KBi4F13:一个具有高激光损伤阈值的中红外非线性光学材料

通过KF和Bi₂O₃在HF的水溶液中的水热反应合成了化合物KBi₄F₁₃,首次用X-射线单晶衍射技术鉴定了它的晶体结构。对它进行了XRD、ATR-FTIR、UV-Vis-NIR、TG、SHG测试。测试结果表明该化合物具有能够相位匹配的二阶非线性光学性能,其粉末倍频效应强度约为KDP的一半;粉末激光损伤阈值为120 MW·cm^-2,远远高于同等条件下测试的商品化红外非线性光学材料AgGaS₂的粉末激光损伤阈值(5 MW·cm^-2);粉末的红外吸收边可达20 μm;热分解温度为220℃。以上结果表明该物是有潜在应用价值的具有高激光损伤阈值的中红外非线性光学晶体材料。     

KBi4F13:一个具有高激光损伤阈值的中红外非线性光学材料

通过KF和Bi₂O₃在HF的水溶液中的水热反应合成了化合物KBi₄F₁₃,首次用X-射线单晶衍射技术鉴定了它的晶体结构。对它进行了XRD、ATR-FTIR、UV-Vis-NIR、TG、SHG测试。测试结果表明该化合物具有能够相位匹配的二阶非线性光学性能,其粉末倍频效应强度约为KDP的一半;粉末激光损伤阈值为120MW·cm^-2,远远高于同等条件下测试的商品化红外非线性光学材料AgGaS₂的粉末激光损伤阈值(5MW·cm^-2);粉末的红外吸收边可达20μm;热分解温度为220℃。以上结果表明该物是有潜在应用价值的具有高激光损伤阈值的中红外非线性光学晶体材料。     

一类五核平面开口型过渡金属原子簇电子吸收光谱和二阶非线性光学性质的TDDFT研究

运用TDDFT B3LYP/LanL2DZ方法, 研究了一类具有非中心对称的五核平面开口构型过渡金属原子簇化合物[MoS₄Cu₄(py)₆X₂] (X＝Br, I)的电子吸收光谱和静态二阶非线性极化率, 估算了晶体的宏观二阶非线性光学系数. 电子吸收光谱的计算结果与实验测量结果比较符合; 碘系簇合物的静态二阶非线性极化率大于溴系. 详细讨论了该类金属簇合物电子吸收光谱的归属及其相关联的电子跃迁方式; 在微观水平上阐述了其二阶非线性光学性质的起源. 研究结果表明外围无机卤素配体4p/5p轨道到簇芯[MoS₄]杂化轨道的电子转移对静态二阶非线性极化率的贡献大于有机配体的贡献; 而过渡金属簇芯内的电子转移也有较大的贡献. 这对于理解过渡金属原子簇化合物内的电子转移对光学激发的作用以及用来设计新的无机-有机杂化二阶非线性光学材料有较大的帮助.     

Pb7F12Br2:一个具有较高激光损伤阈值的潜在中红外非线性光学晶体材料

对一个含Pb的混合卤化物Pb₇F₁₂Br₂进行了合成及单晶结构与性能测试,并首次对它的各种与非线性光学材料相关的主要性能进行了研究。发现该化合物的光学带隙宽达4.32 eV,粉末激光损伤阈值为25 MW·cm^-2,高于同等测试条件下商品化红外非线性光学晶体材料AgGaS₂的粉末激光损伤阈值（<5.2 MW·cm^-2）,它的粉末倍频效应为KDP（KH₂PO₄）的1.5倍并能够实现相位匹配,红外透光范围宽为0.3~14μm,热分解温度超过650℃,展示了较好的综合性能。     

平面四方型混合配体配合物［Pd(γ-CH3py)2(mnt)2］的合成和晶体结构

本文报道标题化合物(其中γ-CH₃py是对-甲基吡啶，mnt=?的合成、鉴定和单晶结构。化合物晶体属三钭晶系，P1空间群，晶胞内分子数为2。分子中与Pd(Ⅱ)配位的四个原子呈平面四方形。讨论了结构与二阶、三阶非线性光学效应的关系。     

新型超支化二阶非线性光学高分子：简便的合成方法和增强的非线性光学效应

通过简单的“A₂+B₃”反应，我们成功地合成了一个新的超支化非线性光学高分子。同时，作为对比，我们还合成了相对应的线型高分子。制备的两个高分子均溶于常见的有机溶剂，并由各种表征手段予以鉴定。超支化高分子的二阶非线性光学性能极大地优于相对应的线型高分子，表明超支化结构有利于提高高分子材料的宏观非线性光学效应。     

K2W3SeO12的合成、晶体结构和非线性光学性质研究

本文通过水热反应得到一种新化合物K₂W₃SeO₁₂,并测试了其单晶结构,该晶体属于三方晶系,空间群R3c,晶胞参数a=b=c=1.25361(10)nm,α=β=γ=33.5390(10)°。对它进行了XRD、EDX、ATR-FTIR、UV-Vis-NIR、TG、SHG测试。测试结果表明化合物有很强的可实现相位匹配的倍频效应(强度约为KDP的9倍),而且具有较宽的带隙(3.24eV)和良好的热稳定性。粉末的红外吸收边达到10μm。结果表明K₂W₃SeO₁₂是一个具有潜在应用价值的中红外非线性光学晶体材料。     

AgGa(S1-xSex)2固溶体的电子结构和光学性质

采用基于赝势平面波基组的密度泛函理论方法, 对一系列具有黄铜矿结构的AgGa(S_1-xSe_x)₂固溶体的构型、电子结构、线性和二阶非线性光学性质进行了系统研究. 结果表明, 各固溶体具有类似的能带结构, 体系带隙随x值增加而逐渐减小. 当所引入的Hartree-Fock交换项贡献为22.56%时, 对应的杂化PBE泛函得到的带隙值与实验结果相近. 固溶体的各种光学性质, 包括折射率、双折射率、反射率、吸收系数和二阶倍频系数等均随着组成的改变呈现出有规律的变化趋势, 变化范围介于AgGaS₂和AgGaSe₂二者之间. 因此, 利用固溶体光学性质的变化规律, 可从中寻找出具有特定光学性能的晶体材料.     

手性配体2, 5-二(4, 5-蒎烯-2-吡啶)吡嗪及其铼配合物的合成与表征

本文报道了手性配体2, 5-二(4, 5-蒎烯-2-吡啶)吡嗪(L)及其铼配合物[Re(CO)₃Cl(L)] ·DMF的合成与表征。X射线单晶衍射分析表明配体L晶体为单斜P2₁空间群, 而配合物[Re(CO)₃Cl(L)] ·DMF晶体为正交P2₁2₁2₁空间群。配合物[Re(CO)₃Cl(L)] ·DMF中铼原子与配体中的2个氮原子、3个羰基中的碳原子以及1个氯原子配位。CD谱和VCD谱测试表明, 配体和配合物都表现出光学活性。受光激发时, 配体和配合物分别在420和650 nm处发光。配体和配合物都具有二阶非线性光学性质, 其二阶非线性光学效应分别为尿素的0.4和0.3倍。     

巴比妥酸葡萄糖基取代衍生物电子光谱和二阶非线性光学性质的理论研究

应用量子化学AM1半经验方法分别对巴比妥酸及硫代巴比妥酸的葡萄糖基系列取代衍生物B_1-5和T_1-5进行几何优化。基于优化后的稳定构型，利用INDO/CI方法计算其电子光谱。同时，根据完全态求和(SOS)公式计算其二阶非线性光学系数。结果显示，当葡萄糖基单元数增加时，无论是巴比妥酸衍生物还是硫代巴比妥酸衍生物，|β_μ| 均增大，尤其是硫代巴比妥酸衍生物增大更为显著，表明此种非共轭取代基同样可以改善材料的非线性光学性质。此外，随葡萄糖基链增长时，光谱的变化并不十分显著，且由于所有吸收带均在紫外光区内，因此推测所有体系均有望成为具有高度透明性的非线性光学侯选材料。     

A Tale of Two Trimers from Two Different Worlds: A COF‐Inspired Synthetic Strategy for Pore‐Space Partitioning of MOFs

The introduction of a symmetry‐ and size‐matching pore‐partitioning agent in the form of either a molecular ligand, such as 2,4,6‐tri(4‐pyridinyl)‐1,3,5‐triazine ( tpt ), or a metal‐complex cluster, into the hexagonal channels of MIL‐88/MOF‐235‐type (the acs net) to create pacs ‐type (partitioned acs ) crystalline porous materials is an effective strategy to develop high‐performance gas adsorbents. We have developed an integrated COF–MOF coassembly strategy as a new method for pore‐space partitioning through the coassembly of [(M₃(OH)_1?x(O)_x(COO)₆] MOF‐type and [B₃O₃(py)₃] COF‐type trimers. With this strategy, the coordination‐driven assembly of the acs framework occurred concurrently and synergistically with the COF‐1‐type condensation of pyridine‐4‐boronic acid into a C₃‐symmetric trimeric boroxine molecule. The resulting boroxine‐based pacs materials exhibited dramatically enhanced gas‐sorption properties as compared to nonpartitioned acs ‐type materials and are among the most efficient NH₃‐sorption materials.     

Lithium Germanate (Li2GeO3): A High‐Performance Anode Material for Lithium‐Ion Batteries

A simple, cost‐effective, and easily scalable molten salt method for the preparation of Li₂GeO₃ as a new type of high‐performance anode for lithium‐ion batteries is reported. The Li₂GeO₃ exhibits a unique porous architecture consisting of micrometer‐sized clusters (secondary particles) composed of numerous nanoparticles (primary particles) and can be used directly without further carbon coating which is a common exercise for most electrode materials. The new anode displays superior cycling stability with a retained charge capacity of 725 mAh g^?1 after 300 cycles at 50 mA g^?1. The electrode also offers excellent rate capability with a capacity recovery of 810 mAh g^?1 (94 % retention) after 35 cycles of ascending steps of current in the range of 25–800 mA g^?1 and finally back to 25 mA g^?1. This work emphasizes the importance of exploring new electrode materials without carbon coating as carbon‐coated materials demonstrate several drawbacks in full devices. Therefore, this study provides a method and a new type of anode with high reversibility and long cycle stability.     

Survey of Chalcogenide Superconductors

The thread that runs through all research in the field of superconductivity is new physics through discovery of new materials. The knowledge of superconducting materials has become voluminous and complex. The comprehensive review of the superconducting materials is of particular importance. The main purpose of this report is to present the results of classification for chalcogenide superconductors. Superconducting critical temperature T_c, crystal-structure type and the references proper to these compounds are summarized. Brief survey of the superconductivity in chalcogen elements is also given. Furthermore, as representative sulfide and selenide, superconducting characteristics of CuRh₂S₄ and CuRh₂Se₄ will be shown.This revised version was published online in November 2005 with corrections to the Cover Date.     

TiO2-polymer Nano-composites by sol-gel

Sol-gel processes make it possible to develop new hybrid electrolyte materials of the type ceramicpolymer, known as Nano-Crystallite-Insertion-Material (NCIM). They can be used in reversible alkali electrochemical cells after insertion with cations such as Li⁺. In the present study, TiO₂-polyethylene oxide hybrid materials were synthesized, from TiCl₄ and from Ti ethoxide. Their structure is analyzed in relation with the processing parameters. A primary evaluation of the nanoscale composite materials for reversible Li insertion was done.     

Structural Tunability and Diversity of Two-Dimensional Lead Halide Benzenethiolate

Two-dimensional (2D) organic-inorganic hybrid materials are currently of great interest for applications in electronics and optoelectronics. Here, the synthesis and optical properties of a new type of halide-organothiolate-mixed 2D hybrid material, Pb₂X(S-C₆H₅)₃, are reported, in which X is a halide (I, Br, or Cl). Different from conventional lead-based 2D layered materials, these compounds feature unusual five-coordinated lead centers with a stereochemically active electron lone pair on the lead atoms and four-coordinated iodine atoms. The Pb₂X(S-C₆H₅)₃ materials feature an indirect bandgap, strongly emissive long-lived self-trap states, and an extremely large Stokes shift. Interestingly, the optical bandgap of the materials can be tuned through variation of the halides; however, the photoluminescence is less sensitive to the composition and is more likely dominated by lead-sulfur lattice interactions or the lead lone-pair electrons. Our results support that a halide–organothiolate mixed anion hybrid structure offers a unique platform for discovering new exciting 2D electronic materials.     

An Abnormal 3.7 Volt O3‐Type Sodium‐Ion Battery Cathode

Layered O3‐type sodium oxides (NaMO₂, M=transition metal) commonly exhibit an O3–P3 phase transition, which occurs at a low redox voltage of about 3 V (vs. Na⁺/Na) during sodium extraction and insertion, with the result that almost 50 % of their total capacity lies at this low voltage region, and they possess insufficient energy density as cathode materials for sodium‐ion batteries (NIBs). Therefore, development of high‐voltage O3‐type cathodes remains challenging because it is difficult to raise the phase‐transition voltage by reasonable structure modulation. A new example of O3‐type sodium insertion materials is presented for use in NIBs. The designed O3‐type Na_0.7Ni_0.35Sn_0.65O₂ material displays a highest redox potential of 3.7 V (vs. Na⁺/Na) among the reported O3‐type materials based on the Ni²⁺/Ni³⁺ couple, by virtue of its increased Ni?O bond ionicity through reduced orbital overlap between transition metals and oxygen within the MO₂ slabs. This study provides an orbital‐level understanding of the operating potentials of the nominal redox couples for O3‐NaMO₂ cathodes. The strategy described could be used to tailor electrodes for improved performance.     

An Above‐Room‐Temperature Ferroelectric Organo–Metal Halide Perovskite: (3‐Pyrrolinium)(CdCl3)

Hybrid organo–metal halide perovskite materials, such as CH₃NH₃PbI₃, have been shown to be some of the most competitive candidates for absorber materials in photovoltaic (PV) applications. However, their potential has not been completely developed, because a photovoltaic effect with an anomalously large voltage can be achieved only in a ferroelectric phase, while these materials are probably ferroelectric only at temperatures below 180 K. A new hexagonal stacking perovskite‐type complex (3‐pyrrolinium)(CdCl₃) exhibits above‐room‐temperature ferroelectricity with a Curie temperature T_c=316 K and a spontaneous polarization P_s=5.1 μC cm^?2. The material also exhibits antiparallel 180° domains which are related to the anomalous photovoltaic effect. The open‐circuit photovoltage for a 1 mm‐thick bulky crystal reaches 32 V. This finding could provide a new approach to develop solar cells based on organo–metal halide perovskites in photovoltaic research.     

A Heterometallic MOF based on Monofunctional Linker by “One-pot” Solvothermal Method for Highly Selective Gas Adsorption

Heterometallic MOFs, as an important branch of MOF materials, open up a new way to design and synthesize innovative MOF materials. Hence, it has positive significance for the development of MOF materials. By utilizing monofunctional linker CBDA [5,5'-(carbonylbis(azanediyl))-diisophthalic acid], a heterometallic MOF In/Gd-CBDA was obtained under “one-pot“ solvothermal method. The three-dimensional framework exhibits (3,4,6)-connected network belonging to a new topology. In addition, the synthetic conditions that affect the growth of crystal have been studied in detail. Numerous experiments led to the finding that the type and composition of solvents are very important for inducing the recognition of carboxylic acid groups at different positions coordination to diverse metals. Furthermore, the mechanism of this kind of heterometallic MOFs assembled by monofunctional linker under “one-pot” solvothermal method has been clarified, which is mainly related to the steric hindrance of functional groups and the properties of heterometals. Based on ideal adsorbed solution theory (IAST), In/Gd-CBDA shows the efficient selective gas adsorption, especially for equimolar mixtures of CO₂/CH₄ (13) and C₃H₈/CH₄ (321). This work of heterometallic MOF material assembled by monofunctional linker under “one-pot” solvothermal method provides a new platform for the development of MOF materials in terms of enriching the topological family and broadening possibilities in advanced applications.     

Coordination‐Assembled Lanthanide‐Organic Ln3L3 Sandwiches or Ln4L4 Tetrahedron: Structural Transformation and Luminescence Modulation

Photo‐functional supramolecular lanthanides assemblies have shown great potential in the materials and biomedical fields. Two new tri(tridentate) ligands ( L3 and L4 ) highlighting small variation of the connection position to the central tridentate linkers have been designed, which leads to the emergent formation of either Ln₃L₃‐type sandwich structures or Ln₄L₄‐type tetrahedral cages. Moreover, nonlinear enhancement of lanthanide luminescence based on the modulation of inter‐ligand charge‐transfer states has been revealed on the mix‐ligand Ln₃L₃ sandwiches. Our results provide important guidance for structure‐design and photoluminescence optimization of supramolecular lanthanide‐organic assemblies.     

From an Impurity to the Pure Compound – an Electron Microscopy Study

The power of electron microscopy techniques for the determination of structure and composition of marginal byproducts is demonstrated for rare earth metal cluster compounds. Small amounts of the new phase Gd₄GaI₆ in samples with the nominal composition Gd₇GaI₁₂ could only be identified by a combined approach of EDX, electron diffraction and HRTEM. The structure of Gd₄GaI₆ can be assigned to the Y₄BBr₆‐type containing chains of Gd₆ octahedra which are centered by Ga atoms. The results of the electron microscopy study initiated the synthesis of homogeneous samples of the new compound Gd₄GaI₆ by applying the correct ratio of the starting materials.