Chlorine reaction with platinum triamine [Pt(N,N-DimeTm)PyCl3]Cl (N,N-DimeTm = (CH3)2N(CH2)3NH2). Crystal structure of [Pt(N,N-DimeTm)Cl2], [Pt(N,N-DimeTm(Py)Cl3]Cl · H2O and [Pt{(CH3)2N(CH2)2C(O)NH}(Py)Cl3]

Treatment of platinum(II) diamine [Pt(N,N-DimeTm)Cl₂] (I) with pyridine gave tetramine [Pt(N,N-DimeTm)Py₂]Cl₂ (II); by oxidation with chlorine this was converted to Pt(IV) triamine, [Pt“(N,N-DimeTm(Py)Cl₃]Cl (III) with a six-membered chelate ring. According to X-ray diffraction data, the reaction of complex II with chlorine is accompanied by removal of the pyridine molecule from the trans-position to the NH₂ group of N,N-dimethyltrimethylenediamine. The reaction of complex III with chlorine at 20°C afforded a mixture of compounds (IV) and the complex [Pt“(CH₃)₂N(CH₂)₂C(O)NH”(Py)Cl₃] (V) with an amidate six-membered metal ring, dimethylpropioamide, which was also isolated upon refluxing a mixture of IV in an aqueous solution. The UV/Vis and IR spectra of the obtained complexes were studied, and X-ray diffraction analysis of I, III, and V was performed. The crystals of I are triclinic, space group P $ \bar 1 $ ; a = 7.6526(4) Å, b = 11.5571(6) Å, c = 12.4432(7) Å, α = 113.85(1)°, β = 96.54(2)°, γ = 106.78(2)°; Z = 4; R _hkl = 0.051. The crystals of III are monoclinic, space group C2/c; a = 36.715(2) Å, b = 7.8179(4) Å, c = 29.721(16) Å, β = 127.80(1)°; Z = 16; R _hkl = 0.036. The crystals of V are monoclinic, space group P2₁/n; a = 7.0398(6) Å, b = 27.458(2) Å, c = 7.687(6) Å, β = 106.270(1)°; Z = 4; R _hkl = 0.052.     

Cluster Complexes of Polythioether Macrocycles: The Synthesis and Molecular Structures of Ru6(CO)13(cis-SCH2 CHMe(CH2SCH2CHMe)2CH2)(μ6-C) and Ru6(CO)13(trans-SCH2 CHMe(CH2SCH2CHMe)2CH2)(μ6-C)

The reaction of a mixture of cis-3,7,11-trimethyl-1,5,9-trithiacyclododecane, cis-Me₃12S3, 1 and trans-3,7,11-trimethyl-l,5,9-trithiacyclododecane, trans-Me₃12S3, 2, with Ru₆(CO)₁₇(μ ₆-C), 3, yielded three new cluster compounds Ru₆(CO)₁₃(μ-η³-cis-SCH₂CHMe(CH₂SCH₂CHMe)₂CH₂)(μ ₆-C) 4, and two isomers of Ru₆(CO)₁₃(μ-η³-cis-SCH₂CHMe(CH₂SCH₂CHMe)₂CH₂)(μ ₆-C) 5a and 5b. The molecular structures of 4 and 5b were established by single crystal X-ray diffraction analyses. In both complexes, the macrocycles have adopted tridentate coordination with one of the sulfur atoms in a bridging position. Two carbonyl ligands occupy bridging positions in each compound. Crystal Data for 4·Me₂CO: space group=P2₁/n, a=11.295(1) Å, b=17.547(3) Å, c=20.318(3) Å, β=93.71(1)°, Z=4, 2900 reflections, R=0.025. Crystal Data for 5b·1.5 C₆H₆: space group=Pbca, a=31.8900(8) Å, b=23.4330(6) Å, c=21.6240(4) Å, Z=16, 12163 reflections, R=0.040.     

Conformational preferences of RCH2CH2CN (R = CH3, F, Cl) cyanides and their corresponding isocyanides

The structure and relative stability of the different conformers of RCH₂CH₂CN (R = CH₃, F, Cl) cyanides and their corresponding isocyanides have been investigated through the use of high-level ab initio G4 theory as well as B3LYP/aug-cc-pVQZ and M06/aug-cc-pVQZ density functional theory calculations. This theoretical survey ratifies that the gauche conformer of butyronitrile is slightly more stable than the anti one, so that in the gas phase and at room temperature this compound should exist as a mixture of 57 % of the former and 43 % of the latter. Similar stability trends are predicted for the corresponding isocyanide isomer. Conversely, when the terminal methyl group of butyronitrile (or its isocyanide isomer) is replaced by F or Cl, the stability trends are reversed and the anti conformer becomes slightly more stable than the gauche one. These changes in relative stabilities could be traced through an analysis of the reduced density gradient which shows the existence of a stabilizing interaction between the terminal methyl group and the cyano (or isocyano) group in butyronitrile (or its isocyanide isomer), which becomes repulsive when this methyl group is replaced by F or Cl.     

Chlorination of charged buckyballs: reactions of C60x+ cations (x = 1–3) with Cl2, CCl4, CDCl3, CH2Cl2, and CH3Cl

The chlorination of singly and multiply charged C₆₀ cations has been investigated with the selected-ion flow tube technique. Observations are reported for the reactions of C₆₀^·+, C₆₀²⁺ and C₆₀^·3+ with Cl₂, CCl₄, CDCl₃, CH₂Cl₂ and CH₃Cl at room temperature (295 ± 2 K) in helium at a total pressure of 0.35 ± 0.02 Torr. C₆₀^·+ and C₆₀²⁺ were observed not to chlorinate, or react in any other way, with these five molecules. Chlorine also did not react with C₆₀^·3+, but bimolecular chloride transfer and electron transfer reactions, reactions that result in charge reduction/charge separation, were observed to occur with CCl₄, CDCl₃, CH₂Cl₂ and CH₃Cl. Chloride transfer was the predominant channel seen with CCl₄, CDCl₃ and CH₂Cl₂ while electron transfer dominates the reaction with CH₃Cl. These results are consistent with trends in chloride affinity and ionization energy. The reluctant chlorination of the first two charge states of C₆₀ is attributed to the energy required to distort the carbon cage upon bond formation, while the observed chloride transfer to C₆₀^·3+ is attributed to the greater electrostatic interactions with this ion.     

Unimolecular reactions in the CF3CH2Cl ↔ CF2ClCH2F system: isomerization by interchange of Cl and F atoms

The recombination of CF(2)Cl and CH(2)F radicals was used to prepare CF(2)ClCH(2)F* molecules with 93 ± 2 kcal mol(-1) of vibrational energy in a room temperature bath gas. The observed unimolecular reactions in order of relative importance were: (1) 1,2-ClH elimination to give CF(2)═CHF, (2) isomerization to CF(3)CH(2)Cl by the interchange of F and Cl atoms and (3) 1,2-FH elimination to give E- and Z-CFCl═CHF. Since the isomerization reaction is 12 kcal mol(-1) exothermic, the CF(3)CH(2)Cl* molecules have 105 kcal mol(-1) of internal energy and they can eliminate HF to give CF(2)═CHCl, decompose by rupture of the C-Cl bond, or isomerize back to CF(2)ClCH(2)F. These data, which provide experimental rate constants, are combined with previously published results for chemically activated CF(3)CH(2)Cl* formed by the recombination of CF(3) and CH(2)Cl radicals to provide a comprehensive view of the CF(3)CH(2)Cl* ? CF(2)ClCH(2)F* unimolecular reaction system. The experimental rate constants are matched to calculated statistical rate constants to assign threshold energies for the observed reactions. The models for the molecules and transition states needed for the rate constant calculations were obtained from electronic structures calculated from density functional theory. The previously proposed explanation for the formation of CF(2)═CHF in thermal and infrared multiphoton excitation studies of CF(3)CH(2)Cl, which was 2,2-HCl elimination from CF(3)CH(2)Cl followed by migration of the F atom in CF(3)CH, should be replaced by the Cl/F interchange reaction followed by a conventional 1,2-ClH elimination from CF(2)ClCH(2)F. The unimolecular reactions are augmented by free-radical chemistry initiated by reactions of Cl and F atoms in the thermal decomposition of CF(3)CH(2)Cl and CF(2)ClCH(2)F.     

Accurate ab initio potential energy surface, thermochemistry, and dynamics of the Cl(2P, 2P(3/2) + CH4 → HCl + CH3 and H + CH3Cl reactions

We report a high-quality, ab initio, full-dimensional global potential energy surface (PES) for the Cl((2)P, (2)P(3/2)) + CH(4) reaction, which describes both the abstraction (HCl + CH(3)) and substitution (H + CH(3)Cl) channels. The analytical PES is a least-squares fit, using a basis of permutationally invariant polynomials, to roughly 16,000 ab initio energy points, obtained by an efficient composite method, including counterpoise and spin-orbit corrections for the entrance channel. This composite method is shown to provide accuracy almost equal to all-electron CCSD(T)/aug-cc-pCVQZ results, but at much lower computational cost. Details of the PES, as well as additional high-level benchmark characterization of structures and energetics are reported. The PES has classical barrier heights of 2650 and 15,060 cm(-1) (relative to Cl((2)P(3/2)) + CH(4)(eq)), respectively, for the abstraction and substitution reactions, in good agreement with the corresponding new computed benchmark values, 2670 and 14,720 cm(-1). The PES also accurately describes the potential wells in the entrance and exit channels for the abstraction reaction. Quasiclassical trajectory calculations using the PES show that (a) the inclusion of the spin-orbit corrections in the PES decreases the cross sections by a factor of 1.5-2.5 at low collision energies (E(coll)); (b) at E(coll) ≈ 13,000 cm(-1) the substitution channel opens and the H/HCl ratio increases rapidly with E(coll); (c) the maximum impact parameter (b(max)) for the abstraction reaction is ~6 bohr; whereas b(max) is only ~2 bohr for the substitution; (d) the HCl and CH(3) products are mainly in the vibrational ground state even at very high E(coll); and (e) the HCl rotational distributions are cold, in excellent agreement with experiment at E(coll) = 1280 cm(-1).     

[C5H4C(CH3)2CH2CH=CH2]Sm(OH)Cl·2MgCl2·4THF的晶体结构分析

用Ｘ－射线晶体结构衍射法测定了［Ｃ５Ｈ４Ｃ（ＣＨ３）２ＣＨ２ＣＨ＝ＣＨ２］Ｓｍ（ＯＨ）Ｃｌ·２ＭｇＣｌ２·４ＴＨＦ的晶体结构。它属三斜晶系,空间群为Ｐ＾－１,ａ＝１０．７７３（２）,ｂ＝１２．８３６（３）,ｃ＝１５．４７８（３）Ａ,ａ＝１１１．４６（３）,β＝１０７．７１（３）,γ＝９２．５４（３）°,Ｖ＝１８６８（１）Ａ＾３,Ｍｒ＝８２７．９１,Ｄｘ＝１．４７２ｇ／ｃｍ＾３,μ＝２．０００６ｍｍ     

Co-ordination of copper and silver by [Co2{μ-C2(CH2SCH2CH2)2S}(CO)6]

The thiamacrocycle [Co₂{μ-C₂(CH₂SCH₂CH₂)₂S}(CO)₆] reacts with Ag[BF₄] and PPh₃ to afford the fluxional compound [Co₂{μ-C₂(CH₂SCH₂)₂S}(CO)₆(AgPPh₃)][BF₄], the structure of which has been established by X-ray crystallography, and with [Cu(CH₃₋CN)₄][PF₆] to afford [Co₂{μ-C₂(CH₂SCH₂CH₂)₂S}(CO)₆(CuCH₃₋CN)][PF₆], which undergoes phosphine sustitution.     

CH2X(X=H,F,Cl)与臭氧反应机理的量子化学研究

用量子化学UMP2方法,在6-311++G**基组水平上研究了CH2X(X=H,F,Cl)与臭氧反应机理,全参数优化了反应过程中反应物、中间体、过渡态和产物的几何构型,在UQCISD(T)/6-311++G**水平上计算了它们的能量,并对它们进行了振动分析,以确定中间体和过渡态的真实性.从CH2X(X=H,F,Cl)与O3的反应机理的研究结果看,它们与O3反应的活性都比较强,相对而言,活性大小顺序为CH2F＞CH3＞CH2Cl,也就是说,CH2F自由基与臭氧间的反应活性最强,对大气臭氧的损耗将是最大的.同时研究还发现CH2X(X=H,F,Cl)系列自由基与O3的反应都是强放热反应.     

Synthesis,molecular structure and reactions of the novel organometallic phosphine ligand, [WI2(CO) (η2-triphos) (η2-MeC2Me)]/0.75CH2Cl2{triphos=PhP(CH2CH2PPh2)2}

Reaction of [WI₂(CO)(NCMe)(η²-MeC₂Me)₂] with an equimolar quantity of triphos {triphos=PhP(CH₂CH₂PPh₂)₂} in CH₂Cl₂ at room temperature gave the triphos complex [WI₂(CO)(η²-MeC₂Me)] (1). The crystal structure of (1) shows that the triphos is attached to the tungsten via two adjacent phosphorus atoms, with the third phosphorus atom uncoordinated. Two crystallographically independent molecules are present, which are diastereoisomers. Preliminary studies of the reactions of (1) are described.     

Geometric shielding corrections for calculation of electron scattering by CO2, C2H2, CHCl3, CH2Cl2, CH3Cl,CHF3, CH2F2 and CH3F at 30–5000 eV

Taking into account the changes of the geometric shielding effect in a molecule as the incident electron energy varies, an empirical fraction, which depends on the energy of the incident electrons, the target's molecular dimension and the atomic and electronic numbers in the molecule, is presented. Using this empirical fraction, a new formulation of the additivity rule is proposed. Using the new additivity rule, the total cross sections of electron scattering by CO₂, C₂H₂, CHCl₃, CH₂Cl₂, CH₃Cl, CHF₃, CH₂F₂ and CH₃F are calculated at the Hartree–Fork level at 30–5000 eV. The quantitative total cross sections are compared with those obtained by experiments and other theories, and good agreement is obtained over a wide energy range, especially above 100 eV.     

Characterization of [Re2Cl3(μ-dppm)2(NCCH3)2][Cl] and [Re2Cl3(μ-dppm)2(NCC6H5)2][Cl]·2CH2Cl2 by X-ray Crystallographic and Two-Dimensional NMR Spectroscopic Techniques

The complex Re₂Cl₆(P-n-Bu₃)₂ prepared in situ reacts with CH₃CN to form a blue-green solution. Addition of the chelating phosphine bis(diphenylphosphino)methane (dppm) results in the formation of the complex [Re₂Cl₃(-dppm)₂(NCCH₃)₂][Cl] (1) upon heating. The two acetonitrile molecules adopt a trans geometry on the rhenium center with the axially coordinated chlorine. The analogous trans benzonitrile species [Re₂Cl₃(-dppm)₂(NCC₆H₅)₂][Cl]·2CH₂Cl₂ (2) is synthesized under the same reaction conditions. The coupling constants of the AABB ³¹P{¹H} NMR spectra of the compounds were elucidated from ³¹P–³¹P homonuclear J-resolved NMR experiments. Additional characterization methods include ³¹P{¹H} NMR spectroscopy, UV-vis spectroscopy, and X-ray crystallography.     

Electronic structure and conformation properties of halogen-substituted acetyl acrylic anhydrides, CX3C(O)OC(O)CH═CH2 (X = H, F, or Cl)

Acetyl acrylic anhydride (CH(3)C(O)OC(O)CHCH(2)) and its halogen-substituted derivatives (CF(3)C(O)OC(O)CHCH(2) and CCl(3)C(O)OC(O)CHCH(2)) were prepared by the heterogeneous reaction of gaseous CH(2)═CHC(O)Cl with CX(3)C(O)OAg (X = H, F, or Cl). The molecular conformations and electronic structure of these three compounds were investigated by HeI photoelectron spectroscopy, photoionization mass spectroscopy, FT-IR, and theoretical calculations. They were theoretically predicted to prefer the [ss-c] conformation, with each C═O bond syn with respect to the opposite O-C bond and the C═C bond in cis orientation to the adjacent C═O bond. The experimental first vertical ionization potential for CH(3)C(O)OC(O)CHCH(2), CF(3)C(O)OC(O)CHCH(2), and CCl(3)C(O)OC(O)CHCH(2) was determined to be 10.91, 11.42, and 11.07 eV, respectively. In this study, the rule of the conformation properties of anhydride XC(O)OC(O)Y was improved by analyzing the different conformations of anhydrides with various substitutes.     

Photoelectron Spectroscopy and Structures of X−⋅⋅⋅CH2O (X=F,Cl, Br,I) Complexes

A combined experimental and theoretical approach has been used to investigate X⁻⋅⋅⋅CH₂O (X=F, Cl, Br, I) complexes in the gas phase. Photoelectron spectroscopy, in tandem with time-of-flight mass spectrometry, has been used to determine electron binding energies for the Cl⁻⋅⋅⋅CH₂O, Br⁻⋅⋅⋅CH₂O, and I⁻⋅⋅⋅CH₂O species. Additionally, high-level CCSD(T) calculations found a C_2v minimum for these three anion complexes, with predicted electron detachment energies in excellent agreement with the experimental photoelectron spectra. F⁻⋅⋅⋅CH₂O was also studied theoretically, with a C_s hydrogen-bonded complex found to be the global minimum. Calculations extended to neutral X⋅⋅⋅CH₂O complexes, with the results of potential interest to atmospheric CH₂O chemistry.     

(CH2)2O, (CH2)2S与双卤分子间卤键的理论研究

运用量子化学密度泛函B3LYP方法, 采用6-311＋＋G(d,p)及aug-cc-pVDZ基组, 通过CP校正的几何梯度优化对(CH2)2O和(CH2)2S与双卤分子XY (XY＝Cl2, Br2, ClF, BrF, BrCl)形成的卤键复合物的几何构型、振动频率和相互作用能等进行了研究. 利用电子密度拓扑分析理论方法对卤键复合物的拓扑性质进行了分析研究, 探讨了该类分子间卤键的作用本质. 结果表明, (CH2)2O和(CH2)2S与双卤分子间的卤键介于共价键与离子键之间, 偏于静电作用成分为主. 形成卤键后, 双卤分子的键长增加, 振动频率减小, 原子积分性质发生改变. 卤键键长的变化、键能的强弱、键鞍点处的电子密度值与双卤分子的电负性有关.     

镍硫配合物(Me3C+)2Ni(SCH2CH2S)2的合成及结构表征

以NiCl2,Bu4NBr,HSCH2CH2SH为原料合成了配合物(Me3C^ )2Ni(SCH2CH2S)2,其结构经元素分析、IR,UV和^1H NMR确证,X-射线四圆衍射仪测其晶胞参数为：a=0.9127(1)nm,b=1．2424(0)nm,c=1．3906(2),v=1．57685(2)nm^3,z=4,晶体属正交晶系。晶体结构经块状矩阵最小二乘法修正后,最终偏离因子R=0．089。     

精确控制合成Au36(SR)24金原子簇(SR = SPh,SC6H4CH3, SCH(CH3)Ph,SC10H7)

近十几年来,具有原子精确的金原子簇(Au_nL_m)逐渐发展成一种新型可靠的金纳米材料。在本研究中,报道一种简单实用合成脂肪或者芳香巯基保护Au₃₆(SR)₂₄金原子簇的方法。通过“尺寸聚焦”方法,成功地获得Au₃₆(SCH(CH₃)Ph)₂₄,Au₃₆(SC₆H₄CH₃)₂₄,Au₃₆(SPh)₂₄及Au₃₆(SC₁₀H₇)₂₄等金原子簇。这些原子簇通过UV-Vis光谱,电喷雾(ESI)和基质辅助激光解析飞行时间(MALDI)质谱以及TGA等表征进行了进一步的确定。同时发现在UV-Vis光谱中,芳香巯基保护Au₃₆(SR)₂₄金原子簇发生了明显的红移现象;例如与Au₃₆(SCH(CH₃)Ph)₂₄原子簇相比,萘巯基保护的Au₃₆(SC₁₀H₇)₂₄原子簇在570 nm左右的吸收峰发生了13 nm的位移。     

Preparation and structural characterization of the hexatungsten cluster complex (EDTEH)2[W6(μ3-Cl)8Cl6], (EDTEH=(MeO2CCH2)2N(H)CH2CH2N(CH2CO2Me)2+

The hexanuclear tungsten cluster complex [W₆(₃-Cl)₈Cl₆]^2–,1 was isolated as a salt of the cation (MeO₂CCH₂)₂N(H)CH₂CH₂N(CH₂CO₂Me)₂₊, EDTEH⁺, by crystallization from methanol solvent of the product obtained from the reaction of (H₃O)₂[W₆(₃-Cl)₈Cl₃] with the disodium salt of ethylenediaminetetraacetic acid. The compound was charcterized by single-crystal X-ray diffraction analysis. The cluster anion contains an octahedral arrangement of six tungsten atoms with chloride ligands bridging the eight triangular faces of the cluster and one chloride ligand terminally coordinated to each of the six tungsten atoms. The cation (EDTEH)⁺ achieves its positive charge by protonation of one of the nitrogen atoms. Crystal data: space group = P2₁/a,a=10.689(2) Å,b=22.931(6) Å,c=12.093(3) Å, =98.41(2)°,Z=2, 2476 reflections,R=0.028.