Atmospheric chemistry of acetone: Kinetic study of the CH3C(O)CH2O2+NO/NO2 reactions and decomposition of CH3C(O)CH2O2NO2

Pulse radiolysis was used to study the kinetics of the reactions of CH₃C(O)CH₂O₂ radicals with NO and NO₂ at 295 K. By monitoring the rate of formation and decay of NO₂ using its absorption at 400 and 450 nm the rate constants k(CH₃C(O)CH₂O₂+NO)=(8±2)×10⁻¹² and k(CH₃C(O)CH₂O₂+NO₂)=(6.4±0.6)×10⁻¹² cm³ molecule⁻¹ s⁻¹ were determined. Long path length Fourier transform infrared spectrometers were used to investigate the IR spectrum and thermal stability of the peroxynitrate, CH₃C(O)CH₂O₂NO₂. A value of k₋₆≈3 s⁻¹ was determined for the rate of thermal decomposition of CH₃C(O)CH₂O₂NO₂ in 700 torr total pressure of O₂ diluent at 295 K. When combined with lower temperature studies (250–275 K) a decomposition rate of k₋₆=1.9×10¹⁶ exp (−10830/T) s⁻¹ is determined. Density functional theory was used to calculate the IR spectrum of CH₃C(O)CH₂O₂NO₂. Finally, the rate constants for reactions of the CH₃C(O)CH₂ radical with NO and NO₂ were determined to be k(CH₃C(O)CH₂+NO)=(2.6±0.3)×10⁻¹¹ and k(CH₃C(O)CH₂+NO₂)=(1.6±0.4)×10⁻¹¹ cm³ molecule⁻¹ s⁻¹. The results are discussed in the context of the atmospheric chemistry of acetone and the long range atmospheric transport of NO_x. © John Wiley & Sons, Inc. Int J Chem Kinet: 30: 475–489, 1998     

UV absorption spectra of HO2, CH3O2, C2H5O2, and CH3C(O)CH2O2 radicals and mechanism of the reactions of F and Cl atoms with CH3C(O)CH3

Pulse radiolysis techniques were used to measure the gas phase UV absorption spectra of the title peroxy radicals over the range 215–340 nm. By scaling to σ(CH₃O₂)_{240 nm} = (4.24 ± 0.27) × 10^?18, the following absorption cross sections were determined: σ(HO₂)_{240 nm} = 1.29 ± 0.16, σ(C₂H₅O₂)_{240 nm} = 4.71 ± 0.45, σ(CH₃C(O)CH₂O₂)_{240 nm} = 2.03 ± 0.22, σ(CH₃C(O)CH₂O₂)_{230 nm} = 2.94 ± 0.29, and σ(CH₃C(O)CH₂O₂)_{310 nm} = 1.31 ± 0.15 (base e, units of 10^?18 cm² molecule^?1). To support the UV measurements, FTIR‐smog chamber techniques were employed to investigate the reaction of F and Cl atoms with acetone. The F atom reaction proceeds via two channels: the major channel (92% ± 3%) gives CH₃C(O)CH₂ radicals and HF, while the minor channel (8% ± 1%) gives CH₃ radicals and CH₃C(O)F. The majority (>97%) of the Cl atom reaction proceeds via H atom abstraction to give CH₃C(O)CH₂ radicals. The results are discussed with respect to the literature data concerning the UV absorption spectra of CH₃C(O)CH₂O₂ and other peroxy radicals. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 283–291, 2002     

Stereochemistry of Octahedral cis-Tetrafluoro Titanium Complexes with Ph2P(O)CH(Me)CH2C(O)Et Enantiomers in CH2Cl2

Russian Journal of Coordination Chemistry - The complex formation of TiF4 with the phosphorylated ketone Ph2P(O)CH(Me)CH2C(O)Et (L), containing an asymmetric carbon atom in the aliphatic...     

Photolysis of CH3C(O)CH3 (248 nm, 266 nm), CH3C(O)C2H5 (248 nm) and CH3C(O)Br (248 nm): pressure dependent quantum yields of CH3 formation

The formation of CH(3) in the 248 or 266 nm photolysis of acetone (CH(3)C(O)CH(3)), 2-butanone (methylethylketone, MEK, CH(3)C(O)C(2)H(5)) and acetyl bromide (CH(3)C(O)Br) was examined using the pulsed photolytic generation of the radical and its detection by transient absorption spectroscopy at 216.4 nm. Experiments were carried out at room temperature (298 +/- 3 K) and at pressures between approximately 5 and 1500 Torr N(2). Quantum yields for CH(3) formation were derived relative to CH(3)I photolysis at the same wavelength in back-to-back experiments. For acetone at 248 nm, the yield of CH(3) was greater than unity at low pressures (1.42 +/- 0.15 extrapolated to zero pressure) confirming that a substantial fraction of the CH(3)CO co-product can dissociate to CH(3) + CO under these conditions. At pressures close to atmospheric the quantum yield approached unity, indicative of almost complete collisional relaxation of the CH(3)CO radical. Measurements of increasing CH(3)CO yield with pressure confirmed this. Contrasting results were obtained at 266 nm, where the yields of CH(3) (and CH(3)CO) were close to unity (0.93 +/- 0.1) and independent of pressure, strongly suggesting that nascent CH(3)CO is insufficiently activated to decompose on the time scales of these experiments at 298 K. In the 248 nm photolysis of CH(3)C(O)Br, CH(3) was observed with a pressure independent quantum yield of 0.92 +/- 0.1 and CH(3)CO remained below the detection limit, suggesting that CH(3)CO generated from CH(3)COBr photolysis at 248 nm is too highly activated to be quenched by collision. Similar to CH(3)C(O)CH(3), the photolysis of CH(3)C(O)C(2)H(5) at 248 nm revealed pressure dependent yields of CH(3), decreasing from 0.45 at zero pressure to 0.19 at pressures greater than 1000 Torr with a concomitant increase in the CH(3)CO yield. As part of this study, the absorption cross section of CH(3) at 216.4 nm (instrumental resolution of 0.5 nm) was measured to be (4.27 +/- 0.2) x 10(-17) cm(2) molecule(-1) and that of C(2)H(5) at 222 nm was (2.5 +/- 0.6) x 10(-18) cm(2) molecule(-1). An absorption spectrum of gas-phase CH(3)C(O)Br (210-305 nm) is also reported for the first time.     

Normal mode analysis of zinc caprate (Zn)1/2O2C(CH2)8CH3

A normal mode analysis was made for zinc caprate with using the Wilson GF matrix method. Based on the analysis and infrared spectra, structural transition behavior of zinc caprate was discussed.     

Solid state and solution study of some phosphoramidate derivatives containing the P(O)NHC(O) bifunctional group: Crystal structures of CCl2HC(O)NHP(O)(NCH3(CH2C6H5))2, p-ClC6H4C(O)NHP(O)(NCH3(CH2C6H5))2, CCl2HC(O)NHP(O)(N(CH2C6H5)2)2 and p-BrC6H4C(O)NHP(O)(N(CH2C6H5)2)2

Synthetic methods for several novel phosphoramidate compounds containing the P(O)NHC(O) bifunctional group were developed. These compounds with the general formula R₁C(O)NHP(O)(N(R₂)(CH₂C₆H₅))₂, where R₁ = CCl₂H, p-ClC₆H₄, p-BrC₆H₄, o-FC₆H₄ and R₂ = hydrogen, methyl, benzyl, were characterized by several spectroscopic methods and analytical techniques. The effects of phosphorus substituents on the rotation rate around the P–N_amine bond were also investigated. ¹H NMR study of the synthesized compounds demonstrated that the presence of bulky groups attached to the phosphorus center and electron withdrawing groups in the amide moiety lead to large chemical-shift non-equivalence (Δδ_H) of diastereotopic methylene protons. The crystal structures of CCl₂HC(O)NHP(O)(NCH₃(CH₂C₆H₅))₂, p-ClC₆H₄C(O)NHP(O)(NCH₃(CH₂C₆H₅))₂, CCl₂HC(O)NHP(O)(N(CH₂C₆H₅)₂)₂ and p-BrC₆H₄C(O)NHP(O)(N(CH₂C₆H₅)₂)₂ were determined by X-ray crystallography using single crystals. The coordination around the phosphorus center in these compounds is best described as distorted tetrahedral and the P(O) and C(O) groups are anti with respect to each other. In the compound Br-C₆H₄C(O)NHP(O)(N(CH₂C₆H₅)₂)₂ (with two independent molecules in the unit cell), two conformers are connected to each other via two different N–H?O hydrogen bonds forming a non-centrosymmetric dimer. In the crystalline lattice of other compounds, the molecules form centrosymmetric dimers via pairs of same N–H?O hydrogen bonds. The structure of CCl₂HC(O)NHP(O)(N(CH₂C₆H₅)₂)₂ reveals an unusual intramolecular interaction between the oxygen of CO group and amine nitrogen.     

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.     

Investigation of the radical product channel of the CH(3)C(O)CH(2)O(2) + HO(2) reaction in the gas phase

The reaction of CH(3)C(O)CH(2)O(2) with HO(2) has been studied at 296 K and 700 Torr using long path FTIR spectroscopy, during photolysis of Cl(2)/acetone/methanol/air mixtures. The branching ratio for the reaction channel forming CH(3)C(O)CH(2)O, OH and O(2) () was investigated in experiments in which OH radicals were scavenged by addition of benzene to the system, with subsequent formation of phenol used as the primary diagnostic for OH radical formation. The observed prompt formation of phenol under conditions when CH(3)C(O)CH(2)O(2) reacts mainly with HO(2) indicates that this reaction proceeds partially by channel , which forms OH both directly and indirectly, by virtue of secondary generation of CH(3)C(O)O(2) (from CH(3)C(O)CH(2)O) and its reaction with HO(2) (). The secondary generation of OH radicals was confirmed by the observed formation of CH(3)C(O)OOH, a well-established product of the CH(3)C(O)O(2) + HO(2) reaction (via channel ). A number of delayed sources of OH also contribute to the observed phenol formation, such that full characterisation of the system required simulations using a detailed chemical mechanism. The dependence of the phenol and CH(3)C(O)OOH yields on the initial peroxy radical precursor reagent concentration ratio, [methanol](0)/[acetone](0), were well described by the mechanism, consistent with a small but significant fraction of the reaction of CH(3)C(O)CH(2)O(2) with HO(2) proceeding via channel . This allowed a branching ratio of k(3b)/k(3) = 0.15 +/- 0.08 to be determined. The results therefore provide strong indirect evidence for the participation of the radical-forming channel of the title reaction.     

Molecular and crystal structures of Ph2P(O)(CH2)2OH and Ph2P(O)CH2(C6H6)OH

The molecular and crystal structures of Ph₂P(O)(CH₂)₂OH and Ph₂P(O)CH₂(C₆H₆)OH have been determined. For the first compound the space group is with unit cell dimensions a=10.505(2), b=13.720(2), c=14.782(3) Å; =72.58(6), =76.95(6), =72.49(6)° for Z=6 (Syntex diffractometer,MoK radiation, 2996 reflections, R=3.2%). The second compound crystallizes in the space group P2₁2₁2₁ with unit cell dimensions a=9.371(3), b=9.014(3), c=18.461(5) Å for Z=4 (DAR-UM diffractometer,CuK radiation, 909 reflections, R=4.9%). In Ph₂P(O)(CH₂)₂OH, three independent molecules differing in structural details are linked by the P=O...O hydrogen bonds (O...H is 1.84, 1.80, and 1.86 Å), to form a chain. In Ph₂P(O)CH₂(C₆H₆)OH, the molecules are joined by pairs of the P=O...H–O bonds (O...H is 1.81 Å) to form 16-membered dimeric associates.Institute of Chemical Physics, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 3, pp. 109–118, May–June 1993.Translated by T. Yudanova     

Synthesis of (CH3C(CH2PPh2)3)CoL complexes (L = O2CO,S2CO,O2SO) through metal-assisted CO2, CS2, SO2 oxidation. Crystal structure of (CH3C(CH2PPh2)3)CO(O2SO)

The solution obtained by reduction of [(triphos)CO(μ-Cl)₂Co(triphos)]⁺² (triphos = CH₃C(CH₂PPh₂)₃) with Na/Hg reacts with CO₂, CS₂ and SO₂ to give (triphos)Co(O₂CO), (triphos)Co(S₂CO), and (triphos)Co(O₂SO), respectively. The molecular structure of the last has been established by X-ray difraction.     

手性二茂铁基氨基酸配合物(S)-[Zn(FcCH2NHCH(CH2Ph)COO)2·H2O](H2O)的合成及性能

以(S)-N-二茂铁甲基苯丙氨酸钠为配体，与Zn(Ac)₂反应合成了一个新型手性单核配合物(S)-[Zn(FcCH₂NHCH(CH₂Ph)COO)₂·H₂O](H₂O)。X-射线单晶结构分析表明，中心离子Zn(Ⅱ)与2个FcCH₂NHCH(CH₂Ph)COO^-和1个水分子配位，形成树状的骨架构型。该配合物晶体属正交晶系，P2₁2₁2₁空间群。晶胞参数为：a=0.893 4(2) nm；b=1.669 8(4) nm；c=2.588 4(6) nm。电化学测试表明该配合物的氧化和还原峰电位同配体相比向高电位方向移动。室温下，标题化合物呈现出较强的固体双重荧光性能,量子化学计算给出了初步的解释。     

Complexes of [(iPrO)2P(O)NHC(S)NHCH2]2CH2 with Co(II), Ni(II), Zn(II), and Pd(II): Reaction of [(iPrO)2P(O)NHC(S)NHCH2]2 with KOH Leading to the Imidazolidine-2-Imine Derivative

Reaction of O,O′-diisopropylphosphoric acid isothiocyanate (iPrO)₂P(O)NCS with NH₂(CH₂)_nNH₂ (n = 3, 2) leads to the N-phosphorylated bis-thioureas [(iPrO)₂C(S)NHP(O) NH]₂Z (Z = —(CH₂)₃—, H₂L^I ; —(CH₂)₂—, H₂L^II ). Reaction of the potassium salt of H₂L^I with Co(II) and Zn(II) in aqueous EtOH leads to complexes of formula M₂(L-O,S)₂. The metal cation in both complexes is coordinated by two deprotonated ligands through the sulfur atoms of the thiocarbonyl groups and the oxygen atoms of the phosphoryl groups. Reaction of K₂L^I with Ni(II) and Pd(II) in the same conditions leads to M₂(L-N,S)₂ complexes. In both compounds, the metal center is found in a square-planar N₂S₂ environment formed by the C=S sulfur atoms and the P—N nitrogen atoms of two deprotonated ligands L^I . Reaction of H₂L^II with KOH leads to a product of heterocyclization, in which one of the thiourea fragments is retained. Compounds obtained were investigated by IR, UV-Vis, ¹H and ³¹P NMR spectroscopy, and microanalysis.     

Comparative reactivity of diacetals of the type (C2H5O)2CH(CH2)nCH(OC2H5)2

Summary The reactivity of diacetals in the reaction with vinyl ether in comparison with the diacetal of malonic dialdehyde increases in the following order: diacetal of glyoxal < malonic diacetal < succinic diacetal < glutaric diacetal < adipic diacetal.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1657–1658, September, 1965     

Syntheses,Crystal Structures and Properties of Three New Complexes [Ni（C9N2O2H7）2（CH3OH）2],[Zn（C9N2O2H7）2（H2O）2] and [Cd（C9N2O2H7）2（CH3OH）2]

Three novel metal-organic complexes with formulas [Ni(C9N2O2H7)2(CH3OH)2](1),[Zn(C9N2O2H7)2(H2O)2](2) and [Cd(C9N2O2H7)2(CH3OH)2](3) were synthesized by the reactions of Ni,Zn and Cd salts with ethyl 2-benzimidazolylacetate under hydrothermal conditions or layering technique,and characterized by single-crystal X-ray diffraction analysis,IR spec-troscopy,solid-state luminescent properties and thermogravimetric(TG) analysis.The crystal data for these three complexes are as follows:for 1,monoclinic,space group P21/c,a = 9.384(3),b = 9.634(3),c = 11.292(3) ,β = 95.787(5)°,V = 1015.7(5) 3,Z = 2,F(000) = 492,Dc = 1.547 Kg/m3,μ = 1.002 mm-1,the final R = 0.0451 and wR = 0.0900 for 1833 observed reflections with Ⅰ 2σ(Ⅰ);for 2,orthorhombic,space group Pbca,a = 10.031(4),b = 10.379(4),c = 17.525(7),V = 1824.6(12) 3,Z = 4,F(000) = 928,Dc = 1.645 Kg/m3,μ = 1.392 mm-1,the final R = 0.0452 and wR = 0.0996 for 1661 observed reflections with Ⅰ 2σ(Ⅰ);for 3,monoclinic,space group P21/c,a = 9.9114(13),b =10.4852(15),c = 10.4120(14) ,β = 108.453(5)°,V = 1026.4(2) 3,Z = 2,F(000) = 532,Dc = 1.705 Kg/m3,μ = 1.110 mm-1,the final R = 0.0322 and wR = 0.0805 for 1822 observed reflections with Ⅰ 2σ(Ⅰ).In the three complexes,the ethyl 2-benzimidazolylacetate shows the same chelating mode,and the adjacent units are interlinked into a two-dimensional layer through hydrogen-bonds(O-H···O,N-H···O).     

Thermal decomposition of peroxy acetyl nitrate CH3C(O)OONO2

The thermal decomposition of peroxy acetyl nitrate (PAN) is investigated by low pressure flash thermolysis of PAN highly diluted in noble gases and subsequent isolation of the products in noble gas matrices at low temperatures and by density functional computations. The IR spectroscopically observed formation of CH3C(O)OO and H2CCO (ketene) besides NO2, CO2, and HOO implies a unimolecular decay pathway for the thermal decomposition of PAN. The major decomposition reaction of PAN is bond fission of the O-N single bond yielding the peroxy radical. The O-O bond fission pathway is a minor route. In the latter case the primary reaction products undergo secondary reactions whose products are spectroscopically identified. No evidence for rearrangement processes as the formation of methyl nitrate is observed. A detailed mapping of the reaction pathways for primary and secondary reactions using quantum chemical calculations is in good agreement with the experiment and predicts homolytic O-N and O-O bond fissions within the PAN molecule as the lowest energetic primary processes. In addition, the first IR spectroscopic characterization of two rotameric forms for the radical CH3C(O)OO is given.     

Bildung und Strukturen von Nickelacyclen des Typs (LL′) NiCH2CH2C(O)O

Synthesis and Structures of Nickelacyclic Compounds of the Type (LL′) NiCH₂CH₂C(O)O In the title indicated type of nickelacyclic compounds could be prepared with bipy or Ph₂P(O)CH₂PPh₂ as stabilizing ligands. The complexes were characterized by means of crystal structure analyses. Additionally, both the synthesis of the methanol adduct of a nickelacyclic carboxylate and cis-(bipy)₂NiCl₂ · 2 DMF was successful as well as their structure analyses. Using the structure data including the data of formerly described nickelcycles, bond lengths and angels within the planar group (LL′)Ni(O)(C) and the mutual trans-influence of the ligands are discussed. The structure of (bipy)₂NiCl₂ · 2 DMF is discussed with respect to other compounds of the type cis-(bipy)₂M^IICl₂. In the case of the corresponding trans-isomeres, steric hindrances between the bipy-ligands are to be expected which can be equalized by a small distortion of the coordination polyhedron.