Monohalogenated ferrocenes C5H5FeC5H4X (X = Cl,Br and I) and a second polymorph of C5H5FeC5H4I

The structures of the three title monosubstituted ferrocenes, namely 1‐chloroferrocene, [Fe(C₅H₅)(C₅H₄Cl)], (I), 1‐bromoferrocene, [Fe(C₅H₅)(C₅H₄Br)], (II), and 1‐iodoferrocene, [Fe(C₅H₅)(C₅H₄I)], (III), were determined at 100 K. The chloro‐ and bromoferrocenes are isomorphous crystals. The new triclinic polymorph [space group P, Z = 4, T = 100 K, V = 943.8 (4) ų] of iodoferrocene, (III), and the previously reported monoclinic polymorph of (III) [Laus, Wurst & Schottenberger (2005). Z. Kristallogr. New Cryst. Struct. 220 , 229–230; space group Pc, Z = 4, T = 100 K, V = 924.9 ų] were obtained by crystallization from ethanolic solutions at 253 and 303 K, respectively. All four phases contain two independent molecules in the unit cell. The relative orientations of the cyclopentadienyl (Cp) rings are eclipsed and staggered in the independent molecules of (I) and (II), while (III) demonstrates only an eclipsed conformation. The triclinic and monoclinic polymorphs of (III) contain nonbonded intermolecular I...I contacts, causing different packing modes. In the triclinic form of (III), the molecules are arranged in zigzag tetramers, while in the monoclinic form the molecules are arranged in zigzag chains along the a axis. Crystallographic data for (III), along with the computed lattice energies of the two polymorphs, suggest that the monoclinic form is more stable.     

NMR study (1H, 13C, 31P) of the (C2H5)3-n. PXn compounds (X = Cl,Br, I; n = 0, 1, 2, 3)

The ¹H, ¹³C and ³¹P NMR data are reported for the (C₂H₅)_3-nPX_n compounds (X = Cl, Br, I; n = 0, 1, 2, 3). The chemical shifts are interpreted in terms of inductive and through-space effects of the X substituents together with a rehybridization of the phosphorous atom. The results of the coupling constants are in good agreement with the chemical shifts.     

Characterization of a DAPI-RIT-DAPI System for Gas-Phase Ion/Molecule and Ion/Ion Reactions

The discontinuous atmospheric pressure interface (DAPI) has been developed as a facile means for efficiently introducing ions generated at atmospheric pressure to an ion trap in vacuum [e.g., a rectilinear ion trap (RIT)] for mass analysis. Introduction of multiple beams of ions or neutral species through two DAPIs into a single RIT has been previously demonstrated. In this study, a home-built instrument with a DAPI-RIT-DAPI configuration has been characterized for the study of gas-phase ion/molecule and ion/ion reactions. The reaction species, including ions or neutrals, can be introduced from both ends of the RIT through the two DAPIs without complicated ion optics or differential pumping stages. The primary reactant ions were isolated prior to reaction and the product ions were mass analyzed after controlled reaction time period. Ion/molecule reactions involving peptide radical ions and proton-transfer ion/ion reactions have been carried out using this instrument. The gas dynamic effect due to the DAPI operation on internal energy deposition and the reactivity of peptide radical ions has been characterized. The DAPI-RIT-DAPI system also has a unique feature for allowing the ion reactions to be carried out at significantly elevated pressures (in 10^–1 Torr range), which has been found to be helpful to speed up the reactions. The viability and flexibility of the DAPI-RIT-DAPI system for the study of gas-phase ion reactions have been demonstrated.

Schwingungsspektroskopische Untersuchungen an den Organohydrogensilanen (XCH2)(CH3)2SiH (X = Cl,Br, J), X(YO)2SiH (X = CH3, C2H5/Y = CH3, C2H5 … tert.-C4H9), (C6H5)2SiH2 und C6H5SiH3

Infrared and Raman Spectroscopic Investigations on the Organosubstituted Silicon Hydrides (XCH₂)(CH₃)₂SiH (X = Cl, Br, J), X(YO)₂SiH (X = CH₂, C₂H₅/Y = CH₃, C₂H₅ … tert.-C₄H₉), (C₆H₅)₂SiH₂ and C₆H₅SiH₃ Typical band splittings, specially for the SiH stretching vibration, are shown in the infrared and Raman spectra of the silicon hydrides (XCH₂)(CH₃)₂SiH (X = Cl, Br, J), and X(YO)₂SiH (X = CH₃, C₂H₅/Y = CH₃, C₂H₅ … tert.-C₄H₉). The cause of this behavior is in all probability the existence of rotational isomers. Raman polarization measurements at organosubstituted silicon di- and trihydrides demonstrate the accidental degeneracy of the SiH valence vibrations.     

Alignment of ethyl halide molecules (C2H5X, X= I, Br, Cl) induced by strong ps laser irradiation

The alignment of polyatomic molecules under strong 35 ps laser irradiation is investigated for a broad range of laser intensities (10(13)-10(15) W/cm(2)) using time-of-flight mass spectrometry. The dynamic alignment of the molecules under study (C2H5X, X = I, Br, Cl) is verified in single-pulse experiments by recording the fragments' angular distributions, their dependence on the laser intensity, and also the comparison of the ionic signal of the various fragments recorded for linear and circular polarization. For all cases, the angular distributions of the Coulomb explosion fragments are found to be independent of the laser peak intensity, implying that the molecular alignment is taking place during the rise time of the laser pulses at relatively low intensities (approximately 10(13) W/cm(2)). Moreover, the same result implies that the alignment mechanism is close to the adiabatic limit, albeit the laser pulse duration is much shorter than the characteristic rotational times (1/2B) of the molecules under study. Finally, by comparing the angular distributions of the different molecules, we conclude that the degree of alignment is only weakly dependent on the molecular mass and the moment of inertia under the irradiation conditions applied.     

Cationic P-S-X cages (X=Br, I)

The first condensed-phase preparation of ternary P-Ch-X cations (Ch=O-Te, X=F-I) is reported: [P5S3X2]+, [P5S2X2]+, and [P4S4X]+ (X=Br, I). [P5S3X2]+ is formed from the reaction of the Ag+/PX3 reagent with P4S3. The [P5S3X2]+ ions have a structure that is related to P4S5 by replacing P=S by P+--X and S in the four-membered ring by P(X). We provide evidence that the active ingredient of the Ag+/PX3 reagent is the (H2CCl2)Ag-X-PX2+ cation. The latter likely reacts with the HOMO of P4S3 in a concerted HOMO-LUMO addition to give the P5S3X2+ ion as the first species visible in situ in the low-temperature 31P NMR spectrum. The [P5S3X2]+ ions are metastable at -78 degrees C and disproportionate at slightly higher temperatures to give [P5S2X2]+ and [P4S4X]+, probably with the extrusion of 1/n (PX)n (X=Br, I). All six new cage compounds have been characterized by multinuclear NMR spectroscopy and, in part, by IR or Raman spectroscopy. The [P5S2X2]+ salts have a nortricyclane skeleton and were also characterized by X-ray crystallography. The structure of the [P4S4X]+ ion is related to that of P4S5 in that the exo-cage P=S bond is replaced by an isoelectronic P+--X moiety.     

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]⁺.     

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.     

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.     

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 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.     

PX4+, P2X5+, and P5X2+ (X=Br,I) salts of the superweak Al(OR)4- anion [R=C(CF3)3

PX(4) (+)[Al(OR)(4)](-) (X=I: 1 a, X=Br: 1 b) was prepared from X(2), PX(3), and Ag[Al(OR)(4)] [R=C(CF(3))(3)] in CH(2)Cl(2) at -30 degrees C in 69-86 % yield. P(2)X(5) (+) salts were prepared from 2 PX(3) and Ag[Al(OR)(4)] in CH(2)Cl(2) at -30 degrees C yielding almost quantitatively P(2)X(5) (+)[Al(OR)(4)](-) (X=I: 3 a, X=Br: 3 b). The phosphorus-rich P(5)X(2) (+) salts arose from the reaction of cold (-78 degrees C) mixtures of PX(3), P(4), and Ag[Al(OR)(4)] giving P(5)X(2) (+)[Al(OR)(4)](-) (X=I: 4 a, X=Br: 4 b) with a C(2v)-symmetric P(5) cage. Silver salt metathesis presumably generated unstable PX(2) (+) cations from PX(3) and Ag[Al(OR)(4)] (X=Br, I) that acted as electrophilic carbene analogues and inserted into the Xbond;X (Pbond;X/Pbond;P) bond of X(2) (PX(3)/P(4)) leading to the highly electrophilic and CH(2)Cl(2)-soluble PX(4) (+) (P(2)X(5) (+)/P(5)X(2) (+)) salts. Reactions that aimed to synthesize P(2)I(3) (+) from P(2)I(4) and Ag[Al(OR)(4)] instead led to anion decomposition and the formation of P(2)I(5)(CS(2))(+)[(RO)(3)Al-F-Al(OR)(3)](-) (5). All salts were characterized by variable-temperature solution NMR studies (3 b also by (31)P MAS NMR), Raman and/or IR spectroscopy as well as X-ray crystallography (with the exception of 4 a). The thermochemical volumes of the Pbond;X cations are 121 (PBr(4) (+)), 161 (PI(4) (+)), 194 (P(2)Br(5) (+)), 271 (P(2)I(5) (+)), and 180 A(3) (P(5)Br(2) (+)). The observed reactions were fully accounted for by thermochemical calculations based on (RI-)MP2/TZVPP ab initio results and COSMO solvation enthalpy calculations (CH(2)Cl(2) solution). The enthalpies of formation of the gaseous Pbond;X cations were derived as +764 (PI(4) (+)), +617 (PBr(4) (+)), +749 (P(2)I(5) (+)), +579 (P(2)Br(5) (+)), +762 (P(5)I(2) (+)), and +705 kJ mol(-1) (P(5)Br(2) (+)). The insertion of the intermediately prepared carbene analogue PX(2) (+) cations into the respective bonds were calculated, at the (RI-)MP2/TZVPP level, to be exergonic at 298 K in CH(2)Cl(2) by Delta(r)G(CH(2)Cl(2))=-133.5 (PI(4) (+)), -183.9 (PBr(4) (+)), -106.5 (P(2)I(5) (+)), -81.5 (P(2)Br(5) (+)), -113.2 (P(5)I(2) (+)), and -114.5 kJ mol(-1) (P(5)Br(2) (+)).     

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。     

Reactions of metal carbonyl complexes III. Synthesis and reactions of Mn(CO)3(Triphos)X(X = Cl,Br, I)

The halopentacarbonylmanganese(I) complexes, Mn(CO)₅X(X = Cl, Br, I), react with PPh(CH₂CH₂PPh₂)₂(Triphos) to give two isomers of fac-Mn(CO)₃(Triphos)X in which the Triphos ligand is only coordinated to the manganese atom through two of its three phosphorus atoms. The fac-Mn(CO)₃(Triphos)X complexes may be considered as “monodentate ligands” in that the free phosphorus atoms readily displace CO and other groups in a variety of metal carbonyls to give a series of novel bimetallic complexes, e.g. Br(CO)₃Mn(Triphos)Cr(CO)₅ and I(CO)₃Mn(Triphos)Mn(CO)₄I. The reactions of Mn(CO)₂[P(OMe)₃](Triphos)Br with Cr(CO)₅THF and Mn(CO)₃(Triphos)X(X = Br, I) with O₂ (and O₃) to produce Br(CO)₂[P(OMe)₃]Mn(Triphos)Cr(CO)₅ and fac-Mn(CO)₃(Triphos=O)X, respectively, are also described. The IR-active COstretching absorptions exhibited by the new complexes are discussed.     

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.     

Efficient generation of 2'-deoxyuridin-5-yl at 5'-(G/C)AA(X)U(X)U-3' (X = Br, I) sequences in duplex DNA under UV irradiation

The photoreactivity of 5-halouracil-containing DNA was investigated using 450 base pair DNA fragments under 302 nm irradiation. Heat-dependent cleavage selectively occurs at 5'-(G/C)AAXUXU-3' and 5'-(G/C)AXUXU-3' (X = Br, I) sequences in double-stranded DNA. HPLC product analysis indicated that 2'-deoxyribonolactone residues are effectively generated at these sequences. These observations will be useful in studying the molecular basis of the sequence-dependent DNA-damaging process in UV-irradiated 5-halouracil-containing DNA.     

Structural isomerism in tris-tolyl halo-phosphonium and halo-arsonium tri-halides, [(CH3C6H4)3EX][X3], (E = P, As; X = Br, I)

The group 15 ligands (o-CH(3)C(6)H(4))(3)P, (m-CH(3)C(6)H(4))(3)P, (p-CH(3)C(6)H(4))(3)P, Ph(3)As, (o-CH(3)C(6)H(4))(3)As and (p-CH(3)C(6)H(4))(3)As have been reacted with two equivalents of di-iodine or di-bromine to yield complexes of formula R(3)EX(4) (E = P, As; X = I, Br). These halogenated group 15 compounds are ionic, [R(3)EX][X(3)] consisting of halo-phosphonium or halo-arsonium cations and trihalide anions. These adducts exhibit structural isomerism and may exist either as simple 1:1 ion pairs, [R(3)EX][X(3)], isomer (A), which display a weak XX interaction between cation and anion, or as a 2:1 complex, which consists of a [{R(3)EX}(2)X(3)](+) cationic species made up of two [R(3)EX](+) cations interacting with one [X(3)](-) anion. The overall charge is balanced by a second [X(3)](-) anion. These 2:1 species also exhibit structural isomerism due to subtle differences in the connectivity of the [{R(3)EX}(2)X(3)](+) fragment, as the {R(3)EX}(+) units may either interact at the same end of the [X(3)](-) ion, to give a Y-shaped motif, isomer (B), or at opposite ends, giving a Z-shaped motif, isomer (C). The type of structural isomer formed is related to the way in which [Ar(3)EX](+) cations pack together via aryl embraces. Isomer (A) and (C) structures form chains of side-to-side, anti-parallel embracing cations. In (A) and (C) structures a square-like stacking motif of cations is observed. In contrast, isomer (B) structures feature side-to-side, parallel embracing cations, and do not exhibit the square motif.     

Ph3PAuX和Ph3AsAuX(X=C1,Br)的最低三重激发态

分子水平上的激发态理论研究能够用来解释分子材料的多色发光机理.采用单组态相瓦作用方法,计算研究了四种二配位的An(Ⅰ)配合物Ph3PAuCl,Ph3PAuBr,Ph3AsAuCl和Ph3AsAuBr的分子结构限制的三重激发态(T1a)和分子结构松弛的三重激发态(T1b)的分子结构与光物理性质.由于θ(PAuX)/θ(AsAuX)从180°扭曲到120°左右,T1b态的能量在单线态组态相互作用(CIS)水平上降低了0.805-1.124 eV,在密度泛函理论(DFT)水平上降低了0.820-0.947 eV.自然键轨道电荷布居数分析表明,在T1a态中两个单电子主要分布在一个苯基上,而在T1b态中两个单电子分布在PAuX/AsAuX上.因此,在晶体中观察到的较高能磷光归属于T1a态的苯基之间的3π*→1π电子跃迁,而较低能磷光主要起源于T1b态的Au的3σ*→1σ电子跃迁.     

同核双卤分子X2(X=F,CI,Br,I)与C2H2相互作用本质的量子化学研究

用对称性匹配微扰理论(SAPT)对C2H2与X2(X=F,CI,Br,I)相互作用进行了量子化学研究.优化所得的4个稳定复合物相互作用能在-3.276 8～-10.639 5 kJ/mol之间.自然键轨道(NBO)理论分析表明,形成复合物分子间的电荷转移量都很少,在0.002 3～0.013 2之间.SAPT2能量分析显示,从F到I,静电能和诱导能先增大后减小,交换能和色散能逐渐增强,相互作用能依次增强.复合物稳定构型的相互作用能中静电能占主导作用,对吸引能的贡献比例在C2H2…F2中最大(57.3％),在C2H2…I2中最小(49.7％);其次为色散能,在吸引能中所占的比例在21.9％(C2H2…F2)～31.2％(C2H2…I2)之间;诱导能在吸引能中所占的比例最小,均小于20.7％.