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Engineering a high-barrier d-f single-molecule magnet centered with hexagonal bipyramidal Dy(Ⅲ)unit

Science China Chemistry 2024年第10期67卷 3291-3298页

作者： Wei Deng Chan-Ying Yao Yan-Cong Chen Ying-Qian Zhou Shan-Nan Du jun-liang liu Ming-liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistryInstitute of Green Chemistry and Molecular EngineeringGuangdong Basic Research Center of Excellence for Functional Molecular EngineeringSun Yat-sen UniversityGuangzhou 510006China

In the pursuit of high-performance single-molecule magnets(SMMs),incorporating intramolecular magnetic coupling emerges as a pivotal *** these,d-f SMMs have garnered significant attention due to their remarkable versatility,which lies in their ability to tune coordination environments and facilely substitute metal ***,achieving performance-centric d-f SMMs through the synergistic interplay between highly anisotropic f ions and d-f magnetic interactions remains a formidable *** mononuclear hexagonal bipyramidal(D_(6h))Dy^(Ⅲ)SMMs have been successfully isolated,the exploration of d-f SMMs featuring D_(6h)-lanthanide metal centers remains uncharted *** this study,we employed planar bipodal ligands in conjunction with“staple-like”axial phenoxide ligands to synthesize the first hexagonal bipyramidal d-f ***,this compound exhibits alternating-current magnetic susceptibilities peaking up to 68 K with an energy barrier surpassing 1,200 K,thus establishing a new benchmark within the heterometallic d-f SMM landscape inclusive of complexes with diamagnetic d metals and paramagnetic f ***,the ferromagnetic interaction at the d-f sites engenders oscillating relaxation times contingent on the magnetic field—a characteristic distinct from mononuclear *** findings shed light on a deliberate design approach for d-f SMMs,emphasizing the cooperative utilization of high-barrier lanthanide modules alongside d ions through magnetic *** synergy significantly enhances and diversifies the magnetic dynamics of these intriguing molecular systems.

关键词： single-molecule magnets magnetic coupling crystal engineering hexagonal bipyramid energy barrier

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分子基磁双稳态材料的研究进展

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中国科学：化学 2024年第9期54卷 1413-1434页

作者：周颖倩姚婵莹倪兆平刘俊良伍思国童明良中山大学化学学院/广东省高等学校功能分子工程基础研究卓越中心/绿色化学与分子工程研究院/生物无机与合成化学教育部重点实验室广州510006

单分子磁体(single-molecule magnets,SMM)和自旋交叉(spin crossover,SCO)材料因其独特的磁学行为以及在器件应用上的巨大潜力,在分子基磁双稳态材料的研究领域中占据了举足轻重的地位.通过精准化学合成和外部刺激等手段,可以在分子层... 详细信息

单分子磁体(single-molecule magnets,SMM)和自旋交叉(spin crossover,SCO)材料因其独特的磁学行为以及在器件应用上的巨大潜力,在分子基磁双稳态材料的研究领域中占据了举足轻重的地位.通过精准化学合成和外部刺激等手段,可以在分子层面上对双稳态材料的磁能级进行精细调控.本文回顾了单分子磁体和自旋交叉材料的发展历程,并基于本课题组研究成果综述了其在设计合成、磁学行为和调制策略等方面的重要研究进展.最后,总结了该领域在分子尺度的精准结构设计、性能提升和多功能化等方面所面临的挑战,展望了分子基磁双稳态材料的未来发展方向.

关键词：双稳态分子磁性单分子磁体自旋交叉

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Preparation of flexible rubber composites with high contents of tungsten powders for gamma radiation shielding

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Rare Metals 2022年第7期41卷 2243-2248页

作者： Xiang-Rong Xu jun-Qing Wu Jian Xu Feng liu An Xie jun-liang liu Ming Zhang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China Environmental Engineering Center China Nuclear Power Research Institute Co.LtdShenzhen 518034China

To prepare tungsten/rubber composites with good gamma-ray shielding performances and fine mechanical properties,a composite surface modifier is employed to make surface modification of the tungsten powders.

关键词： composites composite rubber

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Synthesis of novel hydrated ferric oxide biochar nanohybrids for efficient arsenic removal from wastewater

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Rare Metals 2022年第5期41卷 1677-1687页

作者： Tong Zhu Yun Zhang Yu Chen jun-liang liu Xiao-Li Song College of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

Hydrated ferric oxide(HFO)has high adsorption efficiency for As(Ⅲ).However,its high self-aggregation usually reduces the efficiency and limits the scaledup ***,biochar(BC),with large surface area and amounts of surface functional groups was used to tune the loading and distribution of HFO to prepare an efficient adsorbent(HFO/BC)via in-situ synthesis *** influence of the mass ratio of iron salt to BC on HFO/BC morphology was investigated,and the mechanism was *** results showed that novel HFO was formed and distributed uniformly on the surface of BC when the mass ratio of iron salt to BC was 5:*** adsorption kinetics and isotherms studies show that the novel HFO/BC(5:1)composite can fast treat As(Ⅲ)with a high adsorption capacity of 104.55 mg·g^(-1),indicating that it is a potential material for removing arsenic from polluted water.

关键词： Hydrated ferric oxide Arsenic removal Biochar Water treatment

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Competitive role of film-like austenite and transition carbides on hydrogen embrittlement resistance and impact toughness in bainite-containing quenched and partitioned steel

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Journal of Iron and Steel Research International 2023年第4期30卷 782-794页

作者： Kai Yang Yi Luo Wei Li Li Wang Zhong-qu Sun jun-liang liu Xue-jun Jin Bao Steel-SJTU Joint Research Center of Future Steels School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Lab of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Lab of Development and Application Technology of Automotive Steels(Bao Steel) Research Institute(R&D Center)Baoshan Iron&Steel Co.Ltd.Shanghai 200240China

A microstructure composed of martensite matrix,lower bainite,and stable film-like austenite was designed by a quenching and isothermal bainitic holding process in a 0.30C–2.69Mn–1.71Si(wt.%)*** yield strength,tensile strength,and ductile-to-brittle transition temperature(DBTT)of the high-strength steel thus obtained were 1263 MPa,1521 MPa,and-33℃,respectively,and at-20℃,it showed superior low-temperature toughness,which reached 77.5 J/cm^(2).Meanwhile,it showed excellent hydrogen embrittlement(HE)resistance,and the total elongation loss is only 3.1%after 15 min of hydrogen *** excellent comprehensive performance is attributed to the fact that fine stable austenite with film-like morphology hindered the crack nucleation and propagation,and hindered hydrogen diffusion as a hydrogen ***,with a decrease in the isothermal temperature,transition carbide precipitation was accompanied by a further decrease in austenite grain *** this condition,although transition carbides can act as effective hydrogen traps,excessive precipitation decreased the carbon content of retained austenite and increased the deformation heterogeneity between austenite and martensite matrix,leading to weakened austenite stability and HE resistance,a total elongation loss of approximately 39%(15 min hydrogen charging),a sharp decrease in impact toughness,and an increase in *** competitive role of film-like austenite and transition carbides on the comprehensive mechanical performance of steel is revealed,especially the suppression of crack nucleation and propagation that will provide a guide for the design of high strength steels with excellent impact toughness and HE resistance.

关键词： Quenched and partitioned steel Isothermal bainite transformation Transition carbide Hydrogen embrittlement Impact toughness

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Polyethylene glycol (PEG) as a benign solvent for Knoevenagel condensation

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Chinese Chemical Letters 2008年第9期19卷 1043-1046页

作者： Yang liu jun liang Xiu Hong liu Ji Cai Fan Zhi Cai Shang Department of Chemistry Zhejiang University Hangzhou 310027 China

The Knoevenagel condensation of aromatic aldehydes with active methylene compound proceeded efficiently in polyethylene glycol at room temperature with L-proline as catalyst. The yield is high and the products had E-isomer dominantly. Polyethylene glycol containing L-proline could be recycled and reused for several times without noticeably decreasing in productivity.

关键词： Polyethylene glycol L-Proline Knoevenagel condensation

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Synthesis and microwave absorbing properties of La-doped Sr-hexaferrite nanopowders via sol-gel auto-combustion method

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Rare Metals 2017年第9期36卷 704-710页

作者： jun-liang liu Peng Zhang Xing-Kai Zhang Qing-Qing Xie Dong-jun Pan Jian Zhang Ming Zhang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

La-doped Sr-hexaferrite（Sr（1-x）LaxFe（12）O（19））（x=0.05,0.10,0.15,0.20） nanopowders with particle size ranging from 80 to 110 nm were successfully synthesized by sol-gel auto-combustion. The phase formation temperature increases, while the particle size decreases as the Ladoping content goes up. The partial substitution of Sr^（2＋） by La^（3＋） results in the suppression effects on the growth-up of the crystallites and the enhancement of the electron hopping between Fe^（3＋） with different valences, which leads to the improvement in the dielectric loss and magnetic ***, both the microwave absorbing abilities and absorbing frequency ranges are tuned by La-doping. The synthesized Sr-hexaferrite nanopowders with doping element content of 0.10 demonstrate the fine broad microwave absorbing properties.

关键词： Ferrite La-doping Nanopowders Sol-gelauto-combustion Microwave absorbing properties

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High-stability spherical lanthanide nanoclusters for magnetic resonance imaging

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National Science Review 2023年第4期10卷 123-132页

作者： Hai-Ling Wang Donglin liu Jian-Hua Jia jun-liang liu Ze-Yu Ruan Wei Deng Shiping Yang Si-Guo Wu Ming-liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of Chemistry Sun Yat-sen University College of Chemistry and Materials Science Shanghai Normal University

High-nuclear lanthanide clusters have shown great potential for the administration of high-dose mononuclear gadolinium chelates in magnetic resonance imaging(MRI). The development of high-nuclear lanthanide clusters with excellent solubility and high stability in water or solution has been challenging and is very important for expanding the performance of MRI. We used N-methylbenzimidazole-2-methanol(HL) and LnCl3·6H2O to synthesize two spherical lanthanide clusters, Ln32(Ln = Ho, Ho32; and Ln =Gd, Gd32), which are highly stable in solution. The 24 ligands L-are all distributed on the periphery of Ln32and tightly wrap the cluster core, ensuring that the cluster is stable. Notably, Ho32can remain highly stable when bombarded with different ion source energies in HRESI-MS or immersed in an aqueous solution of different pH values for 24 h. The possible formation mechanism of Ho32was proposed to be Ho(Ⅲ),(L)-and H2O → Ho3(L)3/Ho3(L)4→ Ho4(L)4/Ho4(L)5→ Ho6(L)6/Ho6(L)7→ Ho16(L)19→Ho28(L)15→ Ho32(L)24/Ho32(L)21/Ho32(L)23. To the best of our knowledge, this is the first study of the assembly mechanism of spherical high-nuclear lanthanide clusters. Spherical cluster Gd32, a form of highly aggregated Gd(Ⅲ), exhibits a high longitudinal relaxation rate(1 T, r1= 265.87 mM-1·s-1). More notably, compared with the clinically used commercial material Gd-DTPA, Gd32has a clearer and higher-contrast T1-weighted MRI effect in mice bearing 4T1 tumors. This is the first time that high-nuclear lanthanide clusters with high water stability have been utilized for MRI. High-nuclear Gd clusters containing highly aggregated Gd(Ⅲ) at the molecular level have higher imaging contrast than traditional Gd chelates; thus, using large doses of traditional gadolinium contrast agents can be avoided.

关键词： T1-weighted MRI lanthanide clusters high stability low toxicity assembly mechanism

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From geometric to charge-distribution symmetry:deeper insights into lifting the performance of dysprosium single-ion magnets

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Science China Chemistry 2023年第7期66卷 1989-1996页

作者： Wei Deng Ying-Qian Zhou Shan-Nan Du Ze-Yu Ruan Si-Guo Wu jun-liang liu Ming-liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistrySun Yat-Sen UniversityGuangzhou 510006China

Crystal-field symmetry of lanthanide ions plays a critical role in suppressing quantum tunneling of magnetization(QTM)in single-molecule magnets(SMMs),but high-performance SMM design and modulation remain challenging only in view of the geometric symmetry of the first coordination ***,two bis(semicarbazone)/bis(thiosemicarbazone)dysprosium singleion magnets with pentagonal bipyramid geometry were reported,and bis(thiosemicarbazone)lanthanide complexes have never been reported to the best of our *** served as good archetypes to study the magneto-structural relationships based on the charge *** complex with more ideal geometric symmetry displays fast zero-field QTM with negligible“effective barrier”,owing to the defective charge *** modulating the transverse crystal field via the replacement of the O sites with the less charged and larger radius S atoms,it results in lower geometric but higher charge-distribution symmetry,giving rise to the significant suppression of QTM and the enhancement of reversal barrier up to ca.1,000 *** results demonstrate that the charge-distribution symmetry can be chemically tailored by modification of the crystal field,which is essential for designing high-performance SMMs.

关键词： single-molecule magnets crystal field symmetry strategy electrostatic potential analysis bis(thiosemicarbazone)

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Seeking magneto-structural correlations in easily tailored pentagonal bipyramid Dy (Ⅲ) single-ion magnets

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Science China Chemistry 2020年第8期63卷 1066-1074页

作者： Guo-Zhang Huang Ze-Yu Ruan Jie-Yu Zheng Yan-Cong Chen Si-Guo Wu jun-liang liu Ming-liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistrySun Yat-Sen UniversityGuangzhou 510275China

Controlling molecular magnetic anisotropy via structural engineering is delicate and fascinating,especially for single-molecule magnets(SMMs).Herein a family of dysprosium single-ion magnets(SIMs)sitting in pentagonal bipyramid geometry have been synthesized with the variable-size terminal ligands and counter anions,through which the subtle coordination geometry of Dy(Ⅲ)can be finely tuned based on the size *** effective energy barrier(Ueff)successfully increases from 439 to 632 K and the magnetic hysteresis temperature(under a 200 Oe/s sweep rate)raises from 11 to 24 *** on the crystal-field theory,a semi-quantitative magneto-structural correlation deduced experimentally for the first time is revealed that the Ueff is linearly proportional to the structural-related value S20 corresponding to the axial coordination bond lengths and the bond *** the evaluation of the remanent magnetization from hysteresis,quantum tunneling of magnetization(QTM)is found to exhibit negative correlation with the structural-related value Stun corresponding to the axial coordination bond angles.

关键词： single-molecule magnets magnetic anisotropy crystal field magneto-structural correlation

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