Login In
2022 Volume 41 Issue 3
2022, 41(3): 220300
doi: 10.14102/j.cnki.0254-5861.2011-3247
Abstract:
The electrocatalysts containing cobalt-pyrrolic nitrogen-carbon (Co-N4-C) moiety for CO2 reduction reaction (CO2RR) have caught much attention. However, the effects of Co valence state and its synergy with graphene substrate are not clear yet. In this work, cobalt porphyrin (CoTPP) molecule with the intrinsic Co-N4-C moiety is successfully combined with graphene oxide (GO) via three kinds of liquid-phase methods. The ratio of CoTPP to GO and the valence state of Co atom are studied to explore their catalysis for CO2RR to CO. It is found that axially-coordinated Co(Ⅲ)TPPCl/GO nanocomposites synthesized via a chemical method exhibit better ability for CO2RR, as compared with Co(Ⅱ)TPP+GO and/or Co(Ⅲ)TPPCl+GO nanocomposites obtained via a physically mixing way. After optimizing the ratio of CoTPP to GO, the Faradaic efficiency (FE) is more than 90% for CO2RR to CO between −0.7 and −0.8 V vs. reversible hydrogen electrode (RHE) in Co(Ⅲ)TPPCl/GO75. The synergy between CoTPP and GO and the effect of Co valence state are systematically investigated, indicating that their strong interaction plays the key role in electrocatalytic CO2RR.
The electrocatalysts containing cobalt-pyrrolic nitrogen-carbon (Co-N4-C) moiety for CO2 reduction reaction (CO2RR) have caught much attention. However, the effects of Co valence state and its synergy with graphene substrate are not clear yet. In this work, cobalt porphyrin (CoTPP) molecule with the intrinsic Co-N4-C moiety is successfully combined with graphene oxide (GO) via three kinds of liquid-phase methods. The ratio of CoTPP to GO and the valence state of Co atom are studied to explore their catalysis for CO2RR to CO. It is found that axially-coordinated Co(Ⅲ)TPPCl/GO nanocomposites synthesized via a chemical method exhibit better ability for CO2RR, as compared with Co(Ⅱ)TPP+GO and/or Co(Ⅲ)TPPCl+GO nanocomposites obtained via a physically mixing way. After optimizing the ratio of CoTPP to GO, the Faradaic efficiency (FE) is more than 90% for CO2RR to CO between −0.7 and −0.8 V vs. reversible hydrogen electrode (RHE) in Co(Ⅲ)TPPCl/GO75. The synergy between CoTPP and GO and the effect of Co valence state are systematically investigated, indicating that their strong interaction plays the key role in electrocatalytic CO2RR.
2022, 41(3): 220301
doi: 10.14102/j.cnki.0254-5861.2011-3285
Abstract:
Schiff base pyridine zinc(Ⅱ) complexes 1~4 were synthesized by the reaction of the 2-((2-hydroxybenzylidene)amino)phenol Schiff base with appended donor functionality, zinc acetate, and pyridine. The results of the structural characterization of the complex show that they have the same coordination mode and similar steric structure. Complexes 1 and 3 form a one-dimensional chain structure and two-dimensional grid structure by lots of hydrogen bonds, respectively. Thermogravimetric analysis shows complexes 1~4 can exist stably below 150 ℃. The results of the fluorescence quenching experiments between the complexes and DNA-EB show that the interaction between them is intercalation, and the effect of complex 1 is the most obvious. It is speculated that the steric hindrance of complex 1 is relatively small, and the aromatic ring on the ligand is more likely to inserted into the base pair of DNA.
Schiff base pyridine zinc(Ⅱ) complexes 1~4 were synthesized by the reaction of the 2-((2-hydroxybenzylidene)amino)phenol Schiff base with appended donor functionality, zinc acetate, and pyridine. The results of the structural characterization of the complex show that they have the same coordination mode and similar steric structure. Complexes 1 and 3 form a one-dimensional chain structure and two-dimensional grid structure by lots of hydrogen bonds, respectively. Thermogravimetric analysis shows complexes 1~4 can exist stably below 150 ℃. The results of the fluorescence quenching experiments between the complexes and DNA-EB show that the interaction between them is intercalation, and the effect of complex 1 is the most obvious. It is speculated that the steric hindrance of complex 1 is relatively small, and the aromatic ring on the ligand is more likely to inserted into the base pair of DNA.
2022, 41(3): 220301
doi: 10.14102/j.cnki.0254-5861.2011-3286
Abstract:
Ligands can definitely influence C−H activation at the metal center. A ligand not directly participating in the reaction is called a spectator ligand. We attempt to quantitatively characterize the effects of diverse spectator ligands on C−H activation at palladium. We designed a model palladium catalyst and selected an array of spectator ligands, such as methoxyl, amide, methyl, phenyl, cyanide, fluorine, chlorine, and several neutral ligands, and performed density functional theory calculations on the mechanism and energetics of C−H activation reactions of benzene with different catalysts. Univalent ligands have substantially larger effects than neutral ligands, and strongly σ-donating ligands (e.g., methyl and phenyl) severely hinder the C−H activation in progress. A ligand trans to the reaction site influences C−H activation more than that cis to the reaction site, indicating electronic effects to be at work. For example, the existence of a methyl ligand raises the barrier height of C−H activation by 6.4 or 14.4 kcal/mol when it is placed at the position cis or trans to the C−H activation site. The effects of poorly σ-donating ligands are not significant and similar to those of the κ1-acetate ligand. Some σ-donating and π-accepting ligands, such as cyanide and isonitrile, hinder the C−H activation trans to them but appear to facilitate the C−H activation cis to them. On the basis of molecular orbital analyses, a chemical model is proposed to understand the observed ligand effects. Lastly, the conclusions are applied to explain the plausible mechanism of the dehydrogenative Heck coupling.
Ligands can definitely influence C−H activation at the metal center. A ligand not directly participating in the reaction is called a spectator ligand. We attempt to quantitatively characterize the effects of diverse spectator ligands on C−H activation at palladium. We designed a model palladium catalyst and selected an array of spectator ligands, such as methoxyl, amide, methyl, phenyl, cyanide, fluorine, chlorine, and several neutral ligands, and performed density functional theory calculations on the mechanism and energetics of C−H activation reactions of benzene with different catalysts. Univalent ligands have substantially larger effects than neutral ligands, and strongly σ-donating ligands (e.g., methyl and phenyl) severely hinder the C−H activation in progress. A ligand trans to the reaction site influences C−H activation more than that cis to the reaction site, indicating electronic effects to be at work. For example, the existence of a methyl ligand raises the barrier height of C−H activation by 6.4 or 14.4 kcal/mol when it is placed at the position cis or trans to the C−H activation site. The effects of poorly σ-donating ligands are not significant and similar to those of the κ1-acetate ligand. Some σ-donating and π-accepting ligands, such as cyanide and isonitrile, hinder the C−H activation trans to them but appear to facilitate the C−H activation cis to them. On the basis of molecular orbital analyses, a chemical model is proposed to understand the observed ligand effects. Lastly, the conclusions are applied to explain the plausible mechanism of the dehydrogenative Heck coupling.
2022, 41(3): 220303
doi: 10.14102/j.cnki.0254-5861.2011-3304
Abstract:
Three isomorphic Ln-MOFs [Ln(bcbob)(H2O)(DMF)] (Ln = Tb for 1, Eu for 2, Gd for 3; DMF = N, N-dimethylformamide) have been constructed from a semi-rigid V-shaped organic linker 3, 5-bis((4′-carboxyl-benzyl)oxy)benzoilate acid (H3bcbob) under solvothermal conditions. X-ray single-crystal diffraction analysis reveals that they exhibit a two-dimensional (2D) layered structure. Compounds 1~3 show the characteristic green and red emissions of Ln3+ and blue emission arising from the organic ligand, respectively. Based on their photoluminescence properties, the white-light emitting materials 4 and 5 with longer fluorescence lifetime (ms grade) and higher quantum yield (e.g. 40.61% for 4) are fabricated. Remarkably, 1 exhibits good sensing ability on nitroaromatic compounds, especially for picric acid (PA). In addition, 1 is still a highly selective sensing material for Fe3+ and Al3+.
Three isomorphic Ln-MOFs [Ln(bcbob)(H2O)(DMF)] (Ln = Tb for 1, Eu for 2, Gd for 3; DMF = N, N-dimethylformamide) have been constructed from a semi-rigid V-shaped organic linker 3, 5-bis((4′-carboxyl-benzyl)oxy)benzoilate acid (H3bcbob) under solvothermal conditions. X-ray single-crystal diffraction analysis reveals that they exhibit a two-dimensional (2D) layered structure. Compounds 1~3 show the characteristic green and red emissions of Ln3+ and blue emission arising from the organic ligand, respectively. Based on their photoluminescence properties, the white-light emitting materials 4 and 5 with longer fluorescence lifetime (ms grade) and higher quantum yield (e.g. 40.61% for 4) are fabricated. Remarkably, 1 exhibits good sensing ability on nitroaromatic compounds, especially for picric acid (PA). In addition, 1 is still a highly selective sensing material for Fe3+ and Al3+.
2022, 41(3): 220304
doi: 10.14102/j.cnki.0254-5861.2011-3309
Abstract:
The double crown hexakis[(di-μ-benzylthio) nickel] cluster, [Ni6(SCH2C6H5)12]·C2H5OH, was obtained by reacting C6H5CH2SNa with [(CH3)2CHOCS2]2Ni in EtOH. The results of electrochemical studies show that [Ni6(SCH2C6H5)12] is a quasi-reversible process. The crystal structure of [Ni6(SCH2C6H5)12]·C2H5OH is composed of discrete [Ni6(SCH2C6H5)12] and C2H5OH solvent molecules. Each Ni atom is surrounded by four S atoms of the μ2-SCH2C6H5 ligands in a distorted square-planar structure. The C6H5CH2S- side chains are arranged in the axial and equatorial positions, alternately, concerning the pseudo-hexagonal axis of the molecule. Strong π-π and C–H···π effects form the supramolecular nano-channel along the a-axis in the crystal, which wraps the solvent ethanol molecules in it. In addition, a wall is formed along the b- and c-axes, so that the ethanol molecules can freely enter and leave along the a-axis. These effects result in the ability of the title compound to adsorb and desorb ethanol molecules. Thermogravimetric analysis and powder X-ray diffraction at different temperature are provided to demonstrate this point.
The double crown hexakis[(di-μ-benzylthio) nickel] cluster, [Ni6(SCH2C6H5)12]·C2H5OH, was obtained by reacting C6H5CH2SNa with [(CH3)2CHOCS2]2Ni in EtOH. The results of electrochemical studies show that [Ni6(SCH2C6H5)12] is a quasi-reversible process. The crystal structure of [Ni6(SCH2C6H5)12]·C2H5OH is composed of discrete [Ni6(SCH2C6H5)12] and C2H5OH solvent molecules. Each Ni atom is surrounded by four S atoms of the μ2-SCH2C6H5 ligands in a distorted square-planar structure. The C6H5CH2S- side chains are arranged in the axial and equatorial positions, alternately, concerning the pseudo-hexagonal axis of the molecule. Strong π-π and C–H···π effects form the supramolecular nano-channel along the a-axis in the crystal, which wraps the solvent ethanol molecules in it. In addition, a wall is formed along the b- and c-axes, so that the ethanol molecules can freely enter and leave along the a-axis. These effects result in the ability of the title compound to adsorb and desorb ethanol molecules. Thermogravimetric analysis and powder X-ray diffraction at different temperature are provided to demonstrate this point.
2022, 41(3): 220304
doi: 10.14102/j.cnki.0254-5861.2011-3311
Abstract:
Two novel polynuclear complexes {NaFe4(μ4-O)(L)4(μ2-Cl)[Fe(CN)5NO](H2O)(DMF)2} (1) and {NaFe4(μ4-O)(L)4(μ2-OEt)[Fe(CN)5NO](H2O)(DMF)2} (2) have been prepared using the tetradentate N-(2-hydroxyethyl)-3-methoxysalicylaldimine Schiff-base ligand (H2L) with the help of [Fe(CN)5NO]2- linkers, where the ligand was in situ synthesized through the condensation of o-vanillin and ethanolamine in the formation process of complexes. The resulting complexes possess "boat-like" structure constructed through three Fe ions and one Na ion with the fourth Fe ion acting as the "paddle". The "hull bottom" contains an eight-membered metallamacrocycle with metallacrown-like motif and [-M-O-] repeat unit. Both complexes display three-dimensional frameworks through C–H∙∙∙N hydrogen bonds, C–H∙∙∙Cl hydrogen bonds, and π-π stacking interactions with the introduction of solvent molecules and coordination anions. Variable-temperature magnetic susceptibility measurements reveal strong antiferromagnetic couplings between the metal centers in complexes 1 and 2.
Two novel polynuclear complexes {NaFe4(μ4-O)(L)4(μ2-Cl)[Fe(CN)5NO](H2O)(DMF)2} (1) and {NaFe4(μ4-O)(L)4(μ2-OEt)[Fe(CN)5NO](H2O)(DMF)2} (2) have been prepared using the tetradentate N-(2-hydroxyethyl)-3-methoxysalicylaldimine Schiff-base ligand (H2L) with the help of [Fe(CN)5NO]2- linkers, where the ligand was in situ synthesized through the condensation of o-vanillin and ethanolamine in the formation process of complexes. The resulting complexes possess "boat-like" structure constructed through three Fe ions and one Na ion with the fourth Fe ion acting as the "paddle". The "hull bottom" contains an eight-membered metallamacrocycle with metallacrown-like motif and [-M-O-] repeat unit. Both complexes display three-dimensional frameworks through C–H∙∙∙N hydrogen bonds, C–H∙∙∙Cl hydrogen bonds, and π-π stacking interactions with the introduction of solvent molecules and coordination anions. Variable-temperature magnetic susceptibility measurements reveal strong antiferromagnetic couplings between the metal centers in complexes 1 and 2.
2022, 41(3): 220305
doi: 10.14102/j.cnki.0254-5861.2011-3325
Abstract:
A novel quinazolinone derivative ethyl 2-(2-methyl-4-oxo-1, 2, 3, 4-tetrahydroquinazolin-2-yl) acetate (EMOTA) was synthesized and characterized by HRMS, 1H NMR, 13C NMR spectroscopy and X-ray crystallography, and the ion recognition performance of the compound was studied by fluorescence analysis measurements. The results showed that probe EMOTA has a rapid fluorescence response, good selectivity and sensitivity to Fe3+. When the concentration of Fe3+ was in the range of 0~10.0 × 10-5 mol/L, the fluorescence quenching could be affected by the probe, and the detection limit was 1.65 × 10-6 mol/L. In addition, the identification and detection of Fe3+ in water samples were studied, and the results showed that probe EMOTA has high efficiency, significant sensitivity and high selectivity on the recognition and detection of Fe3+ in water samples, which indicates probe EMOTA has a practical application prospect.
A novel quinazolinone derivative ethyl 2-(2-methyl-4-oxo-1, 2, 3, 4-tetrahydroquinazolin-2-yl) acetate (EMOTA) was synthesized and characterized by HRMS, 1H NMR, 13C NMR spectroscopy and X-ray crystallography, and the ion recognition performance of the compound was studied by fluorescence analysis measurements. The results showed that probe EMOTA has a rapid fluorescence response, good selectivity and sensitivity to Fe3+. When the concentration of Fe3+ was in the range of 0~10.0 × 10-5 mol/L, the fluorescence quenching could be affected by the probe, and the detection limit was 1.65 × 10-6 mol/L. In addition, the identification and detection of Fe3+ in water samples were studied, and the results showed that probe EMOTA has high efficiency, significant sensitivity and high selectivity on the recognition and detection of Fe3+ in water samples, which indicates probe EMOTA has a practical application prospect.
2022, 41(3): 220306
doi: 10.14102/j.cnki.0254-5861.2011-3350
Abstract:
A metal-organic framework (MOF)-conductive polymer composite film was constructed from PCN-222(Fe) nanoparticles and PEDOT: PSS solution by simple drop-casting approach. The composite film was tested as an electrocatalytic device for oxygen reduction reaction (ORR). The combination of PCN-222(Fe) MOF particles and conductive PEDOT matrix facilitates electron transfer in the composite material and improves the ORR performance of PCN-222(Fe). Levich plot and H2O2 quantification experiment show that PCN-222(Fe)/PEDOT: PSS film mainly catalyzes two-electron oxygen reduction and produces H2O2.
A metal-organic framework (MOF)-conductive polymer composite film was constructed from PCN-222(Fe) nanoparticles and PEDOT: PSS solution by simple drop-casting approach. The composite film was tested as an electrocatalytic device for oxygen reduction reaction (ORR). The combination of PCN-222(Fe) MOF particles and conductive PEDOT matrix facilitates electron transfer in the composite material and improves the ORR performance of PCN-222(Fe). Levich plot and H2O2 quantification experiment show that PCN-222(Fe)/PEDOT: PSS film mainly catalyzes two-electron oxygen reduction and produces H2O2.
2022, 41(3): 220307
doi: 10.14102/j.cnki.0254-5861.2011-3351
Abstract:
Crystalline polyoxo-titanium clusters (PTCs), as a molecular model of TiO2 nanomaterials, have attracted unprecedented attention due to their designable structure, tunable band gap, catalysis, and photochromic properties. A new trinuclear Ti3-oxo cluster, [Ti3(μ2-O)(μ3-O)(abz)6(OiPr)2]·CH3CN·H2O (Ti3), was synthesized by solvothermal method with a yield of 60% by using 4-aminobenzoic acid as ligand. Single-crystal X-ray diffraction shows that it has a [Ti3(μ2-O)(μ3-O)(abz)6(OiPr)2] trinuclear cluster structure. Ti3 crystallizes in monoclinic space group P21/c with a = 11.091(1), b = 22.837(2), c = 22.754(1) Å, β = 90.580(6)°, V = 5763.0(6) Å3, Z = 4, Dc = 1.345 g·cm-3, F(000) = 2412, μ = 2.743 mm−1, R = 0.0796, and wR = 0.2260 (I > 2σ(I)). Ti3 shows typical semiconductive behavior determined by temperature-dependent conductivity test. The chemiresistive humidity sensor fabricated by Ti3 showed good performance, including high response (four orders of magnitude current change from 0 to 100% RH) and fast response time (160 s) and recovery time (26 s).
Crystalline polyoxo-titanium clusters (PTCs), as a molecular model of TiO2 nanomaterials, have attracted unprecedented attention due to their designable structure, tunable band gap, catalysis, and photochromic properties. A new trinuclear Ti3-oxo cluster, [Ti3(μ2-O)(μ3-O)(abz)6(OiPr)2]·CH3CN·H2O (Ti3), was synthesized by solvothermal method with a yield of 60% by using 4-aminobenzoic acid as ligand. Single-crystal X-ray diffraction shows that it has a [Ti3(μ2-O)(μ3-O)(abz)6(OiPr)2] trinuclear cluster structure. Ti3 crystallizes in monoclinic space group P21/c with a = 11.091(1), b = 22.837(2), c = 22.754(1) Å, β = 90.580(6)°, V = 5763.0(6) Å3, Z = 4, Dc = 1.345 g·cm-3, F(000) = 2412, μ = 2.743 mm−1, R = 0.0796, and wR = 0.2260 (I > 2σ(I)). Ti3 shows typical semiconductive behavior determined by temperature-dependent conductivity test. The chemiresistive humidity sensor fabricated by Ti3 showed good performance, including high response (four orders of magnitude current change from 0 to 100% RH) and fast response time (160 s) and recovery time (26 s).
2022, 41(3): 220307
doi: 10.14102/j.cnki.0254-5861.2011-3352
Abstract:
Bismuth oxychloride (BiOCl) square microplates were prepared via a facile hydrothermal method. The X-ray diffraction patterns of the samples reveal a tetragonal BiOCl phase, and the scanning electron microscopy images show plate-like structures with large lateral size of 3~6 μm and thickness in the range of 100~300 nm. The effects of surfactant, reaction temperature and duration on the morphology of BiOCl powders are systematically investigated. The polar behavior of a BiOCl single-crystalline microplate is examined by using piezoresponse force microscopy evidenced over 80 pm displacement under 40 V bias voltage. In addition, the photoelectric performance of the BiOCl microplates is evaluated by using electrochemical workstation with three-electrode system, and large photocurrent densities (over 0.5 μA/cm2) and fast photoresponse (0.7~1.1 s) are detected by applying both 365 nm monochromatic light and sunlight illumination. The surface potential changes of BiOCl microplate under different light condition, characterized by in-situ Kelvin probe force microscopy, further verify the separation ability of the photo-induced charge carriers. These findings would be beneficial for further design photocatalytic and piezocatalytic materials.
Bismuth oxychloride (BiOCl) square microplates were prepared via a facile hydrothermal method. The X-ray diffraction patterns of the samples reveal a tetragonal BiOCl phase, and the scanning electron microscopy images show plate-like structures with large lateral size of 3~6 μm and thickness in the range of 100~300 nm. The effects of surfactant, reaction temperature and duration on the morphology of BiOCl powders are systematically investigated. The polar behavior of a BiOCl single-crystalline microplate is examined by using piezoresponse force microscopy evidenced over 80 pm displacement under 40 V bias voltage. In addition, the photoelectric performance of the BiOCl microplates is evaluated by using electrochemical workstation with three-electrode system, and large photocurrent densities (over 0.5 μA/cm2) and fast photoresponse (0.7~1.1 s) are detected by applying both 365 nm monochromatic light and sunlight illumination. The surface potential changes of BiOCl microplate under different light condition, characterized by in-situ Kelvin probe force microscopy, further verify the separation ability of the photo-induced charge carriers. These findings would be beneficial for further design photocatalytic and piezocatalytic materials.
Improvement of the Selectivity for Hydrogen Peroxide Production via the Synergy of TiO2 and Graphene
2022, 41(3): 220308
doi: 10.14102/j.cnki.0254-5861.2011-3299
Abstract:
To replace the four-electron transferred pathway of oxygen reduction reaction (ORR) by two-electron transferred pathway of ORR (2e- ORR) is desirable for the production of hydrogen peroxide with added-value. The development of electrocatalysts with high selectivity toward 2e- ORR is of great interest but it is still a challenge. Here, we synthesized the graphene-supported titanium dioxide nanocomposite as the 2e- ORR catalysts by a combinative process of hydrothermal methods and calcination. Due to the synergistic effect between the graphene with high conductivity and the titanium dioxide with defect sites, the composite TiO2/graphene exhibits the improved selectivity (up to 90%) for oxygen converting into hydrogen peroxide.
To replace the four-electron transferred pathway of oxygen reduction reaction (ORR) by two-electron transferred pathway of ORR (2e- ORR) is desirable for the production of hydrogen peroxide with added-value. The development of electrocatalysts with high selectivity toward 2e- ORR is of great interest but it is still a challenge. Here, we synthesized the graphene-supported titanium dioxide nanocomposite as the 2e- ORR catalysts by a combinative process of hydrothermal methods and calcination. Due to the synergistic effect between the graphene with high conductivity and the titanium dioxide with defect sites, the composite TiO2/graphene exhibits the improved selectivity (up to 90%) for oxygen converting into hydrogen peroxide.
2022, 41(3): 220309
doi: 10.14102/j.cnki.0254-5861.2011-3303
Abstract:
By using solvothermal method, a one-dimensional chain compound [KEu2(FDCA)3(H2O)9·0.5(FDCA)] (1) was synthesized. Single-crystal X-ray diffraction data reveal that 1 crystallizes in monoclinic system, space group P21/n with a = 12.1996(1), b = 18.6454(2), c = 17.7123(2) Å, β = 98.8460(10)°, Dc = 1.753 g/cm3, Z = 2, V = 3981.03(7) Å3, R = 0.0544 and wR = 0.1511 for 7886 observed reflections with I > 2σ(I). In 1, three FDCA2– ligands construct a "23-crown-9-like" structure as the second building units (SBUs) to further form an infinite 1D chain. Meanwhile, the fluorescent result reveals that compound 1 can selectively and sensitively sense Fe3+ by the fluorescence quenching.
By using solvothermal method, a one-dimensional chain compound [KEu2(FDCA)3(H2O)9·0.5(FDCA)] (1) was synthesized. Single-crystal X-ray diffraction data reveal that 1 crystallizes in monoclinic system, space group P21/n with a = 12.1996(1), b = 18.6454(2), c = 17.7123(2) Å, β = 98.8460(10)°, Dc = 1.753 g/cm3, Z = 2, V = 3981.03(7) Å3, R = 0.0544 and wR = 0.1511 for 7886 observed reflections with I > 2σ(I). In 1, three FDCA2– ligands construct a "23-crown-9-like" structure as the second building units (SBUs) to further form an infinite 1D chain. Meanwhile, the fluorescent result reveals that compound 1 can selectively and sensitively sense Fe3+ by the fluorescence quenching.
2022, 41(3): 220310
doi: 10.14102/j.cnki.0254-5861.2011-3357
Abstract:
Silver thiolate polymers are intercepted to form different structural fragments when reacting with variant solubilizing reagents, which usually serve as the starting point for the preparation of clusters. However, such a process is still far from clear. Herein, we report the controlled synthesis of silver-t-butylthiolate clusters from reactions of polymeric [AgtBuS]n and suitable templates in the presence of solubilizing reagents to offer a detailed look at the mechanism of cluster's formation. As the provided solubilizing reagents have weak coordination ability, such as O- or N-donating ligands, the obtained polymeric compound retains the linear structure pattern that S and Ag atoms are arranged alternately. When extra templates NO3– and CO32– are applied, the disk-like clusters Ag19 and Ag20 are constructed with the same [AgtBuS]5 circles that may directly cyclize from the linear [AgtBuS]n fragments. In contrast, (EtO)2PS2– and (iPrO)2PS2– anions have large size and strong coordination ability rendering the structure of the polymer completely fragmented. Thus extremely short [AgtBuS]n pieces with silver ions and solubilizing ligands assemble around the templates V2O74– and W2O94–, leading to the formation of clusters Ag22 and Ag24.
Silver thiolate polymers are intercepted to form different structural fragments when reacting with variant solubilizing reagents, which usually serve as the starting point for the preparation of clusters. However, such a process is still far from clear. Herein, we report the controlled synthesis of silver-t-butylthiolate clusters from reactions of polymeric [AgtBuS]n and suitable templates in the presence of solubilizing reagents to offer a detailed look at the mechanism of cluster's formation. As the provided solubilizing reagents have weak coordination ability, such as O- or N-donating ligands, the obtained polymeric compound retains the linear structure pattern that S and Ag atoms are arranged alternately. When extra templates NO3– and CO32– are applied, the disk-like clusters Ag19 and Ag20 are constructed with the same [AgtBuS]5 circles that may directly cyclize from the linear [AgtBuS]n fragments. In contrast, (EtO)2PS2– and (iPrO)2PS2– anions have large size and strong coordination ability rendering the structure of the polymer completely fragmented. Thus extremely short [AgtBuS]n pieces with silver ions and solubilizing ligands assemble around the templates V2O74– and W2O94–, leading to the formation of clusters Ag22 and Ag24.
2022, 41(3): 220310
doi: 10.14102/j.cnki.0254-5861.2011-3270
Abstract:
Cyclin D dependent kinases 4/6 regulate the entry of cells into S phase and are effective target for the discovery of anticancer drugs. In this article, 3D-QSAR modeling including comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis fields (CoMSIA) was implemented on 52 dual CDK4/6 inhibitors. As a result, we obtained a pretty good 3D-QSAR model, which is CoMFACDK4 with q2 to be 0.543 and r2 to be 0.967; CoMSIACDK4 with q2 being 0.518 and r2 being 0.937; CoMFACDK6 with q2 to be 0.624 and r2 to be 0.984; CoMSIACDK6 with q2 being 0.584 and r2 being 0.975. Molecular docking confirmed the important residues for interactions. Molecular dynamics simulation further confirmed binding affinity with key residues of protein, such as Lys22, Lys35, Val96 for CDK4 and Lys43, His100, Val101 for CDK6 at the active sites. Then these results offered new directions to explore new inhibitors of CDK4/6. Finally, we designed 10 novel compounds with promising expected activity and ADME/T properties, and provided referable synthetic routes.
Cyclin D dependent kinases 4/6 regulate the entry of cells into S phase and are effective target for the discovery of anticancer drugs. In this article, 3D-QSAR modeling including comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis fields (CoMSIA) was implemented on 52 dual CDK4/6 inhibitors. As a result, we obtained a pretty good 3D-QSAR model, which is CoMFACDK4 with q2 to be 0.543 and r2 to be 0.967; CoMSIACDK4 with q2 being 0.518 and r2 being 0.937; CoMFACDK6 with q2 to be 0.624 and r2 to be 0.984; CoMSIACDK6 with q2 being 0.584 and r2 being 0.975. Molecular docking confirmed the important residues for interactions. Molecular dynamics simulation further confirmed binding affinity with key residues of protein, such as Lys22, Lys35, Val96 for CDK4 and Lys43, His100, Val101 for CDK6 at the active sites. Then these results offered new directions to explore new inhibitors of CDK4/6. Finally, we designed 10 novel compounds with promising expected activity and ADME/T properties, and provided referable synthetic routes.
2022, 41(3): 220312
doi: 10.14102/j.cnki.0254-5861.2011-3273
Abstract:
Silver nanoparticles (AgNPs) are widely adopted in polyurethane foams (PUFs) as a type of antibacterial agent. However, due to its poor interfacial interaction, AgNPs are difficult to be dispersed in the polymer matrix uniformly, which deteriorates the enhancement effect. In this paper, silver-coated graphene nanocomposite (Ag/GO) is prepared by an enzyme reductant which is efficient and non-toxic. Compared with traditional antibacterial agent, the Ag/GO nanoparticles can be uniformly dispersed in the nanocomposite, which means that Ag/GO can be well-dispersed into the polyurethane foams (PUFs). Compared with AgNPs modified PUFs, the as-prepared Ag/GO modified PUFs have a 1.85% improvement in resilience, 7.9% improvement in tensile strength, 6.52% improvement in tensile elongation, and 8.74% improvement in bacteriostats rate at a loading of 0.4%.
Silver nanoparticles (AgNPs) are widely adopted in polyurethane foams (PUFs) as a type of antibacterial agent. However, due to its poor interfacial interaction, AgNPs are difficult to be dispersed in the polymer matrix uniformly, which deteriorates the enhancement effect. In this paper, silver-coated graphene nanocomposite (Ag/GO) is prepared by an enzyme reductant which is efficient and non-toxic. Compared with traditional antibacterial agent, the Ag/GO nanoparticles can be uniformly dispersed in the nanocomposite, which means that Ag/GO can be well-dispersed into the polyurethane foams (PUFs). Compared with AgNPs modified PUFs, the as-prepared Ag/GO modified PUFs have a 1.85% improvement in resilience, 7.9% improvement in tensile strength, 6.52% improvement in tensile elongation, and 8.74% improvement in bacteriostats rate at a loading of 0.4%.
2022, 41(3): 220313
doi: 10.14102/j.cnki.0254-5861.2011-3288
Abstract:
A novel Schiff-base fluorescent probe 6, 6'-((1E, 1'E)-(ethane-1, 2-diylbis(azaneylylidene))bis-(methaneylylidene))bis(3-(diethylamino)phenol) (L) was derived from the 2:1 M condensation of 4-(diethylamino)-2-hydroxybenzaldehyde with ethylenediamine and characterized by 1H NMR, 13C NMR and FT-IR spectroscopies. The results of spectral analysis showed that the probe L is selective and sensitive to Cu2+. The detection limit of L is found to be 19 nmol·L-1. There is a good linear relationship between the fluorescence intensity of probe L and the concentration of Cu2+ in the range of 0 to 20 μmol·L-1. X-ray crystal structure of the L-Cu2+ complex and the Job plot revealed a 1:1 L-Cu2+ identification.
A novel Schiff-base fluorescent probe 6, 6'-((1E, 1'E)-(ethane-1, 2-diylbis(azaneylylidene))bis-(methaneylylidene))bis(3-(diethylamino)phenol) (L) was derived from the 2:1 M condensation of 4-(diethylamino)-2-hydroxybenzaldehyde with ethylenediamine and characterized by 1H NMR, 13C NMR and FT-IR spectroscopies. The results of spectral analysis showed that the probe L is selective and sensitive to Cu2+. The detection limit of L is found to be 19 nmol·L-1. There is a good linear relationship between the fluorescence intensity of probe L and the concentration of Cu2+ in the range of 0 to 20 μmol·L-1. X-ray crystal structure of the L-Cu2+ complex and the Job plot revealed a 1:1 L-Cu2+ identification.
2022, 41(3): 220313
doi: 10.14102/j.cnki.0254-5861.2011-3293
Abstract:
Aiming to better understand the physiochemical properties of lignite, we select Zhaotong lignite as object and adopt simulation and experiment data to construct its molecular structure. Firstly, the important parameters including carbon skeleton, valence state and functional group of the sample are obtained by ultimate analysis, 13C NMR, XPS and Py-GC/MS. Results indicate that the ratio of aromatic carbon and aromatic bridge carbon to surrounding carbon of the sample are 40.32% and 0.14, respectively. Such results imply that the aromatic structure of the sample is dominated by benzene and naphthalene. Moreover, the ratio of aliphatic carbon is 51.55%, and the aliphatic structure is mainly comprised by methyl, methylene, quaternary carbon and oxygen-aliphatic carbon. Oxygen atoms principally exist in ether, carbonyl and carboxyl groups, of which ether accounts for 70.2%. Additionally, the contents of pyridine, pyrrole and quaternary nitrogen are 25.2%, 46.3% and 13.0%, respectively. Based on the aforementioned results, the molecular structure model of Zhaotong lignite is constructed by the method of computer-aided molecular design. Subsequently, the molecular formula of Zhaotong lignite is calculated as C183H211O55N4. Finally, in order to verify the reasonability of the constructed model, the 13C NMR of the molecular structure model is simulated by employing the basis set of GIAO/6-31G at the Gaussian 09 computing platform. These simulated results agree well with the experimental ones, which suggests that the molecular structure model of Zhaotong lignite is accurate and reasonable.
Aiming to better understand the physiochemical properties of lignite, we select Zhaotong lignite as object and adopt simulation and experiment data to construct its molecular structure. Firstly, the important parameters including carbon skeleton, valence state and functional group of the sample are obtained by ultimate analysis, 13C NMR, XPS and Py-GC/MS. Results indicate that the ratio of aromatic carbon and aromatic bridge carbon to surrounding carbon of the sample are 40.32% and 0.14, respectively. Such results imply that the aromatic structure of the sample is dominated by benzene and naphthalene. Moreover, the ratio of aliphatic carbon is 51.55%, and the aliphatic structure is mainly comprised by methyl, methylene, quaternary carbon and oxygen-aliphatic carbon. Oxygen atoms principally exist in ether, carbonyl and carboxyl groups, of which ether accounts for 70.2%. Additionally, the contents of pyridine, pyrrole and quaternary nitrogen are 25.2%, 46.3% and 13.0%, respectively. Based on the aforementioned results, the molecular structure model of Zhaotong lignite is constructed by the method of computer-aided molecular design. Subsequently, the molecular formula of Zhaotong lignite is calculated as C183H211O55N4. Finally, in order to verify the reasonability of the constructed model, the 13C NMR of the molecular structure model is simulated by employing the basis set of GIAO/6-31G at the Gaussian 09 computing platform. These simulated results agree well with the experimental ones, which suggests that the molecular structure model of Zhaotong lignite is accurate and reasonable.
2022, 41(3): 220314
doi: 10.14102/j.cnki.0254-5861.2011-3296
Abstract:
The utilization of 2, 6-bis(imidazo[1, 5-a]pyridin-3-yl)pyridine (bipp) and 3-(pyridin-2-yl)imidazo[1, 5-a]pyridine (pip) in the compounds of manganese(Ⅱ) and copper(Ⅰ) ions is presented. Two complexes, [Mn(bipp)(SO4)(H2O)]n (1) and [Cu(pip)2]ClO4 (2), were prepared with different characteristics in structure. Compound 1 exhibits a one-dimensional chain topology, and 2 is a homoleptic Cu(Ⅰ) complex. The dc magnetic susceptibility investigations reveal the antiferromagnetic (AF) MnⅡ…MnⅡ interactions in complex 1. The catalytic activity of compound 2 toward ketalization reactions was studied. Complex 2 exhibits high activity for the ketalization transformations of aliphatic ketones.
The utilization of 2, 6-bis(imidazo[1, 5-a]pyridin-3-yl)pyridine (bipp) and 3-(pyridin-2-yl)imidazo[1, 5-a]pyridine (pip) in the compounds of manganese(Ⅱ) and copper(Ⅰ) ions is presented. Two complexes, [Mn(bipp)(SO4)(H2O)]n (1) and [Cu(pip)2]ClO4 (2), were prepared with different characteristics in structure. Compound 1 exhibits a one-dimensional chain topology, and 2 is a homoleptic Cu(Ⅰ) complex. The dc magnetic susceptibility investigations reveal the antiferromagnetic (AF) MnⅡ…MnⅡ interactions in complex 1. The catalytic activity of compound 2 toward ketalization reactions was studied. Complex 2 exhibits high activity for the ketalization transformations of aliphatic ketones.
2022, 41(3): 220315
doi: 10.14102/j.cnki.0254-5861.2011-3305
Abstract:
Structural growth mechanism, energetics, and electronic properties of cationic, neutral, and anionic lutetium doped germanium cluster LuGen(+/0/-) (n = 6~19) were comprehensively studied by the ABCluster unbiased global search technique with a hybrid density functional theory approach. Compared to the experimental PES, the anion evolution of structure can be clearly defined as four-phase: from the adsorbed to the link structure, then to the half cage motif, and finally to the endohedral structure. The results revealed that the LuGe16- as Frank-Kasper structure with high symmetry of Td can greatly enhance the stabilities. Doped structures have shown thermodynamic stability and appropriate energy gap. These materials are suitable semiconductors. Various approaches, including quasi-spherical geometry with closed-shell model, aromaticity, UV-Vis spectra, density of states (DOS) and partial density of states (PDOS) were applied to further support the results.
Structural growth mechanism, energetics, and electronic properties of cationic, neutral, and anionic lutetium doped germanium cluster LuGen(+/0/-) (n = 6~19) were comprehensively studied by the ABCluster unbiased global search technique with a hybrid density functional theory approach. Compared to the experimental PES, the anion evolution of structure can be clearly defined as four-phase: from the adsorbed to the link structure, then to the half cage motif, and finally to the endohedral structure. The results revealed that the LuGe16- as Frank-Kasper structure with high symmetry of Td can greatly enhance the stabilities. Doped structures have shown thermodynamic stability and appropriate energy gap. These materials are suitable semiconductors. Various approaches, including quasi-spherical geometry with closed-shell model, aromaticity, UV-Vis spectra, density of states (DOS) and partial density of states (PDOS) were applied to further support the results.
2022, 41(3): 220316
doi: 10.14102/j.cnki.0254-5861.2011-3306
Abstract:
Pesticides released into the environment may pose potential risks to the ecological system and human health. However, existing toxicity data on pesticide mixtures still lack, especially regarding the toxic interactions of their mixtures. This study aimed to determine the toxic interactions of binary mixtures of pesticides on Scenedesmus Obliquus (S. obliquus) and to build quantitative structure-activity relationship models (QASR) for predicting the mixture toxicities. By applying direct equipartition ray method to design binary mixtures of five pesticides (linuron, dimethoate, dichlorvos, trichlorfon and metribuzin), the toxicity of a single pesticide and its mixture was tested by microplate toxicity analysis on S. obliquus. The QASR models were built for combined toxicity of binary mixtures of pesticides at the half-maximal effective concentration (EC50), 30% maximal effective concentration (EC30) and 10% maximal effective concentration (EC10). The results showed that the single toxicity follows: metribuzin > linuron > dichlorvos > trichlorfon > dimethoate. The mixtures of linuron and trichlorfon, dichlorvos and metribuzin, dimethoate and metribuzin induced synergetic effects, while the remaining binary mixtures exhibited additive. The developed QSAR models were internally validated using the leave-one-out cross-validation (LOO), leave-many-out cross-validation (LMO), bootstrapping, and y-randomization test, and externally validated by the test sets. All three QSAR models satisfied well with the experimental values for all mixture toxicities, and presented high internally (R2 and Q2 > 0.85) and externally (QF12, QF22, and QF32 > 0.80) predictive powers. The developed QSAR models could accurately predict the toxicity values of EC50, EC30 and EC10 and were superior to the concentration addition model's results (CA). Compared to the additive effect, the QSAR model could more accurately predict the binary mixture toxicities of pesticides with synergistic effects.
Pesticides released into the environment may pose potential risks to the ecological system and human health. However, existing toxicity data on pesticide mixtures still lack, especially regarding the toxic interactions of their mixtures. This study aimed to determine the toxic interactions of binary mixtures of pesticides on Scenedesmus Obliquus (S. obliquus) and to build quantitative structure-activity relationship models (QASR) for predicting the mixture toxicities. By applying direct equipartition ray method to design binary mixtures of five pesticides (linuron, dimethoate, dichlorvos, trichlorfon and metribuzin), the toxicity of a single pesticide and its mixture was tested by microplate toxicity analysis on S. obliquus. The QASR models were built for combined toxicity of binary mixtures of pesticides at the half-maximal effective concentration (EC50), 30% maximal effective concentration (EC30) and 10% maximal effective concentration (EC10). The results showed that the single toxicity follows: metribuzin > linuron > dichlorvos > trichlorfon > dimethoate. The mixtures of linuron and trichlorfon, dichlorvos and metribuzin, dimethoate and metribuzin induced synergetic effects, while the remaining binary mixtures exhibited additive. The developed QSAR models were internally validated using the leave-one-out cross-validation (LOO), leave-many-out cross-validation (LMO), bootstrapping, and y-randomization test, and externally validated by the test sets. All three QSAR models satisfied well with the experimental values for all mixture toxicities, and presented high internally (R2 and Q2 > 0.85) and externally (QF12, QF22, and QF32 > 0.80) predictive powers. The developed QSAR models could accurately predict the toxicity values of EC50, EC30 and EC10 and were superior to the concentration addition model's results (CA). Compared to the additive effect, the QSAR model could more accurately predict the binary mixture toxicities of pesticides with synergistic effects.
2022, 41(3): 220317
doi: 10.14102/j.cnki.0254-5861.2011-3308
Abstract:
The further interaction mechanism towards renin inhibitors was revealed by comparison of renin with different active inhibitors in aqueous solution. Molecular docking and molecular dynamics (MD) simulations were combined for the research. The results reflected that electrostatic and hydrophobic effects were the major interactions for renin inhibitors forming complexes with renin, and some residues were the key to the formation of complex, especially Asp38/Asp226. The factor of different activities performed in renin inhibitors was illustrated as well. For the higher active renin inhibitor, it possessed stronger affinity with renin, and its detected conformation was more extended to fit for the key binding site. This promoted the capacity to form special interactions with the key residues. While conformation of the lower active renin inhibitor performed folded in the active site of renin, the interactions to the important pocket S3sp was restricted, resulting in undesirable bioactivity.
The further interaction mechanism towards renin inhibitors was revealed by comparison of renin with different active inhibitors in aqueous solution. Molecular docking and molecular dynamics (MD) simulations were combined for the research. The results reflected that electrostatic and hydrophobic effects were the major interactions for renin inhibitors forming complexes with renin, and some residues were the key to the formation of complex, especially Asp38/Asp226. The factor of different activities performed in renin inhibitors was illustrated as well. For the higher active renin inhibitor, it possessed stronger affinity with renin, and its detected conformation was more extended to fit for the key binding site. This promoted the capacity to form special interactions with the key residues. While conformation of the lower active renin inhibitor performed folded in the active site of renin, the interactions to the important pocket S3sp was restricted, resulting in undesirable bioactivity.
2022, 41(3): 220318
doi: 10.14102/j.cnki.0254-5861.2011-3312
Abstract:
The preparation method of a funnel like ligand derived from calix[6]arene and tris(2-pyridyl-methyl)anime has been improved. The Cu(II) complex was obtained and characterized by ESI-MS, EPR, UV-Vis spectra and crystallographic analysis. In the complex, a guest acetonitrile molecule is introduced into the cavity of the ligand host via the coordination with Cu(II) center.
The preparation method of a funnel like ligand derived from calix[6]arene and tris(2-pyridyl-methyl)anime has been improved. The Cu(II) complex was obtained and characterized by ESI-MS, EPR, UV-Vis spectra and crystallographic analysis. In the complex, a guest acetonitrile molecule is introduced into the cavity of the ligand host via the coordination with Cu(II) center.
2022, 41(3): 220319
doi: 10.14102/j.cnki.0254-5861.2011-3321
Abstract:
Aldosterone synthase inhibitors can lessen the production of aldosterone in organisms, which effectively affecting the treatment of hypertension. A series of computational approaches like QSAR, docking, DFT and molecular dynamics simulation are applied on 40 benzimidazole derivatives of aldosterone synthase (CYP11B2) inhibitors. Statistical parameters: Q2 = 0.877, R2 = 0.983 (CoMFA) and Q2 = 0.848, R2 = 0.994 (CoMSIA) indicate on good predictive power of both models and DFT's result illustrates the stability of both models. Besides, Y-randomization test is also performed to ensure the robustness of the obtained 3D-QSAR models. Docking studies show inhibitors rely on π-π interaction with residues, such as Phe130, Ala313 and Phe481. Molecular dynamics simulation results further confirm that the hydrophobic interaction with proteins enhances the inhibitor's inhibitory effect. Based on QSAR studies and molecular docking, we designed novel compounds with enhanced activity against aldosterone synthase. Furthermore, the newly designed compounds are analyzed for their ADMET properties and drug likeness and the results show that they all have excellent bioavailability.
Aldosterone synthase inhibitors can lessen the production of aldosterone in organisms, which effectively affecting the treatment of hypertension. A series of computational approaches like QSAR, docking, DFT and molecular dynamics simulation are applied on 40 benzimidazole derivatives of aldosterone synthase (CYP11B2) inhibitors. Statistical parameters: Q2 = 0.877, R2 = 0.983 (CoMFA) and Q2 = 0.848, R2 = 0.994 (CoMSIA) indicate on good predictive power of both models and DFT's result illustrates the stability of both models. Besides, Y-randomization test is also performed to ensure the robustness of the obtained 3D-QSAR models. Docking studies show inhibitors rely on π-π interaction with residues, such as Phe130, Ala313 and Phe481. Molecular dynamics simulation results further confirm that the hydrophobic interaction with proteins enhances the inhibitor's inhibitory effect. Based on QSAR studies and molecular docking, we designed novel compounds with enhanced activity against aldosterone synthase. Furthermore, the newly designed compounds are analyzed for their ADMET properties and drug likeness and the results show that they all have excellent bioavailability.
2022, 41(3): 220321
doi: 10.14102/j.cnki.0254-5861.2011-3326
Abstract:
A variety of new N-(5-(benzofuranol-7-oxymethyl)-1, 3, 4-thiadiazol-2-yl)amide compounds (8a-i) were synthesized through four steps from benzofuranol as raw materials. The crystal structure of compound 8a (C17H21N3O3S, Mr = 347.43) was measured by X-ray diffraction, which was classified as monoclinic system, Z = 4, V = 1742.72(8) Å3, Dc = 1.324 Mg/m3, F(000) = 736, S = 1.03, μ = 0.21 mm-1, space group P21 with a = 9.9177(3), b = 8.9519(2), c = 19.8679(5) Å, the final R = 0.035 and wR = 0.105 for 3873 observed reflections (I > 2σ(I)). The X-ray structure presented N(3)–H(3)···N(2) and C(6)–H(6)···O(3) intermolecular hydrogen bonds, which acted as an important role in stabilizing the crystal structure. Additionally, preliminary biological assay on compound 8a showed good fungicidal activity in vivo, with the inhibition of 75% against Pseudoperonospora cubensis at 200 mg/L.
A variety of new N-(5-(benzofuranol-7-oxymethyl)-1, 3, 4-thiadiazol-2-yl)amide compounds (8a-i) were synthesized through four steps from benzofuranol as raw materials. The crystal structure of compound 8a (C17H21N3O3S, Mr = 347.43) was measured by X-ray diffraction, which was classified as monoclinic system, Z = 4, V = 1742.72(8) Å3, Dc = 1.324 Mg/m3, F(000) = 736, S = 1.03, μ = 0.21 mm-1, space group P21 with a = 9.9177(3), b = 8.9519(2), c = 19.8679(5) Å, the final R = 0.035 and wR = 0.105 for 3873 observed reflections (I > 2σ(I)). The X-ray structure presented N(3)–H(3)···N(2) and C(6)–H(6)···O(3) intermolecular hydrogen bonds, which acted as an important role in stabilizing the crystal structure. Additionally, preliminary biological assay on compound 8a showed good fungicidal activity in vivo, with the inhibition of 75% against Pseudoperonospora cubensis at 200 mg/L.
2022, 41(3): 220321
doi: 10.14102/j.cnki.0254-5861.2011-3332
Abstract:
As a typical electron deficient element, beryllium is potentially suitable for designing the species with novel non-classical planar hypercoordinate carbon due to high preference for the planar structures by small beryllium-containing clusters. In particular, the CBe54– cluster with a planar pentacoordinate carbon (ppC) had been proved by many previous studies to be an excellent template structure for the systematic design of ppC species through attaching various monovalent atoms on the bridging position of Be–Be edges. In this work, based on the analysis and extension on our recently reported CBe4Mnn–2 (M = Li, Au, n = 1~3) species, we propose that ptC cluster CBe42– is similar to CBe54– in that it can also be employed as a template structure to systematically design the ptC species through binding various monovalent atoms on the bridging position of Be–Be edges. Our extensive screening suggests that the feasible bridging atoms (E) can be found in group 1 (H, Li, Na), group 11 (Cu, Ag, Au), and group 17 (F, Cl, Br, I) elements, leading to total thirty eligible ptC species with CBe4 core moiety (CBe4Enn–2). The ptC atoms in these species are involved into three delocalized σ bonds and a delocalized π bond, thereby not only obeying the octet rule, but also possessing novel 6σ +2π double aromaticity, which significantly stabilizes the ptC arrangement. In addition, the attached bridging atoms can stabilize the CBe4 core ptC moiety by replacing the highly diffused Be–Be two-center two-electron bonds with the much less diffused Be–E two-center two-electron bonds or Be–E–Be three-center two-electron bonds, as reflected by the increasing HOMO-LUMO gaps when the number of bridging atoms increases. Remarkably, the stochastic search algorithm in combination with high level CCSD(T) calculations revealed that twenty-six of the thirty-one ptC species (including previously reported six species) were global energy minima on their corresponding potential energy surfaces, in which twenty-five of them were also confirmed to be dynamically viable. They are suitable for the generation and characterization in gas phase experiments and followed spectroscopic studies.
As a typical electron deficient element, beryllium is potentially suitable for designing the species with novel non-classical planar hypercoordinate carbon due to high preference for the planar structures by small beryllium-containing clusters. In particular, the CBe54– cluster with a planar pentacoordinate carbon (ppC) had been proved by many previous studies to be an excellent template structure for the systematic design of ppC species through attaching various monovalent atoms on the bridging position of Be–Be edges. In this work, based on the analysis and extension on our recently reported CBe4Mnn–2 (M = Li, Au, n = 1~3) species, we propose that ptC cluster CBe42– is similar to CBe54– in that it can also be employed as a template structure to systematically design the ptC species through binding various monovalent atoms on the bridging position of Be–Be edges. Our extensive screening suggests that the feasible bridging atoms (E) can be found in group 1 (H, Li, Na), group 11 (Cu, Ag, Au), and group 17 (F, Cl, Br, I) elements, leading to total thirty eligible ptC species with CBe4 core moiety (CBe4Enn–2). The ptC atoms in these species are involved into three delocalized σ bonds and a delocalized π bond, thereby not only obeying the octet rule, but also possessing novel 6σ +2π double aromaticity, which significantly stabilizes the ptC arrangement. In addition, the attached bridging atoms can stabilize the CBe4 core ptC moiety by replacing the highly diffused Be–Be two-center two-electron bonds with the much less diffused Be–E two-center two-electron bonds or Be–E–Be three-center two-electron bonds, as reflected by the increasing HOMO-LUMO gaps when the number of bridging atoms increases. Remarkably, the stochastic search algorithm in combination with high level CCSD(T) calculations revealed that twenty-six of the thirty-one ptC species (including previously reported six species) were global energy minima on their corresponding potential energy surfaces, in which twenty-five of them were also confirmed to be dynamically viable. They are suitable for the generation and characterization in gas phase experiments and followed spectroscopic studies.
2022, 41(3): 220322
doi: 10.14102/j.cnki.0254-5861.2011-3335
Abstract:
To reveal the potential fungicidal mechanism of 5-((4-((4-chlorophenoxy)methyl)-5-iodo-1H-1, 2, 3-triazole-1-yl)methyl)-2-methylpyrimidin-4-amine (PA-1) against Botrytis cinerea (B. cinerea), the three-dimensional structure of B. cinerea pyruvate dehydrogenase complex E1 component (PDHc-E1) is homology modeled, as the PA-1 shows potent E. coli PDHc-E1 and B. cinerea inhibition. Subsequent molecular docking indicates the PA-1 can tightly bind to B. cinerea PDHc-E1. Molecular dynamic simulation and MM-PBSA calculation both demonstrate that two intermolecular interactions, π-π stacking and hydrophobic forces, provide the most contributions to the binding of PA-1 and B. cinerea PDHc-E1. Furthermore, the halogen bonding interaction between the iodine atom in PA-1 and OH in Ser181 is also crucial. The present study provides a valuable attempt to homology model the structure of B. cinerea PDHc-E1 and some key factors for the rational structure optimization of PA-1.
To reveal the potential fungicidal mechanism of 5-((4-((4-chlorophenoxy)methyl)-5-iodo-1H-1, 2, 3-triazole-1-yl)methyl)-2-methylpyrimidin-4-amine (PA-1) against Botrytis cinerea (B. cinerea), the three-dimensional structure of B. cinerea pyruvate dehydrogenase complex E1 component (PDHc-E1) is homology modeled, as the PA-1 shows potent E. coli PDHc-E1 and B. cinerea inhibition. Subsequent molecular docking indicates the PA-1 can tightly bind to B. cinerea PDHc-E1. Molecular dynamic simulation and MM-PBSA calculation both demonstrate that two intermolecular interactions, π-π stacking and hydrophobic forces, provide the most contributions to the binding of PA-1 and B. cinerea PDHc-E1. Furthermore, the halogen bonding interaction between the iodine atom in PA-1 and OH in Ser181 is also crucial. The present study provides a valuable attempt to homology model the structure of B. cinerea PDHc-E1 and some key factors for the rational structure optimization of PA-1.
2022, 41(3): 220323
doi: 10.14102/j.cnki.0254-5861.2011-3339
Abstract:
An unusual iron complex with formally zero oxidation state, iron bis(6, 6΄-dimethyl-2, 2΄-bipyridine), was synthesized and its crystal structure was determined. Combination of experimental and theoretical studies reveals that the electronic structure of the complex is best described as Fe(Ⅱ)(Mebipy-)2 with anionic Mebipy- ligands and high-spin Fe(Ⅱ) center.
An unusual iron complex with formally zero oxidation state, iron bis(6, 6΄-dimethyl-2, 2΄-bipyridine), was synthesized and its crystal structure was determined. Combination of experimental and theoretical studies reveals that the electronic structure of the complex is best described as Fe(Ⅱ)(Mebipy-)2 with anionic Mebipy- ligands and high-spin Fe(Ⅱ) center.
2022, 41(3): 220324
doi: 10.14102/j.cnki.0254-5861.2011-3343
Abstract:
The in vitro anti-proliferative activity (pICi, i = hp, ca, hl) of fluoroquinolone (rhodanine α, β-unsaturated ketone) amide compounds, referred to as "fluoroquinolone amide derivatives (FQADs)" towards Hep-3B, Capan-1 and HL60 cells, was studied by the 3D-QSAR method of comparative molecular field analysis (CoMFA). Based on the training set of 14 compounds, the prediction model was established, which was further verified by the test set of 5 compounds with template molecule included. It is found that steric and electrostatic fields contribute 66.8% and 33.2% to pIChp, 61.4% and 38.6% to pICca, and 61.5% and 38.5% to pIChl, respectively. The Rcv2 (i.e, cross-validation coefficient) is 0.324, 0.381, and 0.421 for pIChp, pICca, and pIChl, respectively, while the corresponding R2 (i.e, non-cross-validation coefficient) all reach 0.999. Then, the models were employed to estimate the activities of the training and test compounds, and the results show that the stability and predictability of developed models are very satisfactory. According to the contour maps of steric and electronic fields, bulky groups linked to 2-, 3-, 4-positions of phenyl ring, and electropositive groups near the 4-position and electronegative groups far away may increase the anti-proliferative activity. Using the information provided by the 3D contour maps, four new FQADs owing higher antiproliferative activity were designed, but their effectiveness should be further tested by experiments.
The in vitro anti-proliferative activity (pICi, i = hp, ca, hl) of fluoroquinolone (rhodanine α, β-unsaturated ketone) amide compounds, referred to as "fluoroquinolone amide derivatives (FQADs)" towards Hep-3B, Capan-1 and HL60 cells, was studied by the 3D-QSAR method of comparative molecular field analysis (CoMFA). Based on the training set of 14 compounds, the prediction model was established, which was further verified by the test set of 5 compounds with template molecule included. It is found that steric and electrostatic fields contribute 66.8% and 33.2% to pIChp, 61.4% and 38.6% to pICca, and 61.5% and 38.5% to pIChl, respectively. The Rcv2 (i.e, cross-validation coefficient) is 0.324, 0.381, and 0.421 for pIChp, pICca, and pIChl, respectively, while the corresponding R2 (i.e, non-cross-validation coefficient) all reach 0.999. Then, the models were employed to estimate the activities of the training and test compounds, and the results show that the stability and predictability of developed models are very satisfactory. According to the contour maps of steric and electronic fields, bulky groups linked to 2-, 3-, 4-positions of phenyl ring, and electropositive groups near the 4-position and electronegative groups far away may increase the anti-proliferative activity. Using the information provided by the 3D contour maps, four new FQADs owing higher antiproliferative activity were designed, but their effectiveness should be further tested by experiments.
2022, 41(3): 220324
doi: 10.14102/j.cnki.0254-5861.2011-3348
Abstract:
A new europium(Ⅲ) complex [Eu2(C14H9O3)6(2, 2΄-bipy)2]·(2, 2΄-bipy)2 has been synthesized with 2-benzoylbenzoic acid and 2, 2΄-bipyridine as ligands. Crystal data: triclinic, space group P\begin{document}$ \overline 1 $\end{document}
A new europium(Ⅲ) complex [Eu2(C14H9O3)6(2, 2΄-bipy)2]·(2, 2΄-bipy)2 has been synthesized with 2-benzoylbenzoic acid and 2, 2΄-bipyridine as ligands. Crystal data: triclinic, space group P
2022, 41(3): 220325
doi: 10.14102/j.cnki.0254-5861.2011-3360
Abstract:
Four novel pyrazole-benzene carboxamide derivatives 2a~2d were synthesized and characterized by NMR, HRMS spectral method and X-ray diffraction analysis, and were further conducted for screening the anti-fungal/anti-oomycete activity. Compound 2d crystallizes as monoclinic space group P21/c with a = 42.260(4), b = 5.3751(4), c = 8.0129(9) Å, β = 92.958(10)°, V = 1817.7(3) Å3, Z = 4, Mr = 385.41, Dc = 1.408 Mg/m3, S = 1.087, μ = 0.773 mm-1, F(000) = 808, the final R = 0.0763 and wR = 0.2136 for 2657 observed reflections (I > 2σ(I)). The preliminary antifungal assay indicates that the title compounds show fair to excellent antifungal/anti-oomycete activity toward four plant fungi and two crop oomycetes. Among them, compound 2b exhibits the strongest in vitro anti-B. cinerea effects (EC50 = 1.61 mg/L). In vivo test presents compound 2b displays considerable protective and curative effects to tomato fruits infected by B. cinerea. These results indicate that compound 2b would be potential fungicides leads for further development.
Four novel pyrazole-benzene carboxamide derivatives 2a~2d were synthesized and characterized by NMR, HRMS spectral method and X-ray diffraction analysis, and were further conducted for screening the anti-fungal/anti-oomycete activity. Compound 2d crystallizes as monoclinic space group P21/c with a = 42.260(4), b = 5.3751(4), c = 8.0129(9) Å, β = 92.958(10)°, V = 1817.7(3) Å3, Z = 4, Mr = 385.41, Dc = 1.408 Mg/m3, S = 1.087, μ = 0.773 mm-1, F(000) = 808, the final R = 0.0763 and wR = 0.2136 for 2657 observed reflections (I > 2σ(I)). The preliminary antifungal assay indicates that the title compounds show fair to excellent antifungal/anti-oomycete activity toward four plant fungi and two crop oomycetes. Among them, compound 2b exhibits the strongest in vitro anti-B. cinerea effects (EC50 = 1.61 mg/L). In vivo test presents compound 2b displays considerable protective and curative effects to tomato fruits infected by B. cinerea. These results indicate that compound 2b would be potential fungicides leads for further development.
2022, 41(3): 220326
doi: 10.14102/j.cnki.0254-5861.2011-3363
Abstract:
Complexes [Zn(pbm)(5-hip)3] (1), [Zn(pbm)(5-nip)3] (2), [Mn(pbm)(H3btc)2(H2O)] (3) and [Mn(pbm)(5-nip)3] (4), where H2HIPA = 5-hydroxyisophthalic acid, H2nip = 5-nitroisophthalic acid, H3btc = trimesic acid and pbm (pyridine benzene chelate material) = 2-(2-pyridyl)benzimidazole, were identified via single-crystal XRD analyses. 1, 2 and 4 pertain to the monoclinic space group C2/c, while 3 belongs to the triclinic space group P\begin{document}$ \overline 1 $\end{document}
Complexes [Zn(pbm)(5-hip)3] (1), [Zn(pbm)(5-nip)3] (2), [Mn(pbm)(H3btc)2(H2O)] (3) and [Mn(pbm)(5-nip)3] (4), where H2HIPA = 5-hydroxyisophthalic acid, H2nip = 5-nitroisophthalic acid, H3btc = trimesic acid and pbm (pyridine benzene chelate material) = 2-(2-pyridyl)benzimidazole, were identified via single-crystal XRD analyses. 1, 2 and 4 pertain to the monoclinic space group C2/c, while 3 belongs to the triclinic space group P
2022, 41(3): 220327
doi: 10.14102/j.cnki.0254-5861.2021-0013
Abstract:
Two series of three dimensional (3D) lanthanide metal-organic frameworks (LnMOFs) of [Ln(tftpa)1.5(phen)(H2O)]n (Ln = Sm 1a, Eu 1b, Tb 1c, Dy 1d, H2tftpa = tetrafluoroterephthalic acid, phen = 1, 10-phenanthrolin) and [Ln(tftpa)1.5(bpy)(H2O)]n (Ln = Sm 2a, Eu 2b, Tb 2c, Dy 2d, bpy = 2, 2΄-bipyridine) are obtained by structural regulation. Results reveal that the 3D LnMOFs show high water- and thermal-stability. Interestingly, through selecting the perfluorinated ligand, and using bpy as an auxiliary ligand to hold back the solvents near to the lanthanide ions, 2b, and 2c show high luminescence quantum yield (QY) of 74.50% and 60.03%, respectively. In order to further improve the luminescence QY, the auxiliary ligand of phen with larger conjugation and more rigid structure is synthesized to replace bpy, and fortunately, higher luminescence QY of 80.73% (1b) and 75.17% (1c) are realized.
Two series of three dimensional (3D) lanthanide metal-organic frameworks (LnMOFs) of [Ln(tftpa)1.5(phen)(H2O)]n (Ln = Sm 1a, Eu 1b, Tb 1c, Dy 1d, H2tftpa = tetrafluoroterephthalic acid, phen = 1, 10-phenanthrolin) and [Ln(tftpa)1.5(bpy)(H2O)]n (Ln = Sm 2a, Eu 2b, Tb 2c, Dy 2d, bpy = 2, 2΄-bipyridine) are obtained by structural regulation. Results reveal that the 3D LnMOFs show high water- and thermal-stability. Interestingly, through selecting the perfluorinated ligand, and using bpy as an auxiliary ligand to hold back the solvents near to the lanthanide ions, 2b, and 2c show high luminescence quantum yield (QY) of 74.50% and 60.03%, respectively. In order to further improve the luminescence QY, the auxiliary ligand of phen with larger conjugation and more rigid structure is synthesized to replace bpy, and fortunately, higher luminescence QY of 80.73% (1b) and 75.17% (1c) are realized.
2022, 41(3): 220327
doi: 10.14102/j.cnki.0254-5861.2011-3359
Abstract:
Three new solvates of 4, 6-diamino-2-cyclopropylamino-5-pyrimidine carbonitrile (DCL): crystal 1 (DCL with N, N-dimethylformamide (DMF)), crystal 2 (DCL with methanol) and crystal 3 (DCL with water) were synthesized and characterized by single-crystal X-ray diffraction, thermal behaviour, Hirshfeld surface and powder X-ray powder diffraction (PXRD). 1H and 13C NMR spectra confirm solvent molecules existing in the crystal lattice. Crystal 1 forms a 1:1 DCL: DMF crystal; crystal 2 gives a 1:0.5 DCL: methanol crystal and crystal 3 gets a 1:1.5 DCL: H2O crystal. The three crystals are all primarily stabilized by a strong N–H⋅⋅⋅N hydrogen bonding interaction between DCL and the solvents. The structures are stabilized by H⋅⋅⋅H, N–H⋅⋅⋅O, N–H⋅⋅⋅N and O–H⋅⋅⋅O intermolecular interactions. When crystal 2 is dried at 150 ℃, the new polymorph with no solvate is obtained.
Three new solvates of 4, 6-diamino-2-cyclopropylamino-5-pyrimidine carbonitrile (DCL): crystal 1 (DCL with N, N-dimethylformamide (DMF)), crystal 2 (DCL with methanol) and crystal 3 (DCL with water) were synthesized and characterized by single-crystal X-ray diffraction, thermal behaviour, Hirshfeld surface and powder X-ray powder diffraction (PXRD). 1H and 13C NMR spectra confirm solvent molecules existing in the crystal lattice. Crystal 1 forms a 1:1 DCL: DMF crystal; crystal 2 gives a 1:0.5 DCL: methanol crystal and crystal 3 gets a 1:1.5 DCL: H2O crystal. The three crystals are all primarily stabilized by a strong N–H⋅⋅⋅N hydrogen bonding interaction between DCL and the solvents. The structures are stabilized by H⋅⋅⋅H, N–H⋅⋅⋅O, N–H⋅⋅⋅N and O–H⋅⋅⋅O intermolecular interactions. When crystal 2 is dried at 150 ℃, the new polymorph with no solvate is obtained.
2022, 41(3): 220328
doi: 10.14102/j.cnki.0254-5861.2011-3340
Abstract:
A microporous and robust bimetal-organic framework [Cd2Ba(NH2-BTB)2]·2(DMA)·2(H2O) (1) was constructed by mixing the heterometallic nodes and an tridentate carboxyl ligand with amino group, benefiting from the synergistic effect of active sites, exposed amino groups and ultramicroporous structure. This compound displays an extraordinary selectivity of CO2/CH4 and C2H2/CH4 (16.7 and 146.3) at 298 K and 1 atm, which can exceed those of many reported MOFs under the same conditions. This work provides an important model to design metal-organic frameworks for the adsorption and separation of small gas molecules.
A microporous and robust bimetal-organic framework [Cd2Ba(NH2-BTB)2]·2(DMA)·2(H2O) (1) was constructed by mixing the heterometallic nodes and an tridentate carboxyl ligand with amino group, benefiting from the synergistic effect of active sites, exposed amino groups and ultramicroporous structure. This compound displays an extraordinary selectivity of CO2/CH4 and C2H2/CH4 (16.7 and 146.3) at 298 K and 1 atm, which can exceed those of many reported MOFs under the same conditions. This work provides an important model to design metal-organic frameworks for the adsorption and separation of small gas molecules.
