Ab initio study of the electronic spectrum of dichlorocarbene CCl2

The equilibrium geometries, excitation energies, force constants and vibrational frequencies for seven low-lying electronic states X ¹A₁, ¹B₁, ³B₁, ¹A₂, ³A₂, ¹B₂ and ³B₂ of dichlorocarbene CCl₂ have been calculated at the MRSDCI level with a double-zeta plus polarization basis set. Our calculated equilibrium geometry for the X ¹A₁ state, excitation energy for X ¹A₁ → ¹B₁ and vibrational frequencies for the X ¹A₁ and ¹B₁ states are in good agreement with experimental data. The electronic transition dipole moments, oscillator strengths for the ¹B₁ → X ¹A₁ and ¹B₂ → X ¹A₁ transitions, radiative lifetimes for the ¹B₁ and ¹B₁ states are calculated using MRSDCI wavefunctions, predicting results in reasonable agreement with experiment.     

CoAl2O4包覆LiNi1/3Co1/3Mn1/3O2的电化学性能

通过共沉淀法制得类球形锂离子电池正极材料LiNi_1/3Co_1/3Mn_1/3O₂,并用非水相共沉法对其进行CoAl₂O₄包覆得到LNCMO(x). 采用X射线衍射（XRD）、扫描电子显微术（SEM）和透射电子显微术（TEM）测试材料的结构和观察材料形貌. 结果表明,CoAl₂O₄在材料表面形成8 nm均匀包覆层,未改变主体材料的结构. 电化学性能测试表明,1%（by mass）CoAl₂O₄包覆量的LiNi1/3Co1/3Mn1/3O2材料（LNCMO(1)）高充电电压（3.0 ~ 4.6 V,150 mA·g^-1）100周期循环放电容量保持率为93.7%（无包覆LNCMO(0)保持率为74.4%）;55 °C高温100周期循环容量保持率为77%（无包覆LNCMO(0)保持率17%）. XRD和电感耦合等离子体原子发射光谱（ICP-AES）测试表明,CoAl₂O₄包覆的LNCMO(x)材料可有效地减缓材料中Mn离子在电解液的溶解,提高材料结构稳定性和热稳定性.     

Soy Oil Microemulsions Made of Anionic Surfactant,Oleic Acid,Diethyleneglycol Ethyl Ether,and Water: Optimized Systems

Soy oil microemulsions has been optimized for systems made of phosphated oleyl ether 3EO as surfactant, oleic acid, diethyleneglycol monoethyl ether, and water. The soy oil solubilization has been estimated as a function of different ratios between surfactant/oleic acid (5/95, 10/90, 15/85, and 20/80) and water/glycol (4/1, 2/1, 1/1, 1/2, and 1/4). The maximum simultaneous solubilization of soy oil and hydrophilic phase (water plus glycol) in ratios 3/1, 1/1, and 1/3 (besides the 1/0 and 0/1) was considered. In order to display the widest microemulsion area, the better ratios surfactant/oleic acid were 10/90, 15/85, and 20/80 when water and glycol ratios were 1/2 and 1/4. For these systems, the transition between W/O, bicontinuous and O/W microemulsions were followed through electrical conductivity changes.     

A new series of nematic and smectic liquid crystals with negative dielectric anisotropy: the effect of terminal chain substitution on thermal and electro-optical properties

Two alkyl (1b and 1c) and four fluoroalkyl derivatives (1d-1f) of 4-arylbutyric acid (1c, 1d and 1e) and 4-arylbutanol (1b, 1f and 1g) [aryl = 2',3'-difluoro-4'-(2-(E-4-pentylcyclohexyl)ethyl)-biphenyl-1-yl] were prepared and investigated in the pure form as nematic materials (1b and 1c) and as additives to a ferroelectric liquid crystal (FLC) host (1d-1f). A comparison of 1b and 1c with the decyl analogue 1a demonstrates the effect of terminal chain modification on thermal and electro-optical properties. The substitution of the -CH₂O- (1b) or -COO- (1c) for -CH₂CH₂- in 1a destabilized the N and SmA phases or completely eliminated the smectic behaviour (1c). Dielectric analysis revealed that the chain modification increased the negative Δε, reduced elastic constant K ₁₁ and moderately decreased rotational viscosity γ₁. The temperature dependence of the key electro-optical parameters was analysed for ester 2, the methyl analogue of 1c, which exhibits a 45 K wide N phase. All four fluoroalkyl derivatives 1d-1f showed enantiotropic SmA phases and 1e also exhibited a monotropic SmC phase. Solutions of 1d-1f in a FLC host (0.2 mmol g^-1) increased the tilt angle Θ (up to 45° for 1g), reduced rotational viscosity γ₁ and the risetime τ. The most dramatic changes were observed for 1g, which contains 15 fluorine atoms.     

266nm激光激励的SO2(X1A1,A1A2,B1B1)体系的态间转移研究

用YAG四倍频激光把SO₂分子从电子基态X¹A₁激励到电子激发态A¹A₂和B¹B₁的高振动耦合区, 获得了320～380um范围内SO₂(B¹B₁→X¹A₁)的激光诱导荧光色散谱, 并给出初步标识;提出一个三能态模型来处理266nm激光激励的SO₂(X¹A₁, A¹A₂, B¹B₁)体系的态间转移, 并获得了A态和B态在高振动能区的耦合系数ξ及耦合达到动态平衡的弛豫时间τ, 发现二者反映的是被研究体系的固有特性, 与提出的模型吻合.     

Unusual demethylation of 1-dimethylamine-1-carba-closo-dodecarbonate(11)

1-Dimethylamine-1-carba-closo-dodecaborane(1), 1-(CH₃)₂NH-1-CB₁₁H₁₁, can be smoothly demethylated with iodine in weakly alkaline solution to produce 1-methylamine-1-carba-closo-dodecarborane(11), 1-CH₃NH₂-1-CB₁₁H₁₁. The latter compound undergoes formylation with formaldehyde and iodine to give 1-hydroxymethylene-methylamine-1-carba-closo-dodecaborane(11). Further chemical transformations of both compounds are reported.     

HS+HO2气相反应机理及主通道速率常数的理论研究

采用CCSD(T)/6-311++G(3df, 2pd)//B3LYP/6-311+G(2df, 2p)双水平计算方法构建了HO₂+HS反应体系的单、三重态反应势能面,并对该反应主通道的速率常数进行了研究。研究结果表明,标题反应经历了八条反应通道,其中三重态反应通道R1是标题反应主通道。此通道包含路径Path 1 (R → ³IM1 → ³TS1 → P1(³O₂+H₂S))和Path 1a (R → ³IM1a → ³TS1a → P1(³O₂+H₂S))两条路径。利用经典过渡态理论(TST)与变分过渡态理论(CVT)并结合小曲率隧道效应模型(SCT),分别计算了主路径Path 1和Path 1a在200-800 K温度范围内的速率常数k^TST、k^CVT和k^CVT/SCT,在此温度区间内路径Path 1和Path 1a具有负温度系数效应。速率常数计算结果显示,对主路径Path 1和Path 1a而言,变分效应在计算温度段内有一定影响,与此同时量子力学隧道效应在低温段有显著影响。路径Path 1和Path 1a的CVT/SCT速率常数的三参数表达式分别为k₁^CVT/SCT(200-800 K) = 1.54×10^-5T^-2.70exp(1154/T) cm³ ·molecule^-1·s^-1和k_1a^CVT/SCT(200-800 K) = 5.82×10^-8T^-1.84exp(1388/T) cm³·molecule^-1·s^-1。     

Synthesis of four enantiomerically pure 4-(4-carbamoyl-1,2,3-triazol-1-yl)-2,3-dihydroxy-1-methoxybutylphosphonic acids

CuCl-catalysed cycloaddition of methyl propiolate to O,O-diisopropyl (1S,2R,3S)- and (1R,2R,3S)-, or O,O-dibenzyl (1S,2R,3S)-, (1R,2R,3S)-, (1S,2R,3R)- and (1R,2R,3R)-4-azido-1,2,3-trihydroxy-2,3-O-isopropylidenebutylphosphonates followed by methylation of HO–C-1, ammonolysis of methoxycarbonyl groups and hydrolysis of isopropylidene acetals led to diisopropyl (1S,2R,3S)- and (1R,2R,3S)-4-(4-carbamoyl-1,2,3-triazol-1-yl)-2,3-dihydroxy-1-methoxybutylphosphonates or, after hydrogenolytic removal of benzyl groups, to (1S,2R,3S)-, (1R,2R,3S)-, (1S,2R,3R)- and (1R,2R,3R)-4-(4-carbamoyl-1,2,3-triazol-1-yl)-2,3-dihydroxy-1-methoxybutylphosphonic acids.     

THE SINGLET OXYGEN REACTIVITY OF BILIVERDIN

Abstract— In 1, 1, 2-trichlorotrifluoroethane solution biliverdin physically quenches singlet oxygen at a rate of 8 × l0^sM-¹s^-1 and reacts chemically at 6 × 10 ⁵M-¹s^-1 to give a red product. In D, O solution the rate constants are PD dependent and range from 1.5–6 times 10¹⁰M-¹s^-1 for quenching and the chemical rate varies from 3–5 × 10⁸ M^-1 s^-1 to give colorless products.     

Study of the N2 bΠu state via 1 + 1 multiphoton ionization

Medium-resolution spectra of the N₂ b¹Π_u-X¹Σ_g⁺ band system were recorded by 1 + 1 multiphoton ionization. In the spectra we found different linewidths for transitions to different vibrational levels in the b ¹Π_u state: Δν₀ = 0.50 ± 0.05 cm⁻¹, Δν₁ = 0.28 ± 0.02 cm⁻¹, Δν₂ = 0.65 ± 0.06 cm⁻¹, Δν₃ = 3.2 ± 0.5 cm⁻¹, Δν₄ = 0.60 ± 0.07 cm⁻¹, and Δν₅ = 0.28 ± 0.02 cm⁻¹. From these linewidths, predissociation lifetimes τ_ν were obtained: τ₀ = 16 ± 3 ps, τ₁ > 150 ps, τ₂ = 10 ± 2 ps, τ₃ = 1.6 ± 0.3 ps, τ₄ = 9 ± 2 ps, and τ₅ > 150 ps. Band origins and rotational constants for the b ¹Π_uν = 0 and 1 levels were determined for the ¹⁴N₂ and ¹⁴N¹⁵N molecules.     

Donor-Acceptor Complexes in Copolymerization. XXVI. Effect of Solvent,Temperature, and Complexing Agent on the Polymerization of Comonomer Charge Transfer Complexes

The copolymerization of styrene with methyl methacrylate (S/MMA = 4/1) or acrylonitrile (S/AN = 1/1) in the presence of ethylaluminum sesquichloride (EASC) yields 1/1 copolymer in toluene or chlorobenzene. In chloroform the S-MMA-EASC polymerization yields 60/40 copolymer while the S-AN-EASC polymerization yields 1/1 copolymer. In the presence of EASC, styrene-α-chloroacrylonitrile yields 1/1 copolymer (DMF or DMSO), S-AN yields 1/1 copolymer (DMSO) or radical copolymer (DMF), S-MMA yields radical copolymer (DMF or DMSO), α-methylstyrene-AN yields radical copolymer (DMSO) or traces of copolymer (DMF), and α-MS-methacrylo-nitrile yields traces of copolymer (DMSO) or no copolymer (DMF). When zinc chloride is used as complexing agent in DMF or DMSO, none of the monomer pairs undergoes polymerization. However, radical catalyzed polymerization of isoprene-AN-ZnCl₂ in DMF yields 1/1 alternating copolymer. The copolymerization of S/MMA in the presence of EASC yields 1/1 alternating copolymer up to 100°C, while the copolymerization of S/AN deviates from 1/1 alternating copolymer above 50°C. The copolymerization of S/MMA deviates from 1/1 copolymer at MMA/EASC mole ratios above 20 while the copolymerization of S/AN deviates from 1/1 copolymer at MMA/EASC ratios above 50.     

The 1B1, 1B2, 1A1, 1A2, 3A′(2B2), and 2A1 states of the 1,1-difluoromethane ion studied using multiconfiguration second-order perturbation theory

The 1²B₁(X²B₁), 1²B₂, 1²A₁, 1²A₂, 2²B₂, and 2²A₁ states of the ion were studied using CASPT2 and CASSCF methods. Calculations suggest that one should consider the 3²A′ state instead of 2²B₂. The CASPT2 T₀ calculations predict the energy ordering of 1²B₁(X²B₁), 1²B₂, 1²A₁, 1²A₂, 3²A′, and 2²A₁, which is in line with the experimental results by Pradeep and Shirley. The CASPT2 T₀ values for the 1²B₂, 1²A₂, 3²A′, and 2²A₁ states are close to the experimental values. The F-loss and H-loss dissociation processes were studied at the CASPT2//CASSCF level. The energy levels of low-lying states of are compared.     

纳米MgO掺杂改善LiNi1/3Co1/3Mn1/3O2正极材料

将氢氧化物共沉淀法制备的(Ni_1/3Co_1/3Mn_1/3)（OH）₂在500℃热处理5 h得到具有尖晶石结构、纳米尺寸的氧化物M₃O₄(M=Ni_1/3Co_1/3Mn_1/3).将其与LiOH及不同量的纳米MgO混合均匀,并在850℃热处理24 h制备了Li(Ni_1/3Co_1/3Mn_1/3)_1/xMg_xO₂（x=0,0.01,0.02,0.03,0.04,0.05）正极村料.随着Mg掺杂量的增大,正极材料的晶胞参数增大;少量的Mg掺杂增大了锂离子的扩散系数,而过度掺杂却使锂离子扩散系数有所降低,其中Li(Ni_1/3Co_1/3Mn_1/3)_0.98Mg_0.02O₂的锂离子扩散系数最大,其脱出和嵌入扩散系数分别为D_Li-dein=29.20×10^-11cm²·S^-1和D_Li-in=4.760×10^-11cm²·s^-1;其以3C倍率充放电的平均放电比容量为139.3 mAh·g^-1,比未掺杂的原粉约高9.5 mAh·g^-1;另外其循环性能也得到了大幅度改善.     

Differential-thermal and thermogravimetric analysis of some gagates from Bulgaria

The thermal behaviour of three gagates (Bulgaria) was investigated by DTA and TG. The characteristic endo- and exoeffects and the sequence of the thermal stabilities are established.

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Zusammenfassung Das thermochemische Verhalten von drei Gagaten (Bulgarien) wurde mittels DTA und TG untersucht. Die charakteristischen endo- und exothermen Effekte und die Reihenfolge der thermischen Stabilitäten wurden ermittelt.

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FLUORESCENCE CHARACTERISTICS OF INDOLES IN NON-POLAR SOLVENTS: LIFETIMES, QUANTUM YIELDS AND POLARIZATION SPECTRA

Abstract— Fluorescence lifetimes, quantum yields and polarization spectra were measured for indole, 3-methylindole and 2,3-dimethylindole in non-polar solvents. The results indicate simultaneous emission from thermally equilibrated ¹L_a and ¹L_b levels, with ¹L_a→¹ A dominating the 2,3-dimethylindole emission, and ¹L_b→¹ A dominating the indole emission. These results are consistent with previous assignments of the 0-0 transitions in absorption for these compounds. Radiative rates are: ¹L_a→¹ A , 2·0 × 10⁸ S^-1 and ¹L_b→¹ A . 0·62 → 10⁸ S^-1. In addition, the temperature dependence of the excitation and emission spectra are presented, which show that aggregation occurs with these indoles in hydrocarbons below approximately - 110°C. Possible applications to tryptophyl emission in the hydrophobic interiors of proteins are briefly discussed.     

Dehydroxylation of kaolinite group minerals

The kinetics of dehydroxylation of kaolinite and halloysite have been tested by the methods of thermal analysis. They are determined by the particle sizes of these minerals and the order of stacking of the layers in their structures. The Arrhenius activation energyE and order of reactionn decrease with the increase in specific surface area of the minerals. An increase in the degree of disorder of the kaolinite lattice diminishes the value ofE. It also influences then value for fractions finer than 1m.

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Zusammenfassung Die Kinetik der Dehydroxylierung von Kaolinit und Halloysit wurde durch Methoden der Thermoanalyse geprüft. Die Bestimmungen erfolgten über die Teilchengrösse dieser Mineralien und die Reihenfolge der AnhÄufung der Schichten in ihrer Struktur. Die AktivierungsenergieE nach Arrhenius und die Reaktionsordnung nehmen mit zunehmender spezifischer OberflÄche der Minerale ab. Die Zunahme des Grades der Unordnung des Kaolinitgitters setzt den Wert vonE herab. Sie beeinflusst auch den Wertn der Fraktionen feiner als 1m.

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Résumé On a étudié par les méthodes de l'analyse thermique, la cinétique de déshydroxylation de la kaolinite et de l'halloysite. Les déterminations ont été effectuées à partir de la taille des particules de ces minéraux et de l'ordre d'empilement des couches dans leur structure. L'énergie d'activationE d'après Arrhénius et l'ordre de réaction diminuent avec l'augmentation de la surface spécifique des minéraux. L'augmentation du degré de désordre du réseau de la kaolinite diminue la valeur deE. Elle influence de mÊme la valeurn des fractions inférieures à 1m.

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. . E . E. n 1.

     

ZnO包覆LiNi1/3Co1/3Mn1/3O2的表面结构和电化学性能

在LiNi_1/3Co_1/3Mn_1/3O₂正极材料表面包覆ZnO,通过X射线衍射（XRD）和光电子能谱（XPS）分析包覆层对正极材料表面状态的改变,并考察了改性后材料的放电容量、首次不可逆容量等电化学性能变化. 结果表明：ZnO主要存在于材料表面并影响着材料表面组成和电化学性质,材料表面镍和锰的含量随着包覆量的增加而增大;400 ^oC热处理可使过渡金属与锌在材料表面形成复合氧化物,过渡金属的结合能增大;包覆2%（by mass,下同）的ZnO可有效抑制55 ^oC下充放电时3.6 V附近的不可逆反应,提高了材料的首次库仑效率;包覆2% ZnO的电池材料在55 ^oC/0.5C的放电比容量和循环寿命最佳.     

Fluorocyclohexanes-II Cis- and trans- 1H:3H- and 1H:4H-decafluorocyclohexanes

An extension of the methods employed in the isolation of (trans) 1H/2H-decafluorocyclohexane,¹ (I) from the polyfluorocyclohexane mixture obtained by the vapour phase fluorination of benzene with cobaltic fluoride at about 150°, has afforded the four remaining members of the series of decafluorocyclohexanes [the cis- and trans-1H:3H- and 1H:4H-isomers (1H:3H/-(IV), 1H/3H-(III), 1H:4H/-(VII), and 1H/4H-(VIII), respectively)] and also the cis-1H:2H-decafluorocyclohexane (II), obtained previously^1,2 by the lithium aluminium hydride reduction of 1:2-dichlorodecafluorocyclohexane. The structures of the 1H:3H- and 1H:4H-decafluorides have been established by dehydrofluorination studies. The six decafluorocyclohexanes have been related to two new nonafluorocyclohexanes³ (IX and X) by further fluorination of the latter. 2H-Heptafluoroadipic acid has been obtained from 3H-nonafluorocyclohex-1-ene (V), one of the dehydrofluorination products of the 1H:3H-decafluorides.     

Molecular structure of 4,4′-sulfandiyl-bis-thiophenol from electron diffraction

The molecular structure of 4,4′-sulfanidyl-bis-thiophenol (C₁₂H₁₀S₃) has been determined by gas electron diffraction. Assuming identical geometry and D_2h local symmetry for ---SC₆H₄S--- moieties, the following bond lengths (r_g) and bond angles were obtained: C---H = 1.101 ± 0.005, S---H = 1.388 ± 0.019, (C---C)_mean = 1.400 ± 0.003, (S---C)_mean = 1.778 ± 0.004 Å, C_ar---S---C_ar = 103.5 ± 1.3, C---C(S)---C = 120.4 ± 0.3, C(H)---C(H)---H = 119.1 ± 0.9 and C---S---H = 94.6 ± 3.1°. Two ratational forms were found to reproduce the experimental data, characterized by dihedral angles of the benzene rings with respect to the C_arSC_ar plane; ₁ = 67.8 ± 2.0°, ₂ = 4.5 ± 7.2°, and ₁ = 69.4 ± 2.0δ, ₂ = −26.6 ± 7.1°. Identical signs of ₁ and ₂ indicate that the two benzene rings are rotated in the same direction about the respective S_central---C axes.     

Infrared studies of chromones—I Carbonyl and hydroxyl regions

Quantitative IR solution data in carbon tetrachloride and chloroform are recorded for the CO and OH regions of 31 chromones. In the 1580–1700 cm⁻¹ region, 5-hydroxychromones show three main maxima, the two of highest frequency, at 1663 ± 3 cm⁻¹ and 1630 ± 5 cm⁻¹ in CCl₄ (1661 ± 2 cm⁻¹ and 1627 ± 5 cm⁻¹ in CHCl₃), being sufficiently intense as to possess high CO character. Typically, 5-alkoxychromones exhibit two intense maxima in this region, 1663 ± 3 cm⁻¹ and 1613 ± 7 cm⁻¹ in CCl₄ (1657 ± 2 cm⁻¹ and 1608 ± 12 cm⁻¹ in CHCl₃). Diagnostically useful changes in contour and principal peak positions can be seen for substituted and annellated 5-hydroxychromones. In the 2500–3650 cm⁻¹ region, the stretching frequencies of OH groups at the most commonly encountered positions (C-5, C-7, and 2-CH₂OH) in natural chromones, are identified.