfonyl side chain (5a and 5b) were synthesized employing Michael addition with acrolein and ring enlargement as the key steps, starting from potassium α-oxocycloalkylsulfonates (1) in total yields of 45 and 57%, respectively.
2008, 19(4): 406-408
doi: 10.1016/j.cclet.2008.01.014
Abstract:
A serial of novel cercaricides that can self-diffuse on the water surface were designed and synthesized according to the special habit of cercariae larvae.These compounds were derived from niphensamide.While the compounds were dropped on the surface of water, the liquor diffused along the air-water interface and formed thin membranes floating on the water surface immediately.The strong cercaricidal activities against the cercariae larvae of Schistosome japonicum of these compounds have been revealed by further experiments.
A serial of novel cercaricides that can self-diffuse on the water surface were designed and synthesized according to the special habit of cercariae larvae.These compounds were derived from niphensamide.While the compounds were dropped on the surface of water, the liquor diffused along the air-water interface and formed thin membranes floating on the water surface immediately.The strong cercaricidal activities against the cercariae larvae of Schistosome japonicum of these compounds have been revealed by further experiments.
2008, 19(4): 409-411
doi: 10.1016/j.cclet.2008.01.040
Abstract:
In order to develop new antibiotics effective against resistant bacteria, a series of novel 15-membered macrolide derivatives were designed and synthesized by the modification of hydroxyl groups at C-11, C-12 and C-4" positions.Their structures were confirmed by MS, IR, 1H NMR or 13C NMR.
In order to develop new antibiotics effective against resistant bacteria, a series of novel 15-membered macrolide derivatives were designed and synthesized by the modification of hydroxyl groups at C-11, C-12 and C-4" positions.Their structures were confirmed by MS, IR, 1H NMR or 13C NMR.
2008, 19(4): 412-414
doi: 10.1016/j.cclet.2008.01.017
Abstract:
A series of 3-(4-arylpiperazin-1-yl)-l-(benzo[b]thiopben-3-yl)-2-methylpropanol derivatives were designed and synthesized based on 5-HT1A/SSRI drugs design strategies.The synthesized compounds were evaluated for their dual 5-HT1A/5-HTT activities.
A series of 3-(4-arylpiperazin-1-yl)-l-(benzo[b]thiopben-3-yl)-2-methylpropanol derivatives were designed and synthesized based on 5-HT1A/SSRI drugs design strategies.The synthesized compounds were evaluated for their dual 5-HT1A/5-HTT activities.
2008, 19(4): 415-418
doi: 10.1016/j.cclet.2008.01.028
Abstract:
An efficient synthesis of α-D-GlcpNAc-(1→2)-[α-D-ManpNAc-(1→3)-]α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap (1), the repeating unit of the O10 antigen from Acinetobacter baumannii was achieved via sequential assembly of the building blocks, p-methoxylphenyl 2, 4-di-O-benzoyl-α-L-rhamnopyranoside (2);2-O-allyloxycarbonyl-3, 4-di-O-benzoyl-α-L-rhanmopyranosyl trichloroacetimidate (3);4-methoxylphenyl 3-O-allyloxycarbonyl-4-O-benzoyl-α-L-rhamnopyranoside (4);2-azido-3-O-benzoyl-2-deoxy-4, 6-O-isopropylidene-α-D-mannopyranosyl trichloroacetimidate (5);2-azido-3, 4, 6-tri-O-benzoyl-2-deoxy-α, β-D-glucopyrano syl trichloroacetimidate (6).The total yield of 1 from 4 was 4.7%.
An efficient synthesis of α-D-GlcpNAc-(1→2)-[α-D-ManpNAc-(1→3)-]α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap (1), the repeating unit of the O10 antigen from Acinetobacter baumannii was achieved via sequential assembly of the building blocks, p-methoxylphenyl 2, 4-di-O-benzoyl-α-L-rhamnopyranoside (2);2-O-allyloxycarbonyl-3, 4-di-O-benzoyl-α-L-rhanmopyranosyl trichloroacetimidate (3);4-methoxylphenyl 3-O-allyloxycarbonyl-4-O-benzoyl-α-L-rhamnopyranoside (4);2-azido-3-O-benzoyl-2-deoxy-4, 6-O-isopropylidene-α-D-mannopyranosyl trichloroacetimidate (5);2-azido-3, 4, 6-tri-O-benzoyl-2-deoxy-α, β-D-glucopyrano syl trichloroacetimidate (6).The total yield of 1 from 4 was 4.7%.
2008, 19(4): 419-422
doi: 10.1016/j.cclet.2008.01.042
Abstract:
To explore the better prodrug of 4-aminosalicylic acid (4-ASA) with higher activity and less side effects against the inflammatory bowel disease.4-ASA, after a succession of synthesis process, was conjugated with various carrier molecules to get seven azo derivatives of 4-ASA.All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectras in detail.New derivatives of 4-ASA were definituded.
To explore the better prodrug of 4-aminosalicylic acid (4-ASA) with higher activity and less side effects against the inflammatory bowel disease.4-ASA, after a succession of synthesis process, was conjugated with various carrier molecules to get seven azo derivatives of 4-ASA.All compounds were characterized by FT-IR, 1H NMR, 13C NMR spectras in detail.New derivatives of 4-ASA were definituded.
2008, 19(4): 423-427
doi: 10.1016/j.cclet.2008.02.001
Abstract:
An expeditious microwave-accelerated one-step synthesis of some new 2-(3, 5-dimethoxy-4-methylphenyl)-5-aryl-1, 3, 4-oxadiazoles by reaction of 3, 5-dimethoxy-4-methyl hydrazide with different carboxylic acids in presence of thionyl chloride under neat conditions, has been achieved.
An expeditious microwave-accelerated one-step synthesis of some new 2-(3, 5-dimethoxy-4-methylphenyl)-5-aryl-1, 3, 4-oxadiazoles by reaction of 3, 5-dimethoxy-4-methyl hydrazide with different carboxylic acids in presence of thionyl chloride under neat conditions, has been achieved.
2008, 19(4): 428-430
doi: 10.1016/j.cclet.2008.01.029
Abstract:
A series of novel benzocycloheptene derivatives have been synthesized.Their structures were confirmed by MS and 1H-NMR.These compounds exhibited potent anti-HIV-1 activities.
A series of novel benzocycloheptene derivatives have been synthesized.Their structures were confirmed by MS and 1H-NMR.These compounds exhibited potent anti-HIV-1 activities.
2008, 19(4): 431-434
doi: 10.1016/j.cclet.2008.02.002
Abstract:
A binaphthyl derivative with pyrene on 3 and 3' positions was synthesized and characterized via Suzuki coupling reaction.Emission maximum in solution was located at 390 nm with a quantum efficiency of 68% by taking 9, 10-diphenyl anthracene as reference, while it is shifted to 450 nm with FWHM of 104 nm resulting from aggregation state in solid film.Glass transition temperature (Tg) and decomposition temperature were measured to be 184 and 447℃, respectively, by DSC and TGA.Unlike its photoluminescence spectrum, electroluminescent spectrum peaked at about 460 nm and shows a FWHM of 69 nm corresponding to a pure blue emission.The turn-on voltage, luminance and efficiency maximum were 5 V, 2953 cd/m2 and 1.37 cd/A with CIE color coordinate of (0.16, 0.15), in the device structure of ITO/NPB (40 nm)/PY-BN-PY (15 nm)/BPhen (40 nm)/Mg:Ag.
A binaphthyl derivative with pyrene on 3 and 3' positions was synthesized and characterized via Suzuki coupling reaction.Emission maximum in solution was located at 390 nm with a quantum efficiency of 68% by taking 9, 10-diphenyl anthracene as reference, while it is shifted to 450 nm with FWHM of 104 nm resulting from aggregation state in solid film.Glass transition temperature (Tg) and decomposition temperature were measured to be 184 and 447℃, respectively, by DSC and TGA.Unlike its photoluminescence spectrum, electroluminescent spectrum peaked at about 460 nm and shows a FWHM of 69 nm corresponding to a pure blue emission.The turn-on voltage, luminance and efficiency maximum were 5 V, 2953 cd/m2 and 1.37 cd/A with CIE color coordinate of (0.16, 0.15), in the device structure of ITO/NPB (40 nm)/PY-BN-PY (15 nm)/BPhen (40 nm)/Mg:Ag.
2008, 19(4): 435-437
doi: 10.1016/j.cclet.2008.01.011
Abstract:
The radical polymerization of maleic anhydride (MA), styrene (ST) with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was developed.The methacryloxypropyl nano-sized silica (MPNS) was used as macromonomer and polymerized with maleic anhydride and styrene by initiating with BPO in toluene.The structure and properties of MPNS/SMA nano-composite were characterized by FT-IR spectra and TEM.Meanwhile, it was applied as tanning agent compared with the traditional styrene-maleic anhydride copolymer in leather.It was found that the applied leather had better quality characteristics with the addition of the nano-sized silica.
The radical polymerization of maleic anhydride (MA), styrene (ST) with the vinyl groups introduced onto the surface of the nano-sized silica via solution polymerization method was developed.The methacryloxypropyl nano-sized silica (MPNS) was used as macromonomer and polymerized with maleic anhydride and styrene by initiating with BPO in toluene.The structure and properties of MPNS/SMA nano-composite were characterized by FT-IR spectra and TEM.Meanwhile, it was applied as tanning agent compared with the traditional styrene-maleic anhydride copolymer in leather.It was found that the applied leather had better quality characteristics with the addition of the nano-sized silica.
2008, 19(4): 438-440
doi: 10.1016/j.cclet.2008.01.019
Abstract:
A new triterpenoid, named 11, 25-anhydro-alisol F, was isolated from the rhizomes of Alisma orientalis together with nine known compounds.Their structures were elucidated by spectroscopic methods.Some compounds showed weak anti-tumor activities in eytotoxic experiments.
A new triterpenoid, named 11, 25-anhydro-alisol F, was isolated from the rhizomes of Alisma orientalis together with nine known compounds.Their structures were elucidated by spectroscopic methods.Some compounds showed weak anti-tumor activities in eytotoxic experiments.
2008, 19(4): 441-443
doi: 10.1016/j.cclet.2008.01.006
Abstract:
Two new ent-kaurane-type diterpenoids, 6β, 7β, 13α-trihydroxy-1α-acetoxy-7α, 20-epoxy-ent-kaur-16-en-15-one (1) and 15β-hydroxy-6, 7-seco-6, 11β:6, 20-diepoxy-1α, 7-olide-ent-kaur-16-ene (2) were isolated from the Isodon nervosus, and the structures were elucidated by spectroscopic analysis.
Two new ent-kaurane-type diterpenoids, 6β, 7β, 13α-trihydroxy-1α-acetoxy-7α, 20-epoxy-ent-kaur-16-en-15-one (1) and 15β-hydroxy-6, 7-seco-6, 11β:6, 20-diepoxy-1α, 7-olide-ent-kaur-16-ene (2) were isolated from the Isodon nervosus, and the structures were elucidated by spectroscopic analysis.
2008, 19(4): 444-446
doi: 10.1016/j.cclet.2008.01.021
Abstract:
A new C21 steroid glycoside, 11a-O-tigloyl-12-β-O-acetyl tenacigenin B 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyr-anosyl-(1→4)-3-O-methyl-6-deoxy-β-D-allopyranosyl-(1→4)-β-D-oleandropyranoside (1), named tenacissoside N was isolated from the stems of Marsdenia tenacissima.The structure of the glycoside was identified by HR-ESI-MS and NMR spectra.
A new C21 steroid glycoside, 11a-O-tigloyl-12-β-O-acetyl tenacigenin B 3-O-β-D-glucopyranosyl-(1→4)-β-D-glucopyr-anosyl-(1→4)-3-O-methyl-6-deoxy-β-D-allopyranosyl-(1→4)-β-D-oleandropyranoside (1), named tenacissoside N was isolated from the stems of Marsdenia tenacissima.The structure of the glycoside was identified by HR-ESI-MS and NMR spectra.
2008, 19(4): 447-449
doi: 10.1016/j.cclet.2008.01.022
Abstract:
A new phenolic compound was isolated from the ethanol extract of the bulbs of Crinum asiaticum L.var.sinicum Baker.Its structure was defined as 1-(2-hydroxy-4-hydroxymethyl) phenyl-6-O-caffeoyl-β-D-gluco-pyranoside on the basis of spectroscopic evidences.
A new phenolic compound was isolated from the ethanol extract of the bulbs of Crinum asiaticum L.var.sinicum Baker.Its structure was defined as 1-(2-hydroxy-4-hydroxymethyl) phenyl-6-O-caffeoyl-β-D-gluco-pyranoside on the basis of spectroscopic evidences.
2008, 19(4): 450-452
doi: 10.1016/j.cclet.2008.01.035
Abstract:
A new iridoid glycoside, versibirioside (1), and a known iridoid glycoside, verbaspinoside (2), were isolated from the whole plant of Veronica sibirica L.Their structures were elucidated by spectroscopic methods, including 2D-NMR spectra.
A new iridoid glycoside, versibirioside (1), and a known iridoid glycoside, verbaspinoside (2), were isolated from the whole plant of Veronica sibirica L.Their structures were elucidated by spectroscopic methods, including 2D-NMR spectra.
2008, 19(4): 453-456
doi: 10.1016/j.cclet.2008.01.031
Abstract:
Two new terpenes, triptobenzene P (1) and wilforone (2) were isolated from Tripterygium wilfordii, as well as 10 known terpenes.Their structures were elucidated by spectroscopic methods.Compounds 2-4, 8, 10, and 11 showed significantimmunosuppressive activities.
Two new terpenes, triptobenzene P (1) and wilforone (2) were isolated from Tripterygium wilfordii, as well as 10 known terpenes.Their structures were elucidated by spectroscopic methods.Compounds 2-4, 8, 10, and 11 showed significantimmunosuppressive activities.
2008, 19(4): 457-460
doi: 10.1016/j.cclet.2008.01.026
Abstract:
Further studies on the sea cucumber Bohadschia marmorata Jaeger led to the isolation of a new holostan-type triterpene glycoside, Marmoroside C (1) together with a known triterpene glycoside (2).On the basis of spectroscopic analyses, including two-dimensional NMR techniques, and chemical reactions, the structure of the new triterpene glycoside was elucidated as 3-0-[3-O-methyl-β-D-glucopyranosyl-(1→3)-13-D-glucopyranosyl-(1→4)-β-D-quinovopyranosyl-(1→2)-4-O-sodium-sulfato-β-D-xylo-pyranosyl]-25-acetoxy-22-oxo-9(11)-holostene-3β, 12α, 17α-triol.
Further studies on the sea cucumber Bohadschia marmorata Jaeger led to the isolation of a new holostan-type triterpene glycoside, Marmoroside C (1) together with a known triterpene glycoside (2).On the basis of spectroscopic analyses, including two-dimensional NMR techniques, and chemical reactions, the structure of the new triterpene glycoside was elucidated as 3-0-[3-O-methyl-β-D-glucopyranosyl-(1→3)-13-D-glucopyranosyl-(1→4)-β-D-quinovopyranosyl-(1→2)-4-O-sodium-sulfato-β-D-xylo-pyranosyl]-25-acetoxy-22-oxo-9(11)-holostene-3β, 12α, 17α-triol.
2008, 19(4): 461-464
doi: 10.1016/j.cclet.2008.02.005
Abstract:
Phytochemical analysis of the n-BuOH extract from the seeds of Allium cepa L.led to isolation of four furostanol saponins, two of which were new compounds, named ceparoside A (1a) and ceparoside B (2a).The chemical structures of the new compounds were elucidated through a combination of NMR, MS spectral data and chemical analysis.
Phytochemical analysis of the n-BuOH extract from the seeds of Allium cepa L.led to isolation of four furostanol saponins, two of which were new compounds, named ceparoside A (1a) and ceparoside B (2a).The chemical structures of the new compounds were elucidated through a combination of NMR, MS spectral data and chemical analysis.
2008, 19(4): 465-468
doi: 10.1016/j.cclet.2007.12.036
Abstract:
New adsorptive anodic differential pulse stripping voltammetry method for the direct determination of morphine at trace levels in human plasma of addicts is proposed.The procedure involves an adsorptive accumulation of morphine on a HMDE, followed by oxidation of adsorbed morphine by voltammetry scan using differential pulse modulation.The optimum conditions for the analysis of morphine are pH 10.5, Eacc of-100 mV (vs.Ag/AgCl), and tacc of 120 s.The peak current is proportional to the concentration of morphine, and a linear calibration graph is obtained at 0.01-3.10 μg mL-1.A relative standard deviation of 1.06% (n=5) was obtained, and the limit of detection was 3 ng mL-1.The capability of the method for the analysis of real samples was evaluated by the determination of morphine in spiked human plasma and addicts human plasma with satisfactory results.
New adsorptive anodic differential pulse stripping voltammetry method for the direct determination of morphine at trace levels in human plasma of addicts is proposed.The procedure involves an adsorptive accumulation of morphine on a HMDE, followed by oxidation of adsorbed morphine by voltammetry scan using differential pulse modulation.The optimum conditions for the analysis of morphine are pH 10.5, Eacc of-100 mV (vs.Ag/AgCl), and tacc of 120 s.The peak current is proportional to the concentration of morphine, and a linear calibration graph is obtained at 0.01-3.10 μg mL-1.A relative standard deviation of 1.06% (n=5) was obtained, and the limit of detection was 3 ng mL-1.The capability of the method for the analysis of real samples was evaluated by the determination of morphine in spiked human plasma and addicts human plasma with satisfactory results.
2008, 19(4): 469-474
doi: 10.1016/j.cclet.2007.12.037
Abstract:
Six ethylene-propylene copolymer samples with different structural parameters were analyzed by 1H NMR, 13C NMR and 1H-13C COSY in this paper.With the aid of the 1H-13C COSY spectra of ethylene-propylene copolymer, the chemical inequivalence behavior of the protons attached to the same carbon in the ethylene-propylene copolymer could be observed.Four basic types of chemical bonds were divided, and two kinds of main conformations were proposed to explain this phenomenon.Based on the calculation of conformation distribution, it can be proved that the explanation of this phenomenon was reasonable.
Six ethylene-propylene copolymer samples with different structural parameters were analyzed by 1H NMR, 13C NMR and 1H-13C COSY in this paper.With the aid of the 1H-13C COSY spectra of ethylene-propylene copolymer, the chemical inequivalence behavior of the protons attached to the same carbon in the ethylene-propylene copolymer could be observed.Four basic types of chemical bonds were divided, and two kinds of main conformations were proposed to explain this phenomenon.Based on the calculation of conformation distribution, it can be proved that the explanation of this phenomenon was reasonable.
2008, 19(4): 475-478
doi: 10.1016/j.cclet.2008.01.023
Abstract:
Under high pressures of several giga-pascals using hydrothermal diamond anvil cell, methane generated directly from CaCO3 reduction in gold-lined chamber is in situ measured by Raman spectroscopy at the temperature of 550℃.The reducing agents include FeO, SiO and natural fayalite (Fe2SiO4), and the resource of hydrogen are water and natural serpentine (Mg3Si2O5(OH)4).The study demonstrates the existence of abiogenic formation of methane under high pressures in the Earth's interior and that the application of high pressure to catalyze multicomponent reactions is a very promising method.
Under high pressures of several giga-pascals using hydrothermal diamond anvil cell, methane generated directly from CaCO3 reduction in gold-lined chamber is in situ measured by Raman spectroscopy at the temperature of 550℃.The reducing agents include FeO, SiO and natural fayalite (Fe2SiO4), and the resource of hydrogen are water and natural serpentine (Mg3Si2O5(OH)4).The study demonstrates the existence of abiogenic formation of methane under high pressures in the Earth's interior and that the application of high pressure to catalyze multicomponent reactions is a very promising method.
2008, 19(4): 479-482
doi: 10.1016/j.cclet.2008.01.002
Abstract:
A novel kind of fluorescent nanoparticles (FNPs) has been prepared using a precipitation polymerization method.Methacrylic acid, trimethylolpropane trimethacrylate and azobisisobutyronitrile were used as functional-monomer, cross-linker and initiator, respectively.Compared with other fluorescent nanoparticles, the FNPs have the characteristics including low dye leakage and good photostability.The fluorescence microscopy imaging indicates that the FNPs can be used as fluorescent labels in bioanalysis.
A novel kind of fluorescent nanoparticles (FNPs) has been prepared using a precipitation polymerization method.Methacrylic acid, trimethylolpropane trimethacrylate and azobisisobutyronitrile were used as functional-monomer, cross-linker and initiator, respectively.Compared with other fluorescent nanoparticles, the FNPs have the characteristics including low dye leakage and good photostability.The fluorescence microscopy imaging indicates that the FNPs can be used as fluorescent labels in bioanalysis.
2008, 19(4): 483-487
doi: 10.1016/j.cclet.2008.01.010
Abstract:
Aqueous solution of anionic surfactant, sodium oleate (NaOA), was studied by means of steady-state shear rheology and dynamic oscillatory technique.The system of NaOA/Na3PO4 showed high viscosity, strong viscoelasticity and good ability of countering Ca2+, Mg2+.The Maxwell model and Cole-Cole plot were applied to study the dynamic viscoelasticity of wormlike micelles.The microstructures of the wormlike micelles were characterized by FF-TEM.
Aqueous solution of anionic surfactant, sodium oleate (NaOA), was studied by means of steady-state shear rheology and dynamic oscillatory technique.The system of NaOA/Na3PO4 showed high viscosity, strong viscoelasticity and good ability of countering Ca2+, Mg2+.The Maxwell model and Cole-Cole plot were applied to study the dynamic viscoelasticity of wormlike micelles.The microstructures of the wormlike micelles were characterized by FF-TEM.
2008, 19(4): 488-492
doi: 10.1016/j.cclet.2007.12.026
Abstract:
A quantum-chemical investigation on the structural and optoelectronic properties of two materials based on carbazole is carried out.The purpose is to display the effect of grafting the fluorine atoms on their optoelectronic and pbysico-chemical properties.In addition to solubility in the polar solvents and the modification in geometric parameters, the substitution of fluorine destabilizes the HOMO and LUMO levels, decreases the band gap energy and raises conjugation length.These properties suggest the substituted fluorine compound as a good candidate for optoelectronic applications.
A quantum-chemical investigation on the structural and optoelectronic properties of two materials based on carbazole is carried out.The purpose is to display the effect of grafting the fluorine atoms on their optoelectronic and pbysico-chemical properties.In addition to solubility in the polar solvents and the modification in geometric parameters, the substitution of fluorine destabilizes the HOMO and LUMO levels, decreases the band gap energy and raises conjugation length.These properties suggest the substituted fluorine compound as a good candidate for optoelectronic applications.
2008, 19(4): 493-496
doi: 10.1016/j.cclet.2008.01.036
Abstract:
The synthesis reaction of trichlorogermyl crylic acid has been studied systematically by using quantum chemistry methods for the first time.Geometries of reactants, transition states, and products have been optimized, respectively at the B3LYP/6-311G (d, p) level.Vibrational frequencies, IR intensities and relative energies for various stationary points have been determined.The reaction pathways are identified by intrinsic reaction coordinate (IRC) calculations.Theoretical analysis provided conclusive evidence that the process is completed through five pathways of addition reaction of double bond, and the transition states are found to be fourmembered ring compounds.Solvent effects are taken into account with the PCM model at the same level.This preliminary study shows that the complex formation is favored by the use of polar solvent.
The synthesis reaction of trichlorogermyl crylic acid has been studied systematically by using quantum chemistry methods for the first time.Geometries of reactants, transition states, and products have been optimized, respectively at the B3LYP/6-311G (d, p) level.Vibrational frequencies, IR intensities and relative energies for various stationary points have been determined.The reaction pathways are identified by intrinsic reaction coordinate (IRC) calculations.Theoretical analysis provided conclusive evidence that the process is completed through five pathways of addition reaction of double bond, and the transition states are found to be fourmembered ring compounds.Solvent effects are taken into account with the PCM model at the same level.This preliminary study shows that the complex formation is favored by the use of polar solvent.
2008, 19(4): 497-500
doi: 10.1016/j.cclet.2008.01.027
Abstract:
To explore the closing mechanism of the substrate pocket, we perform a 16, 000 ps molecular dynamics simulation separately on the ligand-free and actinonin-bound peptide deformylase from Leptospira interrogans. Our results show that the CD-loop, hydrophilic inhibitor and hydrophobic cluster are necessary for the formation of semi-open conformation, and Tyr71 plays an important role in mediating the movements of CD-loop. The average MD structure of the actinonin-bound LiPDF complex approaches to the crystal structure. These are consistent with experiment very well.
To explore the closing mechanism of the substrate pocket, we perform a 16, 000 ps molecular dynamics simulation separately on the ligand-free and actinonin-bound peptide deformylase from Leptospira interrogans. Our results show that the CD-loop, hydrophilic inhibitor and hydrophobic cluster are necessary for the formation of semi-open conformation, and Tyr71 plays an important role in mediating the movements of CD-loop. The average MD structure of the actinonin-bound LiPDF complex approaches to the crystal structure. These are consistent with experiment very well.
2008, 19(4): 501-504
doi: 10.1016/j.cclet.2008.01.041
Abstract:
The potential energy surface for the electronic ground state of the HXeI molecule is constructed by using the internally contracted multi-reference configuration interaction with the Davidson correction (icMRCI+Q) method and large basis sets.The stabilities and dissociation barriers are identified from the potential energy surfaces.The three-body dissociation channel is found to be the dominate dissociation channel for HXeI.Based on the obtained potentials, vibrational energy levels of HXeI are calculated using the Lanczos algorithm.Our theoretical results are in excellent agreement with the available observed values.
The potential energy surface for the electronic ground state of the HXeI molecule is constructed by using the internally contracted multi-reference configuration interaction with the Davidson correction (icMRCI+Q) method and large basis sets.The stabilities and dissociation barriers are identified from the potential energy surfaces.The three-body dissociation channel is found to be the dominate dissociation channel for HXeI.Based on the obtained potentials, vibrational energy levels of HXeI are calculated using the Lanczos algorithm.Our theoretical results are in excellent agreement with the available observed values.
