A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium di...A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium dichloride and potassium chloride in the presence of tetrahydrofuran （THF） as reaction medium instead of dioxane/water system, which has been used since Cope first reported the synthesis of palladium-azobenzene in 1965 . The mesogenic behaviors examined by DSC, temperature-variable X-ray diffraction and polarizing microscopy indicate that the incorporation of Pd ions into the liquid crystal polymer can play a positive effect on the mesogenic property of the parent polymeric ligand. It is exhibited that the isotropization temperature T;is increased and the mesophase range ΔT has been widened, too.展开更多
A new type of palladium chelate of β-diketone-based side chain liquid crystal polysiloxane (Pd-DKLCP) has been synthesized by chelation reaction of palladium dichloride with polymeric ligand, β-diketone polysiloxane...A new type of palladium chelate of β-diketone-based side chain liquid crystal polysiloxane (Pd-DKLCP) has been synthesized by chelation reaction of palladium dichloride with polymeric ligand, β-diketone polysiloxane (DKLCP), using THF as solvent at R.T.. The Pd-chelation results in greatly increasing the phase transition temperature T_K and the enthalpy change △H_K from crystal to liquid crystal state and making the temperature range of LC state △T(△T=T_(Cl)-T_K) widened. All these chelates Pd-DKLCP's do not show T_(Cl) until decomposition at 205℃. It is noteworthy that the Pd-chelation can exert more positive effect on the mesomorphic behaviour of the polymer ligand than the counterpart Cu-DKLCP does. It is probable due to the bigger size of disc-like mesogen formed from β-diketone and Pd^(+2) ion with 4d orbital.展开更多
The implementation of pristine covalent organic polymer(CO_(2)P)with well-defined structure as air electrode may spark fresh vitality to rechargeable zinc-air flow batteries(ZAFBs),but it still remains challenges in s...The implementation of pristine covalent organic polymer(CO_(2)P)with well-defined structure as air electrode may spark fresh vitality to rechargeable zinc-air flow batteries(ZAFBs),but it still remains challenges in synergistically regulating their electronic states and structural porosity for the great device performance.Here,we conquer these issues by exploiting N and S co-doped graphene with COP rich in metal-ligand nitrogen to synergistically construct an effective catalyst for oxygen reduction reaction(ORR).Among them,the N and S co-doped sites with high electronegativity properties alter the number of electron occupations in the d orbital of the iron centre and form electron-transfer bridges,thereby boosting the selectivity of the ORR-catalysed four-electron pathway.Meanwhile,the introduction of COP materials aids the formation of pore interstices in the graphene lamellae,which both adequately expose the active sites and facilitate the transport of reactive substances.Benefiting from the synergistic effect,as-prepared catalyst exhibits excellent half-wave potentials(E_(1/2)=912 mV)and stability(merely 8.8%drop after a long-term durability test of 50000 s).Further,ZAFBs assembled with the N/SG@CO_(2)P catalyst demonstrate exceptional power density(163.8 mW cm^(-2))and continuous charge and discharge for approximately 140 h at 10 mA cm^(-2),outperforming the noble-metal benchmarks.展开更多
Though the photo-physical properties of free base porphyrin are attractive, there are still problems for the materials with weak and narrow range absorption of visible light. The unsymmetrical neo-confused porphyrin d...Though the photo-physical properties of free base porphyrin are attractive, there are still problems for the materials with weak and narrow range absorption of visible light. The unsymmetrical neo-confused porphyrin derivatives were introduced as novel materials for the improvement of photo-chemical and photo-physical properties. The density function theory（DFT）and time dependent density function theory（TDDFT） were applied to calculate the absorption spectrum of unsymmetrical neo-confused porphyrin（N-CP） and metal-coordinated N-CP in various solutions. The Ni and Zn coordinated neo-confused porphyrin dipole moment values are smaller than the values of prototype porphyrin（Pro P） and N–CP. According to the electrophilicity index ω, Ni coordinated N–CP（Ni–N–CP） is susceptible to the polarity of solvents, while the Zn coordinated derivative（Zn–N–CP） is more immune to the solvent environment. Unlike the Gouterman＇s four frontier orbital model of common porphyrin materials, the electron transitions of N–CPs and metalcoordinated N–CPs from H–2 or lower molecular orbitals also contribute to ultraviolet and visible absorption. Most of oscillator strength f values of Zn–N–CP are significantly higher than the values of Ni–N–CP, which reflects the higher absorption intensity of Q and Soret bands. The maximum wavelength at 702.2 nm in vacuum drew our attention to the novel material. The broad absorption range, intense red-shifted Q band and higher stability in solvents suggest that N–CPs, especially Zn–N–CP, can be one class of new candidate dye-sensitized materials.展开更多
New thermotropic chloro-bridged dinuclear palladium coordinating imine side chain liquid crystalline polysiloxanes have been synthesized. Their mesomorphic properties have been investigated by DSC, X-ray diffraction a...New thermotropic chloro-bridged dinuclear palladium coordinating imine side chain liquid crystalline polysiloxanes have been synthesized. Their mesomorphic properties have been investigated by DSC, X-ray diffraction and polarizing microscopy. The polymeric complexes show nematicdiscotic (Nd) mesophase. It is found that the temperature range of liquid crystalline state of chloro- bridged polymeric complexes is much wider than that of acetato- bridged ones and imine side chain polysiloxane. This indicates that the disc-like chloro-bridged palladium complexing units play a role as mesogen in mesophase.展开更多
A new type of metal coordinated liquid crystalline polymers has been synthesized by complexation of metal ions with β-diketone based side chain liquid crystal polysiloxane (DKLCP). The complexation of copper ions wit...A new type of metal coordinated liquid crystalline polymers has been synthesized by complexation of metal ions with β-diketone based side chain liquid crystal polysiloxane (DKLCP). The complexation of copper ions with DKLCP greatly increases the phase transition temperature T_k from crystalline state to liquid crystalline state and T_(cl) from LC to isotropic state and makes the range of phase transition ΔT (ΔT=T_(cl)-T_k) widened. These complexes are soluble in common organic solvents. However, the incorporation of europium ions into DKLCP molecules gives rise to reduction in liquid crystallinity and crosslinking in some cases. The DKLCP coordinated with suitable amount of Eu ions can show good liquid crystallinity and fluorescent property.展开更多
基金This project was supported by the Natural Science Foundation of Henan province, China.
文摘A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium dichloride and potassium chloride in the presence of tetrahydrofuran （THF） as reaction medium instead of dioxane/water system, which has been used since Cope first reported the synthesis of palladium-azobenzene in 1965 . The mesogenic behaviors examined by DSC, temperature-variable X-ray diffraction and polarizing microscopy indicate that the incorporation of Pd ions into the liquid crystal polymer can play a positive effect on the mesogenic property of the parent polymeric ligand. It is exhibited that the isotropization temperature T;is increased and the mesophase range ΔT has been widened, too.
文摘A new type of palladium chelate of β-diketone-based side chain liquid crystal polysiloxane (Pd-DKLCP) has been synthesized by chelation reaction of palladium dichloride with polymeric ligand, β-diketone polysiloxane (DKLCP), using THF as solvent at R.T.. The Pd-chelation results in greatly increasing the phase transition temperature T_K and the enthalpy change △H_K from crystal to liquid crystal state and making the temperature range of LC state △T(△T=T_(Cl)-T_K) widened. All these chelates Pd-DKLCP's do not show T_(Cl) until decomposition at 205℃. It is noteworthy that the Pd-chelation can exert more positive effect on the mesomorphic behaviour of the polymer ligand than the counterpart Cu-DKLCP does. It is probable due to the bigger size of disc-like mesogen formed from β-diketone and Pd^(+2) ion with 4d orbital.
基金supported by the National Key Research and Development Program of China(2022YFB3807500)the Natural Science Foundation of China(22220102003)+3 种基金the Beijing Natural Science Foundation(JL23003)"Double-First-Class"construction projects(XK180301 and XK1804-02)China Postdoctoral Science Foundation 2023TQ0020Dostdoctoral Fellowship Program of CPSF(GZC20230199)。
文摘The implementation of pristine covalent organic polymer(CO_(2)P)with well-defined structure as air electrode may spark fresh vitality to rechargeable zinc-air flow batteries(ZAFBs),but it still remains challenges in synergistically regulating their electronic states and structural porosity for the great device performance.Here,we conquer these issues by exploiting N and S co-doped graphene with COP rich in metal-ligand nitrogen to synergistically construct an effective catalyst for oxygen reduction reaction(ORR).Among them,the N and S co-doped sites with high electronegativity properties alter the number of electron occupations in the d orbital of the iron centre and form electron-transfer bridges,thereby boosting the selectivity of the ORR-catalysed four-electron pathway.Meanwhile,the introduction of COP materials aids the formation of pore interstices in the graphene lamellae,which both adequately expose the active sites and facilitate the transport of reactive substances.Benefiting from the synergistic effect,as-prepared catalyst exhibits excellent half-wave potentials(E_(1/2)=912 mV)and stability(merely 8.8%drop after a long-term durability test of 50000 s).Further,ZAFBs assembled with the N/SG@CO_(2)P catalyst demonstrate exceptional power density(163.8 mW cm^(-2))and continuous charge and discharge for approximately 140 h at 10 mA cm^(-2),outperforming the noble-metal benchmarks.
基金supported by the National Natural Science Foundation of China(Nos.21601025,21677029,21571025)Dalian Young Science and Technology Star Project(2017RQ156)
文摘Though the photo-physical properties of free base porphyrin are attractive, there are still problems for the materials with weak and narrow range absorption of visible light. The unsymmetrical neo-confused porphyrin derivatives were introduced as novel materials for the improvement of photo-chemical and photo-physical properties. The density function theory（DFT）and time dependent density function theory（TDDFT） were applied to calculate the absorption spectrum of unsymmetrical neo-confused porphyrin（N-CP） and metal-coordinated N-CP in various solutions. The Ni and Zn coordinated neo-confused porphyrin dipole moment values are smaller than the values of prototype porphyrin（Pro P） and N–CP. According to the electrophilicity index ω, Ni coordinated N–CP（Ni–N–CP） is susceptible to the polarity of solvents, while the Zn coordinated derivative（Zn–N–CP） is more immune to the solvent environment. Unlike the Gouterman＇s four frontier orbital model of common porphyrin materials, the electron transitions of N–CPs and metalcoordinated N–CPs from H–2 or lower molecular orbitals also contribute to ultraviolet and visible absorption. Most of oscillator strength f values of Zn–N–CP are significantly higher than the values of Ni–N–CP, which reflects the higher absorption intensity of Q and Soret bands. The maximum wavelength at 702.2 nm in vacuum drew our attention to the novel material. The broad absorption range, intense red-shifted Q band and higher stability in solvents suggest that N–CPs, especially Zn–N–CP, can be one class of new candidate dye-sensitized materials.
文摘New thermotropic chloro-bridged dinuclear palladium coordinating imine side chain liquid crystalline polysiloxanes have been synthesized. Their mesomorphic properties have been investigated by DSC, X-ray diffraction and polarizing microscopy. The polymeric complexes show nematicdiscotic (Nd) mesophase. It is found that the temperature range of liquid crystalline state of chloro- bridged polymeric complexes is much wider than that of acetato- bridged ones and imine side chain polysiloxane. This indicates that the disc-like chloro-bridged palladium complexing units play a role as mesogen in mesophase.
文摘A new type of metal coordinated liquid crystalline polymers has been synthesized by complexation of metal ions with β-diketone based side chain liquid crystal polysiloxane (DKLCP). The complexation of copper ions with DKLCP greatly increases the phase transition temperature T_k from crystalline state to liquid crystalline state and T_(cl) from LC to isotropic state and makes the range of phase transition ΔT (ΔT=T_(cl)-T_k) widened. These complexes are soluble in common organic solvents. However, the incorporation of europium ions into DKLCP molecules gives rise to reduction in liquid crystallinity and crosslinking in some cases. The DKLCP coordinated with suitable amount of Eu ions can show good liquid crystallinity and fluorescent property.
