The electronic transition moment function of the E1Πu-X1Σ g+ system of Ag2

Measurement of relative band strengths of 10 absorption bands of the E ¹Π _u -X ¹Σ _g ⁺ system of diatomic silver, ^107,109Ag₂, was performed for the first time. Theoretical analysis of the experimental data, based on Rydberg-Klein-Rees potential energy curves, revealed that assumption of the r-centroid approximation is valid for this system. Comparison of the measured and computed band strength ratios for 5 pairs of bands having common lower levels led to the following linear relative electronic transition moment function for the ^107,109Ag₂ E-X band system: R_e ([`(r)]<sub>V￠V"</sub> ) = 2.36[`(r)]_V￠V" - 5.64R_e (\bar r_{V'V'} ) = 2.36\bar r_{V'V'} - 5.64, in arbitrary units, over the 2.65–2.73 ? of internuclear distance.     

A1∑+ State Lifetime and Predissociation of CuH

A combined cavity ringdown (CRD) and laser induced fluorescence (LIF) spectroscopic study on the A¹∑⁺-X¹∑⁺ transition of CuH has been presented.The CuH molecule,as well as its deuterated isotopologue CuD,are produced in a supersonic jet expansion by discharging H₂(or D₂) and Ar gas mixtures using two copper needles.Different profiles of relative line intensities are observed between the measured LIF and CRD spectra,providing an experimental evidence for the predissociation behavior in the A¹∑⁺ state of CuH.The lifetimes of individual upper rotational levels are measured by LIF,in which the J'-dependent predissociation rates are obtained.Based on the previous theoretical calculations,a predissociation mechanism is concluded due to the strong spin-orbit coupling between the A¹∑⁺ state and the lowest-lying triplet ³∑⁺ state,and a tunneling effect may also be involved in the predissociation.Similar experiments are also performed for CuD,showing that the A¹∑⁺ state of CuD does not undergo a predissociation process.     

Photodissociation Spectra of OCS+ via B2∑+←X2∏ Transitions

In the wavelength range of 231-275 nm, we have studied the mass-resolved dissociation spectra of OCS⁺ via B²∑⁺←X²∏_3/2(000) and B²∑⁺←X²∏_1/2(000, 001) transitions by preparing OCS⁺ ions in the well-defined spin-orbit states. The spectroscopic constants ofυ1(CS stretch)=828.9 (810.4) cm^-1, υ2(bend)=491.3 cm^-1 and υ3(CO stretch)=1887.2 cm^-1 for OCS⁺(B²∑⁺) are deduced. The observed dependence of the υ2(bend) mode excitation of B²∑⁺ on the spin-orbit splitting of X²∏(Ω=1/2, 3/2) in the B²∑⁺←X²∏ transition can be attributed to the K coupling between the (000)²∏_1/2 and (010)²∑⁺_1/2 vibronic levels of X²∏ state, which makes the B²∑⁺(010)←X²∏_1/2(000) transition possible.     

羟基自由基与N6,N6-二甲基腺嘌呤反应机理研究

N^6,N^6-二甲基腺嘌呤(DMAP)是生物分子的组成部分,在决定生物分子的活性和构型性能方面起到了重要作用。羟基自由基(·OH)可与DMAP反应,改变其结构,从而影响它的生物功能。因此有必要了解DMAP与·OH反应的具体过程。本文运用量子化学方法从理论上研究了·OH与DMAP的反应机理。根据反应的能垒及产物的稳定性,DMAP与·OH最可能的反应是·OH夺取DMAP的N(6)甲基H、N(9)H以及·OH加成到DMAP的C(8)位。N(6)位的甲基化提高了腺嘌呤的反应活性,也影响了其与·OH的反应机理。     

Rotational Analysis of A2Πu-X2Σ+g System of 14N2+

The absorption spectrum of N₂⁺ has been studied using optical-heterodyne velocity mod-ulation spectroscopy in the near-infrared region. The observed spectral lines were assigned to the (3,1), (4,2), (5,3), (8,5) bands of the A²Π_u-X²Σ⁺_g system and the line lists were provided. The (5,3) band was studied for the first time. Fourteen rotational-resolved bands in literatures were fitted together with our observed bands and the molecular constants were obtained for υ_A=0-9 and υ_X=0-5.     

Imaging Isocyanic Acid Photodissociation at 193 nm: the NH(a1Δ)+ CO(X1Σ+) Channel

The photodissociation dynamics of isocyanic acid (HNCO) has been studied by the timesliced velocity map ion imaging technique at 193 nm. The NH(aΔ) products were measured via (2+1) resonance enhanced multiphoton ionization. Images have been accumulated for the NH(aΔ) rotational states in the ground and vibrational excited state (v=0 and 1). The center-of-mass translational energy distribution derived from the NH(aΔ) images implies that the CO vibrational distributions are inverted for most of the measured NH(v|j) internal states. The anisotropic product angular distribution observed indicates a rapid dissociation process for the N-C bond cleavage. A bimodal rotational state distribution of CO(v) has been observed, this result implies that isocyanic acid dissociates in the S₁ state in two different pathways.     

Crystal structure of [MnII (1,10-C12H8N2)3]2+[(B9C2H11)CoIII(B8C2H10)CoIII(B9C2H11)]2?·CH3CN

A novel compound, [MnPhen₃][(B₉C₂H₁₁)Co(B₈C₂H₁₀)Co(B₉C₂H₁₁)]· CH₃CN (Phen = 1,10-phenantroline), comprising a Co(III) dicobaltacarborane cluster anion has been prepared and characterized by single crystal X-ray diffraction. Crystal data are the following: C₄₄H₅₉B₂₆N₇Co₂Mn, M = 1139.84, triclinic, space group , unit cell parameters: a = 13.2465(11) Å, b = 14.521(2) Å, c = 15.2536(15) Å; α = 77.027(9)°, β = 88.500(8)°, γ = 77.274(9)°; V = 2788.5(5) ų, Z = 2, d _calc = 1.358 g/cm³, T = 295 K, F(000) = 1162, μ = 0.853 mm⁻¹. The structure was solved by the direct and Fourier methods and refined anisotropically (isotropically for hydrogen atoms) using the full-matrix technique to final factors R ₁ = 0.0374, wR ₂ = 0.0915 for 7397 I _hkl ≥2σ_I of 9779 I _hkl measured (diffractometer Enraf-Nonius CAD-4, λMoK _α , graphite monochromator, θ/2θ-scanning). The structure is formed from [MnPhen₃]²⁺ cations, [(B₉C₂H₁₁)×Co(B₈C₂H₁₀)Co(B₉C₂H₁₁)]₂₋ anions, and acetonitrile molecules CH₃CN. Central Mn atom in the cation has a distorted octahedral coordination environment formed by six nitrogen atoms of three bi-dentate Phen ligands, average Mn-N bond length being 2.263(2) Å. The anion has a chain-like structure built from three icosahedra sharing common vertices occupied by the cobalt atoms. The central icosahedron including ten light atoms (8B, 2C) provides two vertices for the cobalt atoms shared with the other icosahedra having 11 light atoms (9B, 2C). The arrangement of-C₂-groups in the anion corresponds to a quasi-gauche-configuration of asymmetric sandwich complexes of both cobalt atoms. Original Russian Text Copyright ? 2005 by T. M. Polyanskaya, V. V. Volkov, and M. K. Drozdova __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 4, pp.730–740, July–August, 2005.     

Magnetic properties of fullerene salts containing d- and f-metal cations (Co2+, Ni2+, Fe2+, Mn2+, Eu2+, Cd2+). Specific features of the interaction between C60·? and the metal cations

The interaction between the radical anions C₆₀ ^·− and divalent d- and f-metal (Co, Fe, Ni, Mn, Eu, Cd) cations in DMF and acetonitrile-benzonitrile (AN-BN) mixture was studied. Black solid polycrystalline salts (C₆₀ ^·−)₂{(M²⁺)(DMF) _x } (x = 2.4–4, 1–6) containing the radical anions C₆₀ ^·− and metal(ii) cations solvated by DMF were prepared for the first time and their optical and magnetic properties were studied. The salts containing Co²⁺, Fe²⁺, and Ni²⁺ are characterized by antiferromagnetic interactions between the radical anions C₆₀ ^·−, which result in unusually large broadening of the EPR signal of C₆₀ ^·− upon lowering the temperature (from 5.55–12.6 mT at room temperature to 35–40 mT at 6 K for Co²⁺ and Ni²⁺). The salts containing Mn²⁺ and Eu²⁺ form diamagnetic dimers (C₆₀ ⁻)₂, which causes a jumpwise decrease in the magnetic moment of the complexes and disappearance of the EPR signal of C₆₀ ^·− in the temperature range 210–130 K. A feature of salt 6 is magnetic isolation of the radical anions C₆₀ ^·− due to the presence of diamagnetic cation Cd²⁺. The salts prepared are unstable in air and decompose in o-dichlorobenzene or AN. Reactions of C₆₀ ^·− with metal(ii) cations in AN-BN mixture result in decomposition products of the salts that contain neutral fullerene dimers and metals solvated by BN. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1909–1919, September, 2008.     

F2 Σ+ -X 2Σ +Band System of Cobalt Carbide

The laser-induced fluorescence excitation spectrum of CoC was recorded in the spectral region from 13500 cm-1 to 22000 cm-1, in which the CoC molecules were produced by the reaction of sputtered cobalt atoms with methanol under supersonic jet cooled conditions. Much of the visible spectrum was assigned to transitions between the X2∑+ ground state and F2∑+ state. The 11 bands assigned as (v’=3-13, 0) transitions of the F2∑+- X2∑+ band system were observed and rotationally analyzed. Equilibrium constants for the F2∑+ state were Te=1362 cm-1, ωe=669 cm-1 ,ωe?e=4.3 cm-1, Be=0.546 cm-1, and Re=1.758A. Some new bands were observed.     

Fe3+/Ba2+/Co2+/Zn2+/Cu2+在NH4HCO3-NH3·H2O和NaOH-Na2CO3体系中的热力学分析

通过对Fe3+/Ba2+/Co2+/Zn2+/Cu2+在NH4HCO3-NH3·H2O和NaOH-Na2CO3体系中的热力学分析,得到各金属离子总浓度(cMe)与pH值的关系,确定了2种体系中5种离子完全共沉淀的pH值范围.结果表明:在NH4HCO3-NH3·H2O体系中,Co2+、Zn2+、Cu2+3种离子和氨的配位能力很强,其中Cu2+与氨的配位能力最强,在相同的pH值条件下,Cu2+沉淀困难,5种金属离子的完全共沉淀区域由Cu2+决定.在NaOH-Na2CO3体系中,随总碳浓度(cc)的增加,Ba、Co、Zn、Cu的溶解度都随之减小,当cc=1.0 mol·L-1时,各金属离子完全共沉淀的pH值范围为7.5～11.在两种体系中,Fe的溶解度都是随pH值的增大而减小,最终达到平衡.以NaOH-Na2CO3 为沉淀剂.在pH=10.0的条件下,采用化学共沉淀法合成出了晶粒细小、粒度均匀的Y型纯相结构的平面六角铁氧体微粉.     

Calculating the molecular constants for the B1Πu, C1Πu, (1)1Πg, and (2) Σ g+ electronic states of the rubidium dimer

The vibrational, rotational, and centrifugal constants are calculated for the B ¹Π _u , C ¹Π _u , (1) ¹Π _g , and (2) electronic states of a ⁸⁵Rb₂ molecule. The calculations are based on the semi-empirical potential curves obtained in this work. The results from calculating the molecular constants are compared with experimental data. The Franck-Condon factors and R _v′v″ centroids are calculated for the electronic transitions B ¹Π _u -X ¹Σ _g ⁺, C ¹Π _u -X ¹Σ _g ⁺, C ¹Π _u -(1) ¹Π _g , and C ₁Π _u -(2) ¹Σ _g ⁺.     

Photodissociation Dynamics of CS2 Near 204 nm: The S(3PJ)+CS(X1Σ+)Channels

We study the photodissociation dynamics of CS\begin{document}$_2$\end{document} in the ultraviolet region using the time-sliced velocity map ion imaging technique. The S(\begin{document}$^3$\end{document}P\begin{document}$_J$\end{document})+CS(\begin{document}$X^1\Sigma^+$\end{document}) product channels were observed and identified at four wavelengths of 201.36, 203.10, 204.85 and 206.61 nm. In the measured images of S(\begin{document}$^3$\end{document}P\begin{document}$_{J=2, 1, 0}$\end{document}), the vibrational states of the CS(\begin{document}$X^1\Sigma^+$\end{document}) co-products were partially resolved and the vibrational state distributions were determined. Moreover, the product total kinetic energy releases and the anisotropic parameters were derived. The relatively small anisotropic parameter values indicate that the S(\begin{document}$^3$\end{document}P\begin{document}$_{J=2, 1, 0}$\end{document})+CS(\begin{document}$X^1\Sigma^+$\end{document}) channels are very likely formed via the indirect predissociation process of CS\begin{document}$_2$\end{document}. The study of the S(\begin{document}$^3$\end{document}P\begin{document}$_{J=2, 1, 0}$\end{document})+CS(\begin{document}$X^1\Sigma^+$\end{document}) channels, which come from the spin-orbit coupling dissociation process of CS\begin{document}$_2$\end{document}, shows that nonadiabatic process plays a role in the ultraviolet photodissociation of CS\begin{document}$_2$\end{document}.     

Die Reaktion zwischen Thioglykols?ure (TGA) und Zn2+, Hg2+, Cd2+, Pb2+ und Ag+

Ohne Zusammenfassung     

N2O+经由B2Пi←X2П跃迁的光解离机理研究

在超声分子束条件下,利用360.50 nm的电离激光使N₂O分子经由[3+1]共振增强多光子电离（REMPI）产生纯净的N₂O⁺（X²Π（000））分子离子,用另一束解离激光在230-275 nm范围扫描获得N₂O⁺经由B²П_i←X²Π跃迁产生的光解碎片（NO⁺和N₂⁺）激发（PHOFEX）谱. 获得的光解碎片激发谱可以归属为B²П_i（00n）←X²Π（000）序列跃迁. 我们分别将线性三原子分子离子N₂O⁺中N―N伸缩振动简化成NO和N之间的简谐振动,N―O伸缩振动简化成N₂和O之间的简谐振动,用谐振子的简谐势能曲线和波函数对N₂O⁺分子离子X²Π和B²П_i电子态振动能级间跃迁的Franck-Condon因子进行计算,和实验得到的碎片离子增强谱实验强度进行比较,对前人给出的分子数据（分子平衡核间距）进行验证,讨论了N₂O⁺经由B²П_i（00n）←X²Π（000）电子态跃迁的光解离机理和碎片离子的分支比.     

A theoretical study of cation--π interactions: Li+, Na+, K+, Be2+, Mg2+ and Ca2+ complexation with mono- and bicyclic ring-fused benzene derivatives

DFT (B3LYP functional) and MP2 methods using 6-311+G(2d,2p) basis set have been employed to examine the effect of ring fusion to benzene on the cation--π interactions involving alkali metal ions (Li⁺, Na⁺, and K⁺) and alkaline earth metal ions (Be²⁺, Mg²⁺ and Ca²⁺). Our present study indicates that modification of benzene (π-electron source) by fusion of monocyclic or bicyclic (or mixture of these two kinds of rings) strengthens the binding affinity of both alkali and alkaline earth metal cations. The strength of interaction decreases in the following order: Be²⁺ > Mg²⁺ > Ca²⁺ > Li⁺ > Na⁺ > K⁺ for any considered aromatic ligand. The interaction energies for the complexes formed by divalent cations are 4–6 times larger than those for the complexes involving monovalent cations. The structural changes in the ring wherein metal ion binds are examined. The distance between ring centroid and the metal ion is calculated for all of the complexes. Strained bicyclo[2.1.1]hexene ring fusion has substantially larger effect on the strength of cation--π interactions than the monocyclic ring fusion for all of the cations due to the π-electron localization at the central benzene ring.     

Titration of AsO43? ions with 0.1 M magnesium sulphate solution in the presence of Ca2+, Mg2+, Fe3+, Cu2+ ions and some other foreign substances

Summary For the convenient and sufficiently accurate determination of AsO₄ ^3– ions in technical products containing different filling, suspending and colouring materials, as well as impurities—e.g. for the assay of arsenate containing plant protecting materials—the following procedure is recommended.About 5 g of the sample is dissolved, resp. extracted with 4 N hydrochloric acid, and aliquots of the clear filtrate are titrated after elimination of the interfering metal ions by combining them with complexing agents (potassium cyanide and disodium ethylenediamin tetraacetic acid) in a properly buffered medium. The titration with 0.1 M MgSO₄ solution is conducted in the presence of eriochrome black T solution as indicator, first time for eliminating the excess of EDTA added, and afterwards to determine the AsO₄ ^3– ions, after adding about 40% of ethanol.The procedure may be useful chiefly for serial routine analyses.The authors are indebted to engineer L. Fokássy, department leader at the State Institute for Agricultural Quality Control, as well as to engineeress P. Fodor and Mr. Gy. Josepovits, scientific collaborators of the Research Institute for Plant Protection, for kindly supplying some of the samples for the experiments.     

2-nitroguanidine derivatives: VIII. Synthesis and cyclizations of N′1,N′2-bis(N2- nitrocarbamimidoyl) dicarboxylic acid dihydrazides and ethyl [2-(N2-nitrocarbamimidoyl)-hydrazino](oxo)acetate

New methods of synthesis of N¹,N²-bis(N ²-nitrocarbamimidoyl) dicarboxylic acid dihydrazides and ethyl [2-(N ²-nitrocarbamimidoyl)hydrazino](oxo)acetate from 1-methyl-2-nitro-1-nitrosoguanidine and dicarboxylic acid hydrazides were proposed. Cyclization of N¹, N²-bis(N ²-nitrocarbamimidoyl) dihydrazides derived from malonic and succinic acids afforded the corresponding bis(3-nitroamino-1,2,4-triazol-5-yl)-alkanes, while N¹,N ²-bis(N ²-nitrocarbamimidoyl)oxalohydrazide gave rise to previously unknown 5,5-bi-(3-nitroamino-1,2,4-triazole) salts. Heating of ethyl [2-(N ²-nitrocarbamimidoyl)hydrazino](oxo)acetate in water in the presence of alkali metal hydroxides or carbonates resulted in intramolecular ring closure with formation of 5(3)-nitroamino-1,2,4-triazole-3(5)-carboxylic acid or ethyl 5(3)-nitroamino-1,2,4-triazole-3(5)-carboxylate, respectively. Depending on the conditions, ethyl [2-(N ²-nitrocarbamimidoyl)hydrazino](oxo)-acetate reacted with nitrogen-containing nucleophiles (ammonia, hydrazine hydrate, aniline, and phenylhydrazine) to give linear of cyclic products.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 12, 2004, pp. 1787–1793.Original Russian Text Copyright © 2004 by Metelkina, Novikova.For communication VII, see [1].     

Ionophoretische Trennung von ReCl62?, ReBr62? und ReO4?

Zusammenfassung Es wurde die ionophoretische Trennung von ReCl₆ ^2–, ReBr₆ ^2– und ReO₄ ^– unter Verwendung verschiedener Papiersorten untersucht. Am geeignetsten erwies sich das Papier 2045 b Gl von Schl. & Sch.

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Summary The ionophoretic separation of ReCl₆ ^2–, ReBr₆ ^2–, and ReO₄ ^– has been examined using different kinds of paper. Best results have been obtained with the paper 2045 b Gl from Schleicher & Schüll.

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Herrn Prof. G. Brauer danke ich für Förderung. Für die Überlassung von Rheniumverbindungen bin ich der Fa. W. C. Heraeus, Hanau, verpflichtet. Die Neutronenaktivierung wurde freundlicherweise von den Herren Dr. Marth und Dr. Köhler von der Reaktorstation in Garching bei München vorgenommen. Das Bundesministerium für Atomkernenergie und Wasserwirtschaft unterstützte die Untersuchung durch eine Sachbeihilfe.     

Structure of the C17H20FN3O 32+ ·2HSO 4? · H2O compound

A new compound of C₁₇H₂₀FN₃O₃²⁺ · 2HSO₄⁻·H₂O [ciprofloxacindi-um bis(hydrosulfate) monohydrate], C₁₇H₁₈FN₃O₃ 1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic acid (CfH, ciprofloxacin) is obtained and its crystal structure is determined. The crystal contains CfH₃²⁺ and HSO₄⁻ ions and crystallization water molecules. Hydrogen (H3), which forms an intramolecular hydrogen bond with oxygen O2 of the carboxyl group, is attached to the carbonyl O1 atom. Hydrogen H4 of the carboxyl group is hydrogen bonded to the crystallization water molecule which links CfH₃²⁺ with two HSO₄⁻ groups by hydrogen bonds. Both H atoms at N3 of the piperazine ring form hydrogen bonds with two oxygen atoms of other HSO₄⁻ anions. Intramolecular hydrogen bonds of two types are present in the CfH₃²⁺ cation. One of them forms a six-membered ring, bonding O1 and O2 atoms, while the other, also enclosing a six-membered ring, links fluorine and carbon C14 atoms. Original Russian Text Copyright ? 2009 by A. D. Vasiliev, N. N. Golovnev, and I. A. Baidina __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 1, pp. 165–168, January–February, 2009.     

Reaction of tetrahydrofuran with H2S in the presence of Na+/γ-Al2O3

Modification of -Al₂O₃ by sodium hydroxide promotes the increase of surface basicity but does not exert a strong effect on catalytic activity in the reaction of thiolane production from tetrahydrofuran and H₂S. Introduction of NaOH to -Al₂O₃ in small concentration increases the number of Lewis acid centers but decreases their strength. The activity of Na/-Al₂O₃ referred to one Lewis acid center drops.