Crystal structure of [Pt3S2(P(CH2OH)3)6](PF6)(OH)·H2O

[Pt₃S₂(P(CH₂OH)₃)₆](PF₆)(OH)·H₂O (1) is obtained by a reaction of [Pt₃S₂(P(CH₂OH)₃)₆]Cl₂ with NH₄PF₆. The crystal structure of 1 was determined by a single crystal X-ray diffraction analysis (space group R{ie638-1}c, a = 12.0042(2) Å, c = 52.6879(11) Å, V = 6575.2(2), Z = 6, C₁₈H₅₇F₆O₂₀P₇Pt₃S₂, d _x = 2.385 g/cm³, T = 150 K, R ₁ = 0.044 for 2123 F ₀ > 4δ(F) until 2θ_max = 63°). The cations contain a {Pt₃(μ₃-S)₂}²⁺ core with nonbonding Pt…Pt distances of 3.1536(6) Å. The Pt atoms are in a square planar environment; the Pt-S and Pt-P bond lengths are 2.3586(16) Å and 2.260(2) Å respectively.     

High-resolution Fourier transform infrared absorption spectroscopy of the ν6 band of c-C3H2

The gas-phase high-resolution absorption spectrum of the ν(6) band of cyclopropenylidene (c-C(3)H(2)) has been observed using a Fourier transform infrared spectrometer for the first time. The molecule has been produced by microwave discharge in an allene (3.3 Pa) and Ar (4.0 Pa) mixture inside a side arm glass tube. The observed spectrum shows a pattern of c-type ro-vibrational transitions in which the Q-branch lines strongly and distinctly stand out in the spectrum. A combined least-squares analysis of the observed 216 ro-vibrational transitions together with 28 millimeter-wave rotational transitions from the previous study has resulted in an accurate determination of the molecular constants in the ν(6) state. The band center is found to be at 776.11622(13) cm(-1) with one standard deviation in parentheses, which is 2.3% lower than the matrix isolation value. The intensity ratio I(3)(ν(3))/I(6)(ν(6)) obtained from the observed ν(3) and ν(6) bands, 1.90(9), is somewhat lower than the ratio estimated from ab initio (2.4-2.6) and DFT (2.8) calculations.     

A photoionization study of the ion-neutral complexes CH3CH +CH 3 · CH2CH3] and CH3CH2CH+CH 3 · CH3 in the gas phase: Formation,H-transfer and C—C bond formation between partners,and channeling of energy into dissociation

Photoionization mass spectrometry was used to investigate the dynamics of ion-neutral complex-mediated dissociations of the n-pentane ion (1). Reinterpretation of previous data demonstrates that a fraction of ions 1 isomerizes to the 2-methylbutane ion (2) through the complex CH₃CH⁺CH ₃ ^· CH₂CH₃ (3), but not through CH₃CH⁺CH₂CH ₃ ^· CH₃ (4). The appearance energy for C₃Hin ₇ ⁺ formation from 1 is 66 kJ mol^?1 below that expected for the formation of n-C₃H ₇ ⁺ and just above that expected for formation of i-C₃H ₇ ⁺ . This demonstrates that the H shift that isomerizes C₃H ₇ ⁺ is synchronized with bond cleavage at the threshold for dissociation to that product. It is suggested that ions that contain n-alkyl chains generally dissociate directly to more stable rearranged carbenium ions. Ethane elimination from 3 is estimated to be about seven times more frequent than is C-C bond formation between the partners in that complex to form 2, which demonstrates a substantial preference in 3 for H abstraction over C-C bond formation. In 1 → CH₃CH⁺CH₂CH₃ + CH₃ by direct cleavage of the C1–C2 bond, the fragments part rapidly enough to prevent any reaction between them. However, 1 → 2 → 4 → C4H ₈ ⁺ + CH₄ occurs in this same energy range. Thus some of the potential energy made available by the isomerization of n-C₄H₉ in 1 is specifically channeled into the coordinate for dissociation. In contrast, analogous formation of 3 by 1 → 3 is predominantly followed by reaction between the electrostatically bound partners.     

Resonance Raman and infrared spectra of [CH3C5H4NiPh2PC3H6PPh2]·B11H14

Resonance Raman and infrared spectra of (C₂H₅)₄NB₁₁H₁₄ are reported. Based on the appearance of several bands on going from (C₂H₅)₄NCl to (C₂H₅)₄NB₁₁H₁₄, a vibrational assignment is proposed for the B₁₁H⁻₁₄. These results are compared with corresponding results for several other amine boranes. Resonance Raman and infrared spectra of [CH₃C₅H₄NiPh₂PC₃H₆PPh₂]·B₁₁H₁₄ were obtained. An assignment of frequencies to the fundamental modes of vibration has been made for this compound. The Ni-P vibration frequencies are located at about 202 and 177 cm⁻¹. The Ni-MeCp vibration has also been assigned at about 359 and 230 cm⁻¹.     

Study of the solubility of components in the system Mg(ClO3)2-2NH2C2H4OH · H3C6H5O7-H2O

The solubility of components in the system Mg(ClO₃)₂-2NH₂C₂H₄OH · H₃C₆H₅O₇-H₂O was studied from the complete freezing temperature ?59.4°C to 20.0°C. A polythermal solubility diagram was constructed, in which the crystallization fields were determined for ice, Mg(ClO₃)₂ · 16H₂O, Mg(ClO₃)₂ · 12H₂O, Mg(ClO₃)₂ · 6H₂O, 2NH₂C₂H₄OH · H₃C₆H₅O₇ · H₂O, 2NH₂C₂H₄OH · H₃C₆H₅O₇, and two new compounds, [(HOC(CH₂COOH)₂COO)₂Mg · 2H₂O] and [HOC(CH₂COO)₂MgCOOH · 2H₂O], which were identified by chemical and physicochemical analysis methods.     

Calculated energy barriers for the identity SN2 reaction H2O + CH3OH2+ → +H2OCH3 + OH2 in the gas phase,in water clusters,and in aqueous solution

The bimolecular nucleophilic substitution reaction H₂O + CH₃OH₂⁺ → ⁺H₂OCH₃ + OH₂ has been studied using various quantum chemical methods. Accurate barriers for the reaction in the gas phase are presented and discussed. The effect of microsolvation by water molecules in small clusters has been investigated. Extrapolation of the barrier obtained in the small clusters, using a linear relationship between the activation energy and the proton affinity of water clusters, gives a barrier for the reaction in aqueous solution which is in good agreement with that obtained in separate model calculations (polarized continuum model of a super molecule with the first solvation shell included).     

Application of deuterium–hydrogen exchange to study the secondary structure of oligonucleotide ions in a gas phase

At present, the secondary structure of oligonucleotide ions in a gas phase is almost not understood. One of the main points is the retention of a hairpin secondary structure during ionization. In this work, we used a deuterium–hydrogen exchange reaction in a gas phase at atmospheric pressure for studying the conformational dynamics of oligonucleotide ions formed as a result of electrospray ionization. The exchange reactions of two oligonucleotides, which consisted of the identical sets of nucleotides but differed in their sequence, have been studied. One of these oligonucleotides formed a hairpin secondary structure, but the other did not. It has been found that both of the oligonucleotides demonstrate similar reaction dynamics of deuterium/hydrogen exchange in the gas phase; thereby indicating that the secondary structure has been completely destroyed during ionization.     

Argon predissociation infrared spectroscopy of the hydroxide–water complex (OH−·H2O)

We report the first vibrational spectrum of the degenerate proton transfer system OH⁻·H₂O. The complex is cooled by attachment of argon atoms and the spectrum is observed by argon predissociation spectroscopy in the OH stretching region. A strong, sharp transition is observed just below the region usually associated with the free OH stretch, while broader bands appear lower in energy and are weaker than the dominant free OH peak. The latter are assigned with the aid of ab initio calculations to the first overtone of the coupled intramolecular bend and strongly red-shifted H-bonded OH stretching modes.     

Crystal structure of a new π-complex of AgClO4 with 1-allyl-5-(2-pyridyl)-1H-tetrazole of the composition [Ag2(C9H6N5)2](ClO4)2

By the AgClO₄ interaction with 1-allyl-5-(2-Pyridyl)-1H-tetrazolee (1aPyt) in a methanol solution, an [Ag₂(1aPyt)₂](ClO₄)₂ π-complex is obtained, which is studied using single crystal X-ray diffraction.     

Infrared and infrared emission spectroscopy of nesquehonite Mg(OH)(HCO3)·2H2O-implications for the formula of nesquehonite

The mineral nesquehonite Mg(OH)(HCO(3))·2H(2)O has been analysed by a combination of infrared (IR) and infrared emission spectroscopy (IES). Both techniques show OH vibrations, both stretching and deformation modes. IES proves the OH units are stable up to 450°C. The strong IR band at 934 cm(-1) is evidence for MgOH deformation modes supporting the concept of HCO(3)(-) units in the molecular structure. Infrared bands at 1027, 1052 and 1098 cm(-1) are attributed to the symmetric stretching modes of HCO(3)(-) and CO(3)(2-) units. Infrared bands at 1419, 1439, 1511, and 1528 cm(-1) are assigned to the antisymmetric stretching modes of CO(3)(2-) and HCO(3)(-) units. IES supported by thermoanalytical results defines the thermal stability of nesquehonite. IES defines the changes in the molecular structure of nesquehonite with temperature. The results of IR and IES supports the concept that the formula of nesquehonite is better defined as Mg(OH)(HCO(3))·2H(2)O.     

Theoretical study for the CH3C(O)(CH2)2OH + OH reaction

The mechanisms and the kinetics of the OH radical reaction with 4-hydroxy-2-butanone (4H2B) are investigated theoretically. Five hydrogen-abstraction channels are identified for the title reaction. The first potential energy profile of the title reaction is presented. The rate constants for each reaction channel are evaluated using transition state theory method in the temperature range of 200–1,000 K. Branching ratio of the title reaction is calculated and plotted. It is shown that the “in-plane hydrogen abstraction” from the methoxy end is the dominant channel, and the other hydrogen-abstraction channels play the minor role. The comparison between theoretical and experimental results is discussed. The three-parameter Arrhenius expression for the rate constants is also provided.     

Synthesis and structure of [Cr3O(CH3COO)6(H2O)3][UO2 (CH3COO)3] · 3H2O

Crystals of [Cr₃O(CH₃COO)₆(H₂O)₃][UO₂(CH₃COO)₃]·3H₂O (I) were synthesized for the first time and studied by X-ray crystallography. The crystals of I are orthorhombic: a = 8.3561(3) ?, b = 16.8421(5) ?, c = 25.7448(9) ?, V = 3623.2(2) ?³, space group P2₁2₁2₁, Z = 4, R = 0.0409. The structure is composed of trinuclear [Cr₃O(CH₃COO)₆(H₂O)₃]⁺ complexes and mononuclear [UO₂(CH₃COO)₃]^? complexes classified with crystal-chemical groups A₃M³B ₆ ² M ₃ ¹ (A = Cr³⁺, M³ = O^2?, B² = CH₃COO^?, M¹ = H₂O) and AB ₃ ⁰¹ (A = UO ₂ ²⁺ , B⁰¹ = CH₃COO^?), respectively. The complexes are bound to each other by electrostatic interactions and hydrogen bonds involving outer-sphere water molecules. The results of IR spectroscopic study of I are in good agreement with the structural data for the crystal.     

Synthesis and crystal structure of ((NH3CH2CH2)3N)2P6O18·6H2O

Chemical preparation and crystal structure are given for a new cyclohexaphosphate: ((NH₃CH₂CH₂)₃N)₂P₆O₁₈·6H₂O. This compound is triclinic P¯1 with the following unit-cell parameters: a = 10,281(1)Å, b = 11.083(1)Å, c = 9.307(2)Å, α = 103.83(1) °, β = 108.56(1) °, γ = 68.11(1) °, Z = 1, V = 924.2(3)ų and pcal. = 1.582 g.cm⁻³. Its atomic arrangements contain layers built by P₆O₁₈ ring anions spreading in the plans (001). Between these layers are located the organic groups which form hydrogen bonds with oxygen atoms of P₆O₁₈ rings and water molecules. Crystal structure has been solved and refined to R = 0.028 using 4540 independent reflections. The thermal behavior has been investigated and interpreted by comparison with IR absorption spectroscopy and X-ray diffraction experiments.     

Crystal structure,DSC and Raman studies in CH3C6H4NH(CH3)2·SbCl4

The salt para methyl phenyl dimethyl ammonium tetrachloroantimonate (III) crystallizes in the monoclinic system with space group Cc. The unit cell dimensions are: a=13.780(1) Å, b=14.943(2) Å, c=8.192(1) Å, β=113.39(1)°, with Z=4. The structure consists of ammonium cations and polynuclear anions in which distorted SbCl₅ square pyramids sharing a common Cl atom are held together in infinite chains parallel to the c axis. These chains are themselves interconnected by means of the NH⋯Cl hydrogen bonds. Differential scanning calorimetry study was carried out. The Raman of polycrystalline samples have been recorded at different temperatures between 77 and 300 K. A low-temperature phase transition at 230 K of order-disorder type was found.     

Hydrothermal Synthesis,Crystal Structure and Thermal Stability Properties of the Complex [Cd2(phen)2(C14HuO3)4(CH3CH2OH)]·(CH3OH)·(H2O)

T A dinuclear cadmium complex[Cd2(phen)2(C14H11O3)4(CH3CH2OH)]·(CH3OH)·(H2O)has been synthesized with benzilic acid and 1,10-phenanthroline by hydrothermal method.The crystal structure was determined bv X-ray diffraction with crystal parameters as follows:triclinic system with space group P-1,α=1.21298(10),b=1.32586(1 1),c=2.4815(2)nm,α=76.2630(10),β=81.4500(10),γ=69.1700(10)°V=3.6143(5)nm3,Dc=1.438g/cm3,Z=1,F(000)=1600,the final GOOF=0.937,R=0.0521 and wR=0.1328.In the title complex,the dinuclear structure is defined by carboxyl oxygen atoms adopting a monodentate bridged coordination mode.The coordination environment of Cd(Ⅱ)ion is CdO4N2,giving a distorted octahedral coordination geometry.TG analysis shows that the title complex is stable under 140℃.     

Ligand condensation of P(CH2OH)3: Synthesis and structure of [Ni3S2{(CH2OH)2PCH2OP(CH2OH)2}3][Mo6Cl14] · 0.8H2O

Reaction of NiCl₂ · 6H₂O and P(CH₂OH)₃ (THP) with H₂S and (H₇O₃)₂[Mo₆Cl₁₄] · 3H₂O in ethanol produces new trinuclear nickel sulphide complex [Ni₃(μ₃-S)₂{(HOCH₂)₂PCH₂OP(CH₂OH)₂}₃][Mo₆Cl₁₄] · 0.8H₂O (I) with new bidentate phosphine-phosphinite ligand resulted from THP condensation. It was characterized by X-ray structure analysis.     

Crystal and molecular structure and ion selective and complexing properties of 1,5-bis[2-(dioxyphosphoryl-4-methoxy)phenoxy]-3-oxapentane dihydrate [(OH)2(O)P(C6H3OCH3)(OCH2CH2)2 O(C6H4OCH3)P(O)(OH)2] · 2H2O

Ion selective and complexing properties of 1,5-bis[2-(dioxyphosphoryl-4-methoxy)phenoxy]-3-oxapentane dihydrate H₄M² · 2H₂O (I) were described. X-ray diffraction analysis for compound I was performed. The crystals are orthorhombic, a = 7.9818(16) ?, b = 30.553(6) ?, c = 9.0559(17) ?, V = 2208.5(8) ?³, Z = 4, space group Pnma, R = 0.0500 over 1372 reflections with I > 2??(I). In I, the H₄M² molecules are combined by hydrogen bonds (HB) with two crystallographically independent H₂O(7) and H₂O(8) molecules to give neutral H₄M² · 2H₂O aggregates. The HB between the phosphoryl and hydroxyl oxygen atoms of the aggregates and the donor O(7)-H??O(8) HB give rise to a layered structure. Conclusions about the Cu(H₂M²) compound structure were drawn based on the X-ray diffraction, DTA, and vibrational spectroscopy data.     

[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