bluuebunny/crossref_metadata_2025 huggingface dataset:
Anionic Polymerization of Methyl(3,3,3‐Trifluoropropyl)cyclotrisiloxane
Authors: Yang Mei‐Hui , Yang Cheng‐Kan , Chou Chyuan
Published: May 2015

Methods based on anionic ring‐opening polymerization, using n‐butyl lithium as an initiator, were developed to prepare monodispersed (Mw/Mn < 1.2) poly[methyl(3,3,3‐trifluoropropyl)siloxane] (PMFPS) from methyl(3,3,3‐trifluoropropyl)cyclotrisiloxane (F3) in high yield. The resulting polymers have the molecular weights ranged from 4 k to 190 k (k = 1000). Each polymer was characterized by GPC and DSC. The absolute molecular weight (Mw) of each monodispersed PMFPS was determined by means of universal calibration with GPC/DV (coupled differential viscometry‐GPC) technique. Factors that affect the narrowly distributed linearly extended polymer chain, such as solvent, temperature, promoter, monomer concentration etc., were discussed in terms of molecular weight, molecular weight distribution, polymer conversion and the cyclic oligomer content through GPC and GC analyses. Back‐biting occurred either in the bulk or the solution process. However, the presence of a promoter (DMSO or THF) in a proper proportion accelerated the polymerization, and the reaction went to completion in either process before serious backbiting and chain transfer occurred.
Preparations and Reactions of 2‐Cyanoindole Derivatives
Authors: Lin Chih‐Da , Fang Jim‐Min
Published: May 2015

2‐Cyano‐1‐phenylsulfonylindole (1a) and 2‐cyano‐1‐methylindole (1b) were prepared by chemical and electrolytic methods in modest yields. Nucleophiles such as sodium benzenethiolate, butyllithium and lithium dimethylcuprate attacked the sulfonyl group of 1a, whereas they attacked the cyano group of 1b. 1,3‐Dipolar cycloadditions of 1a and 1b with 2,4,6‐trimethylbenzonitrile oxide occurred at the cyano groups. Electrophilic reactions of 1b with N‐bromosuccinimide, Vilsmeir reagent and acetyl chloride afforded the corresponding 3‐bromo‐, 3‐formyl‐ and 3‐acetylindole derivatives in modest or high yields, albeit less rapidly than the reactions of 1‐methylindole. Photochemical addition of dimethyl acetylenedicarboxylate to 1b was followed by cleavage of the cyclobutene intermediate to give dimethyl (2‐cyano‐1‐methylbenzazepine)‐3,4‐dicarboxylate.
3‐Substituted 2‐Cyclopentenones from Cyclopentadienes
Authors: Lin Chu‐Chung , Hsia Ket‐Shang , Wu Hsien‐Jen
Published: May 2015

Oxidation of cyclopentadienes 1a‐1j, which were prepared by alkylation of cyclopentadienyl anion with the corresponding alkyl bromides, with pyridinium chlorochromate (PCC) gave the 2‐cyclopentenones 2a‐2j respectively in 10–15% yields. Reaction of 3 and 5 with PCC gave the spiro compounds 4 and 6 respectively in 75–80% yields.
Dehalogenation and Halogenation of Sydnone Compounds with Duet Electrosynthesis
Authors: Hung Wei‐Jing , Tien Hsien‐Ju
Published: May 2015

Cathodic dehalogenation of 4‐halosydnones was conducted with a mercury electrode at a constant potential (−0.5 – −1.0 vs SCE). The combination of cathodic dedromination of 4‐bromosydnones on a mercury electrode with anodic bromination/chlorination of 3‐substituted sydnones with a platinum electrode in a divided electrolytic cell produced sydnone derivatives with a total current yield 87 ∼ 168%.
Radical‐Induced Ring Opening of Epoxysilane in the Synthesis of (±)‐Supinidine and (±)‐Trachelanthamidine
Authors: Tsai Yeun‐Min , Ke Bor‐Wen
Published: May 2015

An α‐(2‐silyloxiranyl)carbinyl radical fused to a pyrrolizidine skeleton was generated from the corresponding bromide 4. This radical underwent rearrangements followed by hydrogen abstraction to give silyl allyl ether 8 and silyl enol ether 9. The mixture was converted to (±)‐supinidine 1 and (±)‐trachelanthamidine 3. When triethylborane/oxygen was used to initiate the radical reaction, an α,β‐unsaturated aldehyde 15 was obtained, thus to accomplish a formal synthesis of (±)‐1.
Crown Ether As The Phase‐Transfer Catalyst for Free Radical Polymerization of Hydrophobic Vinyl Monomers
Authors: Tarng Jeng‐Yu , Shih Jeng‐Shong
Published: May 2015

Various crown ethers were used as phase‐transfer catalysts for free radical polymerizations of some water‐insoluble vinyl monomers such as acrylonitrile, methylmethacrylate and styrene with persulfate as initiator. The catalytic abilities of these crown ethers for free radical polymerization of acrylonitrile with S2O82−ion as an initiator were in the order: 18‐crown‐6 > 15‐crown‐4 > 12‐crown‐4 > benzo‐15‐crown‐5 > dibenzo‐18‐crown‐6. Among various persulfates such as Na2S2O8 K2S2O8 and (NH4)2S2O8, ammonium persulfate was the optimum initiator for the polymerization of acrylonitrile catalyzed by 18‐crown‐6 or 15‐crown‐5. Among the organic solvents used, chloroform seems to be the best solvent for the catalytic polymerization of acrylonitrile. An apparent activation energy of 72.9 kJ mol−1 was observed for the polymerization of acrylonitrile. The catalytic reaction rates of free radical polymerization for these hydrophobic vinyl monomers were in the order: acrylonitrile > methylmethacrylate > styrene > isoprene. Effects of concentrations of crown ether, initiator, and nitrogen on the polymerization of these vinyl monomers were investigated.
Crystal Structure of L‐Quebrachitol
Authors: Huang Keh‐Feng , Luo Wen‐Lih
Published: May 2015

L‐Quebrachitol (1) isolated from the root of Elaeagnus formosana Nakai (Elaeagnaceae) has not been reported before for any species of the genus of Elaeasnus. Its structure was established from spectral data and was completely characterized by single‐crystal X‐ray analysis. L‐Quebrachitol crystallizes in the monoclinic system, space group P21, with cell parameters are a = 6.702(4), b = 7.207(4), c = 8.758(5) Å, β = 90.24(5)° and Z = 2.
Design and Construction of a Pulsed Field‐Gradient NMR Probe for a High‐Field Superconducting Magnet
Authors: Price William S. , Chang Wen‐Tsung , Kowk Wai‐Ming , Hwang Lian‐Pin
Published: May 2015

We describe the design and construction of a high‐resolution pulsed field‐gradient NMR probe for use in a high‐field superconducting magnet. Overview and details of the design and construction of the probe case, rf circuitry, temperature control and shielded gradient coils for a heteronuclear probe suitable for a spectrometer (Bruker MSL‐300) equipped with a wide bore (i.e., 89 mm) magnet (Oxford) are given. The interior of the probe is designed so mat it may be easily moved to variable height so as to accept easily various gradient coils. A design for a novel jig for the winding of saddle‐geometry rf coils is given.
Reactivity of [Te6Fe8(CO)24]2− and Its Conversion to [Te4Fe5(CO)14]2−
Authors: Shieh Minghuey , Chen Pao‐Fei , Peng Shie‐Ming , Lee Gene‐Hsiang
Published: May 2015

Whereas reaction of [PhCH2NMe3]2|Te6Fe8(CO)24] (1) in refluxing CH2CI2 forms Fe2(CO)6(μ0‐) TeCH2Te), treatment of 1 with Ph2SnCl 2 or Mel gave the oxidation product Te2Fe3(CO)9. Oxidation of 1 with [Cu(CH3CN)4]BF4 afforded Te2Fe3(CO)9 in good yield. Cluster 1 was converted to [PhCH2NMe3][Te4Fe5(CO)14] (2) in MeOH/CH2Cl2 solution. Cluster 2 was structurally characterized by single‐crystal X‐ray diffraction and spectral methods. Complex 2 is composed of two Te2Fe2(CO)6 fragments linked by one Fe(CO)2 group. 2 crystallizes in the orthorhombic space group Pbcn with a = 13.351 (4) Å, b = 13.417 (4) Å, c = 26.077 (3) Å, V = 4671 (2) Å 3, Z = 4.
Kinetics and Thermodynamics of Synthesis of Tertiary‐Amyl Methyl Ether Catalyzed by Ion‐Exchange Resin
Authors: Hwang Wen‐Shwong , Wu Jung‐Chung
Published: May 2015

Synthesis of tertiary‐amyl methyl ether (TAME) was carried out in the temperature range 40–70 ° Cusing a sulfonic acid resin as the catalyst. Thermodynamic data were calculated from the equilibrium concentration of the components in a stirred batch reactor by the Unifac method. The enthalpy change of TAME formation was calculated to be (−20.4 ± 0.8) kJ/mol and the equilibrium constant is expressed as Ka = 3.94 × 10−4 exp (20400/RT). For the kinetic tests, a homogeneous solution system was selected to interpret experimental results. The activation energy of the forward reaction was calculated to be (94.0 ± 1.5) kJ/mol and the rate constant is expressed as k2 = 5.31 × 1011 exp (−94000/RT). The validity of this kinetic model was verified by fitting experimental data.
Determination of Enantiomeric Purity and Absolute Configuration of β‐Lactams by High‐Performance Liquid Chromatography on Chiral Columns
Authors: Lee Chih‐Shone , Chen Hsiu‐Ho
Published: May 2015

Enantiomers of β‐lactams bearing aryl, furyl or styryl substituents in the 4‐position were chromatographically separated by means of high‐performance liquid chromatography on chiral column packed with amino acid‐derived chiral stationary phase. Separation factors are generally modest. To improve further the resolution of enantiomers, the rings of these β‐lactams were opened with octanol in acidic conditions and converted into N‐3,5‐ dinitrobenzoyl ester derivatives of the resulting β‐amino acids. Enantiomers of these derivatives are efficiently separated on an amide‐derived chiral stationary phase. The chromatographic separations enable accurate determination of optical purity of the chiral β‐ lactams, prepared from homochiral ester enolate‐imine condensation. The absolute configuration of the major enantiomer of the β‐amino acid derivatives was determined from elution order on a chiral column.
Synthesis of 4H‐Pyrrolo[2,1‐C][1,4]benzothiazines and 3‐(Methylthio)oxindoles
Authors: Wang Huey‐Min , Lin Meng‐Chiao , Chen Ling‐Ching
Published: May 2015

The Pummerer reaction was carried out with α‐acylsulfides and phenyl iodosyl bis(trifluoroacetate) instead of α‐acylsulfoxides to prepare 4H‐pyrrolo[2,1‐c][1,4]benzothiazines and 3‐(methyIthio)oxindoles.
Vibrational Spectroscopy of Surface Adsorbates by Sum Frequency Generation (SFG)
Authors: Hirose Chiaki , Watanabe Nobuyuki , Yamamoto Hiroyoshi , Wada Akihide , Domen Kazunari , Ohtake T. , Mino Norihisa
Published: May 2015

The vibrational spectroscopy by way of vibrational sum‐frequency generation (VSFG) has been made of formic acid adsorbed on MgO(001) surface and of n‐alkyltrichlorosilanes chemisorbed on quartz plates. It was revealed that the species on the MgO surface was formate ion (HCOO+) with CH bonds standing vertical to the surface and that the different adsorption sites showed up on repeated cycles of adsorption‐desorption processes. The results of chemisorbed films indicated that the g‐t and/or g‐t‐g′ conformational scquences of n‐alkyl chains occurred more frequently by the length of alkyl chain and that the surface hydroxyls, which are the sites of chemisorption, are ripped off by pre‐exposure of substrate to oxygen plasma.
Antineoplastic Alkaloids From Chinese Medicinal Plants and Their Analogs
Authors: Lee Kuo‐Hsiung , Sun Li , Wang Hui‐Kang
Published: May 2015

The Chinese medicinal plant‐derived antineoplastic alkaloids and their analogs are reviewed with emphasis on those discovered from the authors' laboratory. The active compounds include camptothecin, colchicine, ellipticine, harringtonine, Vinca alkaloids, indirubin, (‐)‐sophocarpine, lycobetaine, monocrotaline, d‐tetrandrine, indicine N‐oxide, maytansine, aporphine type alkaloids, palmatine, murrapanine, emarginatine alkaloids, and the alkaloids from Securinega virosa. The compounds are discussed briefly with the recent advances concerning their antitumor activity, structure‐activity relationships and mechanisms of action.
Rhenium(V) Complexes of N,N′‐Ethylenebis(2‐mercaptopropanamide). Synthesis, Characterization, and X‐ray Crystal Structures
Authors: Liao Fen‐Ling , Wang Sue‐Lein , Lin Cheng‐Hsien , Huang Shih‐Tsorng
Published: May 2015

The preparation of benzoyl‐protectcd N,N′‐ethylenebis(2‐mercaptopropanamide) (H4emp) and its ligand‐exchange reaction with ReO2(en)2Cl are described. Three diastereomers, [syn‐ReO(meso‐emp)]; [anti‐ReO(meso‐emp)]‐, and a pair of cnantiomers, [ReO(rac‐emp)]‐, were formed due to syn and anti orientation of the two methyl groups of the ligand relative to the ReO core. The diastereomers were separated by reverse phase C18 semipreparative HPLC and isolated as salts of [Ph4As][ReO‐(emp)]. The structures of [Ph4 As][ReO(meso‐emp)] were determined by single‐crystal X‐ray analyses. [Ph4As][syn‐ReO(mesocmp)]H2O crystallizes in triclinic space group Pl with a = 10.326(3) Å, b = 13.672(4) A, c = 14.023(5) Å, α = 61.20(2)°, β =74.74(3)°, γ= 75.68(2)° V = 1656.6(8) Å3, Z = 2, Dc = 1.676 gmL−1, F(000) = 824 and R = 0.0329 for 5877 unique reflections. For (he complex [Ph4As][anti‐ReO(meso‐emp)], the crystal data are: monoclinic, space group P21/n, a = 9.128(2) Å, b = 24.284(7) Å, c = 14.112(4) Å, β = 93.41(2)° V = 3122.5(15) À3, Z = 4, Dc = 1.740 gmL−1, F(000) = 1608 and R = 0.0361 for 5487 unique reflections. In both structures the rhenium atom is penta‐coordinated and in an approximately square pyramidal environment.
Flash Vacuum Thermolysis of Phenylcyclopropanecarbaldoximes and Its Methyl Ethers
Authors: Wu Pei‐Lin , Wang Wen‐Shan , Chen Chang‐Fu
Published: May 2015

Flash vacuum thermolysis of 1‐phenylcyclopropane‐1‐carbaldoxime at 500 °C produced mainly 3‐phenylpyrrole. The products after thermolysis of its oxime methyl ether were α‐methoxymethylstyrene, α‐methylstyrene, and a dimer 2,5‐dipheny 1‐1,5‐hexadiene.
Synthesis of Thiolato Heterometalllc Clusters from the Reaction of Os3(CO)9(NCMe)(μ‐H)(μ‐SMe) with CpW(CO)3H
Authors: Tsay Chyuan‐Wu , Tu Wen‐Cheng , Chi Yun , Peng Shie‐Ming , Lee Gene‐Hsiang
Published: May 2015

Decarbonylation of triosmium methylthiolato cluster Os3(CO)10(μ‐H)(μ‐SMe) with Me3NO in acetonitrile solution gave cluster Os3(CO)9(NCMe)(μ‐H)(μ‐SMe) (1), in which one axial CO on the non‐bridged Os atom is replaced by an acetonitrile ligand. Crystal data for 2: space group P bca, a = 14.491(1), b = 16.107(5), c = 16.639(5) Å, Z = 8; RF = 0.037, Rw = 0.033. Treatment of 2 with CpW(CO)3H in refluxing THF solution yielded two cluster compounds with formula CpWOs3(CO)11(μ‐H)2(μ3‐SMe) (2) and CpWOs3(CO)11(μ‐H)2(μ‐SMe) (3) as the principle products. The first possesses a spiked‐triangular geometry with a triply bridging thiolato ligand and the second adopts a butterfly metal core arrangement with an edge‐bridging thiolato grouping. The structure of 2 was characterized by single‐crystal X‐ray diffraction. Crystal data: space group P 1, a = 8.865(5), b = 8.959(3), c = 16.688(4) Å, α = 103.49(2), β = 93–58(3), γ = 113.03(4)°, Z = 2, RF = 0.034, Rw = 0.035.
Promotion of Oxidative Dehydrogenation by Cobalt Ions and the Synthesis of Trans‐diaqua(C‐meso‐3,5,7,7,10,12,14,14‐octamethyl‐1,4,8,11‐tetraazacyclotetradeca‐1,4,8,11‐tetraene)cobalt(II) Perchlorate
Authors: Chen Bor‐Hann , Lai Chung‐Yu , Chung Chung‐Sun , Liao Fen‐Ling , Wang Sue‐Lein
Published: May 2015

Aerial dehydrogenation of the Iigand in (C‐meso‐3,5,7,7,10,12,14,14‐octamethyl‐1,4,8,11‐tetraazacyclotetradeca‐4, 11‐diene)cobalt(III) leads to yellow chunky crystals of trans‐diaqua(C‐meso‐3,5,7,7,10,12,14,14‐octamcthyl‐1,4,8,11‐tetraazacyclotetradeca‐1,4,8,11‐tetraene)cobait(II)(1). The crystal structure of this complex was determined by xray crystallography and a mechanism of this reaction is proposed.
Thermal Interchanges in the Relative Stabilities of the C60Ge Specles
Authors: Slanina ZdenêK , Lee Shyi‐Long
Published: May 2015

Bridging a Ge atom across the two C‐C bonds in C60 was treated according to the PM3 method. The C2v (6/6) closed isomer represents the ground state of the system, located 52 kJ/mol below the C5 (5/6) closed structure and 97 kJ/mol below the C5 (5/6) open structure. However, at high temperatures the closed 5/6 isomer becomes the most stable, whereas the ground‐state structure is the least populated component under conditions of thermodynamic equilibrium, although no isomer is negligible. The applicable characteristics indicate a reasonable absolute stability of the whole system.
Temperature Dependence of the Rate Coefficient of the Reaction OH + CF3CH2F over the Range 255‐424 K
Authors: Leu Gen‐Hou , Lee Yuan‐Pern
Published: May 2015

The rate coefficient of the reaction of OH with CF3CH2F at six temperatures in the range 255‐424 K was determined by means of the discharge‐flow/resonance‐fluorescence technique. The resonance fluorescence of OH, excited by emission from a gaseous mixture of H2O and He subjected to a microwave discharge, was detected by photon‐counting technique. The reaction was carried out under pseudo‐first‐order conditions with [CF3CH2F] >> [OH]; the rate coefficient was determined to be k = (3.9±0.6) × 10−15 cm3 molecule−1 s−1 at 298 K; the uncertainty represents the 95% confidence limit. The temperature dependence of the rate coefficient is expressed in the Arrhenius form, k(T) = (9.9±1.0) × 10−13 exp [‐(1640±150)/T] cm3 molecule−1 s1.
The Mn(II)‐Catalyzed Belousov‐Zhabotinsky Reaction with Methyl‐, Ethyl‐ or Butyl‐Malonic Acid
Authors: Sun Shih Sheng , Lin Hong‐Ping , Chen Ying‐Fen , Jwo Jing‐Jer
Published: May 2015

In a batch‐stirred experiment, the Mn(II)‐catalyzed reaction of bromate ion with methyl‐, ethyl‐ or n‐butyl‐malonic acid (MeMA, EtMA or BuMA) exhibits oscillating behavior similar to the prototype Ce(III)‐catalyzed Belousov‐Zhabotinsky (BZ) reaction with malonic acid (MA). The effects of manganese ion, bromate ion, organic substrate, sulfuric acid, and chloride ion on the oscillating pattern were investigated. Both conventional and stopped‐flow spectrophotometric methods were applied to study the kinetics of reactions of Mn(III) ion with MA, MeMA, EtMA, BuMA, bromomalonic acid (BrMA), and dibromomalonic acid (Br2MA). The order of reactivity toward Mn(III) oxidation is MA > BrMA > MeMA > Br2MA > (EtMA, BuMA). The experimental results are rationalized.
A Layer Structure Encapsuling Interlayer K+ Cations: Hydrothermal Synthesis and Crystal Structure of Vanadyl(IV) Arsenate K2[(VO)2(AsO4)(HAsO4)(H2AsO4)(H2O)].0.5H2O
Authors: Wang Sue‐Lein , Hsu Kuei‐Fang
Published: May 2015

A new vanadyl(IV) arsenate, K2[(VO)2(AsO4)(HAsO4)(H2AsO4)(H2O)].0.5H2O, has been synthesized hydrothermally at 230 °C and structurally characterized by single‐crystal X‐ray diffraction. The compound crystallizes in triclinic space group P1 with a= 6.533(2) Å, b = 9.062(3) Å, c = 12.582(5) Å, α = 106.29(3), β = 98.64(3), γ = 103.09(2)° V = 678.0(4) Å3 Z = 2 and R = 0.0428 for 2114 unique reflections. The structure consists of VIVO6 octahedra and tetrahedra of AsO43− HAsO42−, and H2AsO4− groups to form layers along the [001] direction with K+ cations between the layers. Building units of the layers are 4‐connected ribbons connected to each other by dihydrogen arsenate groups to form large tunnels perpendicular to the layers. Cations and water molecules reside in the tunnels. The title compound is isotypic with phosphate K2(VO)2(P3O9)(OH)3‐1.125H2O (Lii et al. Inorg. Chem. 1991, 30, 446), that was synthesized at 450 °C. In contrast to the phosphate, tetranedra of three groups, AsO43−, HAsO42−, and H2AsO4−, were distinctly identified in the arsenate. The sites for lattice water are essentially fully occupied due to the larger space provided by the framework of K2[(VO)2(AsO4)(HAsO4)(H2AsO4)(H2O)].0.5H2O. The structures of this arsenate and K2(VO)2(P3O9)(OH)3·1.125H2O are discussed.
Chemical Synthesis and Characterization of Superconducting YBa2Cu4O8 at Ambient Pressure
Authors: Chen Teng‐Ming , Lin Li‐Fan
Published: May 2015

A monophasic high‐Tc superconductor YBa2Cu4O8 with Tc(onsel), 80 K and fine grain size has beeen synthesized under oxygen at 1 bar employing metal‐ethandiol/citric acid (EG/CA) polyester complex precursors. In addition to the preparation, we report the results of infrared (IR) spectra, thermogravimetric analysis (TGA), and X‐ray diffraction (XRD) relevant to preparation of the YBa2Cu4O8 superconductor. The effect of temperature of preparation and precursor compositions (i.e. EG/CA molar ratio) on the purity and superconductivity of the YBa2Cu4O8 compound was investigated. The temperature dependence of resistivity and normal‐state resistivity of the samples varied systematically with the EG/CA ratio in the precursors. Tc(onset) and the width of the superconducting transition for YBa2Cu4O8 samples were determined to be 80 K for all samples and 6 – 9 K, respectively; the latter depended on the corresponding EG/CA ratios in the precursors. The Meissner fraction of YBa2Cu4O8 samples determined from dc magnetization tests was independent of the EG/CA ratio. Polyester precursors can potentially be applied in large‐scale preparation of high Tc ceramic‐oxide superconductors and superconducting thin films.
Synthesis and Fluxional Behavior of Intramolecular η2‐Arene Complexes via Insertion of Substituted 7‐Oxanorbornene into Palladium‐Carbon Bonds
Authors: Duan Jiun‐Pey , Cheng Chien‐Hong
Published: May 2015

The complexes [C6H6O(CO2CH3)2R]PdI(PPh3) (R = p‐anisyl (4), m‐anisyl (5), p‐tolyl (6), phenyl (7), 1‐naphthyl (8) and 2‐thienyl (9)) were prepared by treating Pd(PPh3)2(R)I with exo‐5,6‐dicarbomethoxy‐7‐OX‐anorbornene (3) or from the reaction of Pd(PPh3)4 with the corresponding organic iodide (RI) followed by addition of 3 and methyl iodide. In complexes 4‐8, the carbon‐carbon double bond between ipso and ortho positions of the aryl ring attached to the 7‐oxanorbornyl group is weakly bound to the palladium (II) center in a η2 fashion, in addition to the three ligands‐the 7‐oxanorbornyl group, PPh3 and I−. This η2‐interaction leads to a dramatic upfield shift of 13C NMR signals of the ipso carbons by 30‐40 ppm. Variable‐temperature NMR studies indicate that complexes 4‐7 are nonrigid on the NMR time scale. Rotation of the weakly η2 bound aryl group is proposed to account for the observed fluxionai behavior. In contrast to 4‐7,8 is static at room temperature, presumably, due to the unsymmetrical nature and the large size of the naphthyl group. In complex 9, the sulfur atom in the thienyl group is coordinated to the palladium center and no intramolecular η2‐bonding is involved.
Insertion Reactions of Square‐Planar Diorganoplatinum. 2. Stereoselective Carbonylation of trans‐Pt(R)(R′)(PPh3)2 Leading to cis‐Pt(R)(COR′)(PPh3)2 and Isomers of Pt(PPh3)(COKCOR′)(R)
Authors: Shu Bor‐Chyr , Huang Tsang‐Miao , Tsai Fu‐Yu , Huang Shou‐Ling , Cheng Ming‐Chu , Lee Gene‐Hsiang , Chen Jwu‐Ting , Wang Yu
Published: May 2015

Synthesis of square‐planar trans dialkyl and alkyl aryl complexes of platinum(II), trans‐Pt(R)(R′)(PPh3)2 (R = Me R′ = Et (2a); R = Me R′ = Ph (2b); R = R′ = Et (2c); R = Et R′ = Ph (2d)) was established employing transmelaiation of trans‐Pt(R)(I)(PPh3)2 with Grignard reagents R′MgX. Complexes 2a‐2c underwent stereoselective carbonylation to produce cis‐Pt(R)(COR′)(PPh3)2 (R = Me R′ = Et (3a); R = Me R′ = Ph (3b); R = R′ = Et (3c)). These facile transformations were exclusive and quantitative. The reactivity of carbonylation followed the order Et > Ph > Me. A similar reaction of 2d with CO yielded EtC(O)Ph instead. The cis acyl alkyl or acyl aryl complexes 3a‐3c suffered substitution of CO for a PPn3, leading to two isomers SP‐4‐3‐ and SP‐4‐4‐Pt(PPb3)(CO)(COR′)(R) (R = Me R′ = Et (4a, 4a′); R ‐ Me R′ = Ph (4b, 4b′); R = R′ = Et (4c, 4c′)), respectively. The reverse reactions of 4 to 3 readily occurred when external PPh3 was provided. The stereoselectivity of carbonylation of trans‐Pt(R)(R′)(PPh3)2 is explained by a mechanism in which reversible displacement of a PPh3 by CO in the reactant precedes to form a four‐coordinate dialkyl carbonyl intermediate Pt(PPh3)(CO)(R)(R′). The ensuing alkyl (or aryl) migration from metal to the carbonyl carbon achieves the cis acyl alkyl (or aryl) configuration. Recoordination of a PPh3 completes the reaction. X‐ray structures of 2b, 2c, 3b and 4b as single crystals are provided.
Chemical Reactivities of [Me2AI (μ‐NiPr2)2MgMe]4 and [Me2AI(μ‐NiPr2)2MgCI]2: Crystal Structures of [Me2AI(μ‐Pz)2AIMe2], [Me2AI(μ‐P2)2Mg(μ‐Pz)2AIMe2], and [Me2Al(μ.‐NiPr2)(μ‐Me)Mg(μ‐NiPr2)(μ‐Me)AIMe2]
Authors: Chang Chung‐Cheng , Her Tzong‐Yih , Hsieh Fang‐Yen , Yang Chung‐Yenn , Chiang Michael Y. , Lee Gene‐Hsiang , Wang Yu , Peng Shie‐Ming
Published: May 2015

[Me2Al(μ‐NiPr2)2MgMc]4 (A) reacted with chloroform to give the starting material [Me2Al(μ‐NiPr2)2MgCl]2 (4) in high yield. Compound 4 underwent metathesis with LiR (R = t‐C4H9, C6H5) to give [Me2Al(μNiPr2)2MgR]n (n = 1, 2). Compound A reacted with pyrazole (Pz) in a molar ratio 1:1 to produce [Me2Al(μ‐NiPr2)2Mg(Pz)]2 (1), and in a molar ratio 1:3 to produce degradation products [Me2Al(μ‐Pz)2AlMe2]4 (2) and [Me2Al(μ‐Pz)2Mg(μ‐Pz )2AlMc2 (3). Compound A reacted with AlMe3 to give [Me2Al(μ‐NiPr2)2Mg(μ‐Me)2AlMe2] (8). Compound 8 isomerized to [Me2Al(μ‐NiPr2)(μ‐Me)Mg(μ‐NiPr2)(μ‐Me)AlMe2] (7) upon heating. Compound 7 was also obtained from reaction of AlMe3 with Mg(NiPr2)2 in a molar ratio 3:1. The crystal structures of compounds 2, 3, and 8 were determined by xray diffraction analysis.
Diels‐Alder Reactions and Synthetic Application of 8‐Trimethylsilyloxy‐1,4‐dioxaspiro[4.5]deca‐6,8‐diene. A Formal Synthesis of (±)‐Compaclin
Authors: Hung Shang‐Cheng , Liao Chun‐Chen
Published: May 2015

Diels‐Alder reactions of title diene 6 with electron‐deficient dienophiles gave cycloadducts in good yields (83‐96%). The application of cycloadduct 10 to a format synthesis of (±)‐compactin in six steps is described.
De Novo Synthesis of Bolvinose Through Diastereoselective Ene Reaction
Authors: Lu Wen‐Fang , Uang Biing‐Jiun
Published: May 2015

Synthesis of DL‐boivinose from reaction of 3‐methyl‐2‐butenal and an allyl Grignard reagent followed by a chemo‐, regio‐, and diastcreoselective ene reaction on a dienol intermediate 3 with singlet oxygen, an ozonolysis, a protection reaction, and a chemoselective hydride reduction is described. The synthesis was completed in six steps with overall yield 29.7%.
Triplex Formation as Functions of Variation of Sequence and Chain Length of Deoxyoligonucleotides at Varied Concentrations of NaCl and MgCl2
Authors: Kan Lou‐Sing , Ono Akira
Published: May 2015

The stahilities of triplexes with two sequences, An and (AG)n were studied by 5′‐C2A16C2/5′‐Tn (n = 12, 14, and 16) and 5′‐(AG)8/5′‐(CT)n (n = 4, 5, 6, and 7) systems by variation of the chain length (of oli‐gopyrimidine sequences), the composition of base triad (T A T versus C G C), pH (acidic and neutral), and the concentration of NaCl and MgCl2. No stable C+‐G‐C base triad was formed at neutral pH. However, C+ G C is more stable than TAT in acidic conditions. The triplex formed from the 5′‐C2A16C2 and T12 mixture with 12TAT units has a melting temperature Tm 11 °C. The triplex formed by 5′‐(AG)8/5′‐(CT)4 with four T A T and four C+ G C base triads shows Tm 41 °C. Tm of 5′‐C2A16C2‐[T16]2 triplex increased proportionally to the increased NaCI and MgCl2 concentrations. Tm of 5′‐(AG)8‐ [5′‐(CT)7]2 became constant when NaCI and MgCl2. attained 0.5 M and 5 mM, respectively. The properties of triplexes with An and (AG)n sequences were discussed.
Organic Reactions upon Dimetalated Olefins. Reactions of the Olefinic Group in the Dirhenlum Complex (OC)4Re[E‐HCC(CO2Me)CS2]Re(CO)4 with Amines
Authors: Adams Richard D. , Chen Linfeng , Huang Mingsheng
Published: May 2015

The reaction of (OC)4Re[μ‐E‐HCC(CO2Me)CS2]Re(CO)4, 1 with EtNH2 yielded two new complexes: Re(CO)4[C(H)C(CO2Me)C(NHEt)S], 2, (52%) and Re(CO)3(NH2Et)[C(H)C(CO2Me)C(NHEt)=S], 3a (24%) by competitive attack of the EtNH2 at the dithiocarboxylate grouping and at the hydrogen substituted olefinic carbon atom in 1. In both cases there is a loss of one of the rhenium groupings. The reaction of the sulfurized and oxygenated derivatives of 1, (OC)4Re[EC(H)C(CO2Me)CS2]Re(CO)4, 4a (E=S), 4b (E=O) with EtNH2 yielded Re(CO)4[C(H)=C(CO2Me)C(NHEt)=S], 5a, the parent carbonyl of 3a, by exclusive attack of the amine at the hydrogen substituted olefinic carbon atom. The reaction of (OC)4Re[μ‐SC(S)C(CO2Me)C(H)S]Re(CO)4,6a (an isomer of 4a) with EtNH2 produced a similar result. The reaction of 4a with Et2NH yielded Re(CO)4[μ‐S2C=C(CO2Me)C=NEt2], 5b an N‐ethyl substituted derivative of 5a. These results indicate that the addition of certain heteroatoms can have a directing effect upon the reactivity of these compounds with amines. Compounds 2 and 5a were characterized by single crystal x‐ray diffraction analyses. Crystal Data: For 2: space group = P1, a = 10.782(1) Å, b = 14.721(2) Å, c = 9.940(2) Å, a = 91.57(1)°, β = 93.61(1)°, γ = 70.774(9)°, Z = 4, 4516 reflections, R = 0.047 and for 5a: space group = P21/n, a = 11.389(2) Å, b = 9.660(2) Å, c = 14.756(3) Å, β = 103.36(2)°, Z = 4, 1601 reflections, R = 0.022.
Removal of Nitrobenzene, Isophorone, 2,6‐Dinitrotoluene and 2,4‐Dinitrotoluene from Aqueous Solution by Solvent Sublation
Authors: Horng Jang‐Yeun , Huang Shang‐Da
Published: May 2015

Nitrobenzene, isophorone, 2,6‐dinitrotoluene and 2,4‐dinitrotoluene were removed from aqueous solution by solvent sublation. The separation efficiencies of three solvents (4‐methyl‐2‐pentanone, 1‐octanol and paraffin oil) as the overlaying layer were compared. The rate of separation of these organic pollutants by solvent sublation depends strongly on the size of air bubbles, which is affected by the overlaying solvent, and concentrations of sodium dodecyl sulfate (NDS), inorganic and polar organic solute.
Rhenium(I) Tellurolate, Telluroether and Bidentate‐Telluroether Complexes: Crystal Structures of Re(CO)3Br(PhTe(CH2)3TePh), PhTeRe(CO)5 Re2(μ‐SePh)2(CO)8 and [(PhTeMe)Re(CO)5][BF4]
Authors: Liaw Wen‐Feng , Horng Yih‐Chern , On Der‐Shiaw , Chuang Chin‐Yuan , Lee Chen‐Kang , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

The monomeric rhenium(I) complex with bidentate telluroether ligand Re(CO)3Br(PhTe(CH2)3TePh) (1) was accessible via reaction of the PhTe(CH2)3TePh with Re(CO)5Br. This chelate complex crystallized in triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document} with a = 9.390(5) Å, b = 10.961(3) Å, c = 11.849(4) Å a = 63.30(3)°, β = 87.49(4)° γ = 69.31(4)°, V = 1009.5(7) Å3 Z = 2, R = 0.033, and Rw = 0.034. Reaction of Re(CO)5Cl with NaTePh yielded the Re(I) specics PhTeRe(CO)5 (2). This complex crystallized in triclinic space group \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm P}\bar 1 $\end{document} with a = 7.085(1) Å, b = 9.203(1) Å, c = 11.341(1) Å, α = 107.24(1)°, β = 100.56(1)°, γ = 96.47(1)°, V = 683.2(2) Å3, Z = 2, R = 0.027, Rw = 0.022. Reaction of PhTeRe(CO)5 and (PhSe)2 in THF at 65 °C yielded a product that was confirmed crystallographically to be the known species Re2(μ‐SePh)2(CO)8 (3), in which two phenylselenolate ligands bridge the two Re(I). Compound 3 crystallized in monoclinic space group P21/n with a = 7.210(2) Å, b = 18.862(6) Å, c = 9.083(3) Å, β = 107.48(3)° V = 1178.2(7) Å3, Z = 2, R = 0.046, and Rw = 0.051. Methylation of PhTeRe(CO)5 with [Me3O][BF4] afforded Re(I) product [(PhTeMe)Re(CO)5][BF4] (4). This monodentate telluroether species crystallized in monoclinic space group P21/n with a = 8.405(1) Å, b = 13.438(3) Å, c = 15.560(2) Å, β = 92.59(1)° V = 1755.5(5) Å3, Z = 4, R = 0.035, and Rw = 0.035.
Towards Total Synthesis of Forskolin I. The Synthesis of Fragment Intermediates A and B
Authors: Tsai Thomas Ying‐Ren , Chen Tsun‐Ren , Sheu Shih‐Yiing
Published: May 2015

Methods for synthesis of two crucial intermediate A and B starting with 2,4,4‐trimethyl‐2‐cyclo‐hexenone 1 and 2,3‐dibromofuran 9 are disclosed.
Constituents of Fruit Bodies of Tramete orientalis
Authors: Chen Huey‐Ling , Chiang Hung‐Cheh
Published: May 2015

A known sterol, 5α,6α‐epoxy‐5α‐crgosta‐8(14),22E‐diene‐3β,7α‐diol (1), and two new sterols, 5α,6α‐epoxy‐3β,8β,14α‐trihydroxy‐5α‐ergost‐22E‐en‐7‐one (2), (3α,5α),(8β,11β)‐diepidioxy‐ergost‐22E‐en‐12‐one (3), were isolated and characterized from dried fruit bodies of Trametes orientalis. Their structures were elucidated according to spectral methods.
A Study of S(3P2,1,0;1D2; 1S0) Production in the 193 nm Photodissociation of CH3SH
Authors: Hsu Chia‐Wei , Liao Chung‐Lin , Ng Cheuk‐Yiu
Published: May 2015

The dynamics of S(3P2,1,0; 1D2; 1S0) production from the 193 nm photodissociation of CH3SH has been examined by 2+1 resonance‐enhanced‐multiphoton‐ionization (REMPI) techniques. Using the rate equation scheme, we have rationalized the intensities of S(3P2,1,0; 1D2; 1S0) observed according to the sequential two‐photon dissociative pathways, (A): CH3SH + hv (193 nm) → CH3S + hv (193 nm) → S and (B): CH3SH + hv (193 nm) → HS + hv (193 nm) → S, as the major mechanisms for S production. We have satisfactorily fitted the photodissociation laser power dependencies for S(3P) and S(1D) produced from CH3SH by invoking photodissociation cross sections and branching ratios S(3P)/S(1D) for CH3S and HS similar to those determined previously in the 193 nm photodissociation of CH3SCH3 and H2S. This observation supports that the 193 nm photodissociation of CH3S and HS prepared from CH3SH yield predominantly S(lD) and S(3P), similar to the cases for CH3S prepared from CH3SCH3 and for HS prepared from H2S, respectively. A small amount of S(1S0) observed from the 193 nm photodissociation of CH3SH is attributed to pathway (B).
Two Recent Studies Involving Pressure Tuning Spectroscopy
Authors: Drickamer Harry G. , Lang Jiamin , Dreger Zbigniew A.
Published: May 2015

In this paper we present two recent studies utilizing pressure tuning spectroscopy. In the first of these we use high pressure photoluminescence to characterize the large difference in luminescence efficiency at one atmosphere between [Ru(bpy)3]2+ and [Ru(bpy)2py2]2+ ions. The lower efficiency of the latter ion is due to dissipation of excitation energy by motion of the pyridines.

The second study involves a combination of photo‐and thermoluminescence of doped ZnS phosphors of technical importance. In the phosphor doped with CI and Cu+ we demonstrate that the donors are pinned to the conduction band and the acceptors to the valence band. We invoke the presence of “deep levels” to describe the behavior of the traps. In the phosphor doped with Mn+2 plus C1‐ and Cu+ a series of traps appeared as the pressure was increased. By comparison with ZnS doped only with Mn+2 it was possible to assign some of the traps to C1‐ and others to Mn+2.
Studies on State‐to‐State Energy Transfer of Electronically Excited Atoms and Molecules
Authors: Li Xue‐Chu , Lou Nan‐Quan
Published: May 2015

Rotationally inelastic collisions of NH2( Ã2A1), ∑(0,9,0), 303, 101 have been studied by measuring the dispersed fluorescence spectra at molecular beam conditions. The results show that the angular momentum transfer rule is much more successful than is that predicted by energy gap law for fitting the rotational energy transfer rate. For ΔN < 2 the transfer rates are getting slow down. Downward transfer rates are faster than those of upward transfer. With same angular momentum transferred, the transfer rates for Δka = 0 process are larger than those for Δka≠0. It is also found that rotation transfer process is a very efficient way for decaying of the initially pumped levels. About 60% of the initially pumped 303 is colliding into other rotational levels. Energy transfer reactions of metastable rare gas atoms (Rg*) with N2, NH3, CS2 were investigated by measuring the emission spectra. The preferential population of n(A″) of NH(c1II) was found in He(23S) + NH3 reaction, the experimental data shows II(A″)/II(A′) = 1.2 at J′ < 13. A high vibrational excitation and low rotational excitation of N2(C3n) were observed in Ne(3P02) + N2 reaction comparing with Ar(3P0.2) + N2 reaction. The detailed vibrational populations of CS2+ (Ã, B̃) achieved by He(23S)/Ne(3P0.2) + CS2 reaction are different from those obtained by PES. The vibrational distributions of CH(A2Δ) obtained by He(23S) + CHC13 (CH3NO2) reactions were discussed based on statistical theory, special attention was paid to reveal the role played by tie angular momentum restriction in this process. The result on energy transfer between N2(a1 Π) and CO(X1 ∑) was firstly presented by VUV emission spectra at single collision condition. The mechanisms of energy transfer related to some of the reactions mentioned above were also discussed in the text.
On Theoretical Treatments of Electronic Excitation Energy Transfer
Authors: Liao D. W. , Cheng W. D. , Bigman J. , Kami Y. , Speiser S. , Lin S. H.
Published: May 2015

In this paper, we review the generalized Forster‐Dexter theory to treat photoinduced electronic energy transfer for a system in dense media and for an isolated system (i.e., a system in the collision‐free condition). Instead of expressing the rate of energy transfer in terms of spectral overlap, the expression of the energy‐transfer rate constant is obtained by evaluating a Fourier integral involved in the energy transfer rate constant using the saddle‐point method. In this way, the energy‐gap dependence, and the effect of temperature and the isotope effect on the energy transfer can be easily studied. The effect of bridge groups connecting between donor and acceptor chromophores on the intramolecular energy transfer is also studied.
New Spectral Techniques: Time‐Resolved Fourier‐Transform Spectroscopy and Two‐Color Laser‐Induced Grating Spectroscopy
Authors: Lee Yuan‐Pern , Yen P.‐S. , Leu G.‐H. , Hung Wen‐Ching , Hung S.‐C. , Chen I‐Chia
Published: May 2015

Time‐resolved Fourier‐transform spectroscopy and two‐color laser‐induced grating spectroscopy are two new techniques recently employed in this laboratory. We recorded emission in the near infrared region during laser photolysis of HONO2 with a step‐scan Fourier‐transform spectrometer and achieved temporal resolution in the microsecond range and spectral resolution of 0.1 cm1. Rotationally resolved emission lines of the (0,0) band of the D 2∑+ →A 2∑ + transition of NO in the region 8900‐9300 cnv−1 with irregular relative intensities were observed when an ArF excimer laser was used to photodissociate HONO2. The spectroscopic parameters of both D 2∑+ and A 2∑+ states agree with those previously reported. When a narrow‐band ArF laser was used, selective rotational levels of the D state of NO were populated depending on the wavelength of the ArF laser. Our results indicate that absorption of a 193‐nm photon by NO(υ″ = 1) is responsible for the observed emission. To test the technique of two‐color laser‐induced grating spectroscopy, we employed the B 3II0U+‐X 1∑g + system of I2. Background‐free spectra with transitions involving rotationally selected states were recorded. Various experimental schemes were employed with population gratings formed in either the B or X state. Signals due to different four‐wave mixing schemes were distinguished by variation of relative timing between the grating beams and the probe beam.
Treatment of Radiation Trapping by Reduced Multiple Scattering Series
Authors: Lai Re , Ma Xingxiao
Published: May 2015

We have developed a form of solution to radiation trapping problems by the reduced multiple scattering series. Much of the power of our approach lies its capability to present a complete description of radiation trapping in a straightforward and systematic manner. This paper presents a review of our work. Generalization of the method to incorporating collisional and radiative transfer of excitation is also reported.
Effect of Solvation on Chemical Reactions, I. Addition of a Single Water Molecule to the H− + H2O → OH− + H2 Reaction
Authors: Xanlheas Sotiris S. , Dunning Thom H.
Published: May 2015

The gas phase chemical reaction, H− + H2O → H2 + OH, and the effect of an additional water molecule on the reaction, H−(H2O) + H2O → H2 + OH(H2O), have been investigated. The optimal structures and energies of the reactants, products, two stable intermediates, and the transition state connecting the two intermediates have been determined. The additional water molecule does not affect the potential surface congruently: it destabilizes the H(H2O) minimum, but stabilizes the H2 ⃛OH minimum and the transition state connecting the two intermediates. However, it stabilizes the products more than the H2 ⃛OH− minimum. Finally, in line with the reduction in the barrier height, the transition state for the H(H20) to H2 ⃛OH− isomerization moves further along the reaction path.
Interaction of Chlorine with Hydrogenated Diamond Surface
Authors: Ando Toshihiro , Yamamoto Kazuo , Suehara Shigeru , Kamo Mutsukazu , Sato Yoichiro , Shimosaki Shinji , Nishitani‐Gamo Mikka
Published: May 2015

The interaction of chlorine with the hydrogenated diamond surface has been investigated by diffuse reflectance Fourier‐transform Infrared (FTIR) spectroscopy, temperature‐programmed desorption (TPD) spectroscopy, and X‐ray photoelectron spectroscopy (XPS). The hydrogenated diamond surface is chlorinated by thermal reaction in chlorine. Hydrogen chemisorbed on the diamond surface is abstracted by chlorine and the chemisorption of chlorine is yielded. Hydroxyl groups are produced by treatment of the chlorinated diamond with water vapor at room temperature. Amino groups are produced by treatment of the chlorinated diamond with ammonia at 425 °C.
Reaction Dynamics of Mg(3s3p1P1) with H2
Authors: Liu Dean‐Kuo , Chin Thou‐Long , Ou Yaw‐Ren , Huang Cheng‐Tsung , Lin King‐Chuen
Published: May 2015

We measured the temperature dependence of rotational population distribution of the nascent product MgH(2∑+) in the reaction of Mg(3s3p1P1) with H2. The results indicate that the reaction is dominated by an Mg‐insertive mechanism, consistent with the isotope effect reported previously. We also presented the vibrational population distribution, and thereby found that two parallel reaction pathways are responsible for the subject reaction following Mg‐H2 collision in a bent configuration. The major one produces MgH in higher rotational levels and comparable v″ = 0 and v″ = 1 populations, while the other minor one produces MgH in low rotational levels and preferentially v″ = 0. By means of a two‐dimensional potential energy sur‐face(PES) calculation, a deep insight into the reaction pathways has been gained. The resulting PES's information reveals the possibility of a nonadiabatic transition between the excited 1B2 PES and the ground PES. The bent intermediate MgH2 near the surface crossing starts trajectories either smoothly following the dissociation coordinate of Mg‐H distance or attractively falling down through a linear HMgH geometry before breaking apart. The former trajectory accounts for the minor reaction pathway to produce MgH, while the latter one responses to the major reaction pathway. The impact of isotope and temperature effects on MgH can also be readily explained with use of the calculated PES's.
Nuclear Wavepacket Study on Unimolecular Reactions of Hydrogen Cyanide Excited by Femtosecond Pulsed Lasers
Authors: Umeda Hiroaki , Fujimura Yuichi
Published: May 2015

The unimolecular reaction dynamics of hydrogen cyanide (HCN) induced by IR multiphoton, femtosecond excitations was studied on the basis of the nuclear wavepacket theory. Both hydrogen dissociation and migration of HCN are taken into account. In evaluating the propagation of the wavepackets in the two‐dimensional potential surface, position grid and eigenfunction basis sets were adopted for the dissociation and hydrogen migration coordinates, respectively. The ground state potential energy function and the dipole moment function calculated by using a MCSCF ab‐initio procedure were used. Laser‐intensity dependencies of the dissociation and hydrogen migration probabilities were evaluated. Effects of mode‐couplings on the hydrogen migration were examined.
Study of the Reaction Rate, in the Critical Regime, of a Solute Embedded in a Lennard‐Jones Crystal
Authors: Singh Surjit , Wilse Robinson G.
Published: May 2015

In a recent study, we showed that the Grote‐Hynes theory for the chemical reaction rate exhibits critical phenomena near a critical coupling strength and large solvent response times. Therefore it is possible to write (he rate in a scaling form with a universal scaling function that depends only on the short‐time behavior of the memory friction kernel. This study involved a friction kernel involving only one relaxation time. In this paper, we apply the same techniques to a crystal friction involving multiple timescales. We show that the rate shows critical behavior and obtain the universal scaling function. We find the asymptotic behavior of the rate in different regimes of interest. In this way, we uncover the rich mathematical structure of the reaction rate associated with the crystal friction with multiple timescales.
Kinetics of Depletion of Electronically Excited Ti Atom by CH4, C2H2, C2H4 and C2H6
Authors: Honma K.
Published: May 2015

The kinetics of depletion of ground state Ti(a3F) and electronically excited state Ti(a5F) upon interactions with CH4, C2H2, C2H4, and C2H6 are studied in a fast‐flow reactor at a He pressure of 0.70 Torr. No depletion of ground state Ti(a3F) was observed upon interaction with all hydrocarbons studied here. Two alkanes, CH4 and C2H6, were also quite inert for depletion of the excited state Ti(a5F), On the other hand, C2H2 and C2H4 deplete the excited state Ti(a5F) very efficiently. Rate constants were determined to be (266 ± 86) and (476 ± 88) × 10−12 cm3s−1 for Ti(a5F) + C2H4 and Ti(a5F) + C2H2, respectively. These large rate constants compared with the ground state Ti were explained by an electron donor‐acceptor interaction model that works in the interaction between C2H4 or C2H2 and the excited state with unfilled 4s orbital.
Laser‐Assisted Chemical Vapor Deposition of Boron
Authors: Boman M. , Bäuerle D.
Published: May 2015

Ar+ laser‐induced chemical vapor deposition (LCVD) of B from gaseous mixtures of BCl3 and H2 has been investigated for temperatures between 1000 K and 2250 K and for partial pressure within the ranges 25 mbar ≤ p(BCI3) ≤ 800 mbar and 10 mbar ≤p(H2) ≤ 400 mbar. For the lowest temperatures, deposition is controlled by the chemical kinetics which, with p(BCI3) = p(H2) = 100 mbar, is characterized by an apparent chemical activation energy of about 26.5 kcal/mol. In this regime, the deposited boron is amorphous. At high temperatures, deposition becomes limited by gas‐phase transport and polycrystalline boron with βrhombohedral structure is obtained.
SO2 Surface Chemistry on Metal Substrates
Authors: Sun Y.‐M. , Sloan D. , White J. M.
Published: May 2015

The surface chemistry, induced by thermal and non‐thermal methods, of SO2 on metal substrates is reviewed. The substrate temperature during dosing is important; regardless of metal, adsorption is dissociative at 300 K and molecular at 100 K. On Ni, Pd, and Pt, molecular adsorption occurs through the S and one O atom, and the molecular plane is perpendicular to the surface. However, on Ag and Cu, adsorption occurs only through the S with the molecular plane perpendicular to the surface. The differences can be attributed to the structure of the metal's molecular orbitals and their interactions with the SO2 orbitals. Upon heating, SO2 dissociates on all transition metal surfaces with the exception of Ag, Au, and Cu, where only molecular desorption occurs. On Pt, Fe, and Pd, additional reactions are observed between SO2 and its dissociation products. The nonthermal reactions induced by photons and electrons for monolayer coverages of SO2 on Ag (111) are dominated by molecular desorption. Desorption cross sections for 313 nm photons and 50eV electrons were 2.8 × 10−20 cm2 and −1 × 10−16 cm2, respectively. Nonthermal excitation mechanisms and quenching processes as well as interesting characteristics of SO2 under irradiation are also reviewed.
Synthesis of Heterobimetallic Phosphido‐Bridged W‐Mo Complexes with Chelating dppe and dppm Ligands
Authors: Wu Wen‐Jin , Hsu Jiun‐Yi , Wen Yuh‐Shang , Shyu Shin‐Guang
Published: May 2015

Reactions between and bidentate phosphines (dppm and dppe) produced complexes and with chelating dppm and dppe ligands as only products. No bridging bidentate phosphine complex was observed. Both complexes were spectroscopically characterized.
Gel Chemistry in Synthesis of AIPO4 Molecular Sieves
Authors: Prasad S. , Chen Wen‐Hua , Liu Shang‐Bin
Published: May 2015

The chemistry of ternary systems, Al2O3‐P2O5‐H2O, particularly on addition of an acid or an amine as fourth component was investigated with 31P and 27Al NMR spectroscopy.