bluuebunny/crossref_metadata_2025 huggingface dataset:
Alkaloids from Houttuyniae Cordata
Authors: Jong Ting‐Ting , Jean Meei‐Yueh
Published: May 2015

The crude extract of Houttuyniae cordata showed potent anti‐platelet and cytotoxic activities. The constituents of this plant, two pyridine alkaloids 1 and 2, along with three aporphine related alkaloids, cepharanone B (3), cepharadione B (4) and 7‐choloro‐6‐demethyl cepharadione B (5) were characterized by spectral methods. Among them, long chain substituted pyridine alkaloids 1 and 2 are rare in nature, and the 7‐choloro‐6‐demethyl cepharadione B (5) is isolated for the first time.
Limonoids from the Stem Bark of Clausena Excavata
Authors: Wu Tian‐Shung , Huang Shiow‐Chyn , Lai Jeng‐Shiow
Published: May 2015

A new pentanortriterpenoid, 1‐O‐methylclausenolide (1) and a known limonoid, zapoterin (4) were isolated from the stem bark of Clausena excavata (Rutaceae). Their structures were elucidated by spectral analysis and chemical transformation.
Functionalized Porphyrin Discotic Liquid Crystals: Photoinduced Charge Separation and Trapping
Authors: Fox Marye Anne , Bard Allen J. , Pan Horng‐Long , Liu Chong‐Yang
Published: May 2015

Individual members of a family of highly absorptive porphyrins bearing symmetrically positioned flexible side chains form discotic liquid crystalline mesophases at modest temperature ranges. The order of this phase is preserved when a thin layer of this self‐assembled material is cooled to room temperature. Exposure of such films to visible excitation, with or without an externally applied electrical field, produces photovoltaic effects and/or charge trapping. The latter effect constitutes the basis for optoelectronic information storage.
Kinetics and Mechanism of the Reaction of Chloroplatinum(II) Complexes with Alkyl Radicals
Authors: Chen Wen‐Jang , Espenson James H. , Bakac Andreja
Published: May 2015

The reaction between certain platinum(II) complexes and alky radicals produces an unstable organoplatinum(III) intermediate, {PtIII ‐R}. The kinetics of this step were evaluated by laser flash photolysis with ABTS2 (2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonate) ion) and TMPD (tetramethylphenylenediamine) as kinetic probes. The rate constants for PtCl42− are: kPt/108 L mol−1 s−1 = 5.2, 2.8 and 0.27 for CH3, C2H5, and CH2Cl in aqueous solution at pH 1. Those with cis‐Pt(NH3)2Cl2 are somewhat smaller, and those for Pt(NH3)42+ too small to measure will) this technique. The product analysis indicates that the decomposition of organoplatinum takes place by hydrolysis and (for R = C2H5 only) by β‐elimination, The kinetic isotope effect on die β‐elimination of DCH2CH2PtC4,2− is kH/kD = 1.2. The β‐elimination step produces a PtIII‐hydride that releases hydrogen gas and forms {PtIII‐OH}. The short‐lived Pt(III) intermediate may disproportionate or oxidize the CoII complex that is produced in the radical‐generating step.
Rate Coefficients of the Reactions of CN and NCO with O2 and NO2 at 296 K
Authors: You Yih‐Yuan , Wang Niann S.
Published: May 2015

The rate coefficients of the reactions of CN and NCO radicals with O2 and NO2 at 296 K: (1) CN + O2 → products; (2) CN + NO2 → products; (3) NCO + O2 → products and (4) NCO + NO2 → products have been measured with the laser photolysis‐laser induced fluorescence technique. We obtained k1 = (2.1 ± 0.3) × 10−11 and k2 = (7.2 ± 1.0) × 10−11 cm3 molecule−t s−1 which agree well with published results. As no reaction was observed between NCO and O2 at 297 K, an upper limit of k3 < 4 × 10−17 cm3 molecule−1 S−1 was estimated. The reaction of NCO with NO2 has not been investigated previously. We measured k4 = (2.2 ± 0.3) × 10−11 cm3 molecule−1 s−1 at 296 K.
Spectrophotometric Determination of Palladium(II) with n‐Hydroxy‐N,N‐Diphenylbenzamidine and 1 ‐(2‐Pyridylazo)‐2‐Naphthol
Authors: Jha Anju , Mishra R. K.
Published: May 2015

A spectrophotometric method to determine palladium(II) at trace levels is based on the extraction of palladium(II) as a binary complex with N‐hydroxy‐N,N′‐diphenylbenzamidine (HDPBA) in chloroform at pH 5.0 ± 0.2. The complex shows maximum absorbance at 400 nm with molar absorptivity 6.4 × 103 L mol−1 cm−1. The sensitivity of the Pd(II)‐HDPBA complex was enhanced by the addition of l‐(2‐pyridylazo)‐2‐naphthol (PAN). The green coloured complex shows maximum absorbance at 620 nm with molar absorptivity 1.58 × 104 L mol−1 cm−1. Sandell's sensitivity and the detection limit of the method are 0.0067 μg cm−2and 0.1 μg Pd(II) mL−1, respectively. Most common metal ions associated with palladium metal do not interfere. The effects of various analytical parameters on the extraction of the metal are discussed.
Magnetic Hyperfine Mössbauer Spectra of Ferrocenyaldimines‐FeCl3 Adducts
Authors: Lee Chiu‐Jhen , Wei Ho‐Hsiang
Published: May 2015

Ferrocenylaldimines (Fc‐CH=N‐R) were prepared by condensation of Schiff base of formylferrocene with polyacenylamines RNH2; R = naphthyl, anthracenyl and pyrenyl groups. This step was followed by oxidation with FeCl3 to give [Fc‐CH=NR]‐FeCl3 adducts. The electronic state of iron in these adducts was investigated by means of 57Fe Mössbauer spectra except for [Fc‐CH=N‐Pyr]‐FeCl3 showed that only a doublet was observed at ambient temperature. As the temperature was decreased below 200 K, additional magnetic hyperfine splitting was observed characteristic of ferric oxide.
Structure and Reactivity of Iron(0)‐Phenyltellurolate [PPN][PhTeFe(CO)4]
Authors: Liaw Wen‐Feng , Chiou Show‐Jen , Lee Way‐Zen , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

Anionic iron(0) tetracarbonyl with terminal phenyltellurolate ligand PhTe−, [PhTeFe(CO)4]−, has been synthesized and characterized. The title compound was obtained by addition of (PhTe)2 to [PPN][HFe(CO)4] THF solution dropwise. [PPN][PhTeFe(CO)4] crystallizes in the monoclinic space group C c, with a = 16.119(4) Å, b = 13.141(3) Å, c = 19.880(8) Å, β = 93.04(3)°, V = 4205(2) Å3, and Z = 4. The [PhTeFe(CO)4]− anion is a trigonal‐bipyramidal complex in which the phenyltellurolate ligand occupies an axial position with Fe‐Te bond length 2.630(5) Å and the Fe‐Te‐C(Ph) angle is 103.4(5)°. The neutral iron(0)‐telluroether compound, (PhTeMe)Fe(CO)4, was prepared by alkylation of the [PhTeFe(CO)4]−. Protonation of [PhTeFe(CO)4]−and reaction of H2Fe(CO)4 and PhTe)2 ultimately lead to formation of the known dimer Fe2(μ‐TePh)2(CO)6 and H2.
Reactivity of fac‐[PPN][Fe(CO)3(TePh)3]: Structure of Fe2(μTePh)2(NO)4
Authors: Liaw Wen‐Feng , Homg Yih‐Chern , Ou Der‐Shiaw , Lee Gene‐Hsiang , Peng Shie‐Ming
Published: May 2015

Addition of NOBF4 to fac‐[PPN][Fe(CO)3(TePh)3] in THF at ambient temperature results in formation of Fe2(μ‐TePh)2(NO)4l Fe2(−TePh)2(CO)6 and organic products. Methylation of fac‐[PPN][Fe(CO)3‐ (TePh)3] by Mel or [Me3O][BF4] leads to the known dimer Fe2(μ.‐TePh)2(CO)6 and organic products. Fe2(μ‐TePh)2(NO)4 crystallizes in the orthorhombic space group P bca, with a = 12.701(5) Å, b = 6.7935(16) Å, c = 21.299(9) Å, V = 1837.8(11) Å3, and Z = 4. The core geometry of Fe2(μ‐TePh)2(NO)4 is best described as a Fe2Te2 planar rhombus with Te‐Fe‐Te bond angle 112.09(4)°. A Fe‐Fe bond (length 2.827(2) Å) is proposed for Fe2(μ‐TePh)2(NO)4 on the basis of the 18‐electron rule. The iron atom adopts a distorted tetrahedral geometry with acute bridge Fe‐Te‐Fe angles 67.91(3)°, and bridging Fe‐Te bond of length 2.53(1) Å.
Synthesis of Five Coordinate Spirocyclic Germanium(IV) Complexes Containing Diethanol Amine
Authors: Chen Deng‐Hai , Chiang Hung‐Cheh
Published: May 2015

Reaction of dihydroxo(2,2′‐iminodiethanolato‐AWO′) germanium(IV) (A) or dihydroxo(2,2′‐methyliminodiethanolato‐N,O.O′) germanium(IV) (B) with bidentate ligands, e.g. diol, α‐hydroxy acid, oxalic acid, 2,6‐pyridinedicarboxylic acid, or 2‐aminophenol in a mixture of ethanol and xylene mixture yielded a series of unsymmetrical spiro‐germanium complexes 1‐6. These complexes were characterized by NMR, IR, mass spectra and elementary analysis. The 1H NMR spectrums of all these compounds show the existence of an intramolecular N–Ge bond. X‐ray analysis of compound 6 shows a short N–Ge bond (2.08 Å).
The Total Synthesis of (±)‐Camphor and (±)‐Epicamphorenone from Methylcyclopentadiene
Authors: Chang Nein‐Cben , Chiu Chih‐Tsao
Published: May 2015

The total synthesis of (±)‐carnphor and (±)‐epicamphorenone from methylcyclopentadiene are described.
Synthesis and Crystal Structures of Nickel(II) and Copper(II) Complexes of Meso‐3,6,6,9‐Tetramethyl‐4,8‐Diazaundecane‐2,10‐Dione Dioxime
Authors: Fun Hoong‐Kun , Lee Tsong‐Jen , Tahirov Tahir , Lu Tian‐Huey , Luh Hung , Chung Chung‐Sun
Published: May 2015

The nickel(II) and copper(II) complexes of meso‐3,6,6,9‐tetramethyl‐4,8‐diazaundecane‐2,10‐dione dioxime (meso‐HM‐PAO) have an intramolecular hydrogen bond between cis oxime groups. [Cu(meso‐HM‐PAO‐H)(H2O)](NCS) crystallizes in space group P21/n with a = 7.692(1), b = 12.028(2), c=20.235(3) Å, β=93.03(1)°, Z = 4 and Dc=1.46 g/cm3. The final R value for this complex was 0.034 for 2223 observed reflections with I ≥ 2.5σ (I). The Cu(II) coordination is a distorted square pyramid. The Cu(II) ion is five‐coorinated with the diazadioxime N atoms equatorial and water O atom axial. The Cu(II) is 0.12 Å from the equatorial plane towards the hydrate. The equatorial Cu‐N distances span a narrow range, 1.953(3)‐1.999(3) Å. The axial Cu‐O distance is 2.314(3) Å. The thiocyanate group is almost linear. The intramolecular O ⃛O hydrogen bond length is 2.479(4) Å. [Ni(meso‐HM‐PAO‐H)](ClO4) crystallizes in space group P21/c with a = 14.774(3), b = 12.752(3), c = 20.035(4) Å, β = 92.94(3)°, Z = 8 and Dc = 1.51 g/cm3. The final R value for the complex was 0.053 for 4794 observed reflections with F ≥ 4σ (F). The coordination about Ni(II) is a slightly distorted square plane. The Ni(II) ion is 0.0673(7) Å from the best plane of the four donor nitrogen atoms away from the perchlorate ion. The Ni‐N distances span a narrow range 1.863(4)‐1.927(4) Å. There are two molecules per asymmetrical unit resulting in eight molecules being packed in an unit cell; they are bound together by van der Waals interactions. The O‐H ⃛O bonds of these complexes give characteristic infrared absorptions as well as chemical shift of the 1H NMR signal (Ni complex).
A Facile Synthesis of Stable Precursors to 2‐Alkylated‐3‐(phenylthio)‐1,3‐Butadienes
Authors: Chou Shang‐Shing P. , Tai Hai‐Ping
Published: May 2015

3‐Sulfolenes 3 which are stable precursors to 2‐alkylated‐3‐(phenylthio)‐1,3‐butadienes (4) are conveniently prepared.
Calculations on Heterofullerenes: C24N4, C36N4 and C52N4
Authors: Wang Bo‐Cheng , Yu Liang‐Jye , Wang Wen‐Jwu
Published: May 2015

According to geometrical considerations, a method is devised to show a geometric relationship between the tetrahedron and the small heterofullerenes below C60: C24N4, C36N4 and C52N4 all of which belong to the Td point group. These simple geometric relationships also allow us to predict the possible structures of heterofullerenes consisting of more than sixty carbons with the Td symmetry. The number of hexagonal faces (besides the 12 pentagonal faces), vertices and edges of these heterofullerenes are obtained by applying Euler's theorem. Calculated by means of molecular mechanics MM2(87), the minimum energy structure, the bond lengths, the bond angles and the torsion angles for such heterofullerenes were generated. The simple Hückel MO calculations are used to determine the HOMO, LUMO and the energy gap between HOMO and LUMO of C24N4 and C36N4 heterofullerenes. The heats of formation of C28 and C40, C24N4 and C36N4 were calculated according to the MNDO method. The ionization energies, die Δϵ (LUMO‐HOMO) and the resonance energies were investigated with semiempirical MNDO methods for comparison with the stabilities of C28, C24N4 and C28H4. The kinetic and thermodynamic stabilities of such tetrahedral derivatives of heterofullerenes were predicted based on the energy gaps and heats of formation.
Extraction of Betel Quid with Supercritical Carbon Dioxide
Authors: Su Sue‐Guane , Tai Dar‐Fu , Shih In‐Lung , Chiou Tzyy‐Wen
Published: May 2015

Supercritical extraction with CO2 as solvent was adopted to remove alkaloids and safrole from the betel quid. The extraction efficiency was significantly affected by the operating pressure and temperature. Results of sensory evaluation showed that the eating qualities of the betel quid decreased but still satisfied the chewer after the extraction treatment.
Chemical Constituents from the Aerial Part of Rosa Transmorrisonensis
Authors: Kao Shu‐Fang , Fang Jim‐Min , Cheng Yu‐Shia
Published: May 2015

The aerial part of Rosa transmorrisonensis Hayata contains chemical constituents of long‐chain alkanes, linolcnic acid, squalenc, catechin, sitosterol, sitosteryl‐)β‐D‐glucoside, 3,4,5‐trimethoxyphenyl‐(β‐D‐glucoside, 9‐glucosyl‐4,7E‐megastigmadien‐3‐one, oleanolic acid and eight ursolic acid derivatives. Among them, the new compound 14a was determined to be 2,3,4,6‐tetraacetyl‐(19α‐hydroxy‐2α,3α,24‐triacetoxyurs‐12‐en‐28‐oyl)‐β‐D‐glucopyranoside by spectral methods.
Fluorescence Quenching of Aminopeptidase‐I from Pronase
Authors: Wu Chien‐Hou , Lin Wann‐Yin
Published: May 2015

Aminopeptidase‐I from pronase contains five tryptophan residues, determined by modification with N‐bromosuccinimide and MCD measurments. The fluorescence of the enzyme is quenched by acrylamide, a neutral quencher, but not by iodide, an anionic quencher. The quenching constant for acrylamide is about one tenth that of acctyltryptophan in aqueous solution because of the steric effect of the large protein molecule. The inaccessibility of iodide to the tryptophans is probably due to the anionic environment of the fluorophores created by the large content of Asp and Glu in the enzyme. Aminopeptidase‐I is quenched by Cu(II) and Co(II) through the formation of a nonfluorescent ground‐state complex. The results indicate that there are three accessible tryptophans for Cu(II) and two for Co(II) suggesting that some tryptophans are buried inside the enzyme and are thus inaccessible to the quencher. In the presence of a competitive inhibitor, the enzyme contains one fewer accessible tryptophan for Cu(II) indicating that this tryptophan is located in the active center. The CD spectrum of the enzyme in the far UV region is unaltered by the presence of Ca(II), whereas that in the aromatic region is enhanced significantly. The perturbation of the CD spectrum probably results from the local conformational change induced by Ca(II) or from the rigidity of the tryptophan being enhanced by the bound Ca(II).
“Truncated” Pagodanes — Synthesis of Functionalized [1.1.1.1] and [1.1.1.0] Pagodanes
Authors: Pracht Thomas , Weber Klaus , Fritz Hans , And Lothar Knothe , Prinzbach Horst
Published: May 2015

“Truncated” [1.1.1.1] pagodanes like the [1.1.0.0] and [0.0.0.0] homologues3 and 4 (EStr = 146.1 – 171.5 kcal mol−1, MM2) are potential precursors of unusual unsaturated homoconjugated radical cations and σ‐bishomoaromatic dications. Attempts are presented toward the synthesis of 3 ‐ starting out from [1.1.1.1] pagodane‐4,9‐dione 9 and diaza [2.2.1.1] pagodadiene 11 by cycloelimination (unsuccessful) and by Favorskii‐type ring contraction methodologies. Control experiments with the model diketone 19 documented the limitations for α,α′‐difunctionalization of 9 as the prerequisite for one‐pot double Favorskii‐type ring contraction. A de novo synthesis for such α,α′‐disubstituted derivatives of 9(54) was not sufficiently expeditious to open a practical access to 3. Sequential double bridgehead hydroxylation of 9, successfully practized with model 19, similarly suffered from inherent cage effects and allowed only limited yields of [1.1.1.0] pagodanone 10, the intermediate on the way to 3.
Mass Spectra of Substituted N‐Alkylpyrroles and Related Compounds
Authors: Lin Shaw‐Tao , Shiue Gong‐Yih , Kuo Yueh‐Hsiung , Shih Kae‐Shyang
Published: May 2015

Under El conditions, substituents on N‐alkylpyrroles affect fragmentation of the alkyl groups. The electron‐withdrawing character of the cyano group retarded formation of a N‐methylene cation, and a labile substituent, i.e., ‐CHO, ‐CH2COOMe, competed with an N‐alkyl group to be a initial fragmentation center, MNDO calculation of the heat of formation of possible fragment ions showed that protonated pyridine is the most stable among the isobaric ions.
Scattering of Laser Light from Mixed Micelles
Authors: Cheng Chien‐Hsin
Published: May 2015

Dynamic and static scattering of light was employed to investigate mixed micelles of two homologous anionic surfactants‐sodium octyl sulfate and sodium hexadecyl sulfate, above the phase boundary temperature and critical micelle concentrations (cmc). The results indicate that the mixed micelles change from prolate to sphcrical as the molar ratio SOS/SHS increases from 1 to 8. Below 1 or above 8, the formation of micelles is due to one surfactant dissolving the other.
Chromium Tricarbonyl η6‐Complexes of (η5‐Cyclopentadienyl)(η4‐1,3‐Diphenylcyclobutadiene)Cobalt
Authors: Hong Fung‐E , Chang Yuan‐Terng , Chen Chi‐Tain
Published: May 2015

The reaction of (η5‐cyclopentadienyl)(η4‐1,3‐diphenylcyclobutadiene)cobalt (I) with excess Cr(CO)3py3 in BF3OEt2 yielded two identified heterometallic compounds. Compounds II and III with one and two phenyl rings complcxed with Cr(CO)3 fragment(s), respectively. These compounds were characterized by mass, infrared, 1H and 13C NMR spectra and elemental analysis. The crystal structure of II was determined. The Cr(CO)3 fragment bends inward toward the cyclobutadicne ring due to its electron‐withdrawing ability, in accord with Hunter's postulate. A sharp line due to the non‐complexed phenyl ring was observed in the 1HNMR spectrum, which implies that five protons are magnetically equivalent. The chemical shifts of two protons of the cyclobutadiene ring decreased from I to II then to III, possibly because of diminished deshielding effect from the phenyl ring in (arene)Cr(CO)3.
Statistical Inference of Distribution of Crystal Size by X‐Ray Powder Diffraction
Authors: Chen Po‐Yi , Mou Chung‐Yuan
Published: May 2015

We describe a method to calculate the distribution of sizes of fine crystals from pure powder‐diffraction profile using a method of maximum entropy (MAXENT). We apply a Monte‐Carlo technique of simulated annealing to seek a global minimum of the error surface in fitting this diffraction profile. We consider pure diffraction profile (instrument de‐convoluted) of a powder specimen without lattice imperfection to a significant extent. Under these circumstances, the distribution of the pure diffraction profile can be attributed to the distribution of crystallite size. We applied this method to three cases of crystal sizes having a highly inhomogeneous distribution with certain noise‐tolerance. The results agree well with synthetic data of diffraction.
Synthesis of Five‐Membered Ring Heteroaryl Pyridines from Heteroaryllithium and N‐Ethoxycarbonylpyridinium Chlorides
Authors: Lai Long‐Li , Shin Li‐Hua , Lin Pen‐Yuan , Wang Jy‐Shih , Shiao Min‐Jen
Published: May 2015

Furylpyridines, thienylpyridines, and imidazolylpyridines were obtained regioselectively in 40‐67% yields from the reaction of heteroaryllithiums with N‐ethoxycarbonylpyridinium chloride or N‐ethoxycarbonyl‐3‐methylpyridinium chloride in the presence of Cul in a catalytic amount at −78 °C or −50°C, then followed by oxidation. The regioselectivity of this reaction depended upon temperature of the reaction and the nature of heteroaryllithiurn.
Diastereoselective Alkylation of (Diene‐Aldehyde)Fe(CO)3 Complexes with Functionalized Zinc‐Copper Reagents NuCu(CN)Znl
Authors: Wang Jeng‐Long , Ueng Chuen‐Her , Yeh Ming‐Chang P.
Published: May 2015

Addition of functionalized zinc‐copper reagents to the title complexes proceeds in a highly diastereoselective fashion to afford dienol complexes. The relative configurations of adducts 3d were determined by single X‐ray diffraction analysis.
Study of Crown Ether Surfactants with Pyrene Fluorescence Probe
Authors: Jane Yih‐Song , Shin Jeng‐Shong
Published: May 2015

Both C10H21‐18‐crown‐5 and C10H21‐15‐crown‐5 were successfully synthesized and exhibited the distinctive characteristics of surfactants. Fluorescence of pyrene was used as a sensitive probe to study the micelle formation of the crown ether surfactant. The variation of the intensity ratio (I1/I3) of the first and third vibrational fluorescence bands of pyrene was employed to determine the critical micellar concentration (CMC). Both CMC and cloud points were found to depend on the kinds of cations and the ionic strength in solution. The quenching of pyrene fluorescence is also investigated for some cations under micelle and non‐micelle circumstances.
Synthesis of Conjugated α‐D‐Hexenopyranosiduloses
Authors: Liang David Woei‐Ming , Lin Shu‐Fu , Yap Wen‐Yen , Deng Yea‐Wen
Published: May 2015

α‐Enone sugars such as 2,3‐dideoxy‐α‐D‐hex‐2‐enopyranasid‐4‐uloses I and 3,4‐dideoxy‐α‐D‐hex‐3‐enopyranosid‐2‐uloses II involving the corresponding C‐2 and C‐4 methylated sugars 5, 10a and 10b were successfully synthesized from D‐glucose in high yields by simple laboratory processes.
Double Michael Additions of Lithium Enolate of 1,4‐Dioxaspiro[4.5]dec‐6‐en‐8‐One to Acrylates
Authors: Hung Shang‐Cheng , Liao Chun‐Chen
Published: May 2015

Double Michael additions of lithium enolaie of 1,4‐dioxaspiro[4.5]dec‐6‐en‐8‐one to four acrylates afforded bicyclo[2.2.2]octan‐2‐ones with high regio‐ and stereoselectivities in moderate yields.
Synthesis and Diazotization of Diethyl 6‐Amino‐2‐Hydroxyazulene‐1,3‐Dicarboxylate and Its 2‐Acetoxyl Derivative
Authors: Huang Tian‐Chyuan , Morita Tadayoshi , Lin Bing‐Bing , Lin Yun‐Shan
Published: May 2015

Diethyl 6‐amino‐2‐hydroxyazulene‐1,3‐dicarboxylate (6a) and 2‐acetoxyl derivative (6b) were synthesized by reduction of the 6‐azido derivatives (5a,b) with zinc/acetic acid in excellent yields.5aand5bwere prepared by azidation of diethyl 2‐acetoxy‐6‐bromoazulene‐1,3‐dicarboxylate (4). Diazotization of6awith sodium nitrite in the presence of concentrated sulfuric acid in dioxane gave diethyl 2‐hydroxy‐ (7a), 2,6‐dihydroxy‐ (8a), and 2‐hydroxy‐6‐[2‐(2‐hydroxyethoxy)ethoxy]‐azulene‐1,3‐dicarboxylates (9a), in 5, 35 and 20% yields, respectively. Similar reaction of6bgave the corresponding acetates7b, 8b, and9b, compounds of the same type from6a. No evidence for the formation of 6‐diazo‐1,3‐diethoxycarbonyl‐2(6H) azulenone (2b) was obtained in the employed reaction conditions.
Asymmetric Reduction Using Lithium Aluminum Hydride Modified with Chiral Ligand Prepared from (1R)‐(‐)‐Myrtenol
Authors: Lu Ta‐Jung , Liu Shew‐Wen
Published: May 2015

The reduction of prochiral ketones with a chiral reducing reagent, prepared from lithium aluminum hydride and (1R,2S,3S,5R)‐(‐)‐10‐methoxypinanediol (2), produced secondary chiral alcohols in good chemical yields (57–98%) and moderate enantiomeric excess (8–72%).
Constituents of Leaves of Uncaria Hirsuta Haviland
Authors: Wu Tian‐Shung , Chan Yu‐Yi
Published: May 2015

Nine compounds, ursolic acid (1), β‐sitosteryl glucoside (2), umbelliferone (3), uncarine‐A (4), chlorogenic acid (5), rutin (6), neohesperidin (7), quercitrin (8)and afzelin (9) were isolated and characterized from fresh leaves of Uncaria hirsuta. Their structures were elucidated by spectral methods. Among them, uroslic acid (I) exhibited a cytotoxic principle of this plant.
Constituents of Flowers of Murraya Paniculata
Authors: Lin Jung‐Kuei , Wu Tian‐Shung
Published: May 2015

Three new coumarins, yuehgesin‐A (1), ‐B (2) and ‐C (3) and 22 compounds—murracarpin (4), mupanidin (5), isomeranzin (6), murralongin (7), scopoletin (10), 7‐methoxy‐8‐(l′‐ethoxy‐2′‐hydroxy‐3′‐methyl‐3′‐butenyl)coumarin (11), umbelliferone (12), paniculatin (13), braylin (14), auraptenol (15), meranzin hydrate (16), minumicrolin (17), scopolin (18), caffeine (19), 3,3′,4′,5,5′,6,7‐heptamethoxyflavone (20), 4‐hy‐droxybenzaldebyde (21), p‐hydroxybenzoic acid (22), cis‐ and trans‐ferulic acid (23), cis‐ and transmethyl ferulate (24) and trans‐ethylferulate (25)—were isolated and characterized from fresh flowers of Murraya paniculata collected in Taiwan. Their structures were elucidated by spectral methods. The chemotaxonomy of Murraya paniculata is, discussed.
Topical Problems in Elemental Analysis of Advanced Ceramic Materials
Authors: Garten Rainer P. H.
Published: May 2015

Selected prominent problems in the analysis of advanced ceramic materials are surveyed. The importance of reliability of results is discussed in the field of elemental trace‐ and microanalysis in view of its interaction with economy, power of detection, local resolution and speciation selectivity. Particular problems in the analysis of major constituents, trace components and microlocal distributions are based on the striking propertics of ceramics; they are exemplified. Analytical assistance must start from the beginning of the production processing, in the preparation of the powdered base materials. Determination of the stoichiometry requires high accuracy and differentiation of chemical species in bulk and surface analysis of ceramic base powders. Element trace determination by direct instrumental methods requires standard reference materials for calibration; these are currently inavailable in a sufficient variety. For optimum reliability and power of detection, element traces must be prepared in isolated form in a small excitation volume for analysis.

A review on the state‐of‐the‐art of wet‐chemical combined procedures is presented. Decomposition position procedures are emphasized, due to their risk of contributing severe systematic error. Combustion in elementary fluorine is presented for decomposition of refractory materials. The performance of some direct procedures is discussed. Very efficient methods are available for element trace determinations in ceramic materials, offering high detection power. Several approaches for high‐resolution local microanalysis in non‐conductive ceramic materials are identified as the most promising development in the analysis of sintered compact ceramic products and devices.
Initial Results From the Non‐Methane Hydrocarbon Intercomparison Experiment
Authors: Apel Eric C. , Calvert Jack G.
Published: May 2015

The Non‐Methane Hydrocarbon Intercomparison Experiment (NOMHICE) is described. This experiment has been designed to evaluate analytical techniques currently being used by scientists throughout the world to measure ambient atmospheric hydrocarbon concentrations. NOMHICE consists of a series of planned experiments designed to identify existing problems in participating scientist's laboratories and to correct them. The various experimental steps (or phases) have been scheduled in order of increasing complexity so that problems can be addressed as they arise. Results are presented for the initial phases of this program. Phase 1 involved the circulation of a 2 component gravimetrically prepared standard to 40 laboratories throughout the world. Participants were asked to quantify but not identify the components. Phase 2 involved the circulation of a more complex 16 component gravimetrically prepared mixture to 32 participants. Participants were asked to identify and quantify the components. Further tasks are described which will be carried out in the future.
In Vivo Monitoring of Neurotransmitters with Voltammetry and Smallbore HPLC
Authors: Justice Joseph B. , Paige Newton A. , Smith Amanda D.
Published: May 2015

The temporal and concentration response of microdialysis probes in vivo was characterized. The temporal response was monitored using step changes in dopamine (DA) concentration which were followed with one minute sampling using smallbore HPLC. The response under three conditions was examined: in vitro sampling of DA, in vitro infusion of DA, and local infusion of DA. The dialysate DA concentration stabilized within two minutes after each change. These results suggest that relatively fast changes in DA levels in tissue can be followed by microdialysis probes. The rapid stabilization also suggests that the DA concentration profile does not extend very far from the probe.

To characterize the concentration response, the linearity of the gain or loss of DA diffusing between the probe and tissue was determined. The difference in the inflow and outflow concentrations was plotted as a function of the inflow concentration. The correlation coefficient of the linear regression curve was 0.99. The zero point intercept, the extracellular concentration of DA, was 3.8 nM and the slope, or recovery, was 63.4%. There was no break at the zero point which is indicative of symmetrical diffusion into and out of the probe.
Applications of Laser‐Enhanced Ionization In Analytical Chemistry
Authors: Lin King‐Chuen
Published: May 2015

Various applications of laser‐enhanced ionization (LEI) in analytical chemistry are reviewed. This technique was applied to determine some physical quantities associated with a flame through development of an appropriate model. Determinations of flame temperature and atomization efficiency of an element in the flame are examples. As trace analysis is an important application of this technique, we compare the ion yield induced in a two‐step LEI with that in a one‐step LEI. The factors governing the ion enhancement via two‐step excitation are examined in order to make efficient use of the two‐step LEI apparatus. A novel technique was designed to couple flow‐injection analysis to a conventional LEI device; in this manner, electrical interference, a severe problem inherent in LEI, was successfully removed.
Liquid Chromatography with Pulsed Amperometric Detection for Speciation of Mercury
Authors: Hsi Tai‐Sung , Tsai Jian‐Shyun
Published: May 2015

Liquid chromatography with pulsed amperometric detection (PAD) at an Au electrode was successfully applied for speciation of mercury: inorganic mercury, methylmercury and ethylmercury. The optimized conditions for triple‐step potential waveforms utilized in PAD were: E1 1800 mV, t1 50 ms; E2 300 mV, t2 3850 ms; E3 750 mV, t3 100 ms; mercury oxidation was monitored at E3. With the eluent of HClO4 (0.10 M) + KCl (1.0 mM) + CH3CN (1.0%) at a flow rate 0.80 mL/min, three mercury species were fully separated in 6 min on a glass column (3 mm × 10 cm) packed with Chemcosorb C18 (5 μm). However, the first peak (inorganic mercury) was commonly overlapped by the solvent front. The relative standard deviations (n = 6) for methylmercury (15 ppb) and ethylmercury (30 ppb) were 4.2% and 2.8%, respectively. The linear range tested was 2 – 500 ppb (r = 0.9998) for methylmercury, and was 4 – 1000 ppb (r = 1.000) for ethylmercury. The detection limits (S/N = 3) were 1.2 ppb and 1.8 ppb for methylmercury and ethylmercury, respectively. The results of determination of the mercury‐containing species thimerosat in three commercial contact‐lens solutions agreed satisfactorily with the expected values.
Microanalysis Using Secondary Ion Mass Spectrometry
Authors: Ling Yong‐Chien
Published: May 2015

Secondary ion mass spectrometry (SIMS) has inherent features of high sensitivity, great dynamic range, and capability to provide spatially resolved chemical information making it well suited for trace and microanalysis of diverse materials. The various SIMS methods used to derive the boron distribution in hepatoma cells, to investigate the intcr‐iayer reactions in multi‐layer ceramic structural materials, and to evaluate the effects of fabrication on microstructural and functional properties in semiconductor devices, are presented to illustrate possible roles of SIMS in microanalysis.
Solvent Effect on Solvolytic Reactivities of 1‐Aryl‐2,2‐Dimethyl‐1‐Propyl Tosylates Containing Ortho‐Methyl Groups. Inconsistency between Theoretical Calculations and Experimental Results
Authors: Liu Kwang‐Ting , Tang Chung‐Shin , Chin Chien‐Pu
Published: May 2015

Solvolyses of tosylates IIB and IIC in a variety of solvents were found to give excellent linear log k ‐YBnOTs plots (R = 0.997 and SD = 0.022) and negative ΔS≠ for IIB, but slight deviations (R = 0.987 and SD = 0.047) from lineation and positive ΔS≠ for several cases for IIC. Limiting SN1 mechanisms with steric hindrance to resonance and solvent intervention at the cationic transition state could thus be confirmed. The inconsistency between theoretical and observed trend of ΔH≠ is attributed to the neglect of solvent effect in MO calculations. Deductions linking theoretical calculation and solvolytic experiments should be drawn with caution.
Protease‐Catalyzed Peptide Synthesis: Basic Principles, New Synthesis Strategies and Medium Engineering
Authors: Jakubke Hans‐Dieter
Published: May 2015

The application of enzymes to perform selective transformations is the central aim of industrial biocatalysis. Since a simple handled C‐N ligase is not available, the only alternative of general practical interest for enzymatic peptide bond formation are proteases due to the principle of microscopic reversibility. The stereo‐ and regiospecifitity of proteases, which guarantee racemization‐free segment condensation and require only minimal side‐chain protection, are significant for preparative purposes. Unfortunately, proteases are not perfect acyltransferases. Both unwanted proteolytic side reactions and the hydrolysis of the acyl‐enzyme in the kinetic approach are the major problems in enzymatic peptide synthesis. The object of this paper was to demonstrate several new synthesis strategies including medium engineering that enables one to bypass unfavorable reaction routes. Planning and optimization of enzymatic peptide synthesis require the S′ subsite mapping of proteases and the knowledge of additional basic parameters that determine the reaction course.
Classical Trajectory Study of HF Desorption on LiF(001) Surface
Authors: Shiang Keh‐Dong
Published: May 2015

We report a classical trajectory study of the molecular desorption of a vibrationaly excited HF adsorbed on a corrugated LiF(001) surface. The desorption is induced by either a vibrational deexcitation of the adsorbed molecule (vibrational desorption) or an active motion of the surface ion (thermal desorption). A brief description of the calculation of the gas molecule/surface interaction potential is first presented. By applying this potential, Hamilton's equations of motion can be numerically integrated with the initial conditions selected, thus the dynamics is simulated. The result gives a clear indication about the features of the evolution of the vibrational, rotational and translational energies with increase of time. The angular momentum and translational energy distributions of the desorbed molecule are presented. Desorption probabilities for different initial states of the adsorbed molecule are also predicted, which are influenced by the polar‐angle‐dependent potential and the excitation of the initial vibrational level. The surface phonon mode is found to be strongly coupled to the vibrational, rotational, translational modes of the molecule and surface bond.
Effect of Temperature and Inhomogeneities on Binding of a Ligand to Haeme Proteins
Authors: Liao Dah‐Wei , Yang Dah‐Yen , Sheu Sheh‐Yi , Hayashi Michitoshi , Tang Chu‐Kang , Suzuki Satoru , Alden Rhett , Lin Sheng Hsien
Published: May 2015

We apply a quantum‐mechanical theory of rate processes to treat the recombination of ligands to haeme proteins such as myoglobin. Emphasis is placed on the effect of temperature in the low‐temperature regime.

We present a theory of time‐resolved spectra pertaining to protein dynamics. We emphasize the analysis of the entire spectrum rather than spectral shifts as a function of time.
Capillary Zone Electrophoresis of Eleven Priority Phenols with Amperometric Detection
Authors: Chen I‐Chih , Whang Chen‐Wen
Published: May 2015

A scheme for separation and detection of eleven priority phenols using capillary zone electrophoresis (CZE) coupled with amperometric detection is described. With a capillary of I.D. 50 μm and length 62.5 cm at 9 kV and an electrophoretic buffer of 20 mM CHES (pH 10.1), complete separation of the eleven compounds was achieved in less than 17 min. Amperometric detection was carried out using a carbon fiber microelectrode of diameter 9 μm inserted into the end of the detection capillary. Linearity over two orders of magnitude was generally obtained for the eleven priority phenols. With an electrode potential+1.10 V (vs. Ag/AgCl reference), the concentration limits of detection were in the sub‐ppm (10−6 M) level. This method was successfully applied to analysis of priority phenols in industrial waste water.
Synthesis and Crystal Structure of CpFe(CO)l(η1‐Ph2PCH2P(O)Ph2)
Authors: Hsu Ming‐Ann , Yeh Wen‐Yann , Peng Shie‐Ming , Lee Gene‐Hsiang
Published: May 2015

CpFe(CO)I(η1‐Ph2PCH2P(O)Ph2) 2 was obtained in small yield from reaction of [CpFe(CO)]2[μ‐(Ph2P)2CH2] with diiodine in benzene, or prepared in 82% yield on treating CpFe(CO)I(η1‐Ph2PCH2PPh2) 1 with H2O2. Compound 2 crystallizes in the space group P21/n, with a = 8.441(2) Å, b = 10.054(2) Å, c = 33.343(8) Å, β = 92.33(2)°, Z = 4, V = 2827(1) Å3, RF = 0.057, and Rw = 0.056.
Multiple Enantioselection by an Enzyme‐Catalyzed Transacylation Reaction
Authors: Lin Gialih , Chen Show‐Jane , Sun Hwey‐Lin
Published: May 2015

Multiply enantioselective enzyme‐catalyzed transacylation reactions are described. Two instances of triply enantioselective enzyme‐catalyzed transacylations are 1) the reaction of rac‐1‐indanol with rac‐1,1′‐bi‐2‐naphthy]‐2,2′‐dibutyrate to afford (S)‐1‐indanoL (R)‐1‐indanylacetate, (S)‐1,1′‐bi‐2‐naphthyl‐2,2′‐diol, and (R)‐1,1′‐bi‐2‐naphthyl‐2,2′‐dibutyrate and 2) the reaction of rac‐1‐indanol with rac‐2,2′‐bis(butyroxymethyl)biphenyl to afford (S)‐1‐indanol, (R)‐1‐indanylbutyrate, (S)‐2,2′‐biphenyldimethanol, and (R)‐2,2′‐bis(butyroxy‐methyl)biphenyl. Doubly enantioselective enzyme‐catalyzed transacylations are described according to two instances: 1) the reaction of rac‐1‐indanol with rac‐1,1′‐bi‐2‐naphthyl‐2‐ol‐2′‐butyrate afforded (S)‐1‐indanol, (R)‐1‐indanylacetate, (S)‐1,1′‐bi‐2‐naphthyl‐2,2′‐diol, and (R)‐1,1′‐bi‐2‐naphthyl‐2‐ol‐2′‐butyrate, and 2) the reaction of rac‐1‐indanol with 1,3,5‐O‐methylidne‐2,4,6‐tri‐O‐butyrate‐myo‐inositol to afford (S)‐1 ‐indanol, (R)‐l‐indanylbutyrate, and 1,3,5‐O‐methylidne‐2,6‐di‐O‐butyrate‐myo‐inositol. Multiply enantioselective enzyme‐catalyzed reactions have a merit of the enhancement of enantiomeric excess over singly enantioselective ones.
Asymmetric Reduction Using Lithium Aluminum Hydride Modified with Chiral Ligands Prepared from (1R)‐(‐)‐β‐Pinene
Authors: Lu Ta‐Jung , Liu Shew‐Wen
Published: May 2015

The reduction of prochiral ketones using chiral reducing reagents, prepared from lithium aluminum hydride and (‐)‐(1R, 2S, 3S, 5R)‐10‐anilinopinanediol (5) and (‐)‐(1R, 2S, 3S, 5R)‐10‐N‐methylanilinopinanediol (6), affords chiral secondary alcohols in useful chemical yields (70 ∼ 93%) but in low optical purity (8 ∼ 33% ee). Modifiers 5 and 6 are synthesized from (lR)‐(‐)‐β‐pinene in three steps.
Multiflorin, A New Secoiridold Lactone from Jasminum Multiflorum
Authors: Shen Ya‐Ching , Chen Chung‐Hsiung
Published: May 2015

A new secoiridoid, multiflorin (1) has been isolated from the EtOAc‐soluble fraction of Jasminum multiflorum (Oleaceace). The structure of I was determined by application of spectral methods.
Synthesis and Chemistry of 4‐Aroyl‐3‐oxo‐ and 3‐Chloropyridazine Derivatives
Authors: Shalaby Alyaa A. , Youssef Ali M. , Youssef Wael A. , Shams Nabil A.
Published: May 2015

4H,5H‐6‐Phenyl (1a) and 6‐p‐phenoxyphenyl (1b) pyridazin‐3(2H)‐ones were reacted with aromatic aldehydes to give 4‐arylmethylpyridazm‐3(2H)‐ones (2a‐g), Oxidation of (2a‐g) with various oxidising agents (selenium dioxide in ethanol or chromium trioxide in acetic acid) gave 4‐aroyl‐6‐arylpyridazin‐3(2H)‐ones (3a‐g). Chlorination of (3a‐g) with phosphorous oxychloride afforded 4‐aroyl‐6‐aryl‐3‐chloropyridazine (4a‐g). 1H‐3‐Aryl‐5‐phenylpyrazolo[3,4‐c]pyridazines (5a‐d) were obtained by heating (4a‐d) with excess hydrazine hydrate. Hydroxyamination of (3e‐g) with iydroxylamine gave aryl‐4(6‐p‐phenoxyphenyl‐2,3‐dihydro‐3‐oxo)pyridazinyl oxime (6a‐c). Silylation of oximes (6b & 6c) gave (7a & 7b) as acyclic compound instead of the expected seven ‐ membered ‐ ring compound (8).
Progress in the Development of Methods for Asymmetric Organic Synthesis
Authors: Schultz Arthur G.
Published: May 2015

Methods for the enantioselective synthesis of chiral cyclohexane derivatives from aromatic carboxylic acids are presented. Birch reduction‐alkylation of chiral benzamides of type 1 occur with high diastereose‐lectivities to give 1,4‐cyclohexadiene derivatives with quaternary centers located at C(6). Early applications of this chemistry provided target structures with a quaternary center derived from C(1) of the starting benzoic acid derivative. Herein are described 1) the development of a more versatile Birch reduction‐alkylation, 2) a practical “asymmetric linkage” between aromatic carboxylic acids and chiral acyclic structures, and 3) asymmetric syntheses of unnatural alkaloids; applications to opiate receptor pharmacology.
Diels‐Alder Reactions of 5,8‐Ethano‐5,8‐dihydro‐1,4‐naphthoquinone with Cyclic Dienes
Authors: Chou Teh‐Chang , Liou Jing‐Ann , Lin Cheng‐Tung
Published: May 2015

Diels‐Alder cycloadditions of 1,3‐cyclohexadiene and cyclopentadiene to π ‐facially dissymmetric 5,8‐ethano‐5,8‐dihydro‐1,4‐naphtboquinone (1) were examined. The stereochemical outcome of the reactions, determined by a combination of chemical and spectral methods, indicates that addition of cyclic dienes to 1 occurs preferentially at the face syn to the etheno‐bridge of 1. Cycloadducts 7a/7b and 8a/8b obtained from Diels‐Alder reactions of 1 with cyclopentadiene and 1,3‐cyclohexadiene undergo [2+2]‐photocyclization to give caged compounds 9a/9b and 10a/10b, respectively. Stereoselective reduction of the enedione double bond in 7a/7b and 8a/8b with aqueous TiCl3 in acetone affords cis‐bis‐bicyclic ring‐fused 1,4‐cyclo‐hexadiones 11a/11b, and 12a/12b, respectively.
Synthesis of 1‐Methyl‐2,5‐dimethylene‐2,5‐dihydropyrrole by the Flash Vacuum Pyrolysis of N‐(1,5‐Dimethyl‐2‐pyrryl)methyl Benzamide
Authors: Tseng Pen‐Wen , Chou Chin‐Hsing
Published: May 2015

Pyrolysis of N‐(1,5‐dimethyl‐2‐pyrryl)methyl benzamide (7) gaved a 1:1 ratio of 1‐methyl‐2,5‐dimethylene‐2,5‐dihydropyrrole (4b) and 1,2‐dimetbylpyrrole (10) as the primary pyrolysis products in 88% total yield. The reactive compound 4b was detected with low‐temperature 1H NMR spectroscopy. Upon warming, 4b reacted rapidly with 10 to give one‐on‐one, two‐on‐one and three‐on‐one adducts, 11, 12 and 13, respectively.
Synthesis of β‐Disubstituted Enones from Ynones. An Alternative Route to 1,4‐Addition of Cuprate to the Ynone System
Authors: Luo Fen‐Tair , Hsieh Li‐Chen , Fwu Shiang‐Long , Hwang Wen‐Shu
Published: May 2015

A one‐pot reaction of 4‐phenyl‐3‐butyn‐2‐one with hydrogen iodide generated in situ gave a hydroiodinated product that underwent cross coupling with organozinc compounds in the presence of palladium catalyst to provide a simple preparation of 4‐disubstituted‐3‐alken‐2‐ones in fair to good yields.
Bicyclo[3.2.1]octenones As Building Blocks in Natural Products Synthesis (III). Total Synthesis of (±)‐10‐Deoxygeniposide Aglucone
Authors: Hsu Lung‐Fu , Chang Nein‐Chen
Published: May 2015

The title compound was synthesized from bicyclo[3.2.1]octenone 1 in six steps and in overall yield 59%. Photochemical rearrangement of β,γ‐unsaturated enone 1 is the key step.
Effect of Orbital Overlap in Thermal Reverse Homo‐Diels‐Alder Reaction and Intramolecular Reverse Ene Reaction
Authors: Tsai Tzeng‐Guang , Yu Chin‐Hui
Published: May 2015

Semiempirical calculations of activation energies confirm the importance of orbital overlap effect on thermal reverse homo‐Diels‐Alder reactions and intramolecular reverse ene reactions. Computations of the transition states of cis‐3,6‐dimethyl‐3,6‐dihdropyridazine, 2,5‐dimethyl‐3,4‐diaza bicyclo[4.1.0]hept‐3‐ene, 2,5‐dimethyl‐3,4‐diaza bicyclo[4.2.0]oct‐3‐ene and (cis‐2(S)‐(2(S)‐isopropyl‐1‐d3)‐1(S)‐(1(E)‐propenyl‐2‐d)cyclopropane indicate that activation energies are considerably decreased when optimal overlap is accomplished. The orbital overlap effect overcomes the steric effect in intramolecular reverse ene reaction of compounds such as (cis‐3‐R‐2(S)‐(2(S)‐isopropyl‐1‐d3)‐1(S)‐(1(E)‐propenyl‐2‐d)cycIopropane in which R is a chlorine atom or a methyl group.
Analysis of Vibration‐rotational Spectra of BiH
Authors: Ogilvie J. F.
Published: May 2015

Analysis of measurements of vibration‐rotational transitions of 209Bi1H and 209Bi2H in electronic ground state × 0+ yielded values of coefficients of radial functions that represent the intemuclear potential energy and adiabatic and nonadiabatic rotational effects of the hydrogen atomic centre. Both these effects have exceptionally large magnitudes, tentatively attributed in part to interaction with nearby electronically excited state A 1. The maximum range of validity of radial functions of BiH is 1.49 ≤ R/10−10 m ≤ 2.4; the equilibrium intemuclear distance Re is (1.8041955 ± 0.00000186) × 10–10 m.
Structure and Stability of XNP and NPX, X = H+, CH3+, O, F+
Authors: Ou Ming‐Chiu , Chu San‐Yan
Published: May 2015

The bonding in a triatomic molecule XNP and its isomer NPX with X = H+ CH3+, O and F+ was investigated with ab initio molecular orbital calculation using a 6‐31G** basis set at Hartree‐Fock and MP4(sdtq) level. The bonding comparison is based on interaction between NP and X for the two structures. The result that NPX is less stable than XNP is rationalized according to greater promotion energy required for the lone pair of phosphorus in NP to form the P‐X bond than for that of nitrogen to form the N‐X bond. This a energy contribution is counterbalanced by the π energy contribution to a varying extent depending on X.
Determination in Situ of Chemical Solvent Vapors in a Semiconductor Workplace with an Open Path FTIR Spectrometer
Authors: Chang Shih‐Yi , Tso Tai‐Ly , Lo Jiunn‐Gung
Published: May 2015

An FTIR spectrometer having a long absorbing path in an open field mode is applied to measure the air quality of semiconductor facilities, especially for chemical solvent vapors. This spectrometer is demonstrated to be a proper instrument to monitor chemical solvents widely used in the manufacture of integrated circuits. By means of the great sensitivity accruing from the kilometer pathlength, we discovered that many residual chemical solvent vapors are released in these workplaces; the limit of detection can attain the level of parts per billion by volume. Recognized spectra of chemical solvents, such as 2‐ethoxyethyl acetate, 2‐propanol, hexamethyl disilazane, aromatic hydrocarbons, alkyl derivatives of phenol, alkyl benzene sulfonate and dimethyl sulfoxide, are calibrated qualitatively and quantitatively. The related integrated absorption coefficients (or band intensities) are listed in this paper. By examining the measured spectra, we found two chemical solvents (2‐propanoI and hexamethyl disilazane) in the workplace, at concentrations about 20‐500 ppbv in such environments.
Ionization Efficiency of Dicopper Complex in Electrospray Ionization Mass Spectrometry
Authors: Lee Mei‐Kuei , Ling Yong‐Chien , Huang Pei J. , Wang Sung M.
Published: May 2015

Dicopper complex Cu2(PDTB)(CIO4)4 was analyzed by electrospray technique under varied conditions in order to investigate the effects of important factors on ionization efficiency. The factors taken into account are spray voltage (Vn), temperature of the drying gas, needle layer distance (Dnl), potential difference between the capillary and skimmer (Vcs), potential difference between skimmers 1 and 2 (Vss), and concentration of analyte. The total ion current increases proportionally with Vn varied from 2.0 to 4.0 kV. The ionic stales are not influenced by the variation of Vn and temperature of the drying gas. Variation in nebulization efficiency caused by varied Dnl appears to influence the detected ions in several ways. Structurally characteristic ions are preserved with Vcs smaller than 50 V, dissociate into fragments of smaller molar mass with Vcs 80 V or greater, and disappear with Vcs 200 V or greater. Vss influences the relative intensities of detected ions by an effect of ion focusing. The dependence of the intensity of detected ions on analyte concentration at 10−4 M or greater is ascribed to the principle of equilibrium in solution.