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}.     

Unusual ion UO4? formed upon collision induced dissociation of [UO2(NO3)3]?, [UO2(ClO4)3]?, [UO2(CH3COO)3]? ions

The following ions [UO₂(NO₃)₃]⁻, [UO₂(ClO₄)₃]⁻, [UO₂(CH₃COO)₃]⁻ were generated from respective salts (UO₂(NO₃)₂, UO₂(ClO₄)₃, UO₂(CH3COO)2) by laser desorption/ionization (LDI). Collision induced dissociation of the ions has led, among others, to the formation of UO₄ ⁻ ion (m/z 302). The undertaken quantum mechanical calculations showed this ion is most likely to possess square planar geometry as suggested by MP2 results or strongly deformed geometry in between tetrahedral and square planar as indicated by DFT results. Interestingly, geometrical parameters and analysis of electron density suggest it is an U^VI compound, in which oxygen atoms bear unpaired electron and negative charge.     

Regioselectivity of the addition of ?CCl3 and ?But radicals to (η2-C70)[Os(CO)(PPh3)2(CNBut)]n (n = 1, 2): an ESR study

The addition of ^•CCl₃ and ^•Bu^t radicals to (η²-C₇₀)Os(CO)(PPh₃)₂(CNBu^t) (1) and (η²-C₇₀)[Os(CO)(PPh₃)₂(CNBu^t)]₂ (3) was studied by ESR spectroscopy. The metal fragment in complex 1 does not influence the regioselectivity of the addition of the radicals to it. The stability of the spin adducts formed upon addition of free radicals to complexes 1 and 3 is mainly governed by delocalization of the unpaired electron over three hexagonal rings.     

Collisional Line Assignments and Hyperfine Structure Interpretation in Cs2 23△1g State

Accurately known energy level structure of the Cs₂ A¹∑⁺_u -b³Πu complex of states from a recent global de-perturbation of these states has enabled additional assignments of 140 per-turbation facilitated infrared-infrared double resonance (PFIIDR) transitions to the 2³△_1g state from collisionally populated intermediate A¹∑⁺_u levels. Together with the 221 previ-ously observed 2³△_1g←A¹∑⁺_u← X¹∑⁺_g double resonance lines [J. Chem. Phys. 128, 204313 (2008)], molecular constants and the Rydberg-Klein-Rees potential energy curve of the 2³△_1g state have been recalculated (excluding 54 perturbed levels). The centrifugal distortion con-stant has been determined and agrees well with the value calculated based on standard empirical formulas. The hyperfine structure of the 2³△_1g state, which has not resolved in our sub-Doppler excitation spectra of the 2³△_1g state, has been interpreted with a preliminary simulation.     

无水AlCl3催化合成N,N-二氰乙基甲基苯胺的研究

报道了AlCl₃和AlCl₃-ZnCl₂组成的催化体系对邻、间、对甲基苯胺三种异构体与丙烯腈发生加成反应合成相应的N,N-二氰乙基甲基苯胺. 其结果表明: AlCl₃对该类反应具有很高的催化效率, AlCl₃-ZnCl₂组成的催化体系比AlCl₃的催化效率更高, 其中间位、对位产物收率达92%～94%.     

Synthesis and structure of the platinum complexes [Bu4N]+[PtBr5(DMSO)]?, [Ph4P]+[PtBr5(DMSO)]?, and [Ph3(n-Am)P]+[PtBr5(DMSO)]?

The complexes [Bu₄N]₂⁺[PtBr₆]²⁻ (I), [Ph₄P]₂⁺[PtBr₆]²⁻ (II), and [Ph₃(n-Am)P]₂⁺ (III) are synthesized by the reactions of tetrabutylammonium bromide, tetraphenylphosphonium bromide, and triphenyl(n-amyl)-tetraphenylphosphonium bromide, respectively, with potassium hexabromoplatinate (mole ratio 2: 1). After recrystallization from dimethyl sulfoxide, complexes I, II, and III transform into [Bu₄N]⁺[PtBr₅(DMSO)]⁻ (IV), [Ph₄P]⁺[PtBr₅(DMSO)]⁻ (V), and [Ph₃(n-Am)P]⁺[PtBr₅(DMSO)]⁻ (VI). According to the X-ray diffraction data, the cations of complexes IV–VI have a slightly distorted tetrahedral structure. The N-C and P-C bond lengths are 1.492(7)–1.533(6) and 1.782(10)–1.805(10) ?, respectively. The platinum atoms in the mononuclear anions are hexacoordinated. The dimethyl sulfoxide ligands are coordinated with the Pt atom through the sulfur atom (Pt-S 2.3280(18)–2.3389(11) ?). The Pt-Br bond lengths are 2.4330(6)–2.4724(6) ?.     

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.     

Li＋在基于N,N-二甲基甲酰胺混合溶剂中的溶剂化

利用红外和拉曼光谱技术研究了Li^＋在不同浓度、不同溶剂组成的LiBF₄/N,N-二甲基甲酰胺-乙腈、LiBF₄/N,N-二甲基甲酰胺-四氢呋喃电解质溶液中的优先溶剂化现象. 红外和拉曼光谱的分析表明, Li^＋主要与DMF分子相互作用, 导致该分子的C＝O伸缩振动谱带、N—C＝O形变谱带、CH₃摇摆谱带等发生了分裂. Li^＋与其它溶剂分子的相互作用较弱, 谱带的分裂现象并不明显. Li^＋溶剂化数的计算显示, Li^＋第一溶剂化层内DMF分子的数目一般大于2, 这说明 Li^＋在混合溶剂体系内优先与DMF分子相互作用. 量子化学计算支持了这一结论.     

12,52-二羟基-15,55-二甲基-14,16,34,36,54,56,74,76-八硝基-2,4,6,8-四氧桥连-1,3,5,7（1,3）-杯[4]芳烃的合成

以1,5-二氟-2,4-二硝基苯和3,4,5-三甲氧基甲苯为起始原料,经环化、甲基化、硝化和去甲基化反应,合成了一种新型杯芳烃衍生物,其结构经¹H NMR,¹³C NMR,¹⁵N NMR和元素分析表征。      

13C NMR spectra of coordinated propargyl cations [Cp2Mo2(CO)4(μ-η2,η3-(HC≡CCR1R2)]+ BF4/?

A strong deshielding effect is observed for the carbon signal of carbocation center (C⁺) in the ¹³C NMR spectra of coordinated propargyl cations [Cp₂Mo₂(CO)₄(μ-η²,η³-(HC≡CCR¹R²)]⁺ BF₄⁻ (R¹ = R² = H) 1, (R¹ = Me, R² = H) 2, and (R¹ = R² = Me) 3 when hydrogen is replaced by methyl; the effect increases with the Mo-C⁺ distance (75.37, 98.3, and 148.68 ppm for compounds 1, 2, and 3, respectively). This indicates that the back-donation of electron density from the metal onto the ligand makes a substantial contribution to the stabilization of these cations. Original Russian Text ? I.V. Barinov, V.A. Chertkov, 2009, published in Vestnik Moskovskogo Universiteta. Khimiya, 2009, No. 1, pp. 29–34.     

Stable radical adducts of diisopropylphosphoryl radicals with fullerene complexes (η2-C60)Os(CO)(PPh3)2(CNBut) and (η2-C70)Os(CO)(PPh3)2(CNBut)

It was determined by ESR spectroscopy that the UV irradiation of toluene solutions containing Hg[P(O)(OPrⁱ)₂ and the complex (²-C₆₀)Os(CO)(PPh₃)₂(CNBu^t) produces six stable regioisomeric adducts of phosphoryl radicals with complexes, which are not demetallated under UV irradiation and do not dimerize in the absence of UV irradiation. This is caused by the addition of the phosphoryl radicals to the carbon atoms of fullerene localized near the metal-containing moiety. The addition of the phosphoryl radicals to (²-C₇₀)Os(CO)(PPh₃)₂(CNBu^t) gives rise to the formation of nine stable regioisomeric radical adducts. A comparison of the composition of regioisomers of the radical adducts of C₇₀ with the phosphoryl radicals, which were formed directly from C₇₀ and from the radical adducts of ²-C₇₀)Os(CO)(PPh₃)₂(CNBu^t) by the demetallation of the latter, revealed an orienting effect of the osmium-containing moiety on the addition of the phosphoryl radicals to the fullerene complex.Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1968–1972, September, 2004.     

Coherent Vibrational Dynamics of [Au25(SR)18]- Nanoclusters?

Coherent vibrational dynamics can be observed in atomically precise gold nanoclusters using femtosecond time-resolved pump-probe spectroscopy. It can not only reveal the coupling between electrons and vibrations, but also reflect the mechanical and electronic properties of metal nanoclusters, which holds potential applications in biological sensing and mass detection. Here, we investigated the coherent vibrational dynamics of [Au₂₅(SR)₁₈]^- nanoclusters by ultrafast spectroscopy and revealed the origins of these coherent vibrations by analyzing their frequency, phase and probe wavelength distributions. Strong coherent oscillations with frequency of 40 cm^-1 and 80 cm^-1 can be reproduced in the excited state dynamics of [Au₂₅(SR)₁₈]^-, which should originate from acoustic vibrations of the Au₁₃ metal core. Phase analysis on the oscillations indicates that the 80 cm^-1 mode should arise from the frequency modulation of the electronic states while the 40 cm^-1 mode should originate from the amplitude modulation of the dynamic spectrum. Moreover, it is found that the vibration frequencies of [Au₂₅(SR)₁₈]^- obtained in pump-probe measurements are independent of the surface ligands so that they are intrinsic properties of the metal core. These results are of great value to understand the electron-vibration coupling of metal nanoclusters.     

D-苯丙氨酸与Cu＋(1S0, 3d10)气相反应理论研究

用量子化学密度泛函(DFT)方法研究D-苯丙氨酸与一价基态金属阳离子Cu^＋在气相中反应的机理. 在B3LYP/6-31G*水平上, 优化了反应包含的4个反应通道的反应物、中间体、过渡态和产物的几何构型, 并采用B3LYP/DZVP, B3LYP/[6-311＋G**(C,H,O)＋Lanl2dz(Cu)], B3LYP/6-311＋G**, MP2/6-311＋G** 等方法对各驻点进行了单点能计算. 通过对计算结果的分析, 获得了其单重态反应势能面的一般轮廓、各驻点几何构型优化参数, 明确了其反应机理.     

Photoinduced Decomposition of Formaldehyde on Rutile TiO2(100)-(1×1)?

We have investigated the photoinduced decomposition of formaldehyde (CH₂O) on a rutile TiO₂(100)-(1×1) surface at 355 nm using temperature-programmed desorption. Products, formate (HCOO^-), methyl radical (CH₃·), ethylene (C₂H₄), and methanol (CH₃OH) have been detected. The initial step in the decomposition of CH₂O on the rutile TiO₂(100)-(1×1) surface is the formation of a dioxymethylene intermediate in which the carbonyl O atom of CH₂O is bound to a Ti atom at the five-fold-coordinated Ti⁴⁺ (Ti_5c) site and its carbonyl C atom bound to a nearby bridge-bonded oxygen (O_b) atom, respectively. During 355 nm irradiation, the dioxymethylene intermediate can transfer an H atom to the O_b atom, thus forming HCOO^- directly, which is considered as the main reaction channel. In addition, the dioxymethylene intermediate can also transfer methylene to the O_b row and break the C-O bond, thus leaving the original carbonyl O atom at the Ti_5c site. After the transfer of methylene, several pathways to products are available. Thus, we have found that O_b atoms are intimately involved in the photoinduced decomposition of CH₂O on the rutile TiO₂(100)-(1×1) surface.     

Crystal structure of K2[Mo3(PdPPh3)S4(C2O4)3(H2O)3]·0.5H2O

By the reaction of [Mo₃S₄(C₂O₄)₃(H₂O)₃]²⁻ with PdCl₂ and NH₄H₂PO₂ as a reducing agent, followed by the addition of PPh₃, a new oxalate cuboidal cluster complex [Mo₃(PdPPh₃)S₄(C₂O₄)₃(H₂O)₃]²⁻ is obtained. It was isolated and structurally characterized as K₂[Mo₃(PdPPh₃)S₄(C₂O₄)₃(H₂O)₃]·0.5H₂O. Original Russian Text Copyright ? 2008 by A. L. Gushchin, M. N. Sokolov, D. Yu. Naumov, and V. P. Fedin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 4, pp. 775–778, May–June, 2008.     

Photodissociation Dynamics of Carbon Dioxide Cation via the Vibrationally Mediated Ã2Πu,1/2 State: A Time-Sliced Velocity-Mapped Ion Imaging Study

We report on the photodissociation dynamics of CO₂⁺ via its òΠ_u,1/2 state using the scheme of [1+1] photon excitation that is intermediated by the mode-selected òΠ_u,1/2( u1,u2,0) vibronic states. Photodissociation fragment exciation spectrum and images of photofragment CO⁺ have been measured to obtain reaction dynamics parameters such as the available energy and the average translational energy. Combining with the potential energy functions of CO₂⁺, the dissociation mechanism of CO₂⁺ is discussed. The conformational variation of CO₂⁺ from linear to bent on the photodissociation dynamics of CO₂⁺ is verified.     

Structural Dynamics of Isomorphic Substitution in N,N′-Diallylbenzimidazolium Copper Halide π-Complexes [C7H5N2(C3H5)2]+[Cu2Cl3?xBrx]? (x=0, 1.60, 2.33, 3)

Two new -complexes of copper(I) halides with the 1,3-diallylbenzimidazolium cation, [C₇H₅N₂(C₃H₅)₂]⁺[Cu₂Cl_1.40Br_1.60]^– and [C₇H₅N₂(C₃H₅)₂]⁺[Cu₂Br₃]^–, have been synthesized and structurally defined (space group P2 ₁/c for both; a = 22.094(6), b = 9.272(8), c = 9.22(1) , = 118.26(4)° and a = 22.267(5), b = 9.311(3), c = 9.263(2) , = 117.51(2)°). The mutual effects of chlorine–bromine substitution and the efficiency of -interactions are discussed based on XRD data for these two compounds and for the compounds [C₇H₅N₂(C₃H₅)₂]⁺[Cu₂Cl₃]^– and [C₇H₅N₂(C₃H₅)₂]⁺[Cu₂Cl_0.67Br_2.33]^– studied previously.     

Molecular and crystal structures of [FeCl(HMPA)3(H2O)2]2+(FeCl4) 2? · 3HMPA

IR and single-crystal X-ray diffraction study are carried out for compound, C₃₆H₁₁₂Cl₉Fe₃N₁₈O₈P₆(I). It crystallizes in the orthorhombic space group P2₁2₁2₁ with a = 14.2992(3), b = 21.4351(4), c = 25.5407(5) ?, V = 7828.3(3) ?³, ρ_calcd = 1.553 g/cm³, Z = 4. The FeCl fragment is coordinated with chlorine atom of two water molecules and three HMPA molecules to form a cation, with a distorted octahedral coordinate geometry. In the crystal I, the cation is linked with HMPA by the O-H…O hydrogen bond. The chiral crystal is formed through self-assembly even from achiral molecules.