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2020 Volume 39 Issue 1
2020, 39(1): 1-1
Abstract:
2020, 39(1): 79-85
doi: 10.14102/j.cnki.0254-5861.2011-2367
Abstract:
The oxygen-bridged dinuclear rare earth complexes (Ln = Nd (1), Y (2)) bearing N-heterocyclic olefin moieties were synthesized by treating the imidazolidinium salt [SIMes-H]Br with potassium amide and rare earth bis(trimethylsilyl)amides. Complex 1 was characterized by X-ray diffraction analysis and complex 2 was characterized by 1H NMR spectroscopy. Both complexes were characterized by elemental analysis. Crystal data of complex 1: C74H138O2N8Si8Nd2, Mr = 1685.12, orthorhombic, space group Pbca, a = 25.1105(7), b = 11.9188(2), c = 29.6151(7) Å, V = 8863.4(4) Å3, Z = 4, Dc = 1.263 g·cm-3, μ = 1.311 mm-1, F(000) = 3544, the final R = 0.0418 and wR = 0.0770 for all data. The ring-opening of tetrahydrofuran molecule was proven, the possible mechanism for the formation of N-heterocyclic olefin (NHO)-rare earth complexes was speculated and the electronic and steric properties of SIMes and rare earth amides were discussed. This work provides a better understanding of N-heterocyclic carbene rare earth chemistry.
The oxygen-bridged dinuclear rare earth complexes (Ln = Nd (1), Y (2)) bearing N-heterocyclic olefin moieties were synthesized by treating the imidazolidinium salt [SIMes-H]Br with potassium amide and rare earth bis(trimethylsilyl)amides. Complex 1 was characterized by X-ray diffraction analysis and complex 2 was characterized by 1H NMR spectroscopy. Both complexes were characterized by elemental analysis. Crystal data of complex 1: C74H138O2N8Si8Nd2, Mr = 1685.12, orthorhombic, space group Pbca, a = 25.1105(7), b = 11.9188(2), c = 29.6151(7) Å, V = 8863.4(4) Å3, Z = 4, Dc = 1.263 g·cm-3, μ = 1.311 mm-1, F(000) = 3544, the final R = 0.0418 and wR = 0.0770 for all data. The ring-opening of tetrahydrofuran molecule was proven, the possible mechanism for the formation of N-heterocyclic olefin (NHO)-rare earth complexes was speculated and the electronic and steric properties of SIMes and rare earth amides were discussed. This work provides a better understanding of N-heterocyclic carbene rare earth chemistry.
2020, 39(1): 86-95
doi: 10.14102/j.cnki.0254-5861.2011-2352
Abstract:
The title complex SalenCo(III)Cl (Salen = 6, 6'-((1E, 1'E)-(cyclohexane-1, 2-diylbis(azaneylylidene))bis(methaneylylidene))bis(2, 4-di-tert-butylphenol)) was synthesized and characterized by elemental analysis, IR spectroscopy, 1H NMR and UV-Vis. The complex can be used as catalyst for the propylene oxide (PO)/CO2 copolymerization in different conditions of reaction time, reaction temperature, carbon dioxide pressure and monomer concentration, and the optimum conditions for copolymerization were obtained.
The title complex SalenCo(III)Cl (Salen = 6, 6'-((1E, 1'E)-(cyclohexane-1, 2-diylbis(azaneylylidene))bis(methaneylylidene))bis(2, 4-di-tert-butylphenol)) was synthesized and characterized by elemental analysis, IR spectroscopy, 1H NMR and UV-Vis. The complex can be used as catalyst for the propylene oxide (PO)/CO2 copolymerization in different conditions of reaction time, reaction temperature, carbon dioxide pressure and monomer concentration, and the optimum conditions for copolymerization were obtained.
2020, 39(1): 96-103
doi: 10.14102/j.cnki.0254-5861.2011-2363
Abstract:
A novel energetic ionic salt, hydroxylammonium potassium 3, 3'-dinitro-5, 5'-bis-1, 2, 4-triazole-1, 1'-diolate dihydrate [(NH3OH)2K(DNOBT)1.5∙2H2O], was synthesized and structurally characterized by elemental analysis, IR spectra, 13C NMR and single-crystal X-ray diffraction. (NH3OH)2K(DNOBT)1.5∙2H2O crystallizes in triclinic system, space group P\begin{document}$ \overline 1 $\end{document}
A novel energetic ionic salt, hydroxylammonium potassium 3, 3'-dinitro-5, 5'-bis-1, 2, 4-triazole-1, 1'-diolate dihydrate [(NH3OH)2K(DNOBT)1.5∙2H2O], was synthesized and structurally characterized by elemental analysis, IR spectra, 13C NMR and single-crystal X-ray diffraction. (NH3OH)2K(DNOBT)1.5∙2H2O crystallizes in triclinic system, space group P
2020, 39(1): 104-109
doi: 10.14102/j.cnki.0254-5861.2011-2381
Abstract:
Under hydrothermal conditions, a new lanthanide coordination polymer, [Er3(oba)4(na)]n (1, oba = 4, 4'-oxybis(benzoate), na = nicotinic acid) has been synthesized. Compound 1 shows a 3D framework by incorporating tri-nuclear [Er3(COO)6] unit and the mixed ligands of oba2- and na-. It is interesting that decarboxylation occurred in the ortho position and 2, 3-pyridinedicarboxylic acid was partially transformed into na under hydrothermal conditions. Compound 1 can be reduced into a (3, 11)-connected net and displays weak second-harmonic generation response. Furthermore, the PXRD, TGA and IR spectra were also studied.
Under hydrothermal conditions, a new lanthanide coordination polymer, [Er3(oba)4(na)]n (1, oba = 4, 4'-oxybis(benzoate), na = nicotinic acid) has been synthesized. Compound 1 shows a 3D framework by incorporating tri-nuclear [Er3(COO)6] unit and the mixed ligands of oba2- and na-. It is interesting that decarboxylation occurred in the ortho position and 2, 3-pyridinedicarboxylic acid was partially transformed into na under hydrothermal conditions. Compound 1 can be reduced into a (3, 11)-connected net and displays weak second-harmonic generation response. Furthermore, the PXRD, TGA and IR spectra were also studied.
2020, 39(1): 110-117
doi: 10.14102/j.cnki.0254-5861.2011-2388
Abstract:
Two novel coordination polymers, [Zn(ImNIPA)(DMSO)]n (1) and [Cd(ImNIPA)(DMSO)]n (2) (H2ImNIPA = 5-(6-(1H-imidazol-1-yl)-1, 3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)isophthalic acid, DMSO = dimethylsulfoxide), were prepared under solvothermal conditions through the reactions of Zn2+/Cd2+ and a new imidazole-containing isophthalic ligand H2ImNIPA. The compounds were fully characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction analysis and X-ray single-crystal diffraction analysis. Both 1 and 2 are two-dimensional (2D) coordination layers via the combination of 3-connected metal nodes and ImNIPA2- linker, featuring (6, 3) honeycomb-type topology. In addition, the 2D layers in the two compounds are further extended into 3D supramolecular frameworks via π-π stacking interactions. Finally, the thermal-stability and solid-state luminescence properties of them were also investigated.
Two novel coordination polymers, [Zn(ImNIPA)(DMSO)]n (1) and [Cd(ImNIPA)(DMSO)]n (2) (H2ImNIPA = 5-(6-(1H-imidazol-1-yl)-1, 3-dioxo-1H-benzo[de]isoquinolin-2(3H)-yl)isophthalic acid, DMSO = dimethylsulfoxide), were prepared under solvothermal conditions through the reactions of Zn2+/Cd2+ and a new imidazole-containing isophthalic ligand H2ImNIPA. The compounds were fully characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction analysis and X-ray single-crystal diffraction analysis. Both 1 and 2 are two-dimensional (2D) coordination layers via the combination of 3-connected metal nodes and ImNIPA2- linker, featuring (6, 3) honeycomb-type topology. In addition, the 2D layers in the two compounds are further extended into 3D supramolecular frameworks via π-π stacking interactions. Finally, the thermal-stability and solid-state luminescence properties of them were also investigated.
2020, 39(1): 118-125
doi: 10.14102/j.cnki.0254-5861.2011-2395
Abstract:
A new penta-nuclear FeIII cluster, [HN(C2H5)3]·[Fe5(timb)4(ATZ)4(μ3-O)2]·(H2O)5 (1), (H2timb is 4-bromo-2-[(1H-tetrazol-5-ylimino)-methyl]-phenol; HATZ is 5-amino-1, 2, 3, 4-tetrazole), was synthesized through micro-vial synthesis methods, which was characterized by elemental analysis, FT-IR spectra, X-ray single-crystal diffraction, thermogravimetric analysis. The single crystal belongs to the tetragonal system, space group I\begin{document}$ \bar 4 $\end{document}
A new penta-nuclear FeIII cluster, [HN(C2H5)3]·[Fe5(timb)4(ATZ)4(μ3-O)2]·(H2O)5 (1), (H2timb is 4-bromo-2-[(1H-tetrazol-5-ylimino)-methyl]-phenol; HATZ is 5-amino-1, 2, 3, 4-tetrazole), was synthesized through micro-vial synthesis methods, which was characterized by elemental analysis, FT-IR spectra, X-ray single-crystal diffraction, thermogravimetric analysis. The single crystal belongs to the tetragonal system, space group I
2020, 39(1): 126-131
doi: 10.14102/j.cnki.0254-5861.2011-2425
Abstract:
A coordination polymer of [Tb(ntb)]n (1) based on 4, 4′, 4′′-nitrilotribenzoate ligand (ntb3–) was synthesized. Compound 1 crystallizes in the monoclinic system, space group C2/c with a = 13.7318(4), b = 27.5628(9), c = 5.4046(2) Å, β = 111.142(3)°, V = 1907.88(12) Å3, Z = 4, C21H12NO6Tb, Mr = 533.24, Dc = 1.856 g/cm3, μ = 3.745 mm–1, F(000) = 1032, the final R = 0.0184 and wR = 0.0456 for 1883 observed reflections with I > 2σ(I). In compound 1, the eight-coordinated Tb(III) atoms are bridged by the carboxylate groups of ntb3– ligands to generate a one-dimensional Tb-carboxylate chain, which is further linked by the ntb3– ligands to form a three-dimensional structure. Compound 1 exhibits characteristic Tb(III) luminescent emissions in the solid state.
A coordination polymer of [Tb(ntb)]n (1) based on 4, 4′, 4′′-nitrilotribenzoate ligand (ntb3–) was synthesized. Compound 1 crystallizes in the monoclinic system, space group C2/c with a = 13.7318(4), b = 27.5628(9), c = 5.4046(2) Å, β = 111.142(3)°, V = 1907.88(12) Å3, Z = 4, C21H12NO6Tb, Mr = 533.24, Dc = 1.856 g/cm3, μ = 3.745 mm–1, F(000) = 1032, the final R = 0.0184 and wR = 0.0456 for 1883 observed reflections with I > 2σ(I). In compound 1, the eight-coordinated Tb(III) atoms are bridged by the carboxylate groups of ntb3– ligands to generate a one-dimensional Tb-carboxylate chain, which is further linked by the ntb3– ligands to form a three-dimensional structure. Compound 1 exhibits characteristic Tb(III) luminescent emissions in the solid state.
2020, 39(1): 132-139
doi: 10.14102/j.cnki.0254-5861.2011-2380
Abstract:
Two coordination polymers based on the mixed ligands of biphenyl-3, 3'-disulfonyl-4, 4'-dicarboxylate (BPDSDC4–) and 2, 2'-bipyridine (2, 2'-bpy), {[Cd(BPDSDC)0.5(2, 2'-bpy)(H2O)]·(H2O)}n (1) and {[Cd(BPDSDC)0.5(2, 2'-bpy)2]·(H2O)}n (2) were synthesized. Both compounds crystallize in the monoclinic system, space group P21/n. For 1, a = 7.5737(2), b = 17.4284(5), c = 13.5982(5) Å, β = 90.788(3)°, V = 1794.76(10) Å3, Z = 4, C17H15N2O7SCd, Mr = 503.77, Dc = 1.864 g/cm3, μ = 1.378 mm-1, F(000) = 1004, the final R = 0.0299 and wR = 0.0644 for 3137 observed reflections with I > 2σ(I). For 2, a = 13.3097(2), b = 10.66240(10), c = 17.6583(3) Å, β = 91.779(2)°, V = 2504.74(6) Å3, Z = 4, C27H21N4O6SCd, Mr = 641.94, Dc = 1.702 g/cm3, μ = 1.008 mm-1, F(000) = 1292, the final R = 0.0244 and wR = 0.0583 for 4594 observed reflections with I > 2σ(I). The Cd(II) atoms in both compounds are six-coordinated. In 1, the Cd(2, 2'-bpy) units are connected by BPDSDC4– ligands to generate a one-dimensional (1D) ribbon structure. The 1D ribbons are linked by the hydrogen bonds and π···π interactions to give a three-dimensional (3D) structure. In compound 2, the Cd(2, 2'-bpy)2 units are linked by the BPDSDC4– ligands to form a 1D chain. Compounds 1 and 2 show luminescent emissions.
Two coordination polymers based on the mixed ligands of biphenyl-3, 3'-disulfonyl-4, 4'-dicarboxylate (BPDSDC4–) and 2, 2'-bipyridine (2, 2'-bpy), {[Cd(BPDSDC)0.5(2, 2'-bpy)(H2O)]·(H2O)}n (1) and {[Cd(BPDSDC)0.5(2, 2'-bpy)2]·(H2O)}n (2) were synthesized. Both compounds crystallize in the monoclinic system, space group P21/n. For 1, a = 7.5737(2), b = 17.4284(5), c = 13.5982(5) Å, β = 90.788(3)°, V = 1794.76(10) Å3, Z = 4, C17H15N2O7SCd, Mr = 503.77, Dc = 1.864 g/cm3, μ = 1.378 mm-1, F(000) = 1004, the final R = 0.0299 and wR = 0.0644 for 3137 observed reflections with I > 2σ(I). For 2, a = 13.3097(2), b = 10.66240(10), c = 17.6583(3) Å, β = 91.779(2)°, V = 2504.74(6) Å3, Z = 4, C27H21N4O6SCd, Mr = 641.94, Dc = 1.702 g/cm3, μ = 1.008 mm-1, F(000) = 1292, the final R = 0.0244 and wR = 0.0583 for 4594 observed reflections with I > 2σ(I). The Cd(II) atoms in both compounds are six-coordinated. In 1, the Cd(2, 2'-bpy) units are connected by BPDSDC4– ligands to generate a one-dimensional (1D) ribbon structure. The 1D ribbons are linked by the hydrogen bonds and π···π interactions to give a three-dimensional (3D) structure. In compound 2, the Cd(2, 2'-bpy)2 units are linked by the BPDSDC4– ligands to form a 1D chain. Compounds 1 and 2 show luminescent emissions.
2020, 39(1): 140-146
doi: 10.14102/j.cnki.0254-5861.2011-2376
Abstract:
A new square-planar platinum(II) complex, [Pt(Me3SiC≡Cphen)(C≡CC6H4Cl-3)2] (1), was synthesized by using 3-trimethylsilylethynyl-1, 10-phenanthroline (Me3SiC≡Cphen) and 3-chlorophenylacetylene ligands, and its structure was characterized by single-crystal X-ray crystallography. 1 crystallizes in triclinic, space group P\begin{document}$ \overline 1 $\end{document}
A new square-planar platinum(II) complex, [Pt(Me3SiC≡Cphen)(C≡CC6H4Cl-3)2] (1), was synthesized by using 3-trimethylsilylethynyl-1, 10-phenanthroline (Me3SiC≡Cphen) and 3-chlorophenylacetylene ligands, and its structure was characterized by single-crystal X-ray crystallography. 1 crystallizes in triclinic, space group P
2020, 39(1): 147-153
doi: 10.14102/j.cnki.0254-5861.2011-2385
Abstract:
Two novel metal-organic coordination compounds, [Co2(OH)(chdc)1.5(bibp)]n (1) and [Ni(chdc)(bib)]n·2nH2O (2) (H2chdc =1, 4-cyclohexanedicarboxylic acid, bibp = 4, 4'-bis(1-imidazolyl)biphenyl, bib=1, 4-bis(1-imidazolyl)benzene), were synthesized and characterized. Compound 1 crystallizes in monoclinic, space group P\begin{document}$ \overline 1 $\end{document}
Two novel metal-organic coordination compounds, [Co2(OH)(chdc)1.5(bibp)]n (1) and [Ni(chdc)(bib)]n·2nH2O (2) (H2chdc =1, 4-cyclohexanedicarboxylic acid, bibp = 4, 4'-bis(1-imidazolyl)biphenyl, bib=1, 4-bis(1-imidazolyl)benzene), were synthesized and characterized. Compound 1 crystallizes in monoclinic, space group P
2020, 39(1): 154-163
doi: 10.14102/j.cnki.0254-5861.2011-2371
Abstract:
An unprecedented 4f-5d material (La6Hg5Br26)[4(HgBr2)](2Br) (1) was syn-thesized by hydrothermal reactions and structurally characterized by single-crystal X-ray diffraction method. Complex 1 crystallizes in the Pbam space group of orthorhombic system with a = 13.0980(10), b = 13.6650(9), c = 28.010(2) Å, V = 5013.4(6) Å3, Br36Hg9La6, Mr = 5515.53, Z = 2, Dc = 3.613 g/cm3, μ(MoKα) = 29.457 mm–1 and F(000) = 4598. Compound 1 is characteristic of a two-dimensional (2D) layered structure. The photoluminescent measurements with solid-state samples reveal that compound 1 has a strong emission in the green region of light spectrum. It has remarkable CIE chromaticity coordinates of (0.2499, 0.3589). A wide optical band gap of 3.41 eV is discovered by the solid-state UV/vis diffuse reflectance spectrum. The variable-temperature magnetic susceptibility obeys the Curie-Weiss law (χm = c/(T – θ)) with C = 2.48 K and a negative Weiss constant θ = –169.07 K as revealed by the magnetic measurements, indicating the existence of an antiferromagnetic interaction in compound 1.
An unprecedented 4f-5d material (La6Hg5Br26)[4(HgBr2)](2Br) (1) was syn-thesized by hydrothermal reactions and structurally characterized by single-crystal X-ray diffraction method. Complex 1 crystallizes in the Pbam space group of orthorhombic system with a = 13.0980(10), b = 13.6650(9), c = 28.010(2) Å, V = 5013.4(6) Å3, Br36Hg9La6, Mr = 5515.53, Z = 2, Dc = 3.613 g/cm3, μ(MoKα) = 29.457 mm–1 and F(000) = 4598. Compound 1 is characteristic of a two-dimensional (2D) layered structure. The photoluminescent measurements with solid-state samples reveal that compound 1 has a strong emission in the green region of light spectrum. It has remarkable CIE chromaticity coordinates of (0.2499, 0.3589). A wide optical band gap of 3.41 eV is discovered by the solid-state UV/vis diffuse reflectance spectrum. The variable-temperature magnetic susceptibility obeys the Curie-Weiss law (χm = c/(T – θ)) with C = 2.48 K and a negative Weiss constant θ = –169.07 K as revealed by the magnetic measurements, indicating the existence of an antiferromagnetic interaction in compound 1.
2020, 39(1): 164-173
doi: 10.14102/j.cnki.0254-5861.2011-2383
Abstract:
Lithium ion battery cathode material LiNi0.8Co0.1Mn0.1O2 (NCM811) was synthe-sized via a spray drying method. The effect of different spray drying flow-rates (200, 250, 300, and 400 mL·min-1) on the structural and electrochemical properties of NCM811 are investigated. We find that the contents of Ni, Co, and Mn in the NCM811 cathode materials do not change significantly with the changing flow-rate, but the lattice parameter and morphology of the materials are significantly affected. Under the optimal spray drying flow-rate (250 mL·min -1), the obtained NCM811 cathode (250NCM811) exhibits the best crystallinity, with the highest ratio of I(003)/I(104) in the XRD pattern. SEM images reveal the spherical morphology of 250NCM811 and the average diameter of about 5 μm. The results of electrochemical test show that the reversible capacity of 250NCM811 reaches 210 mA·g-1 at 0.2 C (1 C = 280 mA·g-1). After 100 charge-discharge cycles at 1 C, the battery retains more than 94% of its initial capacity. Overall, spray drying flow-rate demonstrates great effect on the electrochemical properties of NCM811.
Lithium ion battery cathode material LiNi0.8Co0.1Mn0.1O2 (NCM811) was synthe-sized via a spray drying method. The effect of different spray drying flow-rates (200, 250, 300, and 400 mL·min-1) on the structural and electrochemical properties of NCM811 are investigated. We find that the contents of Ni, Co, and Mn in the NCM811 cathode materials do not change significantly with the changing flow-rate, but the lattice parameter and morphology of the materials are significantly affected. Under the optimal spray drying flow-rate (250 mL·min -1), the obtained NCM811 cathode (250NCM811) exhibits the best crystallinity, with the highest ratio of I(003)/I(104) in the XRD pattern. SEM images reveal the spherical morphology of 250NCM811 and the average diameter of about 5 μm. The results of electrochemical test show that the reversible capacity of 250NCM811 reaches 210 mA·g-1 at 0.2 C (1 C = 280 mA·g-1). After 100 charge-discharge cycles at 1 C, the battery retains more than 94% of its initial capacity. Overall, spray drying flow-rate demonstrates great effect on the electrochemical properties of NCM811.
2020, 39(1): 174-181
doi: 10.14102/j.cnki.0254-5861.2011-2366
Abstract:
A new hybrid organic-inorganic perovskite (HOIP) material, [C6H14N2]KBr3, has been synthesized via hydrothermal method and fully characterized. [C6H14N2]KBr3 has a three-dimensional perovskite structure and crystalizes in a trigonal P3121 space group. The elastic properties of [C6H14N2]KBr3 were fully calculated via the density functional theory calculations, which reveal the elastic moduli (11.54~14.07 GPa), shear moduli (4.56~5.68 GPa), Poisson's ratios (0.18~0.32), bulk modulus (8.51 GPa) and acoustic velocity (2.57~2.74 kms-1). Additional nanoindentation experiments in the form of single-crystals confirmed the validity of our theoretical approach. [C6H14N2]KBr3 exhibits higher stiffness and thermal stability than the well-known photovoltaic CH3NH3PbI3, which makes it worthwhile for exploring optoelectronic properties.
A new hybrid organic-inorganic perovskite (HOIP) material, [C6H14N2]KBr3, has been synthesized via hydrothermal method and fully characterized. [C6H14N2]KBr3 has a three-dimensional perovskite structure and crystalizes in a trigonal P3121 space group. The elastic properties of [C6H14N2]KBr3 were fully calculated via the density functional theory calculations, which reveal the elastic moduli (11.54~14.07 GPa), shear moduli (4.56~5.68 GPa), Poisson's ratios (0.18~0.32), bulk modulus (8.51 GPa) and acoustic velocity (2.57~2.74 kms-1). Additional nanoindentation experiments in the form of single-crystals confirmed the validity of our theoretical approach. [C6H14N2]KBr3 exhibits higher stiffness and thermal stability than the well-known photovoltaic CH3NH3PbI3, which makes it worthwhile for exploring optoelectronic properties.
2020, 39(1): 8-10
doi: 10.14102/j.cnki.0254-5861.2011-2710
Abstract:
Machine learning is an emerging method to discover new materials with specific characteristics. An unsupervised machine learning research is highlighted to discover new potential lithium ionic conductors by screening and clustering lithium compounds, providing inspirations for the development of solid-state electrolytes and practical batteries.
Machine learning is an emerging method to discover new materials with specific characteristics. An unsupervised machine learning research is highlighted to discover new potential lithium ionic conductors by screening and clustering lithium compounds, providing inspirations for the development of solid-state electrolytes and practical batteries.
2020, 39(1): 11-15
doi: 10.14102/j.cnki.0254-5861.2011-2717
Abstract:
Li[NixMnyCoz]O2 cathodes are currently the most practicable materials in the timing of developing high-performance rechargeable batteries for next-generation technologies. With the ever-growing demand for energy density, a significant breakthrough has been achieved by the controllable concentration design forming core-shell and concentration gradient structures to push Li[NixCoyMnz]O2 toward higher energy density, longer lifetime and safety. Herein, we review the recent progress on advanced concentration gradient cathode materials. Furthermore, we prospect that this novel approach will continuously extend its advantages in developing extremely fast charging and Co-free cathode materials in the near future.
Li[NixMnyCoz]O2 cathodes are currently the most practicable materials in the timing of developing high-performance rechargeable batteries for next-generation technologies. With the ever-growing demand for energy density, a significant breakthrough has been achieved by the controllable concentration design forming core-shell and concentration gradient structures to push Li[NixCoyMnz]O2 toward higher energy density, longer lifetime and safety. Herein, we review the recent progress on advanced concentration gradient cathode materials. Furthermore, we prospect that this novel approach will continuously extend its advantages in developing extremely fast charging and Co-free cathode materials in the near future.
2020, 39(1): 16-19
doi: 10.14102/j.cnki.0254-5861.2011-2715
Abstract:
Lithium-ion batteries, first commercialized in 1991, have been thriving for the past 30 years and become an important basis for portable electronics and electric vehicles. However, this first generation of lithium-ion batteries built on the intercalation materials has limited energy density and can not meet the increased demand of various applications. Thus, a transition from intercalation to alloying chemistry for anodes is on call. Silicon, as the most attractive alloying anode material, has been on the research focus for next-generation high-energy density battery. Alloying mechanism benefits silicon a large capacity while brings silicon the challenge of volume expansion. This article discusses the structure design strategies to address the issues of large volume change and interface instability.
Lithium-ion batteries, first commercialized in 1991, have been thriving for the past 30 years and become an important basis for portable electronics and electric vehicles. However, this first generation of lithium-ion batteries built on the intercalation materials has limited energy density and can not meet the increased demand of various applications. Thus, a transition from intercalation to alloying chemistry for anodes is on call. Silicon, as the most attractive alloying anode material, has been on the research focus for next-generation high-energy density battery. Alloying mechanism benefits silicon a large capacity while brings silicon the challenge of volume expansion. This article discusses the structure design strategies to address the issues of large volume change and interface instability.
2020, 39(1): 20-25
doi: 10.14102/j.cnki.0254-5861.2011-2718
Abstract:
Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage. However, their commercial applications are hindered by irreversible capacity loss in the first charge-discharge process, voltage decay during cycling, inefficient cyclability and rate capability. Many attempts have been performed to solve such issues, including the mechanism study and strategies to improve the electrochemical performance. This article provides a brief review and future perspective on the main challenges of the high-capacity Li-rich Mn-based cathodes for Li-ion batteries.
Layered Li-rich Mn-based oxides are promising cathode materials for Li-ion batteries due to their high capacity and high operation voltage. However, their commercial applications are hindered by irreversible capacity loss in the first charge-discharge process, voltage decay during cycling, inefficient cyclability and rate capability. Many attempts have been performed to solve such issues, including the mechanism study and strategies to improve the electrochemical performance. This article provides a brief review and future perspective on the main challenges of the high-capacity Li-rich Mn-based cathodes for Li-ion batteries.
2020, 39(1): 26-30
doi: 10.14102/j.cnki.0254-5861.2011-2719
Abstract:
Developing a variety of in situ characterization techniques to unravel the structural/chemical evolution during the synthesis of various advanced energy materials for studying the relationship among those experimental conditions and the structure is the key to implement the controllable synthesis of battery materials. This perspective summarizes the recent studies into structural evolution during in situ synthesis of various advanced energy materials by synchrotron X-ray diffraction technique and forecasts the more extensive applications in the future.
Developing a variety of in situ characterization techniques to unravel the structural/chemical evolution during the synthesis of various advanced energy materials for studying the relationship among those experimental conditions and the structure is the key to implement the controllable synthesis of battery materials. This perspective summarizes the recent studies into structural evolution during in situ synthesis of various advanced energy materials by synchrotron X-ray diffraction technique and forecasts the more extensive applications in the future.
2020, 39(1): 31-35
doi: 10.14102/j.cnki.0254-5861.2011-2706
Abstract:
2020, 39(1): 36-40
doi: 10.14102/j.cnki.0254-5861.2011-2375
Abstract:
Peripherally low symmetric substitution with electron-donating (EDG) and electron-withdrawing (EWG) substituents caused the rational modulation of geometric structure and even the electronic structure of triazasubporphyrin, the smallest 14π conjugated aza-porphyrinoids. Both structural characterization and spectroscopic investigation were discussed to provide an in-depth understanding of the relationship between peripheral push-pull substituents and SubPz core.
Peripherally low symmetric substitution with electron-donating (EDG) and electron-withdrawing (EWG) substituents caused the rational modulation of geometric structure and even the electronic structure of triazasubporphyrin, the smallest 14π conjugated aza-porphyrinoids. Both structural characterization and spectroscopic investigation were discussed to provide an in-depth understanding of the relationship between peripheral push-pull substituents and SubPz core.
2020, 39(1): 41-47
doi: 10.14102/j.cnki.0254-5861.2011-2461
Abstract:
The abilities and performances of Mn–C76, Mn–B38N38, Zn–CNT (6, 0) and Zn–BNNT (6, 0) to the oxidation of NO2 and CO are investigated. The oxidation reactions of NO2 and CO through the Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms by theoretical methods are examined. The most stable intermediates of oxidation reactions of NO2 and CO on Mn–C76, Mn–B38N38, Zn–CNT (6, 0) and Zn–BNNT (6, 0) are obtained from thermodynamics view point. In the LH pathway, Mn–C76, Mn–B38N38, Zn–CNT (6, 0) and Zn–BNNT (6, 0) catalysts are deactivated via the second NO2 and CO molecules. In the ER pathway, the second NO3 and CO2 molecules are separated. Finally, the Mn–C76, Mn–B38N38, Zn–CNT (6, 0) and Zn–BNNT (6, 0) are proposed to oxidize NO2 and CO molecules with high performances at room temperature.
The abilities and performances of Mn–C76, Mn–B38N38, Zn–CNT (6, 0) and Zn–BNNT (6, 0) to the oxidation of NO2 and CO are investigated. The oxidation reactions of NO2 and CO through the Langmuir-Hinshelwood (LH) and Eley-Rideal (ER) mechanisms by theoretical methods are examined. The most stable intermediates of oxidation reactions of NO2 and CO on Mn–C76, Mn–B38N38, Zn–CNT (6, 0) and Zn–BNNT (6, 0) are obtained from thermodynamics view point. In the LH pathway, Mn–C76, Mn–B38N38, Zn–CNT (6, 0) and Zn–BNNT (6, 0) catalysts are deactivated via the second NO2 and CO molecules. In the ER pathway, the second NO3 and CO2 molecules are separated. Finally, the Mn–C76, Mn–B38N38, Zn–CNT (6, 0) and Zn–BNNT (6, 0) are proposed to oxidize NO2 and CO molecules with high performances at room temperature.
2020, 39(1): 48-56
doi: 10.14102/j.cnki.0254-5861.2011-2509
Abstract:
OH addition reactions of cationic, neutral and anionic forms of three sulfonamides (sulfamethoxazole, sulfadiazine and sulfapyridine) in aqueous solution were theoretically studied using density functional theory (DFT) method at the M06-2X/6-311+G(3df, 2p) level. Transition state theory was applied to estimate the secondary rate constants for these elementary reactions. The obtained results indicate that OH addition reactions of sulfonamides can take place spontaneously at standard conditions. The anionic form of three sulfonamides has the highest addition activity, while the corresponding cationic form is the most inactive addition reagent. The benzene ring of neutral forms of three sulfonamides is always a more favorable site for OH radical addition than the oxazole, pyrimidine or pyridine ring. C(3) or (and) C(5) atoms of benzene ring are the most favorable positions for OH addition occurring in benzene ring. Although the water solvent has no remarkable effect on OH addition reactions of neutral sulfonamides, it exerts a significant adverse influence on OH addition reactions of ionic sulfonamides.
OH addition reactions of cationic, neutral and anionic forms of three sulfonamides (sulfamethoxazole, sulfadiazine and sulfapyridine) in aqueous solution were theoretically studied using density functional theory (DFT) method at the M06-2X/6-311+G(3df, 2p) level. Transition state theory was applied to estimate the secondary rate constants for these elementary reactions. The obtained results indicate that OH addition reactions of sulfonamides can take place spontaneously at standard conditions. The anionic form of three sulfonamides has the highest addition activity, while the corresponding cationic form is the most inactive addition reagent. The benzene ring of neutral forms of three sulfonamides is always a more favorable site for OH radical addition than the oxazole, pyrimidine or pyridine ring. C(3) or (and) C(5) atoms of benzene ring are the most favorable positions for OH addition occurring in benzene ring. Although the water solvent has no remarkable effect on OH addition reactions of neutral sulfonamides, it exerts a significant adverse influence on OH addition reactions of ionic sulfonamides.
2020, 39(1): 57-65
doi: 10.14102/j.cnki.0254-5861.2011-2391
Abstract:
In order to study the free radical scavenging capacity and molecular structures of baicalein and scutellarein, the structure-activity relationship of these two molecules was analyzed. The geometric structures of the compounds were optimized by DMol3 code based on density functional theory. The theoretical parameters of the atomic charge distribution, the distribution of molecular frontier orbital, the energy difference and Fukui functions were calculated. Meantime, superoxide anion free radical and 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH) methods were used to determine the scavenging capacity of the compounds. The results showed that the scavenging rate of DPPH radicals and superoxide anion radicals increased with the increase of sample concentration, and had a dose-effect relationship. The radical-scavenging activities in the order of baicalein > scutellarein > BHT were showed. The p-π conjugation of the hydroxyl oxygen atom influenced the certain ability to repelling electrons in the molecular structures of baicalein and scutellarein based on the data of the atomic charge distribution, the distribution of molecular frontier orbital, the energy difference and Fukui functions. Hydroxyl groups were more susceptible to attack and exhibit free radical scavenging activity. The oxygen atom in the phenolic hydroxyl group of the molecule structure of the samples may be the reaction active sites where the electrophilic reaction occurred. These results offer useful theoretical bases for the research and application of antioxidant activities of substances containing such molecular structures.
In order to study the free radical scavenging capacity and molecular structures of baicalein and scutellarein, the structure-activity relationship of these two molecules was analyzed. The geometric structures of the compounds were optimized by DMol3 code based on density functional theory. The theoretical parameters of the atomic charge distribution, the distribution of molecular frontier orbital, the energy difference and Fukui functions were calculated. Meantime, superoxide anion free radical and 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH) methods were used to determine the scavenging capacity of the compounds. The results showed that the scavenging rate of DPPH radicals and superoxide anion radicals increased with the increase of sample concentration, and had a dose-effect relationship. The radical-scavenging activities in the order of baicalein > scutellarein > BHT were showed. The p-π conjugation of the hydroxyl oxygen atom influenced the certain ability to repelling electrons in the molecular structures of baicalein and scutellarein based on the data of the atomic charge distribution, the distribution of molecular frontier orbital, the energy difference and Fukui functions. Hydroxyl groups were more susceptible to attack and exhibit free radical scavenging activity. The oxygen atom in the phenolic hydroxyl group of the molecule structure of the samples may be the reaction active sites where the electrophilic reaction occurred. These results offer useful theoretical bases for the research and application of antioxidant activities of substances containing such molecular structures.
2020, 39(1): 66-78
doi: 10.14102/j.cnki.0254-5861.2011-2477
Abstract:
We design and synthesize a series of novel silicon(IV) phthalocyanines (SiPcs, 1a, 2a, 1b, and 2b) axially conjugated with arginine or arginine-containing oligopeptides (Arg-Arg, Cys-Arg, Cys-Arg-Arg) through ester or ether linkers to demonstrate the effects of substituents and coupling ways on the spectral behaviors and photodynamic activities. The ester-linked SiPcs (1a and 2a) show slight red-shift, higher fluorescence emission and singlet oxygen generation compared to the ether-linked analogues (1b and 2b) due to the stronger electron-withdrawing ability of the ester group, suggesting that electronic effect of the linkers plays an important role in their spectral properties. The introduction of arginine could effectively reduce the aggregation of phthalocyanine in aqueous solutions. With higher cellular uptake and plasma membrane localization ability, 1b and 2b exhibit significantly higher photocytotoxicity against both HepG2 and Hela cells. Moreover, the in vivo fluorescence imaging suggests that 2b is the most specific toward H22 tumor-bearing ICR mice, and it shows efficient tumor growth inhibition with the tumor inhibition rate up to 93%. Thus, this work would provide a new reference for the development of phthalocyanine-based photosensitizers.
We design and synthesize a series of novel silicon(IV) phthalocyanines (SiPcs, 1a, 2a, 1b, and 2b) axially conjugated with arginine or arginine-containing oligopeptides (Arg-Arg, Cys-Arg, Cys-Arg-Arg) through ester or ether linkers to demonstrate the effects of substituents and coupling ways on the spectral behaviors and photodynamic activities. The ester-linked SiPcs (1a and 2a) show slight red-shift, higher fluorescence emission and singlet oxygen generation compared to the ether-linked analogues (1b and 2b) due to the stronger electron-withdrawing ability of the ester group, suggesting that electronic effect of the linkers plays an important role in their spectral properties. The introduction of arginine could effectively reduce the aggregation of phthalocyanine in aqueous solutions. With higher cellular uptake and plasma membrane localization ability, 1b and 2b exhibit significantly higher photocytotoxicity against both HepG2 and Hela cells. Moreover, the in vivo fluorescence imaging suggests that 2b is the most specific toward H22 tumor-bearing ICR mice, and it shows efficient tumor growth inhibition with the tumor inhibition rate up to 93%. Thus, this work would provide a new reference for the development of phthalocyanine-based photosensitizers.
