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。     

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.     

Electronic structures and optical properties of BiOX (X = F,Cl, Br,I) via DFT calculations

Based on the density functional theory (DFT), the lattice constants and atomic positions of BiOX (X = F, Cl, Br, I) species have been optimized, and the electronic and optical properties of the relaxed species have been calculated, with Bi 5d states considered or not. Relaxation generally results in the shrinkage in a and the expansion of c. Relaxed BiOCl, BiOBr, and BiOI present indirect band gaps, whereas BiOF exhibits a direct or somewhat indirect band‐gap feature corresponding to the relaxation and calculation with the Bi 5d states or not. The bottom of the conduction band is quite flat for relaxed BiOI, and apparently flat in BiOBr, and shows observable flatness in BiOCl as well when considering the Bi 5d states. The top of the valence band is rather even as well for some species. The obtained maximum gaps for relaxed BiOF, BiOCl, BiOBr, and BiOI are 3.34, 2.92, 2.65, and 1.75 eV, respectively. The density peak of X np states in the valence band shifts toward the valence band maximum with the increasing X atomic number. The bandwidths, atomic charges, bond orders, and orbital density have also been investigated along with some optical properties. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009     

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     

Ab initio study of hydrated potassium halides KX(H2O)1-6 (X=F,Cl,Br,I)

The ionic dissociation of salts was examined with a theoretical study of KX (X=F,Cl,Br,I) hydrated by up to six water molecules KX(H2O)n (n=1-6). Calculations were done using the density functional theory and second order M?ller-Plesset (MP2) perturbational theory. To provide more conclusive results, single point energy calculations using the coupled cluster theory with single, double, and perturbative triple excitations were performed on the MP2 optimized geometries. The dissociation feature of the salts was examined in terms of K-X bond lengths and K-X stretch frequencies. In general, the successive incorporation of water molecules to the cluster lengthens the K-X distance, and consequently the corresponding frequency decreases. Near 0 K, the KX salt ion pairs can be partly separated by more than five water molecules. The pentahydrated KX salt is partly dissociated, though these partly dissociated structures are almost isoenergetic to the undissociated ones for KFKCl. For the hexahydrated complexes, KF is undissociated, KClKBr is partly dissociated, and KI is dissociated (though this dissociated structure is nearly isoenergetic to a partly dissociated one). On the other hand, at room temperature, the penta- and hexahydrated undissociated structures which have less hydrogen bonds are likely to be more stable than the partly dissociated ones because of the entropy effect. Therefore, the dissociation at room temperature could take place for higher clusters than the hexahydrated ones.     

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.     

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.     

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).     

Zweiwertiges Samarium: AISmX5 (AI = K,Rb; X = Cl,Br, I)

Divalent Samarium: A^ISm X₅ (A^I = K, Rb; X = Cl, Br, I) Ternary halides with divalent Samarium ASm₂X₅ were prepared and investigated by X-ray techniques. The paramagnetic susceptibility of Sm²⁺ has been measured with a Faraday balance and calculated theoretically.     

Synthesis, crystal structure, thermal and luminescence properties of CuX(2,3-dimethylpyrazine) (X=Cl, Br, I) coordination polymers

Three new coordination polymers based on CuI and 2,3-dimethylpyrazine (2,3-dmpyz) were prepared, structurally characterized and investigated for their thermal and luminescence properties. In the ligand rich 2:3 compound [(CuI)2(2,3-dmpyz)3] (CuI)2 dimers are found, which are connected by the N-donor ligands into chains, whereas in the structure of the 1:1 intermediate [(CuI)(2,3-dmpyz)] (CuI)4 tetramers are found, which are also connected into chains. The crystal structure of the ligand deficient 2:1 compound [(CuI)2(2,3-dmpyz)] is built up of CuI double chains, which are connected by the 2,3-dmpyz ligands into layers. Thermal decomposition of results in its direct transformation into the ligand deficient compound , without the formation of the 1:1 compound as an intermediate. A similar thermal reactivity is found for compound , which transforms into on heating. Stirring of a crystalline suspension of pure or in acetonitrile, always leads to a transformation into the ligand deficient compound indicating that compound is the most stable of all the coordination polymers, whereas compounds and are metastable. The luminescence properties of the CuCl and CuI coordination polymers were investigated at 298 and 77K. It was observed that the emission maxima strongly depends on the nature of the halide atom and the composition and structure of the coordination polymers. In addition, several of these compounds show luminescence thermochromism. These results are compared with those obtained for the previously reported CuCl and CuBr(2,3-dimethylpyrazine) coordination polymers.     

Nanosecond CO photodissociation and excited-state character of [Ru(X)(X')(CO)2(N,N'-diisopropyl-1,4-diazabutadiene)] (X=X'=Cl or I; X=Me, X'=I; X=SnPh3, X'=Cl) studied by time-resolved infrared spectroscopy and DFT calculations

The character and dynamics of the low-lying excited states of [Ru(X)(X')(CO)2(iPr-dab)] (X=X'=Cl or I; X=Me, X'=I; X=SnPh3, X'=Cl; iPr-dab=N, N'-diisopropyl-1,4-diazabutadiene) were studied experimentally by pico- and nanosecond time-resolved IR spectroscopy (TRIR) and (for X=X'=Cl or I) computationally using density functional theory (DFT) and time-dependent DFT (TD-DFT) techniques. The lowest allowed electronic transition occurs between 390 and 460 nm and involves charge transfer from the Ru(halide)(CO) 2 unit to iPr-dab, denoted (1)MLCT/XLCT (metal-to-ligand/halide-to-ligand charge transfer). The lowest triplet state is well modeled by UKS-DFT-CPCM calculations, which quite accurately reproduce the excited-state IR spectrum in the nu(CO) region. It has a (3)MLCT/XLCT character with an intraligand (iPr-dab) (3)pipi* admixture. TRIR spectra of the lowest triplet excited state show two nu(CO) bands that are shifted to higher energies from their corresponding ground-state positions. The magnitude of this upward shift increases as a function of the ligands X and X' [(I)2 < (Sn)(Cl) < (Me)(I) < (Cl)2] and reveals increasing contribution of the Ru(CO)2-->dab MLCT character to the excited state. The lowest triplet state of [Ru(Cl)2(CO)2(iPr-dab)] undergoes a approximately 10 ps relaxation that is followed by CO dissociation, producing cis(CO,CH 3CN),trans(Cl,Cl)-[Ru(Cl)2(CH 3CN)(CO)(iPr-dab)] with a unity quantum yield and 7.2 ns lifetime and without any observable intermediate. To our knowledge, this is the first example of a "slow" CO dissociation from a thermally equilibrated triplet charge-transfer excited state.     

First examples of Au(I)-X-Ag(I) halonium cations (X = Cl and Br)

Novel {[(mu-PAnP)(AuX)2]2Ag}+SbF6- halonium ions (X = Cl, Br; PAnP = 9,10-bis(diphenylphosphino)anthracene) were synthesized from the reactions between (mu-PAnP)(AuX)2 and 1/2 mol equiv of AgSbF6. The compounds feature an unprecedented distorted Au4X4 dodecahedron which encapsulates a silver(I) ion at its center. The halonium ions are stabilized by collective actions of metallophilic Au-Ag, aromatic pi-pi, and Ag-X interactions.     

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。     

HCHO+X(X=F、Cl、Br)的反应机理

采用CCSD/6-311++G(d,p)//B3LYP/6-311++G(d,p)方法研究了HCHO与卤素原子X(X=F、Cl、Br)的反应机理. 计算结果表明, 卤素原子X(X=F、Cl、Br)主要通过直接提取HCHO中的H原子生成HCO+HX(X=F、Cl、Br). 另外还可以生成稳定的中间体, 中间体再通过卤原子夺氢和氢原子直接解离两个反应通道分别生成HCO+HX(X=F、Cl、Br)和H+XCHO(X=F、Cl、Br). 其中卤原子夺氢通道为主反应通道, HCO和HX(X=F、Cl、Br)为主要的反应产物; 且三个反应的活化能均较低, 说明此类反应很容易进行, 计算结果与实验结果符合很好. 电子密度拓扑分析显示, 在HCHO+X反应通道(b)中出现了T型结构过渡态, 结构过渡态(STS)位于能量过渡态(ETS)之后. 并且按F、Cl、Br的顺序, 结构过渡态出现得越来越晚.     

The compounds KAs4O6 X (X=Cl,Br, I) and NH4As4O6 X (X=Br,I): Hydrothermal syntheses and structure determinations

The crystal structures of five isotypic hexagonal compounds with general formulaMAs₄O₆ X [M=K, NH₄;X=Cl, Br, I; space group: P622;Z=1] were determined from 370 single crystal X-ray data and refined toR values <0.05. The structure type is characterized by neutral charged [As₂O₃] sheets arranged parallel (00.1). The As atoms of neighbouring two sheets point to each other and the sheets are combined by interlayeredM andX atoms, respectively. TheM atoms are coordinated to twelve oxygen atoms, theX atoms are coordinated to twelve arsenic atoms. In both cases the coordination polyhedron is a hexagonal prism. The compounds were synthesized by thermal treatments of cubic As₂O₃ and potassium or ammonium haloids in a saturated aqueous solution of potassium acetate resp. ammonia [500 K, saturation vapour pressure].

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Die Verbindungen KAs₄O₆ X (X=Cl, Br, I) und NH₄As₄O₆ X (X=Br, I): Hydrothermalsynthese und Strukturbestimmung

Zusammenfassung Die Kristallstrukturen der fünf isotypen hexagonalen Verbindungen mit der allgemeinen FormelMAs₄O₆ X [M=K, NH₄;X=Cl, Br, I; Raumgruppe: P622;Z=1] wurden anhand von 370 Einkristall-Röntgendaten bestimmt und aufR-Werte <0.05 verfeinert. Der Strukturtyp ist ausgezeichnet durch neutrale [As₂O₃]-Schichten, die parallel (00.1) angeordnet sind. Die As-Atome zweier benachbarter Schichten weisen jeweils aufeinander zu, und die Schichten selbst werden durch zwischengelagerteM- bzw.X-Atome verbunden. DieM-Atome werden jeweils von zwölf O-Atomen, dieX-Atome von zwölf As-Atomen umgeben. Das Koordinationspolyeder ist in beiden Fällen ein hexagonales Primsa. Die einzelnen Verbindungen wurden unter Hydrothermalbedingungen aus kubischem As₂O₃ und dem jeweiligen Kalium- oder Ammoniumhalogenid in einer gesättigten wäßrigen Lösung von Kaliumacetat bzw. Ammoniak synthetisiert (500 K, Sättigungsdampfdruck).

     

The Coordination Polyhedra PdX n (X = 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 106 compounds containing palladium atoms surrounded by halogen atoms. Depending on the oxidation number (2 or 4), Pd atoms can bind 4 to 6 X atoms (X = Cl, Br, I) and form PdX _n coordination polyhedra shaped like octahedra or square pyramids (n = 6), square pyramids (n = 5), or squares (n = 4). A lone electron pair on Pd(II) was found on the basis of X-ray diffraction data. The influence of the palladium valence state on the key stereochemical features of palladium halide complexes is considered in terms of the 18-electron rule. The tendency of palladium atoms to Pd···H aghostic interactions was noted.     

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.     

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.