Schwingungs-Raman-Spektren von Hexahalogenokomplexen von OsIV (X = Cl,I) und IrIV (X = Cl,Br) bei 80 K

Vibrational Raman Spectra of Hexahalo Complexes of Os^IV (X = Cl, I) and Ir^IV (X = Cl, Br) at 80 K The Resonance-Raman (RR) spectra of the tetrabutyl- resp. tetraethylammonium salts of [OsCl₆]^2?, [OsI₆]^2?, [IrCl₆]^2?, and [IrBr₆]^2? have been investigated with the excitation-lines of an Ar⁺ and Kr⁺ laser. Devices with a movable sample holder for low-temperature experiments (80 K) are described. The anormal intensities of some of the Ra-active fundamentals are attributed to the RR effect. As a rule the deformation vibration υ₅(T_2g) is RR enhanced if excited within a π—π*(dt_2g)-CT-transition and the stretching vibration υ₂(E_g) is RR-enhanced within a π—σ*(de_g)-CT-transition. The dispersion of the degree of depolarisation of the three Ra-active fundamentals of [IrBr₆]^2? demonstrates, that this rule cannot only be applicated to the symmetrical but also to the antisymmetrical part of the scattering tensor.     

[Pd(en)2Pd(en)2X2]4+n(X=Cl,Br,I)链的畸变研究

对一维卤桥过渡金属化合物〔Ｐｄ（ｅｎ）２Ｐｄ（ｅｎ）２Ｘ２〕ｎ＾４＋（Ｘ＝Ｃｌ,Ｂｒ,Ｉ）应用量子化学从头算及ＥＨＴ能带计算进行了研究,发现Ｐｅｉｅｒｌｓ畸变的产生及程度取决于填充轨道能量的降低与核间及电子间相互作用。     

CsPbX3(X=Cl,Br,I)纳米晶的制备及其应用

全无机钙钛矿CsPbX₃(X = Cl, Br, I) 纳米晶作为一类新型的低成本直接带隙半导体材料,具有优异的光学性质,如吸收系数高、尺寸和发射波长易调节、半峰宽窄、荧光量子产率高等特性,在照明、能源、信息显示和探测等领域表现出巨大的应用潜力,成为材料领域的研究热点。本文从CsPbX₃纳米晶的结构组成入手,重点综述了其常见的制备方法如高温热注入法、室温再沉淀法、溶剂热法、液滴微流控法、阴离子交换法等,对常见的形貌尺寸控制策略如反应温度和表面配体进行归纳,以及改善CsPbX₃纳米晶稳定性的策略,总结了此类材料在白色发光二极管、电致发光二极管、激光器、光电探测器、太阳能电池等光电领域的应用情况,最后对CsPbX₃纳米晶领域存在的问题和面临的挑战进行了分析和评述。     

Kristallstrukturen und Phasentransformationen von Caesiumtrihalogenogermanaten(II) CsGeX3 (X = Cl,Br, I)

Crystal Structures and Phase Transformations of Cesium Trihalogenogermanates CsGeX₃(X = Cl, Br, I) The compounds CsGeX₃ (X ? Cl, Br, I) have been obtained by reactions of Ge(OH)₂ with CsX in aquaeous HX solutions. The thermal behavior has been studied by X-ray diffraction. Raman spectroscopy, and DTA/DSC. The compounds are dimorph. The low temperature modifications L-CsGeX₃ show a rhomboedric deformed perovskite type structure. The high temperature phases H-CsGeX₃ form the cubic perovskite type structure. The reversible phase transitions are interpreted as a result of position changes of the Ge atoms in the H-forms (Order-Disorder transitions). The transition temperatures increase in the sequence CsGeCl₃ (155°C), CsGeBr₃ (238°C), CsGeI₃ (277°C).     

Ionization energies of LinX (n = 2, 3; X = Cl, Br, I) molecules

Molecules of Li(n)X (n = 2, 3; X = Cl, Br, I) were examined with a magnetic sector mass spectrometer by surface ionization using a triple rhenium filament impregnated with fullerene (C60). The ionization energies obtained for Li(2)Cl, Li(2)Br and Li(2)I molecules are 3.8 +/- 0.1, 3.9 +/- 0.1 and 4.0 +/- 0.1 eV, respectively. The first ionization energy of Li(2)Cl is documented, while there are no literature data for the ionization energies of Li(2)Br and Li(2)I. The molecules of Li(3)Cl, Li(3)Br and Li(3)I were detected experimentally for the first time with ionization energies of 4.0 +/- 0.1, 4.1 +/- 0.1 and 4.1 +/- 0.1 eV, respectively. The ionization energies of Li(n)X (n = 2, 3; X = Cl, Br, I) are in correlation with the theoretical prediction of their hyperlithiated configurations.     

Die Gadoliniumcarbidhalogenide Gd4C2X3 (X = Cl,Br)

The Gadolinium Carbide Halides, Gd₄C₂X₃ (X = Cl, Br) The compounds Gd₄C₂X₃ (X = Cl, Br) and Tb₄C₂Br₃ have been prepared by reaction of the metals (RE), REX₃, and C in sealed Ta capsules at 1 100° and 1 300°C, respectively. Monophasic samples of Gd₄C₂Br₃ and Tb₄C₂Br₃ were obtained by reacting stoichiometric mixtures of the starting materials for five days. The needle shaped crystals are bronze-coloured and sensitive to air and moisture. Gd₄C₂X₃ crystallizes in the space group Pnma (No. 62) with lattice constants a = 1 059.6(4), b = 368.4(1), c = 1 962.7(8) pm (Gd₄C₂Cl₃), a = 1 084.4(1), b = 373.0(1), c = 2 036.1(1) pm (Gd₄C₂Br₃). According to Guinier photographs, Tb₄C₂Br₃ is isotypic (a = 1 074.3(2), b = 370.6(1), c = 2 019.4(1) pm). In the crystal structure C is octahedrally coordinated by Gd. The Gd₆ octahedra are linked via common edges to form corrugated layers. The X-anions coordinate all free edges and corners of these layers and connect them via Xⁱ? Xⁱ contacts parallel [001]. Gd₄C₂Br₃ shows metallic conductivity. The magnetic susceptibility follows at high temperatures a Curie Weiss law with an effective moment of 7.95 μ_B. At temperatures below 50 K antiferromagnetic order is observed.     

Ag(PPh3)nX(n=1,2,3；X=Cl,Br,I)的电化学合成

银配合物;;三苯基膦;电合成;Ag(PPh3)nX(n=1;2;3；X=Cl;Br;I)的电化学合成     

Synthesis,Crystal Structure,and Optical Properties of (CH3NH3)2CoX4 (X = Cl,Br, I,Cl0.5Br0.5, Cl0.5I0.5, Br0.5I0.5)

The reaction of methylammonium halides and cobalt halides yielded the organic‐inorganic hybrid compounds of general formula (CH₃NH₃)₂CoX₄. By varying the different halides, we were able to synthesize the whole row from Cl to I as well as some mixed halides compounds and to determinate the crystal structures. (CH₃NH₃)₂CoX₄ (X = Cl, Br, Cl_0.5Br_0.5, Br_0.5I_0.5) crystallize isotypic to (CH₃NH₃)₂HgCl₄ in space group P2₁/c with Z = 4 [X = Cl: a = 7.6483(9), b = 12.6885(18), c = 10.8752(12) Å, β = 96.639(9)°; X = Cl_0.5Br_0.5: a = 7.8271(9), b = 12.9543(9), c = 11.1007(11) Å, β = 96.320(8)°; X = Br: a = 7.9782(2), b = 13.1673(2), c = 11.2602(2) Å, β = 96.3260(10)° and X = Br_0.5I_0.5: a = 8.2435(12), b = 13.645(2), c = 11.5856(18) Å, β = 95.54(2)°]. The mixed halides show a statistic distribution in both cases. In (CH₃NH₃)₂CoCl₂I₂ an ordered variant is realized representing a new structure type [C2/m, Z = 4, a = 18.808(4), b = 7.3604(7), c = 10.4109(17) Å, β = 120.364(13)°]. (CH₃NH₃)₂CoI₄ crystallizes again isotypic to the respective mercury compound [(CH₃NH₃)₂HgCl₄] [Pbca, Z = 8, a = 10.9265(5), b = 12.1552(5), c = 20.9588(9) Å]. All structures are build up by inorganic tetrahedral [CoX₄]^2– anions and organic (CH₃NH₄)⁺ cations. Additionally the Raman spectra as well as the optical reflectance spectra are discussed.     

Luminescent Thin Films Enabled by CsPbX3 (X=Cl,Br, I) Precursor Solution

Inorganic cesium lead halide perovskite nanocrystals are candidates for lighting and display materials due to their outstanding optoelectronic properties. However, the dissolution issue of perovskite nanocrystals in polar solvents remains a challenge for practical applications. Herein, we present a newly designed one-step spin-coating strategy to prepare a novel multicolor-tunable CsPbX₃ (X=Cl, Br, I) nanocrystal film, where the CsPbX₃ precursor solution was formed by dissolving PbO, Cs₂CO₃, and CH₃NH₃X into the ionic liquid n-butylammonium butyrate. The as-designed CsPbX₃ nanocrystal films show high color purity with a narrow emission width. Also, the blue CsPb(Cl/Br)₃ film demonstrates an absolute photoluminescence quantum yields (PLQY) of 15.6 %, which is higher than 11.7 % of green CsPbBr₃ and 8.3 % of red CsPb(Br/I)₃ film. This study develops an effective approach to preparing CsPbX₃ nanocrystal thin films, opening a new avenue to design perovskite nanocrystals-based devices for lighting and display applications.     

The reactions of K2ReX6 (X = Br OR I) and Re3X9 (X = Cl,Br OR I) with alkyl and aryl isocyanides

The reactions of alkyl isocyanides (RNC) and aryl isocyanides (ArNC) with the rhenium halides K₂ReX₆ (X = Br or I) and Re₃X₉ (X = Cl, Br or I) have been investigated. When the K₂Rex₆ salts are treated with neat isocyanide at room temperature, or with isocyanide ligands in polar solvents under reflux conditions, then the homoleptic isocyanide cations [Re(CNR)₆]⁺ or [Re(CNAr)₆]⁺, are isolated. Under less forcing conditions, various rhenium(III) and rhenium(I) species, e.g. [Re(CNCMe₃)₅I₂]⁺ and Re(CNAr)₅I, which may be considered as intermediates on the way to the formation of the homoleptic species, can be obtained. The rhenium(I) complexes Re(CNAr)₅I₃, which are believed to contain the coordinated triiodide ligand, have also been isolated and characterized. One route to these complexes is through the reaction of Re(CNAr)₅I with I₂. Reactions of the trinuclear halides Re₃X₉ (X = Cl, Br or I) with alkyl isocyanides at room temperature are found, in all instances, to provide adducts of the type Re₃X₉(CNR)₃. Under reflux conditions, Re₃Cl₉ and Re₃Cl₉(PEtPh₂)₃ react with Me₃CNC to fom products of cluster disruption, viz. [Re(CNCMe₃)₆]⁺ and [Re(CNCMe₃)₄(PEtPh₂)₂]⁺, respectively. The spectroscopic and electrochemical properties of complexes derived in this study are reported. These results are compared with those reported previously by Freni et al.     

Single-crystal absorption spectra of CsVX3 (X = Cl,Br, I)

Polarized single-crystal absorption spectra of CsVCl₃, CsVBr₃ and CsVI₃ have been measured between 5000 and 30000 cm^?1 at temperatures ranging from 6 to 273 K. Spin-allowed transitions arise through a vibronic single-ion mechanism. Spin-forbidden transitions are strongly enhanced through an exchange intensity mechanism.     

Topological characterization of HXO2 (X = Cl, Br, I) isomerization

The isomerization reactions of HOOX --> HOXO --> HXO2 (X = Cl, Br, I) have been studied by using the density functional theory. The breakage and formation of the chemical bonds of the titled reactions have been discussed by the topological analysis method of electronic density. The calculated results show that there is a transitional structure of a three-membered ring on each of the isomerization reaction paths. The "energy transition state (ETS)" and the "structure transition state (STS)" in all of the studied reactions have been found. In all these reactions, the position of the structure transition state and the scope of the structure transition region correlate well with the reaction energy. The STS appears after the ETS in the exothermic reaction but it appears before the ETS in the endothermic reaction. The less reaction energy there is, the wider scope of the structure transition region.     

Vibrational spectra of the trihalocyclopropenium ions [C3X3]+ (X = Cl,Br or I)

Vibrational spectra are reported and assigned for the planar D_3h symmetry cyclopropenium cations [C₃X₃]⁺ (X= Cl, Br or I) from investigations of the compounds C₃Cl₃AlCl₄, C₃Cl₃GaCl₄, C₃Cl₃FeCl₄, C₃Cl₃SbCl₆, C₃Br₃AlBr₄ and C₃l₄, using conventional infrared and Raman spectroscopy and Fourier transform Raman spectroscopy. The symmetric C—X stretching modes of [C₃X₃]⁺ occur at 458, 269 and 180 cm⁻¹ and the ring-breathing modes at 1790, 1732 and ca. 1650 cm⁻¹ in [C₃Cl₃]⁺, [C₃Br₃]⁺ and [C₃I₃]⁺, respectively. A normal coordinate calculation is performed for [C₃Cl₃]⁺.     

Schwingungsspektren und Normalkoordinatenanalyse von (CF3)2SbX-Verbindungen (X = H,Cl, Br,I)

The gas phase i.r. and liquid phase Raman spectra of (CF₃)₂SbX (X = H, Cl, Br, I) have been investigated. The spectra are assigned on the basis of C_s local symmetry and a normal coordinate analysis making use of a transferred force field.     

Low energy electron energy-loss spectroscopy of CF3X (X=Cl,Br)

We report threshold electron energy-loss spectra for the fluorohalomethanes CF3X (X=Cl,Br). Measurements were made at incident electron energies of 30 and 100 eV in energy-loss range of 4-14 eV, and at scattering angles of 4 degrees and 15 degrees. Several new electronic transitions are observed which are ascribable to excitation of low-lying states as well as are intrinsically overlapped in the molecules themselves. Assignments of these electronic transitions are suggested. These assignments are based on present spectroscopic and cross-section measurements, high-energy scattering spectra, and ab initio molecular orbital calculations. The calculated potential curves along the C-X bond show repulsive nature, suggesting that these transitions may lead to dissociation of the C-X bond. The present results are also compared with the previous ones for CF3H, CF4, and CF3I.     

Computational study of the reactions of SiH3X (X=H, Cl, Br, I) with HCN

Ab initio calculations were carried out for the reactions of silane and halosilanes (SiH3X, X=H, Cl, Br, I) with HCN. Geometries of the reactants, transition states, intermediates and products were optimized at HF, MP2, and B3LYP levels of theory using the 6-31G(d) and 6-31G(d,p) basis sets. Energies were also obtained using G3MP2 and G3B3 levels of theory. Intrinsic reaction coordinate (IRC) calculations were performed to characterize the transition states on the potential energy surface. It was found that HCN can react with silane and halosilanes via three different mechanisms. One involves HX elimination by a one-step pathway producing SiH3CN. The second mechanism consists of H2 elimination, producing SiH2XCN via a one-step pathway or three multiple-step pathways. The third mechanism involves dissociation of SiH3X to various products, which can then react with HCN. Activation energies, enthalpies, and free energies of activation along with the thermodynamic properties (DeltaE, DeltaH, and DeltaG) of each reaction pathway were calculated. The reaction of SiH3X with HCN produce different products depending on substituent X. We have found that the standard 6-31G(d) bromine basis set gave results which were in better agreement with the G3MP2 results than for the Binning-Curtiss basis set. Computed heats of formation (DeltaHf) for SiH3CN, SiH3NC, SiH2ClCN, SiH2BrCN, SiH2ICN, SiHCl, SiHBr, and SiHI were found to be 133.5, 150.8, -34.4, 23.6, 102.4, 48.7, 127.1, and 179.8 kJ mol-1, respectively. From enthalpies calculated at G3MP2, we predict that the DeltaHf for SiH2 to be 262.8 kJ mol-1 compared to the experimental value of 273.8+/-4.2 kJ mol-1.     

The heI photoelectron spectra of the halogen azides,XN3(X = Cl and Br) and the halogen isocyanates,XNCO(X = Cl,Br and I)

High yield routes to the unstable halogen azides and isocyanates have permitted vacuum ultraviolet photoelectron spectra to be obtained for the chlorine and bromine azides, and the chlorine, bromine and iodine isocyanates. The results are compared with ab initio and semi-empirical calculations, leading to a reassignment of the photoelectron spectra of the parent acids, HN₃ and HNCO in the high energy region. The halogen azide and isocyanate photoelectron spectra provide an interesting investigation into how the orbitals of a linear pseudohalide grouping are perturbed by an off-azis halogen atom. A photoelectron spectrum for the unknown molecule FNCO is predicted.     

Fe+与CH3X（X=Cl,Br,I）反应的理论研究

铁及其复合物催化的C—X键功能化日益引起人们的重视.采用密度泛函理论(DFT),在B3LYP/def2-SVP水平下详细研究了Fe+与CH3X(X=Cl,Br,I)的反应活性和机理.计算结果表明标题反应存在两种反应机制,即插入机制和SN2机制.从机理上来看,在插入机理中,反应都始于Fe+离子从侧面进攻CH3X,生成产物FeX+和CH3;而在SN2机制中,反应则始于Fe+离子从背后进攻CH3X,生成产物3FeCH+和X.从我们的计算可以看出,四重态或六重态下的Fe+离子在C—X键活化中展现了截然不同的催化活性;在所有通道中,都以四重态为主导;SN2机制中相对较高的决速能垒使其丧失了竞争性.再者,计算表明在所有的插入机制中,所有通道都是放热的,而在SN2机制中,仅有X=I时,反应是放热的.此外,计算表明这些反应属于两态反应活性,两种机制中,在反应的入口和出口存在最小能量交叉点.此外,反应途径电子结构追踪分析表明自旋极化对能量影响较大,调控着反应采取的反应通道和主副产物比例.通过本文的理论研究,尤其是详细的电子结构分析,为铁催化剂活化C—X键和C—C耦联反应提供了线索和以铁为基的催化剂设计提供理论依据.     

Coordination Polyhedra OsXn(X = F, Cl, Br, I) in Crystal Structures

The Voronoi–Dirichlet polyhedra (VDP) and the method of intersecting spheres were used to perform crystal-chemical analysis of compounds containing complexes [Os _a X _b ] ^z–(X = F, Cl, Br, I). Atoms of Os(V) at X = F and Cl, of Os(IV) at X = Cl, Br, and of Os(III) at X = Br were found to exhibit a coordination number of 6 with respect to the halogen atoms and to form OsX₆octahedra. The coordination polyhedra of Os(III) for X = Cl, I are square pyramids OsX₄. Each Os(III) atom forms one Os–Os bond; as a consequence, the OsBr₆octahedra share a face in forming Os₂Br^3– ₉complexes, while the OsX₄pyramids (X = Cl, I) dimerize to produce [X₄Os–OsX₄]^2–ions. The influence of the valence state of the Os atoms and of the nature of the halogen atoms on the composition and structure of the complexes formed and some characteristics of the coordination sphere of Os were considered.