Instead of Br_2 and Cl_2,NBS and NCS are applicable to the thiocyanation of o-nitroaniline and carbendazim.The results show that NBS and NCS are superior to Br_2 and Cl_2 due to their easier operation.
The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone ...The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone compounds, 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene and 1-(4-chlorobenzoyl)-2-hydroxy-7-methoxynaphthalene. In crystals, three aromatic rings in a molecule of the methyl ether-retained imine compound are positioned almost perpendicularly to each other by giving non-coplanar spatial organization of the single molecular structure [dihedral angles: 85.32(18)° for C-linked phenyl ring and naphthalene ring;79.27(17)° for N-linked phenyl ring and naphthalene ring;84.78(17)° for C-linked phenyl ring and N-linked phenyl ring]. Spatial organization of the analogous methyl ether-cleaved imine compound has essentially same topology [dihedral angles 80.39(6)° for the C-linked phenyl ring and naphthalene ring;82.35(6)° for the N-linked phenyl ring and naphthalene ring;87.09(7)° for C- and N-linked phenyl rings]. These structural features of triarylimines apparently differ from those of the precursor ketones. Two aromatic rings in the methyl ether-cleaved ketone compound make smaller dihedral angle [58.10(6)°] by intramolecular hydrogen bond between ketonic carbonyl group and hydroxy group [2.5573(16) A] than that of the methyl ether-retained ketone [72.06(7)°]. In molecular packing, the methyl ether-retained imine forms tubular molecular alignments composed of R—S dimeric molecular pairs, whereas the methyl ether-retained ketone affords consecutively stacks of one configurated molecules.展开更多
Surfactant/alkali flooding is one of the best chemical flooding methods to enhance the oil Recovery Factor(RF).In this research,Ionic Liquid/Alkali(ILA)mixtures were chosen to represent a form of chemical flooding exp...Surfactant/alkali flooding is one of the best chemical flooding methods to enhance the oil Recovery Factor(RF).In this research,Ionic Liquid/Alkali(ILA)mixtures were chosen to represent a form of chemical flooding experiments.The selected Ionic Liquids(ILs),{[EMIM][Cl],[THTDPH][Cl],[EMIM][Ac],[BzMIM][Cl],[DMIM][Cl],[BzMIM][TOS],[dMIM][TOS]and[MPyr][TOS]},were introduced to investigate their efficiency in improving heavy oil(14o API)RF from the sand packs.Besides,the use of mixtures of the same ionic liquids and brine(3.37 wt.% salts)with an alkali(Sodium Bicarbonate[NaHCO3])were also investigated.In this experimental study,the flooding process started with injecting about 3.2 Pore Volumes(PVs)of only brine,followed by one PV of the chemical composites,and flushed with two PVs of formation brine.The study discussed the influence of cation type,anion type,the structure of the ILs,and the effect of combining ILs/alkali on the RF.The results revealed that the proposed chemical mixtures are effective in enhancing the recovery factor.ILs with shorter alkyl chain and more aromatic rings are noticeably more efficient in enhancing the RF.Finding the optimum composition of([DMIM][Cl]+NaHCO3)the chemical slug increased the additional RF up to 31.55(%OOIP).Also,increasing the slug size to two PVs improved the RF to 42.13(%OOIP).The recovery factor mechanism was explained and supported by measuring the effect of IL types on the viscosity,Surface Tension(SFT),and Zeta Potential(ZP)of the mixture.展开更多
The stability constants of some ternary mixed-ligand complexes, Pt(Phen)(CA)+, where Phen=1,10-phenanthroline and CA- =carboxylate, were determined by means of potentiometric pH titration in aqueous solutions(I=0.1 mo...The stability constants of some ternary mixed-ligand complexes, Pt(Phen)(CA)+, where Phen=1,10-phenanthroline and CA- =carboxylate, were determined by means of potentiometric pH titration in aqueous solutions(I=0.1 mol/L, KNO 3; 25 ℃), and the stability of them was compared with that of the corresponding binary complexes. It was revealed that the ternary complexes containing phenylalkane carboxylates ligands(PCA-) are much more stable than those formed with formate and acetate. The results indicate that there exist the intramolecular aromatic-ring interactions between the phenanthroline ring of Phen and the phenyl moiety of ligand PCA- in the ternary mixed-ligand Pt(Phen)(PCA)- complexes. The extent of the stacking interactions, which depends on the number of methylene groups between the phenyl moieties and the coordinated phenylalkane carboxylate groups, was calculated. The best-fitted stack was obtained for the complexes with 2-phenylacetate and 3-phenylpropionate as the ligands.展开更多
Abstract Asphaltene, from co-processing of coal and petroleum residues is one of the most precious and complex molecular mixtures existing, with tremendous economic relevance. Asphaltene was separated by Soxhlet extra...Abstract Asphaltene, from co-processing of coal and petroleum residues is one of the most precious and complex molecular mixtures existing, with tremendous economic relevance. Asphaltene was separated by Soxhlet extraction with methylbenzene and then divided into three parts by distillation. Gas chromatography （GC） and high-performance liquid chromatography （HPLC） were coupled with quadrupole time-of-flight mass spectrometry （Q-TOF MS） to separate and characterize organic nitrogen species in the distillates of asphaltene at molecular level. Molecular mass of compounds was mainly distributed from 150 to 600 ~t. Number of rings plus double bonds （rdb） and synchronous fluorescence spectra indicated that most of the organonitrogen compounds （NPAC） contained heterocyclic aromatic rings, including pyridines, anilines, quinolins, pyrroles, carbazoles and indoles plus various alkyl groups. Constant-wavelength synchronous fluo- rescence spectrometry （CWSFS） indicated NPAC with 2-3 rings were the main structures of organonitrogen compounds and the corresponding structural information was proposed. Some organic nitrogen isomers were separated and identified by atmospheric pressure chemical ionization （APCI） GC-Q-TOF MS and electrospray ionization （ESI） HPLC-Q-TOF MS. The methodology applied here contained chromatographic injection of the diluted sample using conventional columns sets and Data Analysis 4.2 software. Identifying molecular structures provides a foundation to understand all aspects of coal- derived asphaltene, enabling a first-principles approach to optimize resource utilization.展开更多
Parkinson's disease,the second most prevalent neurodegenerative disorder worldwide,is characterized by a progressive loss of dopaminergic neurons in substantia nigra pars compacta,causing motor symptoms.This disor...Parkinson's disease,the second most prevalent neurodegenerative disorder worldwide,is characterized by a progressive loss of dopaminergic neurons in substantia nigra pars compacta,causing motor symptoms.This disorder's main hallmark is the formation of intraneuronal protein inclusions,named Lewy bodies and neurites.The major component of these arrangements is α-synuclein,an intrinsically disordered and soluble protein that,in pathological conditions,can form toxic and cell-to-cell transmissible amyloid structures.Preventing α-synuclein aggregation has attracted significant effort in the search for a disease-modifying therapy for Parkinson's disease.Small molecules like Synu Clean-D,epigallocatechin gallate,trodusquemine,or anle138 b exemplify this therapeutic potential.Here,we describe a subset of compounds containing a single aromatic ring,like dopamine,ZPDm,gallic acid,or entacapone,which act as molecular chaperones against α-synuclein aggregation.The simplicity of their structures contrasts with the complexity of the aggregation process,yet the block efficiently α-synuclein assembly into amyloid fibrils,in many cases,redirecting the reaction towards the formation of non-toxic off-pathway oligomers.Moreover,some of these compounds can disentangle mature α-synuclein amyloid fibrils.Their simple structures allow structure-activity relationship analysis to elucidate the role of different functional groups in the inhibition of α-synuclein aggregation and fibril dismantling,making them informative lead scaffolds for the rational development of efficient drugs.展开更多
One of the typical phenomena of intramolecular ligand-ligand interaction in complexes is the aromatic-ring stacking which depends on the stacking of those non-coordinating aromatic rings. Since 1974 H. Sigel reported ...One of the typical phenomena of intramolecular ligand-ligand interaction in complexes is the aromatic-ring stacking which depends on the stacking of those non-coordinating aromatic rings. Since 1974 H. Sigel reported that the stacking interaction was observed between pyridine ring of bpy（bpy=2, 2′-bipyridyl） and purine ring of ATP<sup>4-</sup>(ATP<sup>4-</sup>=adenosine 5′-triphosphate) among the mixed-ligand Cu（bpy） （ATP）<sup>2-</sup> complexes. The study on this field has been extended to a large amount of ligands such as nucleotides, xanthosines,展开更多
Theoretical calculations of Double Hanging Ring Molecule(DHRM) [(GnHn-1^m)(GnHn-1^m)](G=C,Si,Ge;n=3,5,6,7,8;m=+1,-1,0,+1,+2) were performed via Gaussian 09 with the method of Density Functional Theory(DFT). Geometrica...Theoretical calculations of Double Hanging Ring Molecule(DHRM) [(GnHn-1^m)(GnHn-1^m)](G=C,Si,Ge;n=3,5,6,7,8;m=+1,-1,0,+1,+2) were performed via Gaussian 09 with the method of Density Functional Theory(DFT). Geometrical optimization, Potential Energy surface Scan(PES), Degree of Aromaticity(DOA) and Nucleus Independent Chemical Shift(NICS) were computed to study the optimal structures and aromaticity of DHRMs. Ring Stretching Vibration Raman Spectroscopy(RSVRSF) was predicted to seek the relation between RSVRSF and aromaticity of DHRMs. The results show optimal structures of DHRMs[(GnH(n-1)~m)(GnH(n–1)~m)](n = 3, 5~8);DA = 90° is the stable structure when n = 3, 7, 8;while n = 5 corresponds to DA = 30°, n = 6 corresponds to DA = 50°;the correlation between DOA and NICS of DHRMs is quadratic;the value of RSVRSF of DHRM approximates to its corresponding single ring molecule, which could act as characteristic frequency of ring molecule to identify its aromaticity;the correlation between RSVRSF and DOA is quadratic, and that between RSVRSF and NICS is linear.展开更多
So far, more attention was paid to the fact that the kind, position and properties of the substituted radicals of coordinating or non-coordinating groups in the complexes exert an important influence on the stability ...So far, more attention was paid to the fact that the kind, position and properties of the substituted radicals of coordinating or non-coordinating groups in the complexes exert an important influence on the stability of the complexes, but less to the interaction between those non-coordinating groups. Although the existence of hydrogen bonds between ligands and the formation of covalent and ionic bonds have been reported, it is only about ten展开更多
The localized molecular orbitals and energy levels for four typical conjugated six-membered ring systems C_6H_6, C_3N_3H_3, B_3N_3H_6, and (B_3O_6)^(3-) as well as a non-aromatic reference molecule N_3Cl_6 have been ...The localized molecular orbitals and energy levels for four typical conjugated six-membered ring systems C_6H_6, C_3N_3H_3, B_3N_3H_6, and (B_3O_6)^(3-) as well as a non-aromatic reference molecule N_3Cl_6 have been calculated by using Edmiston-Ruedenberg energy localization technique under the CNDO/2 approximation in order to investigate the nature of aromaticity or quasi-aromaticity of the six-membered ring systems studied. The contour maps for π-type localized MO's (LMO) have been plotted to illustrate the bonding characteristics of the five ring systems studied. These LMO calculations show that for all the conjugated six-membered ring systems considered there exists local delocalization of π-bonds or three-centered and occasionally four-centered two-electron π-bonds in our terminology, and the cooperative effect among these π-bonds leading to the formation of a closed continuous x-conjugation system around the ring, which is necessary for the creation of aromaticity in the systems studied. We have been able to discuss the properties of these three-centered π-bonds in terms of the constituent atoms and electrons and the relevant orbitals involved.展开更多
The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its...The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its bridged derivatives by replacing the substituent grouppara to CF_3, whereas ethanedithiol reacts either by replacing the substituent group para to CF_3 or by displacing both groups and a nitro group.The results have been rationalized in terms of electronic effects and nucleophilicity of the nucleophiles.展开更多
文摘Instead of Br_2 and Cl_2,NBS and NCS are applicable to the thiocyanation of o-nitroaniline and carbendazim.The results show that NBS and NCS are superior to Br_2 and Cl_2 due to their easier operation.
文摘The X-ray crystal structures of C,C,N-triaryl-substituted imine compounds, which have methoxy or hydroxy group adjacent to the imino moiety, are reported and discussed in comparison with those of the precursor ketone compounds, 1-(4-chlorobenzoyl)-2,7-dimethoxynaphthalene and 1-(4-chlorobenzoyl)-2-hydroxy-7-methoxynaphthalene. In crystals, three aromatic rings in a molecule of the methyl ether-retained imine compound are positioned almost perpendicularly to each other by giving non-coplanar spatial organization of the single molecular structure [dihedral angles: 85.32(18)° for C-linked phenyl ring and naphthalene ring;79.27(17)° for N-linked phenyl ring and naphthalene ring;84.78(17)° for C-linked phenyl ring and N-linked phenyl ring]. Spatial organization of the analogous methyl ether-cleaved imine compound has essentially same topology [dihedral angles 80.39(6)° for the C-linked phenyl ring and naphthalene ring;82.35(6)° for the N-linked phenyl ring and naphthalene ring;87.09(7)° for C- and N-linked phenyl rings]. These structural features of triarylimines apparently differ from those of the precursor ketones. Two aromatic rings in the methyl ether-cleaved ketone compound make smaller dihedral angle [58.10(6)°] by intramolecular hydrogen bond between ketonic carbonyl group and hydroxy group [2.5573(16) A] than that of the methyl ether-retained ketone [72.06(7)°]. In molecular packing, the methyl ether-retained imine forms tubular molecular alignments composed of R—S dimeric molecular pairs, whereas the methyl ether-retained ketone affords consecutively stacks of one configurated molecules.
文摘Surfactant/alkali flooding is one of the best chemical flooding methods to enhance the oil Recovery Factor(RF).In this research,Ionic Liquid/Alkali(ILA)mixtures were chosen to represent a form of chemical flooding experiments.The selected Ionic Liquids(ILs),{[EMIM][Cl],[THTDPH][Cl],[EMIM][Ac],[BzMIM][Cl],[DMIM][Cl],[BzMIM][TOS],[dMIM][TOS]and[MPyr][TOS]},were introduced to investigate their efficiency in improving heavy oil(14o API)RF from the sand packs.Besides,the use of mixtures of the same ionic liquids and brine(3.37 wt.% salts)with an alkali(Sodium Bicarbonate[NaHCO3])were also investigated.In this experimental study,the flooding process started with injecting about 3.2 Pore Volumes(PVs)of only brine,followed by one PV of the chemical composites,and flushed with two PVs of formation brine.The study discussed the influence of cation type,anion type,the structure of the ILs,and the effect of combining ILs/alkali on the RF.The results revealed that the proposed chemical mixtures are effective in enhancing the recovery factor.ILs with shorter alkyl chain and more aromatic rings are noticeably more efficient in enhancing the RF.Finding the optimum composition of([DMIM][Cl]+NaHCO3)the chemical slug increased the additional RF up to 31.55(%OOIP).Also,increasing the slug size to two PVs improved the RF to 42.13(%OOIP).The recovery factor mechanism was explained and supported by measuring the effect of IL types on the viscosity,Surface Tension(SFT),and Zeta Potential(ZP)of the mixture.
基金Supported by the Foundation of Academ y L eader of Zhejiang Gongshang U niversity(No.19972 0 0 2 )
文摘The stability constants of some ternary mixed-ligand complexes, Pt(Phen)(CA)+, where Phen=1,10-phenanthroline and CA- =carboxylate, were determined by means of potentiometric pH titration in aqueous solutions(I=0.1 mol/L, KNO 3; 25 ℃), and the stability of them was compared with that of the corresponding binary complexes. It was revealed that the ternary complexes containing phenylalkane carboxylates ligands(PCA-) are much more stable than those formed with formate and acetate. The results indicate that there exist the intramolecular aromatic-ring interactions between the phenanthroline ring of Phen and the phenyl moiety of ligand PCA- in the ternary mixed-ligand Pt(Phen)(PCA)- complexes. The extent of the stacking interactions, which depends on the number of methylene groups between the phenyl moieties and the coordinated phenylalkane carboxylate groups, was calculated. The best-fitted stack was obtained for the complexes with 2-phenylacetate and 3-phenylpropionate as the ligands.
基金Acknowledgements The authors gratefully acknowledge the financial support of this work by the National Natural Science Foundation of China （No. U1510122）. The authors declare that the experiments comply with the current laws of China.
文摘Abstract Asphaltene, from co-processing of coal and petroleum residues is one of the most precious and complex molecular mixtures existing, with tremendous economic relevance. Asphaltene was separated by Soxhlet extraction with methylbenzene and then divided into three parts by distillation. Gas chromatography （GC） and high-performance liquid chromatography （HPLC） were coupled with quadrupole time-of-flight mass spectrometry （Q-TOF MS） to separate and characterize organic nitrogen species in the distillates of asphaltene at molecular level. Molecular mass of compounds was mainly distributed from 150 to 600 ~t. Number of rings plus double bonds （rdb） and synchronous fluorescence spectra indicated that most of the organonitrogen compounds （NPAC） contained heterocyclic aromatic rings, including pyridines, anilines, quinolins, pyrroles, carbazoles and indoles plus various alkyl groups. Constant-wavelength synchronous fluo- rescence spectrometry （CWSFS） indicated NPAC with 2-3 rings were the main structures of organonitrogen compounds and the corresponding structural information was proposed. Some organic nitrogen isomers were separated and identified by atmospheric pressure chemical ionization （APCI） GC-Q-TOF MS and electrospray ionization （ESI） HPLC-Q-TOF MS. The methodology applied here contained chromatographic injection of the diluted sample using conventional columns sets and Data Analysis 4.2 software. Identifying molecular structures provides a foundation to understand all aspects of coal- derived asphaltene, enabling a first-principles approach to optimize resource utilization.
文摘Parkinson's disease,the second most prevalent neurodegenerative disorder worldwide,is characterized by a progressive loss of dopaminergic neurons in substantia nigra pars compacta,causing motor symptoms.This disorder's main hallmark is the formation of intraneuronal protein inclusions,named Lewy bodies and neurites.The major component of these arrangements is α-synuclein,an intrinsically disordered and soluble protein that,in pathological conditions,can form toxic and cell-to-cell transmissible amyloid structures.Preventing α-synuclein aggregation has attracted significant effort in the search for a disease-modifying therapy for Parkinson's disease.Small molecules like Synu Clean-D,epigallocatechin gallate,trodusquemine,or anle138 b exemplify this therapeutic potential.Here,we describe a subset of compounds containing a single aromatic ring,like dopamine,ZPDm,gallic acid,or entacapone,which act as molecular chaperones against α-synuclein aggregation.The simplicity of their structures contrasts with the complexity of the aggregation process,yet the block efficiently α-synuclein assembly into amyloid fibrils,in many cases,redirecting the reaction towards the formation of non-toxic off-pathway oligomers.Moreover,some of these compounds can disentangle mature α-synuclein amyloid fibrils.Their simple structures allow structure-activity relationship analysis to elucidate the role of different functional groups in the inhibition of α-synuclein aggregation and fibril dismantling,making them informative lead scaffolds for the rational development of efficient drugs.
基金Project supported by the National Natural Science Foundation of China
文摘One of the typical phenomena of intramolecular ligand-ligand interaction in complexes is the aromatic-ring stacking which depends on the stacking of those non-coordinating aromatic rings. Since 1974 H. Sigel reported that the stacking interaction was observed between pyridine ring of bpy（bpy=2, 2′-bipyridyl） and purine ring of ATP<sup>4-</sup>(ATP<sup>4-</sup>=adenosine 5′-triphosphate) among the mixed-ligand Cu（bpy） （ATP）<sup>2-</sup> complexes. The study on this field has been extended to a large amount of ligands such as nucleotides, xanthosines,
基金Supported by the National Natural Science Foundation of China(No.21563023)the Graduate Education Innovation Program funded Projects of Inner Mongolia(No.S20161013506)inner Mongolia Normal University Graduate Students'Research&Innovation Fund(No.CXJJS16090)。
文摘Theoretical calculations of Double Hanging Ring Molecule(DHRM) [(GnHn-1^m)(GnHn-1^m)](G=C,Si,Ge;n=3,5,6,7,8;m=+1,-1,0,+1,+2) were performed via Gaussian 09 with the method of Density Functional Theory(DFT). Geometrical optimization, Potential Energy surface Scan(PES), Degree of Aromaticity(DOA) and Nucleus Independent Chemical Shift(NICS) were computed to study the optimal structures and aromaticity of DHRMs. Ring Stretching Vibration Raman Spectroscopy(RSVRSF) was predicted to seek the relation between RSVRSF and aromaticity of DHRMs. The results show optimal structures of DHRMs[(GnH(n-1)~m)(GnH(n–1)~m)](n = 3, 5~8);DA = 90° is the stable structure when n = 3, 7, 8;while n = 5 corresponds to DA = 30°, n = 6 corresponds to DA = 50°;the correlation between DOA and NICS of DHRMs is quadratic;the value of RSVRSF of DHRM approximates to its corresponding single ring molecule, which could act as characteristic frequency of ring molecule to identify its aromaticity;the correlation between RSVRSF and DOA is quadratic, and that between RSVRSF and NICS is linear.
基金Project supported by the National Natural Science Foundation of China.
文摘So far, more attention was paid to the fact that the kind, position and properties of the substituted radicals of coordinating or non-coordinating groups in the complexes exert an important influence on the stability of the complexes, but less to the interaction between those non-coordinating groups. Although the existence of hydrogen bonds between ligands and the formation of covalent and ionic bonds have been reported, it is only about ten
文摘The localized molecular orbitals and energy levels for four typical conjugated six-membered ring systems C_6H_6, C_3N_3H_3, B_3N_3H_6, and (B_3O_6)^(3-) as well as a non-aromatic reference molecule N_3Cl_6 have been calculated by using Edmiston-Ruedenberg energy localization technique under the CNDO/2 approximation in order to investigate the nature of aromaticity or quasi-aromaticity of the six-membered ring systems studied. The contour maps for π-type localized MO's (LMO) have been plotted to illustrate the bonding characteristics of the five ring systems studied. These LMO calculations show that for all the conjugated six-membered ring systems considered there exists local delocalization of π-bonds or three-centered and occasionally four-centered two-electron π-bonds in our terminology, and the cooperative effect among these π-bonds leading to the formation of a closed continuous x-conjugation system around the ring, which is necessary for the creation of aromaticity in the systems studied. We have been able to discuss the properties of these three-centered π-bonds in terms of the constituent atoms and electrons and the relevant orbitals involved.
文摘The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its bridged derivatives by replacing the substituent grouppara to CF_3, whereas ethanedithiol reacts either by replacing the substituent group para to CF_3 or by displacing both groups and a nitro group.The results have been rationalized in terms of electronic effects and nucleophilicity of the nucleophiles.
