Birefringence Regulation by Clarifying the Relationship Between Stereochemically Active Lone Pairs and Optical Anisotropy in Tin-based Ternary Halides

It is important to establish and clarify the relationship between stereochemically active lone pairs and birefringence, since it is one of the significantly effective routes to explore birefringent crystals by introducing Sn-centered polyhedra with stereochemically active lone pairs. Herein, four tin(II)-based ternary halides A₃SnCl₅ and ASn₂Cl₅ (A=NH₄ and Rb) have been synthesized successfully. The experimental birefringence of Rb₃SnCl₅ and RbSn₂Cl₅ is larger than or equal to 0.046 and 0.123@546 nm, respectively. Through investigating the alkali or alkaline-earth metal tin(II)-based ternary halides, the structure-performance relationship has been concluded between stereochemically active lone pairs and optical anisotropy. It is beneficial to the analysis and prediction of birefringence in tin-based halides and provides a guide for exploring tin(II)-based optoelectronic functional materials.     

Mg(C3O4H2)(H2O)2: A New Ultraviolet Nonlinear Optical Material Derived from KBe2BO3F2 with High Performance and Excellent Water-Resistance

Acquiring high-performance ultraviolet (UV) nonlinear optical (NLO) materials that simultaneously exhibit a strong second harmonic generation (SHG) coefficients, as short as possible SHG phase-matching (PM) wavelength and non-hygroscopic properties has consistently posed a significant challenge. Herein, through multicomponent modification of KBe₂BO₃F₂ (KBBF), an excellent UV NLO crystal, Mg(C₃O₄H₂)(H₂O)₂, was successfully synthesized in malonic system. This material possesses a unique 2D NLO-favorable electroneutral [Mg(C₃O₄H₂)₃(H₂O)₂]_∞ layer, resulting in the rare coexistence of a strong SHG response of 3×KDP (@1064 nm) and short PM wavelength of 200 nm. More importantly, it exhibits exceptional water resistance, which is rare among ionic organic NLO crystals. Theoretical calculations revealed that its excellent water-resistant may be originated from its small available cavity volumes, which is similar to the famous LiB₃O₅ (LBO). Therefore, excellent NLO properties and stability against air and moisture indicate it should be a promising UV NLO crystal.     

含咪唑基配体的Co(Ⅱ)超分子配合物的合成、晶体结构和光谱性质

采用改进的固相Wittig反应, 合成了一种新型的具有电子给受体和π共轭结构的咪唑衍生物1-{反式4-[4-(-N,N-二乙基氨基)苯乙烯基]苯}咪唑(C21H23N3, 简作L). 室温下, 将L与Co(SCN)2在甲醇中反应, 合成了配合物Co(SCN)2(C21H23N3)4. X射线单晶衍射分析结果表明, 该晶体属于三斜晶系, P1空间群, 晶胞参数a=0.931 7(3) nm, b=1.275 3(4) nm, c=1.669 1(5) nm, α= 89.521(5)°, β=84.591(5)°, γ=80.052(5)°, V=1.944 6(11) nm3, Z=1, μ=0.329 mm-1, Dc=1.234 Mg/m3, F(000)=765, R1=0.060 1, wR=0.138 1, GOF=1.030, 中心原子Co(Ⅱ)的配位数为6, 分别与来自4个L的咪唑N及2个SCN-的N配位, 形成八面体的空间构型. 配合物分子通过非典型氢键和π-π堆积作用形成三维超分子结构. 研究结果表明, 配合物具有很好的光学性质.     

Design of the Ionic Organic Nonlinear Optical Material NH4[LiC3H(CH3)O4] with Ultrawide Band Gap and Moderate Birefringence

Ionic organic crystals containing organic planar π-conjugated units has become one of the hot spots as nonlinear optical (NLO) materials. However, although this type of ionic organic NLO crystals commonly have remarkable second harmonic generation (SHG) responses, they also suffer from overlarge birefringences and relatively small band gaps that be hardly beyond 6.2 eV. Herein, a flexible π-conjugated [C₃H(CH₃)O₄]²⁻ unit was theoretically revealed, showing great potential for designing NLO crystals with balanced optical properties. Accordingly, through the reasonable NLO-favourable layered design, a new ionic organic material, NH₄[LiC₃H(CH₃)O₄], was successfully obtained. As expected, it achieves not only a large SHG effect (4×KDP), but also a suitable birefringence (0.06@546 nm) and an ultrawide band gap (>6.5 eV). This study provides a new flexible π-conjugated NLO-active unit, contributing to design more ionic organic NLO materials with excellent balanced optical properties.     

Three Phenoxo‐Bridged Dinuclear Lanthanide Complexes: Syntheses,Crystal Structures,and Magnetic Properties

Three dinuclear lanthanide complexes [Ln₂(H₂L)₂(NO₃)₄] [Ln = Dy ( 1 ), Tb ( 2 ), and Gd ( 3 )] [H₃L = 2‐hydroxyimino‐N′‐[(2‐hydroxy‐3‐methoxyphenyl)methylidene]‐propanohydrazone] were solvothermally synthesized by varying differently anisotropic rare earth ions. Single‐crystal structural analyses demonstrate that all the three complexes are crystallographically isostructural with two centrosymmetric Ln^III ions aggregated by a pair of monodeprotonated H₂L^– anions. Weak intramolecular antiferromagnetic interactions with different strength were mediated by a pair of phenoxo bridges due to superexchange and/or single‐ion anisotropy. Additionally, the Dy^III‐based entity shows the strongest anisotropy exhibits field‐induced single‐molecule magnetic behavior with two thermally activated relaxation processes. In contrast, 3 with isotropic Gd^III ion has a significant cryogenic magnetocaloric effect with the maximum entropy change of 25.7 J · kg^–1 · K^–1 at 2.0 K and 70.0 kOe.     

戈德施米特：地球化学和晶体化学的奠基人

戈德施米特(1888—1947),地球化学的奠基人,他发现了元素在地球中的分布规律。他在元素的相对丰度、原子和离子半径、离子间距、半径比对晶体配位数的影响、镧系收缩等方面的成果,为晶体化学奠定了基础。本文介绍了戈德施米特的生平和成就。     

蝎型钒氧配合物的合成、结构及量子化学研究

设计合成了两种新型的以聚类吡唑硼酸盐为配体的钒氧配合物VO(acac)[HB(pz)3](1)和VO(acac)[HB(3,5-Me2pz)3]·CH3CN(2). 运用元素分析、 红外光谱和紫外光谱对所合成的配合物进行了表征, 并用X射线衍射测定了它们的晶体结构. 同时, 采用量子化学的Hartree Fock方法和自然轨道分析方法(NBO), 使用3-21G*(6d, 7f)基组计算得到了两个分子体系的分子轨道、原子电荷以及键级, 并对其结构进行了分析.     

光散射技术在蛋白质晶体生长研究中的应用和进展

光散射技术广泛应用于生物大分子的晶体生长研究中,它包括静态光散射和动态光散射两种。利用静态光散射可以测定蛋白质溶液渗透的第二维里系数;利用动态光散射可以测定蛋白质溶液的平动扩散系数,获得溶液中蛋白质粒子的流体力学半径及分布情况,分离蛋白质结晶的成核与生长过程,研究大分子的聚集行为和晶体生长的动力学。借助光散射技术可以实现蛋白质晶体生长过程的动态控制。近些年光散射仪器向着小型化、轻便化的方向发展,光散射技术不断得到改进,日益完善,不仅用于地面实验,也应用于空间领域蛋白质晶体生长的研究中。     

Syntheses and Characterization of Mixed‐Anions Lead(II) Complexes, [Pb(phen)2(CH3COO)]X (X=NCS—, NO3— and ClO4—), Crystal Structure of [Pb(phen)2(CH3COO)](ClO4)

The 1:2 adduct lead(II) complexes with 1, 10‐phenanthroline (phen) containing three different anions, [Pb(phen)₂(CH₃COO)X] (X=NCS^—, NO₃^— and ClO₄^—), have been synthesized and characterized by CHN elemental analysis, IR‐, ¹H‐ and ¹³C NMR spectroscopy. The structure of [Pb(phen)₂(CH₃COO)(ClO₄)] was determined by single crystal X‐ray analysis. The Pb atom of the monomeric complex is coordinated by four nitrogen atoms of two 1, 10‐phenanthroline ligands and two oxygen atoms of the acetate ligand to form an irregular octahedron. The arrangement of the 1, 10‐phenanthroline and acetate ligands, exhibits a coordination gap around the Pb^II ion, possibly occupied by a stereochemical electron active lone pair on lead(II), which results in a hemidirected lead compound. The π‐π stacking interaction between the parallel aromatic rings may help to increase the coordination ‘gap’ around the Pb^II ion.     

Semicarbazones and thiosemicarbazones,XII: Crystal structure of salicylaldehyde semicarbazone

Summary The crystal and molecular structure of salicylaldehyde semicarbazone was obtained by single crystal X-ray diffraction. The O atom of the semicarbazone fragment isanti to the N atom of the hydrazinic group. The distribution of bond lengths in the semicarbazone fragment indicates delocalization of the -electrons. The crystal structure is stabilized by intra- and intermolecular hydrogen bonds.

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Semicarbazone und Thiosemicarbazone, 12. Mitt.: Die Kristallstruktur des Salicylaldehyd-Semicarbazons

Zusammenfassung Die Kristallstruktur und die molekulare Struktur des Salicylaldehyd-Semicarbazons wurde über Einkristall-Röntgenstreuung ermittelt. Das O-Atom des Semicarbazonteils stehtanti zum N-Atom der Hydrazin-Gruppierung. Die Bindungslängen in der Semicarbazoneinheit zeigen eine Delokalisierung der -Elektronen an. Die Geometrie der Verbindung wird durch stabilisierende intra- und intermolekulare Wasserstoffbrückenbindungen bestimmt.

     

Coordination Chemistry of Acrylamide 4. Crystal Structures and IR Spectroscopic Properties of Acrylamide Complexes with CoII,NiII, and ZnII nitrates

Acrylamide complexes of metal nitrates: [M(O‐OC(NH₂)CHCH₂)_n(H₂O)_m][NO₃]₂ (M = Co( 1 ), Ni( 2 ) (n = 6 and m = 0) and Zn( 3 ) (n = 4 and m = 2)) have been determined by using single crystal X‐ray diffraction analysis. All complexes crystallize in the triclinic space group . The structures of 1 and 2 represent octahedral species [M(AAm)₆]²⁺ (AAm = O‐OC(NH₂)CHCH₂ and M = Co or Ni) and uncoordinated nitrate ions. The structure of 3 involves the octahedral cation [Zn(AAm)₄(H₂O)₂]²⁺ in which the Zn²⁺ environment includes oxygen atoms of four acrylamide and two water molecules that are stabilized using ionic nitrate ions. The observations of the solid‐state IR spectroscopic vibrational frequencies of these acrylamide complexes are in agreement with the crystal structures.     

2-(2-苯并咪唑基)-4,4,5,5-四甲基-3-氧化咪唑啉-1-氧基自由基的合成、晶体结构与量化计算

报道了2-(2-苯并咪唑基)-4, 4, 5, 5-四甲基-3-氧化咪唑啉-1-氧基自由基(NITBzImH)的合成和晶体结构.晶体属正交晶系Pbca空间群.a=0.87446(4), b=1.55600(8), c=2.01139(1) nm,α=β=γ=90°,Z=8,V=2.7368(2) nm³, R=0.0478,ωR=0.1101;并用密度泛函(DFT)计算了该自由基的自旋密度分布.     

Coordination Chemistry of Acrylamide: 1. Cobalt(II) Chloride Complexes with Acrylamide – Synthesis and Crystal Structures

The molecular structures of blue dichloro‐tetrakis(acrylamide) cobalt(II), [Co{O‐OC(NH₂)CH=CH₂}₄Cl₂] ( 1 ) and pink hexakis(acrylamide)cobalt(II) tetrachlorocobaltate(II), [Co{O‐OC‐(NH₂)CH=CH₂}₆][CoCl₄] ( 2 ), characterized by single X‐ray diffraction, IR spectroscopy and elemental analyses, are described. The coordination of Co^II in 1 involves a tetragonally distorted octahedral structure with four O‐donor atoms of acrylamide in the equatorial positions and two chloride ions in the apical positions. The second complex 2 in ionic form contains Co^II cations surrounded by an octahedral array of O‐coordinated acrylamide ligands, accompanied by a [CoCl₄]^2? anion.     

Synthesis, Crystal Structure and Quantum Chemistry Study of Tri（o-bromobenzyl）tin Ferrocenecarboxylate

A novel complex tri(o-bromobenzyl)tin ferrocenecarboxylate has been synthesized and its crystal structure was determined by X-ray diffraction. It belongs to orthorhombic, space group Pbca with a = 1.1340(3), b = 1.7823 (4), c = 3.0119(8) nm, V = 6.088(3) nm3, Mr = 857.81, Z = 8, Dc = 1.872 g/cm3, μ(MoKα) = 52.63 cm-1, F(000) = 3328, R = 0.0683 and wR = 0.1057. The tin atom adopts a distorted tetrahedral coordination geometry. Further studies on the title com- plex have been performed with quantum chemistry calculation at the Lanl2dz basis set level using G98W package. The stability of the complex, some frontier molecular orbital energies and com- position characteristics of some frontier molecular orbitals have been investigated.     

Coordination Chemistry of Sulfonyl Amides. 2 The Crystal Structure of Copper(II) and Silver(I) Complexes of N,N-4-Toluenesulfonyl-2-Pyridylaminato Ligand

Three structures containing the N,N-4-toluenesulfonyl-2-pyridylaminato ligand are presented. The brown crystal of Cu₂L₄ (L =N,N-4-toluenesulfonyl-2-pyridylaminato) was found to crystallize in the monoclinic space group P2,/c with a = 15.762(12), b = 15.552(5), c = 20.505(11) Å, β = 104.14(7)°; V = 4874(5) Å^3;Z = 4; the final R_F = 0.050, R_WF = 0.049 for 5142 observed reflections and 612 variables. The Cu-Cu distance is small, 2.516(2) Å and the complex is diamagnetic at room temperature. The colorless crystal of Ag₂L was found to crystallize in the monoclinic space group P2_t/n with a = 9.620(2), b = 5.625(2), c ? 23.250(3) Å, Å = 94.72(1)°; V = 1254.0(5) ų; Z = 2; the final R_F = 0.027; R_WF = 0.028 for 1929 observed reflections and 164 variables. The Ag-Ag distance is 2.739(1) Å The green crystal of CuL₂ (py)₂was found to crystallize in the monoclinic space group P2₁ with a = 9.366(2), b = 20.615(7), c = 9.862(2) Å,β = 116.73(2)°; V = 1700.5(8) ų; Z = 2; the final R_F = 0.037; R_WF = 0.038 for 1636 observed reflections and 423 variables. A reversible transformation between Cu₂L₄ and CuL₂(py)₂ is reported.     

Synthesis,Crystal and Electronic Structure,and Optical Property of the Quaternary Selenide: La3Sb0.33SiSe7

The quaternary selenide, La₃Sb_0.33SiSe₇, was prepared from stoichiometric mixtures of elements by solid‐state reactions at 1223 K in an evacuated silica tube. La₃Sb_0.33SiSe₇ crystallizes in the chiral P6₃ space group and belongs to the Ce₃Al_1.67S₇ structure type. Its structure features one‐dimensional chains of face‐sharing SbSe₆ octahedra running parallel to the c direction surrounded by the discrete SiSe₄ tetrahedra and La cations. UV/Vis/NIR diffuse reflectance spectroscopy study shows its optical gap of around 1.75 eV. DFT study indicates an indirect bandgap with an electronic transfer excitation from Se 4p to La 5d orbital electrons.     

Polymorphism in a benzo[b][1,4]diazepine derivative: Crystal structure,phase behavior and selective influence of solvents

Ethyl 4-[(Z)-3-ethoxy-2,3-dioxopropylidene]-4,5-dihydro-1H-benzo[b][1,4]diazepine-2-carboxylate forms two polymorphic modifications α and β, which differ in molecular conformations, as well as in the dimension of H-bonded supramolecular motifs in crystals that are a 1D chain or a 0D dimer, respectively. The formation of polymorphs can be controlled by choice of the solvent used. Crystallization from a solution in a polar protic solvent, ethanol, results in the thermodynamically favorable α-form, while using a low-polarity solvent, chloroform, and melt crystallization lead to the metastable β-form.     

A New Samarium(III) Complex of Liriodenine: Synthesis,Crystal Structure,Antitumor Activity,and DNA Binding Study

A novel Sm^III complex [Sm^III(LA)₂(pic)₃] (Hpic = picric acid), in which LA is a natural‐derived alkaloid, liriodenine, was synthesized and characterized by IR, elemental analysis, and single‐crystal X‐ray diffraction analysis. This complex showed enhanced solubility compared with liriodenine and its metal complexes that have been previously reported. The interaction of the Sm^III complex with ct‐DNA was further investigated by various spectroscopic techniques, such as UV/Vis spectroscopy, fluorescence spectroscopy, circular dichroism spectroscopy (CD), and viscosity measurement. The results showed that the intrinsic binding constant K_b of the Sm^III complex with ct‐DNA was calculated to be 5.03 × 10³ L·mol^–1 by UV/Vis absorption spectral analysis. The thermodynamic fluorescent spectral analysis suggested that the fluorescence intensity of the Sm^III complex was weakened by ct‐DNA mainly through a dynamic quenching mechanism. The presence of Sm complex could increase the viscosity of DNA solution, so it was concluded that the complex bound with ct‐DNA via a moderate intercalative mode. Furthermore, this Sm^III complex exhibited significant growth inhibition on the three typical tumor cell lines, HepG2, T‐24, and SK‐OV‐3, with the corresponding IC₅₀ values, 10.76 ± 0.19, 8.85 ± 1.12, and 10.01 ± 0.55 μM, respectively. The in vitro antitumor activity was comparable with LA and cisplatin, which suggested that it might be a new broad spectrum antitumor agent with more satisfying solubility.     

Rare-earth hexaborides nanostructures: Recent advances in materials, characterization and investigations of physical properties

Nanostructured rare-earth hexaborides (REB₆) are promising materials for photonic and electronic applications due to their unique characteristic. These include high melting point, hardness, chemical stability, low work function, low volatility at high temperatures, superconductivity, magnetic properties, efficiency, thermionic emission, and narrow band semiconductivity. This article focuses on recent developments regarding the synthesis, characterization, and applications of REB₆ nanostructures. We first summarize information regarding the classification and crystal chemistry of REB₆. Next, we examine the means by which researchers have successfully synthesized REB₆. We consider the structural properties and morphology of REB₆, and the growth mechanism involved in their fabrication. Finally, we offer suggestions for the use of REB₆ nanostructures in photonic and electronic applications, and identifying four areas for further research.     

Cobalt(III) Supramolecuar Complex: Synthesis,Crystal Structure and Anions Recognition Properties of 6,7-Dinitroquinoxaline-2,3-dione

A 3D supramolecular complex [Co(III)(Phen)₂Cl₂][DNQ]Cl·H₂O (DNQ = 6,7-dinitroquinoxaline-2,3-dione) has been synthesized and determined by single-crystal X-ray analysis. Anion binding studies carried out using ¹H NMR and UV-visible revealed that a genuine hydrogen bond interaction between anion receptor 2 and Cl^?  can be detected, but fluoride is deprotonating the anion receptor 2. X-ray analysis results show that it is not possible for the two amide nitrogen atoms of anion receptor to form hydrogen bonds to a chloride ion in the presence of small aliquots of water.