bluuebunny/crossref_metadata_2025 huggingface dataset:
Iodination with Potassium Permanganate/Hydroiodic Acid/Acetonitrile Reagent
Authors: Chen Jyh‐An , Lin Ching‐Shan , Liu Lilian Kao
Published: May 2015

Iodination of various aromatic amines proceeds smoothly with a preformed homogeneous mixture of hydroiodic acid potassium permanganate in acetonitrile. para‐Substituted products were obtained in high yields (71‐78%) within twelve hours at room temperature.

With a slight modification of the permanganate, hydroiodic acid and substrate ratio, iodination of alkynes to vic‐diiodoalkenes can be carried out at 60 °C in 65‐87% yield.
Photochemical Experiments with 2,3‐Bis(Tert‐Butylsulfonyl)Bicyclo[2.2.2]Octa‐2,5‐Diene and Related Systems
Authors: Gleiter Rolf , Ohlbach Frank
Published: May 2015

The irradiation of 2,3‐bis(tert‐butylsulfonyl)norbornadiene (5) and 2‐(tert‐butylsulfonyl)norbornadiene (6) yielded the expected quadricyclane derivatives as stable molecules. The irradiation of 2,3‐bis(tert‐butylsulfonyl)bicyclo[2.2.2]octa‐2,5‐diene(7) 2,3‐bis(tert‐butylsulfonyl)‐exo‐7,8‐epoxybicyclo[2.2.2]‐octa‐2,5‐diene (8) and 8,9‐bis(tert‐butylsulfonyl)‐4‐anti‐phenyl‐3,5‐dioxa‐exo‐tricyclo[5.2.2.02,6] undeca‐8,10‐diene 9a and its syn‐isomer 9b yielded the corresponding tetracyclic and pentacyclic systems, respectively. The photoproducts of 8 and 9 reverted to the starting products slowly at room temperature. The half‐life of the photoproduct of 7 was determined to be 34 min at 50 °C. Compound 9a reacted with n‐BuLi to yield the unexpected desulfonylation product 27a.
Synthesis and Physical Properties of New Ferroelectric Liquid Crystals Consisting of 2(S)‐[2 (S)‐Methylbutyloxy] Propanol
Authors: Tsai Wen‐Liang , Lee Chein‐Dhau
Published: May 2015

New ferroelectric liquid crystals containing two chiral centers, 4‐(4′‐n‐alkyloxyphenyl)phenyl 4‐{2(S)‐[2(S)‐methylbutyloxy]propoxy}benzoate (4a‐4f) and 4‐(n‐alkyloxy)phenyl 4‐{4′‐[2(S)‐(2(S)‐methylbutyloxy)propoxy]phenyl}benzoate (5a‐5f) were synthesized and their physical properties studied. A phase‐transition sequence of C‐Sc*‐N*‐I was observed in most cases. Some homologues of them, 4a‐4d, possess monotropic Sc * phase. Not only the Sc* phase‐transition temperature of 5a‐5f is lower than that of the corresponding 4a‐4f, but their Sc * phase‐transition temperature range is also wider than the corresponding 4a‐4f. The Sc * phase temperature range can be up to 48 °C. The spontaneous polarization of 8‐28 nC/cm2 and the electric rise time of 240‐420 μs were measured in FLCs 4a‐5f.
Preparation of Y2Ba4Cu7O15‐δ Superconductor without High Oxygen Pressure
Authors: Huang Ju‐Chun , Cheng Chien Hong , Sheen Shyang Roeng , Lee Zhi Ling , Lei Chien Ming , Wu Maw Kuen
Published: May 2015

The synthesis of bulk Y2Ba4Cu7O15‐δ superconductor at atmospheric oxygen pressure via solid state sintering is reported. Temperature ranging from 860 to 890 °C as well as time interval over 2 to 15 days were used to investigate the formation of the Y2Ba4Cu7O15‐δ phase. A time‐temperature profile characterizing the conditions for the preparation of Y2Ba4Cu7O15‐δ phase suggests the optimal condition to be sintering at 890 °C for over 10 days. Detailed results of X‐ray diffraction, electrical resistivity, iodometric titration and magnetization measurements are described.
Surface Hydroxyls and Chemisorbed Hydrogen on Titania and Titania Supported Cobalt
Authors: Ho Sui‐Wen
Published: May 2015

The dehydroxylation and rehydroxylation properties of titania (Degussa P‐25) were investigated. FTIR and TPD‐MS data indicate that hydroxyl groups are not completely removed at 500 °C in vacuo, and rehydration/rehydroxylation occur under helium (water content < 1 ppm) flow at room temperature. In addition, repeating dehydroxylation/rehydroxylation treatments for ten times does not significantly modify the dehydroxylation/rehydroxylation property of titania surface. Desorption of hydrogen from titania was observed at 535 °C after titania was reduced above 400 °C. The maximum surface density of hydrogen was determined to be 0.75 H atom/nm2. TPD data show four types of hydrogen on 3% titania supported cobalt catalysts: hydrogen adsorbed on cobalt metal (desorption temperature around 100 °C), reverse spillover hydro gen (150‐250 °C), hydrogen from H‐TiO2‐x‐ Co interacting species (‐330 °C), and recombined hydrogen from Ti3+‐H on titania (‐535 °C). The absence of hydrogen desorption peak at 535 °C for titania supported cobalt reduced above 400 °C can be explained in terms of the migration of H‐TiO2‐x moieties onto cobalt metal surface during reduction. Removal of hydroxyl groups by thermal treatment before reduction enhanced the amount of hydrogen desorption from normal cobalt surface. This indicates that the hydroxyl groups play a role in the surface migration of H‐Ti2‐x.
Tanshinketolactone, A New Tanshinone from Salvia Miltiorrhiza
Authors: Lin Hang‐Ching , Chang Wen‐Liang , Wu Pei‐Lirt , Wu Tian‐Shung
Published: May 2015

A seven‐membered ketolactone, tanshinketolactone (1), was isolated from the root of Salvia miltiorrhiza. Its structure was established by spectroscopic analysis.
Planar Schlegel Diagram's Illustrations of Fullerene's Structural Changes and Fullerene's Cage Interactions with Metals and Hydrogens
Authors: Chiu Ying‐Nan , Yu Yaxiong , Xiao Jimei
Published: May 2015

Two‐dimensional planar Schlegel diagrams are used to displace fullerenes and to exhibit cage cluster's vertices, faces and edges as well as cluster's extensions and changes such as isomerization, addition, elimination etc. The Schlegel diagrams also show the possible π bondings and free π radicals to determine symmetry group structures as well as to interact with the corresponding number of electrons in metals. The diagrams also show the possible addition of outside hydrogens and their movements.
Cadmium Determination in Human Whole Blood by Electrothermal Atomic Absorption Spectrometry with Magnesium Chloride and Sodium Hydroxide as a Combined Chemical Modifier
Authors: Hsieh Ling‐Ling , Yang Mo‐Hsiung , Lin Song‐Shei
Published: May 2015

In this work, we propose a method to determine trace amounts of Cd in human whole blood samples by electrothermal atomic absorption spectrometry (ETAAS) with the combined chemical modifier including magnesium chloride and sodium hydroxide. Prior to the ETAAS analysis, dissolution of the blood samples is accomplished using a HNO3‐HClO4double closed‐vessel microwave digestion technique followed by drying of the dissolved blood samples by means of an infrared lamp. In using this approach, a MgCl2 chemical modifier is added to the digested samples, then they are injected into the graphite furnace for detecting the Cd level via atomic absorption spectrometer. Besides we used a NaOH chemical modifier, which removed the matrix major elements through prior ashing at 1200 ° C for 30 s, and the Cd is subsequently volatilized at 2200 °C and determined by AAS. However, the proposed method can be employed to determine the of Cd level in whole blood samples by the calibration technique and the standard‐additions method. Its validity is confirmed with two certified reference whole blood materials (Seronorm Trace Elements Whole Blood Batch no. 205052 and Batch no. 203056). By using 10 μL injections, a detection limit of 0.052 ng mL−1 is achieved.
Thermodynamics of the High‐Spin‐Low‐Spin Conversion of Nickel(II)Complexes with Tetraamine Ligands
Authors: Lai Chung‐Yu , Liu Yuh‐Liang , Shu Kelen , Wang Chi , Chung Chung‐Sun , Luh Hung
Published: May 2015

Six tetraamine ligands, 2,5,8,11‐tetraazadodecane, 2,5,9,12‐tetraazatridecane, 3,7‐dimethyl‐3,7‐diazanonane‐l,9‐diamine, 2,6,9,13‐tetraazatetradecane, 4,7‐dimethyl‐4,7‐diazadecane‐l,10‐diamine, 4‐methy]‐4,7‐diazadecane‐l,10‐diamine, and their nickel(II) complexes have been synthesized. The equilibrium constants and thermodynamic parameters of the high‐spin‐low‐spin conversion of these complexes at various temperatures in 0.10 M NaC1O4 have been investigated by spectrophotometric techniques. Influences of the enthalpies of these reactions are attributed to an endothermic contribution due to the breaking of the two Ni‐OH2 bonds, an exothermic contribution due to the strengthening of the four in‐plane Ni‐N bonds, an exothermic contribution due to the different ligand field stabilization energies of the square‐planar and the octahedral complexes, an endothermic contribution due to the steric repulsions between the N‐methyl group(s) and methylene groups as well as that between the two N‐methyl groups of the tetraamine, an exothermic contribution due to the steric repulsions between the N‐methyl group(s) and the coordinated water molecules, and an exothermic contribution due to the inductive effect of the N‐methyl group(s). The important factors influencing the values of the entropies of these reactions are a negative term due to the reduction of spin multiplicity and a large positive term due to the release or the mobilization of the two coordinated water molecules.
The Synthesis and Chemistry of 9‐Chlorobicyclo[6.1.0]Non‐1(9)‐Ene
Authors: Lee Gon‐Ann , Chen Jay , Chen Chi‐Sheng , Shiau Chaur‐Shenq , Cherng Chih‐Hwa
Published: May 2015

9‐Chlorobicyclo[6.1.0]non‐l(9)‐ene (4), a 2‐chlorinated 1,3‐fused cyclopropene, is synthesized and isolated from the dehalogenation of the l‐bromo‐9,9‐dichlorobicyclo[6.1.0]nonane, itself derived from cyclooctene. Compound 4 undergoes ring opening reaction to generate cyclooctenyl chlorocarbene (9) which reacts with water via conjugate addition and ipso‐addition to give (E)‐2‐(chloromethylene)cyclooctanol (7) and cyclooctene‐l‐carboxaldehyde (8), respectively. The conjugate addition of 9 with water is more favorable than the ipso‐addition by 3:1. Compound 4, which is stable at −25 °C for weeks without any decomposition, reacts with oxygen to produce 2‐chlorocyclonon‐2‐enone (12) via the ring‐opening reaction adduct, vinyl alkylcarbene 10.
Rapid Formation of the Textured (Bi, Pb)2(Sr, Ca)4Cu3Oy Superconductor by Multiple Pressing and Sintering Process
Authors: Sheen Shyang‐Roeng , Wu Maw‐Kuen , Shei Cheng‐Yie , Hurng Weir‐Mirn , Chen Dian‐Hau , Chang Chau‐Ting
Published: May 2015

A superconducting (Bi, Pb)2(Sr, Ca)4Cu3O2 material has been prepared by tbe oxalate coprecipitation method. The high‐Tc 110 K phase was effectively promoted by application of an intermediate grinding and pressing between the sintering heat treatments. The powder X‐ray diffraction shows the existence of single high‐Tc and high‐textured microstructures with strong (001) reflections within a short sintering time ( 18 h). The morphology of the sintered samples was examined by scanning electron microscopy (SEM). Also, the kinetics of the formation of the high‐Tc phase were investigated by the isothermal method. A possible mechanism of the formation of high‐Tc 2223 phase was proposed.
Emissive Annular Digold(I) Compounds Containing Diphosphine and Dithiolate Ligands
Authors: Tang Shaw Shiah , Lin Ivan J. B. , Liu Lin‐Shuh , Wang Iu‐Chun
Published: May 2015

Molecular structures of three emissive annular digold compounds [Au2(dmpm)(dtc)]Cl (dmpm = Me2PCH2PMe2,dtc = S2CNEt2), 1, [Au2(dppm)(dtc)]PF6, (dppm = Ph2PCH2PPh2),2,and [Au2(dppe)(dtc)]‐(PF2) (dppe = Ph2P(CH2)2PPh2), 3, were determined. All three compounds are dimetallacycles having two gold atoms bridged by a dithiolate ligand and a diphosphine ligand, the geometry around each gold atom being almost linear. All the dimetal lacy die rings are slightly distorted from planarity with intramolecular Au‐Au distances shorter than 3.0 Å. Compound 1 forms a polymeric chain through intermolecular Au‐Au contacts (3.061 − 3.135 Å). Compound 2 forms a tetramer through intermolecular Au‐Au interactions (Au‐Au distances ranging from 3.086 to 3.222 ). Compound 3 is monomeric. All of the compounds luminesce at 77 K in the solid state. Emissions originating from 3LMCT from dtc ligand to Au excited states are assigned. The emission maxima of 1 − 3 are at 541,535 and 520 nm respectively and are blue shifted as the number of Au‐Au interactions is decreased.
Discotic Metallomesogens: Effects of Sidechains Density in Transition Metal Bis(β‐Diketonate) Complexes
Authors: Fan Pei‐Chen , Lai Chung K.
Published: May 2015

The preparation and mesogenic properties of a series of discotic β‐diketonate metal complexes are reported. The results show that the density of side chains, positions of side chains, and the geometries of the metal centers play important roles in determining the mesomorphic behaviors and thermodynamic stability of these complexes. In the series of copper complexes 3, all these disc‐like molecules with eight alkoxy side chains exhibit columnar hexagonal disordered (Dhd) mesophases. In the series of copper complexes 2 with six side chains, only compounds substituted with longer alkoxy chains (n = C14 or C16) exhibit discotic columnar mesophase. However, in the series of complexes 1, only crystal‐to‐isotropic transitions were observed. The results showed that induction of liquid crystallinity not only depends on the numbers of side chains (i.e. side chain density), but also on the degree of distribution over the central core. Palladium complexes analogs exhibit similar discotic mesophases, and due to their greater core‐core organization, they also have higher clearing points and wider temperature range of mesophases than copper complexes.
Transformation of Cedrane Skeleton to Noracorane and Decahydroazulene Skeletons via Free Radical Reaction. Autooxidation of 8β‐Hydroxycedran‐13‐Al
Authors: Kuo Yuch‐Hsiung , Lin Yun‐Lian , Wang Eng‐Chi
Published: May 2015

8‐Cedren‐14‐ol (4d) was oxidized with PCC, followed by autooxidation to yield 8,14‐cedranolide (2a) and 8‐cedren‐14‐carboxylic peracid (4e). 8β‐Hydroxycedran‐l3‐al (1d) was subjected to autooxidation in three different solvents to give eight products, from which the transformation from cedrane skeleton to noracorane and decahydroazulene skeletons were observed. A free radical pathway was proposed.
Nucleophilic Addition Reactions of Tricarbonyl [η5‐1‐(Phenylthio)Cyclohexadienyl]Iron(I) Complex
Authors: Chou Shang‐Shing P. , Hsu Chien‐Hung
Published: May 2015

Hydride abstraction of tricarbonyl[η4phenylthio)‐l,3‐cyclohexadiene]iron(0) complex 2 with Ph3C+PF6− regiospecifically provided the title compound 3 in excellent yield. Cationic complex 3 could react with a variety of nucleophiles in good yield. Hard nucleophiles prefer to attack at the C‐l position, whereas soft and hindered nucleophiles favor attack at the C‐5 position. Some synthetic applications were also studied.
Application of a Hexa‐Electrode Electrochemical Detector for Flow Injection Analysis
Authors: Chen Mei‐Cheng , Huang Hsuan‐Jung
Published: May 2015

Extending from the development of dual‐electrode electrochemical detector, a hexa‐electrode electrochemical detector for use with the FIA was proposed. With this hexa‐electrode detector, the in‐series and in‐parallel modes of dual‐electrode can be easily performed either individually or simultaneously. Feasibility of the hexa‐electrode detector for repetitive analyses which would result in an enhancement of S/N ratio was demonstrated by running the square wave anodic stripping voltammetry (SWASV) analysis of cadmium. From the normalized linear calibration graph and the enhanced sensitivity obtained. applicability of the HED as a versatile electrochemical detector for flow injection analysis was confirmed.
Micellar Electrokinetic Chromatography of Cephalosporin Antibiotics
Authors: Chen Su‐Hwei , Wu Hsin‐Lung , Wu Shou‐Mei , Kou Hwang‐Shang , Lin Shun‐Jin
Published: May 2015

A simple micellar electrokinetic chromatographic (MEKC) method is described for the simultaneous separation of twelve cephalosporin antibiotics. The separation was performed in a phosphate buffer (0.1 M, pH 6.6) with sodium dodecyl sulfate (SDS) (0.1 M) as an anionic surfactant. The complete separation of twelve cephalosporins was attained in 36 min. Application of the method to the quantitative analysis of cefuroxime, cephalexin, cephapirin and cephradine in pharmaceutical preparations was demonstrated.
Substitution Reaction of Tetracyanoethylene with Acetone‐Anils
Authors: Lin Wen‐Chung , Huang Shing‐Ting , Lin Shaw‐Tao
Published: May 2015

The products from the condensation of acetone‐anils (1) and TCNE reaction were characterized after separation. The main products, tricyanoethylene derivatives (7–9) were isolated with the malonodinitrile derivatives (10–12), respectively. The [2+2] cycloaddition product (13), namely 5‐methoxy‐3,4‐(2′,2′,3′,3′‐tetracyanocyclobutano)‐l,2‐dihydro‐2,2,4‐trimethylquinoline also has been isolated. The distribution of these three products is substituent dependent.
The Substituent Effects of tert‐Butyl Radical Addition to 2‐Substituted Allyl Chlorides
Authors: Wu Yuh‐Wern
Published: May 2015

The relative rates for the addition reactions of tert‐butyl radical to 2‐substituted ally chlorides I have een determined. The correlation of log k/k0, vs. σm gives a ρ mvalue of 3.59 with correlation coefficient of 0.930. When the substituent CH2Cl is excluded, correlation coefficient raises to 0.990 and ρ value becomes 3.39. The large p value and the deviation of relative rate of substituent CH2C1 are discussed.
New Naphthoquinones from the Stem of Diospyros maritime Blume
Authors: Kuo Yueh‐Hsiung , Chang Chi‐I , Kuo Yao‐Haur
Published: May 2015

Four naphthoquinones together with one known naphthoquinone were isolated from the stems of Diospyros maritima Blume. Four naphthoquinones were elucidated as 2,2′‐, 2,3′‐, 3,2′‐, and 3,3′‐diethoxy‐isodiospyrins, respectively, on the basis of spectral properties.
Electrochemical Study of the Micellization of Hexadecylpyridinium Bromide in the Presence of Some Crown Ethers
Authors: Shamsipur Mojtaba , Alizadeh Naader , Gharibi Hossein , Mousavi Mir Fazlollah
Published: May 2015

A membrane electrode selective to hexadecylpyridinium bromide was used to study the micellization of the surfactant in the presence of varying concentrations of crown ethers 15‐crown‐5, dicyclohexyl‐18‐crown‐6 and dicyclohexyl‐24‐crown‐8 at 27°C. The critical micelle concentration of surfactant was largely influenced by the crown ethers used, indicating their participation in the structure of the resulting micelle. The degree of attachment of crown ethers to the surfactant in the micellar structure was found to be 1. An estimation of the Kf for the 1:1 surfactant‐crown interaction in the micellar region is reported. The degree of counter ion dissociation was found to increase with the crown ether concentration, and with the nature of macrocyclic ligands in the order 15‐crown‐5 < dicyclohexyl‐ l8‐crown‐6 < dicyclohexyl‐24‐crown‐8. There was also some evidences for a rather strong interaction between dicyclohexyl‐24‐crown‐8 and the surfactant in the submicellar concentration ranges in solution.
Calibration of CCl2FCCIF2 (CFC‐113) and its Effects on the Atmospheric Long‐Term Measurements
Authors: Wang Jia‐Lin
Published: May 2015

A simple but innovated calibration procedure for the measurements of volatile organic compounds in the atmosphere is introduced via the use of CCI2FCCIF2 (CFC‐113) long‐term global data set as an illustration. Non‐linear response for the electron capture detector toward CFC‐113 was carefully calibrated within and beyond the measurement working range. Our measurement results, after correction for non‐linearity, are in excellent agreement with those of the ALE/GAGE monitoring program, suggesting our calibration method along with its results are experimentally sound and well executed.

Our global measurements show that, after years of rapid growth of CFC‐113 in the atmosphere, its concentration had been leveling‐off and even started to decline in 1995.
Synthesis and Characterization of Push‐Pull Porphyrins
Authors: Chen Chin‐Ti , Hsieh Shih Jung
Published: May 2015

A series of “push‐pull” porphyrins with 4‐nitrophenyl and 4‐aminophenyl substituents were synthesized and separated by flash column chromatographic techniques. They were fully characterized by elemental analysis, FAB‐MS, FTIR, UV‐visible, and 1H NMR spectroscopies. The unsymmetrical π‐electron distribution of the porphyrins caused by the donor (amino) and acceptor (nitro) substituents were investigated by 1H NMR technique. The pyrrole‐H resonance positions can be correlated to the Hammett σ constants of the substituents. Although with strong donor and acceptor substituents, UV‐visible spectra show the push‐pull porphyrins have rather weak solvatochromism and hence limited intramolecular charge‐transfer character.
The Diphenylacetylene Reaction with Tricarbonylbis(η2‐cis‐cyclooctene)iron in the Presence or Absence of Carbon Monoxide
Authors: Liu Ling‐Kang , Chang Kuo‐Yang , Wen Yuh‐Sheng
Published: May 2015

Known to be a facile irontricarbonyl transfer reagent, (η2‐cis‐C8H14)2Fe(CO)3 1 transfers its Fe(CO)3 unit to a variety of ligands at low temperature. Stirring a THF mixture of 1 and PhC=CPh under N2(g) at −60 °C for 1 h then at room temperature overnight provides mainly a flyover‐bridge product [‐CPh=CPhC(0)‐CPh=CPh‐]Fe2(CO)6 2 with the organic bridge on diiron core in a complicated μ‐(1,2,5‐η3:1,4,5‐η3) fashion. The keto fragment in 2 comes presumably from the decomposition of 1 that liberates CO. However, stirring a THF mixture of 1 and PhC=CPh under CO(g) at −60 °C for 3 h then at room temperature overnight results in [‐C(0)CPh=CPhC(0)‐]Fe(CO)4 3, a compound not isolated in the earlier thermal or photochemical reactions of PhC=CPh with ironcarbonyl. The X‐ray structure determinations for both 2 and 3 have been performed.
Chemical Transformations of 4,6‐Dimethyl‐2β‐hydroxy‐8‐oxo‐3,5,7‐trioxatetracyclo[7.2.1.04,11.06,10]dodecane
Authors: Chern Jyh‐Haur , Wu Hsien‐Jen
Published: May 2015

Reactions of 4,6‐dimethyl‐2β‐hydroxy‐8‐oxo‐3,5,7‐trioxatetracyclo‐[7.2.1.0.4,11.06,10]dodecane 1 with nucleophiles have been studied. Reaction of 1 with alcohols, triethylsilane, allyltrimethylsilane, and methylthiotrimethylsilane in CH2Cl2 in the presence of TiCL4, gave the substitution products 2,7a, 7b, and 7c in 80‐90% yields. The substitution reaction took place chemoselectively on the hemiacetal group of I. Reaction of 1 with cyanotrimethylsilane in CH2C12 in the presence of TiCL4, gave compound 8 and the rearranged product 9. The structure of 9 was proven by X‐ray analysis.
Synthesis of α‐Arylthioalkyl Esters: The Addition Reactions of Vinyl Esters with Arylthiols Catalyzed by Lipase
Authors: Lee Ren‐Shen
Published: May 2015

α‐Arylthioalkyl esters can be prepared by the addition reactions of vinyl esters with arylthiols in the presence of Pseudomonas lipase (PSL) as catalyst. In the toluene, the reaction mixtures were stirred at 60 °C for three days, the chemical yields up to 85% were obtained.
Smectic Bimetallomesogens: Synthesis and Mesomorphic Properties in Oxygen‐Bridged Dicopper and Divanadyl Complexes
Authors: Leu Yi‐Fun , Lai Chung K.
Published: May 2015

The synthesis and mesomorphic properties of a homologous series of N‐(3‐hydroxypropyl)‐4‐alkoxylsalicylaldimine, N‐(3‐hydroxypropyl)‐4‐(4′‐alkoxybenzoxy)salicylaldimine, and their dicopper(II) and di‐oxovanadium(VI) complexes are reported. Copper complexes exhibited monotropic smectic A phases; however, vanadyl complexes showed no mesomorphism. A systematic comparison revealed that the meso‐genie behaviors of these bimetallic complexes are induced by the weak intermolecular force and determined mainly by the central metal. The effects on the structural variations near the metal central cores and side chain density are also discussed.
Microwave‐Optical Double Resonance and Intermodulated Fluorescence Studies of Thioformaldehyde
Authors: Ramsay Donald A.
Published: May 2015

Studies of the 410 band of the Ã 1A2 X̃1A1 transition of thioformaldehyde by means of intermodulated fluorescence and microwave‐optical double resonance have revealed numerous small perturbations in the excited state levels caused by high rovibronic levels of the ground state. Singlet‐triplet perturbations have been studied by the same techniques and also by anticrossings produced in the presence of a magnetic field. The use of microwave‐optical double resonance for studying collisional processes is discussed.
Mass Spectra of Substituted Butenolides
Authors: Lin Shaw‐Tao , Kuo Yuch‐Hsiung , Wang Eng‐Chi , Lin Wen‐Chung
Published: May 2015

The mass spectra of a series of substituted butenolides were studied. Their fragmentations in the mass spectrometer strongly depend upon the nature of the substitutents. The fragment's ions include the lactone skeletons, substituents, and resultant derived from the loss of a carbon dioxide from lactone.
Active Chemical Constituents from Sauropus androgynus
Authors: Wang Perng‐Haur , Lee Shoei‐Sheng
Published: May 2015

This paper describes the chemical investigation on BuOH‐soluble EtOH extract from the aerial part of Sauropus androgynus. This study led to the characterization of six bioactive ingredients including three nucleosides—adenosine (1), 5′‐deoxy‐5′‐methylsulphinyl‐adenosine (2), and uridine (3), two flavonol dioside — 3‐O‐β‐D‐glucosyl‐7‐O‐α‐L‐rhamnosyl‐kaempferol (4), 3‐O‐β‐D‐glucosyl‐(1→6)‐β‐D‐glucosyl‐kaempferol (5), and one rare flavonol trioside — 3‐O‐β‐D‐glucosyl‐(1→6)‐β‐D‐glucosyl‐7‐O‐α‐L‐rhamno‐syl‐kaempferol (6). Their structures were determined on the basis of spectral analysis.
Tannins and Related Compounds from Quisqualis Indica
Authors: Lin Ta‐Chen , Ma Ying‐Tsun , Wu Jender , Hsu Feng‐Lin
Published: May 2015

Continuous exploration of the chemical constituents of Combretaceous plants has led to the discovery of two novel ellagitannins, quisqualin A (1) and quisqualin B (2), from the fruits of Quisqualis indica. A total of twenty‐one other tannins were also isolated from either the fruits or leaves of Q. indica. including [I] eleven ellagitannins: 2,3‐(S)‐HHDP‐D‐glucose (3), 2,3‐(S)‐HHDP‐4‐O‐galloyl‐D‐glucose (4), 2,3‐(S)‐HHDP‐6‐O‐galloyl‐D‐glucose (5), 2,3‐(S)‐HHDPA6‐di‐O‐galloyl‐D‐glucose (6). pedunculagin (7), punicalagin (8), eugeniin (9), 1‐desgalloyleugeniin (10), casuariin (11), 5‐desgalloylstachyurin (12), castalagin (13); [II] five gallotannins‐. 6‐O‐galloyl‐D‐glucose (14), 1,6‐di‐O‐galloyl‐β‐D‐glucose (15), 2,3‐di‐O‐galloyl‐D‐glucose (16), 3,4‐di‐O‐galloyl‐D‐glucose (17), 4,6‐di‐O‐galloyl‐D‐glucose (18); [III] four phenol‐carboxylic acids: gallic acid (19), ellagic acid (20), flavogallonic acid (21), brevifolin carboxylic acid (22) and [IV] one other hydrolyzable tannin: punicalin (23).
Ab‐inito Calculations in Reductive Bond‐breaking Reaction of C‐X Bond in CH3X and CH2X2 with X = F and CI
Authors: Lu Shih‐I , Mou Chung‐Yuan
Published: May 2015

MP4/6‐31+G* level calculations are performed to study the reductive bond‐breaking reaction of the C‐X bond in halomethanes, CH3X and CH2X2 where X is a fluorine atom or chlorine atom. This type of reaction involves a radical anion, after attaching an extra electron to the halomethane molecule, in which a C‐X bond‐breaking takes place. Products are a radical and a halogen anion. The equilibrium geometry and bond dissociation energy of the C‐X bond thus found are in good agreement with previous theoretical and experimental results. The anomeric effect, electrostatic effect, and radical re‐stabilization effect, are investigated to find their influences on bond length and bond dissociation energy in CH3X and CH2X2. Potential energy curves are calculated for the reductive bond‐cleavage process, and trends in activation energy for various cases are discussed.
Synthesis and Characterization of Oligo(2,7‐biphenylenylene‐(E)‐vinylene)s: Conjugated Oligomers Containing Antiaromatic 12‐π Electron Units
Authors: Kwong Chi‐Yuen , Chan Tze‐Lock , Chow Hak‐Fun , Lin Shi‐Chun , Leung Man‐Kit
Published: May 2015

The syntheses and the electronic properties of oligo(2,7‐biphenylenylene‐(E)‐vinylene)s are reported. According to our spectral analysis, a limit of 2.5 ev for the peak band‐gap of poly(2,7‐biphenylenylene‐(E)‐vinylene)s is estimated. In addition, we discovered that oligo(2,7‐biphenylenylene‐(E)‐vinylene)s are amphoteric and can be either oxidized or reduced electrochemically.
Manganese(III) Acetate Initiated Oxidative Free Radical Reaction between 2‐Anilino‐1,4‐naphthoquinones and Diethyl Malonate
Authors: Chuang Che‐Ping , Wang Sheow‐Fong
Published: May 2015

A free radical reaction between 2‐anilino‐1,4‐naphthoquinones and diethyl malonate initiated by manganese (III) acetate is described. This reaction provides a novel method for the synthesis of 5,6,11,12‐tetra‐hydro‐6,11‐dioxo‐benzo[b]acridines. With a meta substituent on the anilino group, this reaction shows poor to high regioselectivity depending on the steric effect of the substituents on the anilino group and malonate.
Synthesis of Tricyclic Skeletons Mediated by (Diene)Fe(CO)3 Complexes
Authors: Yeh Ming‐Chang P. , Chuang Li‐Wen
Published: May 2015

Sequential additions of carbon nucleophiles to the (η5‐pentadienyl)Fe(CO)3 cation afforded tricyclo[6.3.0.02.6]undecane, tricyclo[6.4.0.02.6]dodecane, tricyclo[7.3.0.02.7]dodecane and tricyclo[7.4.0.02.7]‐tridecane derivatives. The same strategy can also be applied to construct heterotricyclic skeletons.
Production, Purification and Characterization of the Hen Egg‐White Lysozyme Inhibitor from Enterobacter cloacae M‐1002
Authors: Wang San‐Lang , Pai Chyi‐Sheng , Shieh Sun‐Tung
Published: May 2015

Three hen egg‐white lysozyme inhibitor producing strains, Enterobacter cloacae M‐1002, E. sakazakii M‐1204, and Erwinia rhapontici H‐55, were isolated from the soils of Taiwan. E. cloacae M‐1002 appeared to be a promising inhibitor producing strain. One inhibitor was isolated from the culture broth of this strain. Maximum lysozyme inhibitory activity was obtained when the bacterium was grown aerobically in a medium consisting of 0.75% glucose, 0.25% beef extract, 1.0% polypeptone, and 0.25% sodium L‐glutamate (pH 70) at 37 °C after 36–48 hrs. A hen egg‐white lysozyme inhibitor was isolated from the culture broth of this strain. The inhibitor was purified from the culture supernatant of E. cloacae M‐1002 by ammonium sulfate fractionation, DEAE‐Sepharose CL‐6B column chromatography and Fractogel TSK HW‐55 (S) gel chromatography. Molecular weight of the purified lysozyme inhibitor was estimated to be 18, 000–20, 000 by SDS‐PAGE and HPLC, and was composed of 71% amino acid and 23% total sugar. Serine, glycine, and alanine in a 3:2:1 molar ratio were the major amino acids, calculated to be 32.8, 20.3, and 11.4% (mol%), respectively. Glucose and mannose were the major sugar components of the inhibitor. The inhibitor was stable at pH 5 to 8 and was stable under 50 °C. Only hen egg‐white lysozyme was inhibited by the purified inhibitor but not the other tested enzymes such as lysozyme of celery, turnip; lytic enzyme of Pseudomonas aeruginosa M‐1001; chitinase/lysozyme of P. aeruginosa K‐187; or cellulase and xylanase of Streptomyces actuosus A‐151 and Aspergillus sp. G‐393. The inhibition of lysozyme to the bacterial cell lytic activity by the purified inhibitor was 100%.
Cytotoxic Principles from Saussurea Lappa and Corydalis Turtshaninovii f. Yanhusuo
Authors: Wu Tian‐Shung , Leu Yann‐Lii , Kuoh Chang‐Sheng , Jiang Shwu‐Duan , Chen Chieh‐Fu , Lee Kuo‐Hsiung
Published: May 2015

Four protoberberine alkaloids, berberine, palmatine, dehydrocorydaline and coptisine were characterized as cytotoxic principles from the tuber of Corydalis turtshaninovii f. yanhusuo. On the other hand, dehydrocostus lactone and costunolide demonstrated cytotoxicity from the root of Saussurea lappa. Their structures were elucidated by spectral analyses.
Intramolecular Diels‐Alder Reactions of Thio‐Substituted Dienes with Enones
Authors: Chou Shang‐Shing P. , Yu Yu‐Ju
Published: May 2015

Thio‐substituted dienes bearing an enone moiety were readily prepared from 3‐sulfolenes, and their intramolecular Diels‐Alder (IMDA) reactions were studied. Octahydronaphthalenones were produced in good yield with high stereoselectivity. Hexahydroindenones were also obtained, but the stereoselectivity was lower.
Lead Tetraacetate Oxidation on Caryachine, A Phenolic Pavine
Authors: Chiou Chi‐Ming , Lee Shoei‐Sheng
Published: May 2015

Lead tetraacetate oxidation on caryachine, a pavine alkaloid possessing a phenolic group at the position para to the N‐methine, in dichloromethane yielded four products — 10‐acetoxy‐O‐acetyl‐caryachine, 10‐acetoxycaryachine, 7‐acetoxy‐O‐acetylcaryachine and (6S, 11R, 12R)‐11‐acetoxy‐O‐acetyl‐caryachine. The reaction took place via adoption of an acetoxy group at a position majorly ortho to the phenolic group, but very minorly at the desired benzylic position para to the phenolic group.
Synthetic and Spectral Studies of Some Nickel Complexes Involving the Iminoquinolinone‐Type Ligand
Authors: Ou Jiunn Yau , Kuo Kung Tu
Published: May 2015

In this study we prepared N,O‐bidentate ligands, sodium salt of 5‐(4′‐hydroxyphenylimino)quinolin‐8‐one, and sodium salt of 5,8‐quinolinequinone‐5‐(8‐hydroxy‐5‐quinolylimide) [indoöxine]. According to experimental results, formation of nickel complexes causes a large bathochromic shift of the absorption bands; in addition, these absorption bands appear in the near‐infrared region at 678‐812 nm. Also, EA, 13C NMR, UV, and IR were performed to characterize these complexes. The above results suggest that coordination occurs via the oxygen atom of the quinoneimine moiety and the nitrogen atom of the pyridine moiety.
Improved Syntheses of Halofuranose Derivatives with the Desired α‐Configuration
Authors: Chin Tsung‐Mei , Huang Liang‐Kuen , Kan Lou‐Sing
Published: May 2015

Chlorination of ribofuranose or 2‐deoxyribofuranose derivatives was carried out in a 1,4‐dioxane solution of hydrogen chloride. This improved procedure allowed the syntheses of 1‐chloro‐α‐D‐ribofuranose and 1‐chloro‐2‐deoxy‐α‐D‐ribofuranose derivatives and offered ease of handling, high yield, and the stereo‐controlled α‐configuration at C‐I.
Synthetic Approach Towards Hexaprismane. A Novel Entry to Homosecohexaprismane Skeleton by Cage Enlargement
Authors: Chou Teh‐Chang , Lin Gerng‐Horng , Yeh Yu‐Lin , Lin Kuan‐Jiuh
Published: May 2015

A series of caged 1,4‐diols, 26, 29a/29b, 31, were synthesized from the Diels‐Alder cycloadduct 21 of 1,2,3,4‐tetrachloro‐5,5‐dimethoxycyclopentadiene and 1,4‐benzoquinone. Reduction of enedione 21 with aqueous TiCl3, followed by base‐catalyzed enolization in the presence of acetic anhydride, gave diene 23b, which reacted with maleic anhydride and 1,4‐benzoquinone to produce the corresponding [4+2] cycloadducts 24b and 27, respectively. The adduct 24b was converted to birdcaged 1,4‐diol 26 by photocyclization followed by decarboxylative olefination of resulted caged anhydride 25b. The adduct 27 was photocyclized to cage compound 28, which was aromatized to dihydroquinone 29a by acid‐catalyzed enolization, or benzo‐annulated compound 31 by reduction and dehydration. The birdcaged 1,4‐diols 26 and 31 underwent fragmentation induced by (diacetoxyiodo)benzene to give enediones 38/39 and 41/42, respectively. Photocyclization of 38 and 39 produced the corresponding caged compounds 43 and 44, respectively, possessing homosecohexaprismane skeletons. The corresponding monohydrate 43a of 43 was structurally characterized by single‐crystal X‐ray diffraction.
Studies on Condensed Heterocyclic Compounds XVI. Synthesis of 3‐Alkyl‐6‐(2,4‐Dichlorophenoxymethyl)‐s‐Triazolo[3,4‐b]‐1,3,4‐Thiadiazoles and 6,6′‐Bis(3‐Aryl‐s‐Triazolo[3,4‐b]‐1,3,4‐Thiadiazoles)
Authors: Zhang Zi‐Yi , Sun Xiao‐Wen , Chu Chang‐Hu , Zhao Lan
Published: May 2015

Several 3‐alkyl‐6‐(2,4‐dichlorophenoxymethyl)‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles 3a‐3e and 6,6′‐bis(3‐aryl‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazoles) 3f‐3j were synthesized. The structures of all the compounds synthesized were elucidated by elemental analyses and spectral data. The representative compounds 3a and 3b exhibited moderate biological activities.
Characterization of the Effects of Vanadium Traps in Cracking Catalysts by Imaging Secondary Ion Mass Spectrometry and Microactivity Test
Authors: Lin Long‐Hui , Chao Kuei‐Jung , Ling Yong‐Chien , Hwang Jan‐Fu , Hou Liang‐Yuan
Published: May 2015

The vanadium trapping effect of Mg and La containing additives in cracking catalyst contaminated with 2300 ppm Ni and 4700 ppm V has been analyzed by microactivity test (MAT) and imaging secondary ion mass spectrometry (SIMS). The results of SIMS imaging are consistent with cracking activity data and show that the La/spinel is a superior vanadium trap for the fluid catalytic cracking of hydrocarbons (FCC) operation. La/spinel serves as a dual function additive for both vanadium trap and SOx removal. The optimum amount of La/spinel added to the cracking catalyst is about 15% by weight. This results in an increased catalytic activity, an increase in gasoline yield, and a decrease in coke and gas factors. The MgAl2O4 phase of Mg/Al2O3 additive is found capable of trapping vanadium while its MgO of Mg/Al2O3 phase can migrate to zeolite particles (the active component of the FCC catalyst) that, in turn, causes a decline in the activity of that catalyst.
Effects of Ethanol Impregnation on the Catalytic Properties of Silica‐Supported Cobalt Catalysts
Authors: Ho Sui‐Wen , Su Yu‐Shu
Published: May 2015

Silca‐supported Co3O4 (6 wt% as Co) catalysts were prepared by pore volume impregnation of ethanol or aqueous cobalt nitrate solutions, and calcined in vacuo to 300 °C. The catalytic performances of these catalysts for oxidation and hydrogenation of CO were examined. All Co3O4/SiO2 catalysts were found to be very active in catalyzing oxidation of CO to CO2 as compared to a commercial 1 wt% Pt/Al2O3. The ethanol‐prepared catalysts exhibited higher activity than those of the aqua‐prepared catalysts. Pre‐calcination of the ethanol‐prepared catalysts in oxygen at 600 °C resulted in a dramatic decrease in the activity. Temperature programmed oxidation indicated the presence of carbon deposits on the surface of used catalysts. Infrared spectra showed the continuous generation of CO2 when these catalysts were exposed to CO. These indicate the primary role of CO disproportionation in catalytic oxidation of CO on Co3O4 at low temperature and explain the sharp decrease in activity in the initial period. After reduction at 400 °C, the ethanol‐prepared catalysts were also found to be more active in catalyzing hydrogenation of CO, and produced less methane and olefin (C2‐C4) fraction. Higher turnover frequencies were observed after high temperature reduction (600 °C) as well, at which ethoxyl groups were removed from silica surface. In both reactions, the enhanced activity for the ethanol‐prepared catalysts can not be fully accounted for by the increase in the dispersion of Co3O4 or CO metal. This suggests that the surface structures of Co3O4 or CO were further modified by the carbonaceous species derived from ethanol.
Heterocycles from Pyrazoloylhydroximoyl Chloride: Synthesis of Certain Quinoxaline, Benzothiadiazine, Benzoxadiazine, Quinazolinone, Imidazo[1,2‐a]pyridine, Imidazo[1,2‐a]pyrimidine, Isoxazole, Pyrazolo[3,4‐d]pyridazine and Pyrrolidino[3,4‐d]isoxazolin‐4,6‐dione Derivatives
Authors: Zohdi Hussein F. , Osman Tabia A. , Abdelhamid Abdou O.
Published: May 2015

3‐Ethoxycarbonyl‐5‐methyl‐1‐(4‐methylphenyl)‐4‐pyrazoloylhydroximoyl chloride (1) reacted with o‐phenylenediamine, o‐aminothiophenol, o‐aminophenol and methyl anthranilate to afford 3‐nitrosoquinoxaline, benzothiadiazine, benzoxadiazine, and 3‐hydroxyquinazoline, respectively. Imidazo[1,2‐a]pyridine, imidazo[1,2‐a]pyrimidine and isoxazole derivatives were obtained via the reaction of 1 with 2‐aminopyridine, 2‐aminopyrimidine and the appropriate active methylene compounds, respectively. Pyrazolo[3,4‐d]pyridazines, and pyrrolidino[3,4‐d]isoxazolines derivatives were also synthesized. The structures of the newly synthesized compounds were established on the basis of spectral data and alternate synthesis whenever possible.
Lewis Acid‐Promoted Reduction of Bis(triorganotin) Oxides to Hexaorganoditins
Authors: Lee Adam Shih‐Yuan , Zhang Shi‐Lien , Pan Ohm‐Guo
Published: May 2015

Hexalkylditin is prepared by a Lewis acid‐promoted (MgCl2) reductive reaction of bis(trialkyltin) oxide using magnesium metal as reducing agent. Hexabutyl‐ and hexaphenylditin are synthesized with 95% and 80% yield separately and a radical mechanism is proposed for the reaction condition. Unsymmetric ditin, Bu3Sn‐SnPh3, was first synthesized by this reductive method.
Differential Cross Sections for the F + H2 Reaction: A Comparison of Classical Trajectory Results for Two Potential Energy Surfaces
Authors: Budenholzer Frank E. , Lin Miao‐Chuan
Published: May 2015

Classical trajectories were calculated for the F + H2 reaction over two potential energy surfaces: (1) the well known Muckerman 5 surface (Theoretical Chemistry: Advances and Perspectives 1981, 6A, 1) and (2) the recent surface of Stark and Werner (J. Chem. Phys. 1996, 104, 6515). Integral cross sections, state specified cross sections, differential cross sections and product energy distributions were calculated for the two surfaces. Since the methods for calculating the trajectories and expressing differential cross sections were identical for both surfaces, the rather substantial differences in the results are clearly due to differences in the potential surfaces. The results are discussed in terms of the special characteristics of the two surfaces.
Kinetic Study of S. griseus Aminopeptidase by Stopped‐Flow Fluorescence Energy Transfer
Authors: Yu Hsien‐Cheng , Lin Wann‐Yin
Published: May 2015

The stopped‐flow fluorescence traces for the hydrolysis of Leu‐Ala‐DED catalyzed by Streptomyces griseus aminopeptidase isolated from pronase exhibits a two‐phase fluorescence change with comparable rates of formation and breakdown of the ES complex. We have developed a method for the determination of the individual rate constants from the stopped‐flow traces. The kinetic parameters for the enzyme‐catalyzed hydrolysis of Leu‐Ala‐DED at 25 °C and pH 8.0 are: k1 = (1.6±0.1) × 105 M−1s−1, k−1, = 0.089 ± 0.001 s−1, and k2 = 0.58 ± 0.01 s−1. For the observed stopped‐flow traces, the steady state approximation is valid only within a very small region around the maximal ES concentration and a large proportion (> 20%) of the substrate has already been hydrolyzed during the pre‐steady state. For a very fast formation of ES complex, the steady state approximation is valid for almost the entire trace. The activation energies for each individual rate constant were determined to be 10.0 ± 0.7, 35 ± 5, and 21.2 ± 0.8 kcal mol−1 for k1, k−1, and k2, respectively. Binding of E and S to form ES was accompanied by a decrease in Gibbs free energy, whereas a dramatic increase in free energy was observed for the conversion of ES to ES≠. The dissociation of ES to form E and S had a very large activation energy, but it was also accompanied by a large increase in entropy.
Pulse Perturbation‐Facilitated Optical‐Optical Double Resonance Spectroscopy of the 43σ+g State
Authors: Tsai King‐Li , Whang Thou‐Jen
Published: May 2015

Twenty‐three rovibronic levels of the Na2 43σ+g state were observed by pulse perturbation‐facilitated optical‐optical double resonance (PFOODR) excitation spectroscopy through the A1σ+u‐b3πu, mixed intermediate levels. The molecular constants and the Rydberg‐Klein‐Rees (RKR) potential energy curve of the 43σ+g state are derived in this work.
Bonding Nature in Photoelectron Spectra of the Molecules XY2
Authors: Chen Erh‐Hao , Chang Tse‐Chiang
Published: May 2015

The vibrational structures of photoelectron spectra can reveal the bonding nature of molecular orbitals. For diatomic molecules the bonding nature of molecular orbitals can be rationalized by the concepts of non‐bonding lone pair type and bonding type bond orbitals consisting of Lewis structures.

For the simplest polyatomic molecules XY2 the concepts of nonbonding lone pair type and bonding type bond orbitals and the method of expanding the canonical molecular orbitals into the bond orbitals are not quite appropriate.

Two correlation diagrams, the distance correlation diagram and the angle correlation diagram, provide us with a better theoretical tool. The molecular orbital with the energy curve having positive slope in the distance correlation diagram (or angle correlation diagram) is identified as the R‐bonding (or 9‐bonding) orbital. The removal of an electron from the R‐bonding (or θ‐bonding) gives rise to vibrational excitation with decreasing frequency for the bond stretching (or bending) mode in the photoelectron spectra.
Dehydration of CuSO4 5H2O Studied by Thermo‐Raman Spectroscopy
Authors: Chang Hua , Huang Pei Jane
Published: May 2015

In this work, Raman spectra were taken continuously from CuSO4‐5H2O powders during a dehydration process at temperatures up to 400 °C. The spectra showed the variation in structures for both SO42 and H2O. Furthermore, the band positions, band intensities, and their derivatives also showed these variations in structure and the amount of each component. From the intensities of the OH bands the amounts of water lost were found to be 2:2:1 in three stages as indicated by TGA/DTA. This method of monitoring variations in structure by Raman spectroscopy as a function of temperature can identify individual species and could be important to the study of a material's thermal properties.
Sydnone Complexes of Pentacyanoferrate(II)
Authors: Shi Cheng‐Hsiang , Wang Shiao‐Tsun , Yang Shiao‐Yun , Yeh Andrew , Tien Hsien‐Ju
Published: May 2015

The 3‐methylsydnone (CH3Sd) and 3‐phenylsydnone (PhSd) complexes of pentacyanoferrate(II) were prepared in aqueous solution by the reaction of Fe(CN)5OH23− with excess ligand. Metal to ligand charge transfer transitions were observed for both complexes at 442 nm (CH3Sd) and 494 nm (PhSd), respectively. The reduction potentials were measured with the Ef values of 0.65 and 0.67 V (vs. NHE) for CH3Sd and PhSd, respectively, at 25 °C, μ = 0.10 M LiClO4 and pH = 5. The kinetics of the substitution reaction were also investigated, and kf and kd values (25 °C, μ = 0.10 M LiClO4,pH = 5) are (5.4 ± 0.2) × 10−2M−1s−1 and (1.4 + 0.1) × 10−5s−1 (CH3Sd), (8.8 ±0.1) × 10−2M−1s−1 and (4.7 ±0.1) × 10−5s−1 (PhSd). The kf values for both sydnone complexes are approximately four orders of magnitude smaller than other pentacyanoferrate(II) complexes with neutral ligands. The difference may arise from the mesoionic character of the sydnone compounds rather than via a different reaction mechanism. Spectroscopic, kinetic and electrochemical results all suggest that the sydnone ring shows a better π‐backbonding stabilization with Fe(CN)53− moiety than that of the pyridine ring.
Peroxycoumarins from the Root Bark of Zanthoxylum schinifolium
Authors: Tsai Ian‐Lih , Lin Wei‐Yu , Chang Chin‐Teng , Chen Ih‐Sheng
Published: May 2015

Two new peroxyterpenyl coumarins including peroxyschininallylol [7‐(3′, 7′‐dimethyl‐6′‐hydroperoxyocta‐2′, 7′‐dienyloxy)‐8‐methoxy coumarin] and peroxyschinilenol [7‐(3′, 7′‐dimethyl‐7′‐hydroperoxyocta‐2′, 7′‐dienyloxy‐8‐methoxy coumarin] were isolated from the chloroform‐soluble part of the root bark of Zanthoxylum schinifolium. The structures of these compounds were elucidated by spectral analyses.