bluuebunny/crossref_metadata_2025 huggingface dataset:
Metal String Complexes: Synthesis, Crystal Structures and Magnetic Properties of Heptanuclear Nickel(II) Complexes, [Ni7(μ7‐teptra)4X2] (teptra = tetrapyridyltriamido, X = Cl−, NCS−)
Authors: Lai Shie‐Yang , Wang Chih‐Chieh , Chen Yu‐Hua , Lee Chung‐Chou , Liu Yi‐Hung , Peng Shie‐Ming
Published: May 2015

The synthesis, crystal structures and magnetic properties of linear heptanuclear nickel(II) complexes [Ni7(μ7‐teptra)4X2], (teptra = tetrapyridyltriamido), with the axial ligand X = Cl− (1), NCS− (2), are reported. The hepta‐nuclear metal chain is helically wrapped by four syn‐syn‐syn‐syn‐syn‐syn teptra3− ligands. Both of the [Ni7(μ7‐teptra)4]2+ moiety are isostructural involving a Ni7 linear chain unit with all of the ∠Ni‐Ni‐Ni being 180°, terminated by two axial ligands. Three types of NiNi distances are found in these complexes. The longest ones bonded with the axial ligands are 2.383(1), 2.374(2) and 2.375(2), 2.354(2), and the intermediate ones are 2.310(1), 2.304(1) and 2.300(2), 2.303(2) Å for (1) and (2), respectively. The innermost NiNi distances are the shortest ones with the distances of 2.226(2), 2.214(2) and 2.194(2), 2.206(2) Å for (1) and (2), respectively. Two terminal Ni(II) ions bonded with the axial ligands are in a square‐pyramidal (NiN4X) environment and exhibit long NiN bonds (−2.10 Å) which are consistent with a high‐spin Ni(II) configuration. The inner five Ni(II) ions displayed short NiN (∼1.90 Å) bond distances which are consistent with a square‐planar (NiN4), diamagnetic arrangement of a low‐spin Ni(II) configuration. The magnetic measurement of (1) shows an antiferromagnetic interaction of two terminal high‐spin Ni(II) ions with the coupling constant J = −3.8 cm−1. The NiNi, NiN distances and magnetic behavior among tri‐, penta‐, and hepta‐nickel(II) complexes are compared and discussed.
Synthesis of Two N,N′‐bis(N,N‐dialkylamide) Derivatives of Diethylenetriaminepentaacetic Acid and the Stabilities of Their Complexes with Gd3+, Ca2+, Cu2+, and Zn2+
Authors: Wang Yun‐Ming , Wang Yueh‐Ju , Liu Gin‐Chung , Kuo Yu‐Ting
Published: May 2015

Two bis(N,N‐dialkylamide) derivatives of DTPA [(carboxymethyl)iminobis (ethylenenitrilo) tetraacetic acid], DTPA‐BDMA = the bis(N,N‐dimethylamide) and DTPA‐BDEA = the bis(N,N‐diethylamide) were synthesized. Their protonation constants were determined by potentiometric titration in 0.10 M Me4NNO3 and by NMR pH titration at 25.0 ± 0.1 °C. Stability and selectivity constants were measured to evaluate the possibility of using the corresponding gadolinium(III) complexes for magnetic resonance imaging contrast agents. The stability constants of gadolinium(III), copper(II), zinc(II), and calcium(II) complexes with DTPA‐BDMA and DTPA‐BDEA were investigated quantitatively by potentiometry. The stability constant for gadolinium(III) complexes is larger than those for Ca(II), Zn(II), and Cu(II) complexes. The selectivity constants and modified selectivity constants of the amides for Gd3+ over endogenously available metal ions were calculated. Effectiveness of these two ligands in binding divalent and trivalent metal ions in biological media is assessed by comparing pM values at physiological pH 7.4. Spin‐lattice relaxivity values R1 for Gd(III) complexes were also determined. The observed relaxivity values were found to decrease with increasing pH in the acid range below pH 4 and relaxivity values became invariant with respect to pH changes over the range of 4–10. 17O NMR shifts showed that the [Dy(DTPA‐BDMA)] and [Dy(DTPA‐BDEA)] complexes had one inner‐sphere water molecule. Water proton spin‐lattice relaxation rates for the [Gd(DTPA‐BDMA)] and [Gd(DTPA‐BDEA)] complexes were also consistent with one inner‐sphere gadolinium(III) coordination position.
First Total Synthesis of (±)‐13‐Hydroxyneocembrene
Authors: Xing Yacheng , Cen Wen , Lan Jiong , Li Ying , Li Yulin
Published: May 2015

First total synthesis of (±)‐13‐hydroxyneocembrene (1), starting from 6‐methyl‐5‐hepten‐2‐one (6) and geraniol (7), is described. The key steps are (i) the addition of sulfur‐stabilized carbanion 12 to aldehyde 9, (ii) the synthesis of 18 by using phase‐transfer catalyzed coupling reaction, and (iii) low‐valent titanium‐induced intramolecular coupling of oxo aldehyde 3 to afford the target molecule after the final deprotection.
A Sensitive Colorimetric Method for the Determination of Arsenic in Environmental and Biological Samples
Authors: Agrawal Omi , Sunita G. , Gupta V. K.
Published: May 2015

Results of a thorough study and application of leucocrystal violet for the determination of arsenic in parts per million (ppm) levels in environmental and biological samples is described here. The proposed method is based on the reaction of arsenic with potassium iodate to liberate iodine. The liberated iodine selectively oxidises leucocrystal violet to form crystal violet dye in the presence of sodium hydroxide. The dye formed shows maximum absorbance at 592 nm. The detection limit of arsenic is 0.002 μgmL−1 and the method obeys Beer's law over the concentration range of 0.1 μg ‐ 1.0 μg of per 25 mL of final solution (0.004–0.04 ppm). The molar absorptivity was found to be 1.49 × 106 L mol−1 cm−1. The proposed method was successfully applied for the determination of arsenic in various environmental and biological samples. The results are in good agreement with the standard reported method.
A Theoretical Study of Photocurrent in Conjugated Polymer Systems
Authors: Chang R. , Lin S. H.
Published: May 2015

We present a theory of photocurrent spectra for a light‐emitting diode fabricated by a π‐conjugated polymer system. The tunneling through a barrier induced by the DC field dominates the dissociation of excitor states (i.e., photoionization of vibronic states) below the threshold. The spectra thus obtained explain most of the experimental results and also allows us to more easily position the S2 state and other higher states in the conjugated polymer.
Systematic NMR Assignments of DNA Exchangeable Protons
Authors: Tseng Yu‐Yu , Chou Shan‐Ho
Published: May 2015

Exchangeable proton information is of critical importance in the NMR structural studies of DNA/RNA oligomers and/or their complexes with protein. However, no systematic NMR assignment strategy about these protons has been reported until now, although similar studies about non‐exchangeable proton assignment have been well established in the past decade. We now report detailed NMR studies of a DNA duplex (d20‐mer) containing the recognition site (5′‐ATGAC‐3′) of GCN4 basic zinc finger protein. All exchangeable and non‐exchangeable protons except H5′/H5″ protons could be assigned from a single H2O/NOESY spectrum at 25°C. The assignment strategy reported in this paper shall be useful to NMR studies of unusual DNA/RNA structures and their complexes with peptides/proteins.
Purification and Characterization of a Cephalexin‐Synthesizing Enzyme from Gluconobacter oxydans CCRC10383
Authors: Yang Fang‐Lin , Wu Shih‐Hsiung
Published: May 2015

A cephalexin‐synthesizing enzyme which catalyzes the synthesis of cephalexin from two substrates, 7‐amino‐3‐deacetoxy cephalosporanic acid (7‐ADCA) and D‐phenylglycine methyl ester (D‐MEPG) was isolated, purified and characterized from G. oxydans CCRC 10383 by ammonium sulfate precipitation, CM‐Fractogel and Sephadex G‐200 chromatography. The molecular weight of the enzyme was estimated to be 270 kd by gel filtration. From the analysis of SDS‐PAGE, the enzyme is a tetramer and consists of two 53 kd subunits and two 73 kd subunits. The isoelectric point of the enzyme was estimated to be 7.5. The optimal pH and temperature for the synthetic reaction of cephalexin were 5–7 and 30–50°C, respectively, with a maxium reaction rate at pH 6 or 50°C. Metal ions are not essential for the enzymatic activity because EDTA (ethylenediaminetetraacetic acid) exerts no influence upon the enzyme activity. The growth medium containing 0.25% DL‐phenylglycine (DL‐PG) or 0.25% D‐phenylglycine (D‐PG) as inducers could obtain 1.4 times higher enzyme activity than the growth medium without inducers. The values of Km, Kcat, Vmax and bimolecular constant Kcat/Km were 19 mM, 1.2 × 104 s−1, 30 unit/mg of protein and 6.2 × 105 M−1s−1, respectively. The Km values for D‐MEPG and 7‐ADCA were determined as 13.9 mM and 3.08 mM, respectively. The conversion of cephalexin was found to be 60% when the synthesis was carried out in the 0.1 M phosphate buffer solution (pH 6.2) containing 40 mM of 7‐ADCA and 118 mM of MEPG at 37°C.
Design and Synthesis of an Activity Probe for Protein Tyrosine Phosphatases
Authors: Lo Lee‐Chiang , Wang Hsin‐Yi , Wang Zi‐Jien
Published: May 2015

Protein tyrosine phosphatases (PTPases) are an important class of enzymes involved in the regulation of many cellular events. Here we describe the design and synthesis of an activity probe 2 targeting these PTPases. This mechanism‐based activity probe adopts a cassette‐like design; a phosphate group serves as the recognition head and a fluorescent diethylaminocoumarin derivative acts as the reporter group. Compound 3 was phosphorylated with diallyl phosphorochloridate and then fluorinated with DAST to give versatile intermediate 5. The Boc protective group of compound 5 was removed by TEA to make available the amino group where a diethylaminocoumarin chromophore was later attached. Final deprotection of the allyl group from the phosphate head gives our complete activity probe 2. It will be used in the labeling study of PTPases from various sources.
Expression, Purification, and Characterization of the Infectious Bursal Disease Virus‐Like Particles Produced by Insect Cells
Authors: Ho Jin‐Yi , Lai Su‐Yuan , Lee Long‐Huw , Wang Min‐Ying
Published: May 2015

The cDNA of the large genomic segment A (ORF A1) of infectious bursal disease virus (IBDV) strain P3009 was synthesized and cloned into the transfer vector pBlueBac4. Following cotransfection and plaque purification, a plaque‐pure recombinant baculovirus, vIBDVJ6, was selected to express IBDV capsid proteins. When Sf9 cells were infected with vIBDVJ6, IBDV precursor protein (polypeptide of VP2‐VP4‐VP3) was expressed and proteolytically processed to give VP2, VP3, and VP4 proteins by a viral protease. These resulting recombinant proteins can self‐assemble to form virus‐like particles (VLPs). The shape and size of the negatively stained purified IBDV‐like particles were demonstrated to be similar to those of the complete P3009 IBDV particles under direct electron microscopic observation. Furthermore, the purified particles were strongly recognized by an anti‐VP2 monoclonal antibody as confirmed by an immuno‐gold labeling experiment. IBDV‐like particles will offer a unique opportunity to create completely non‐infectious viral vaccines for use in the vaccination of chickens. The immunologic response in chickens stimulated by IBDV‐like particles is currently being evaluated.
Applications of Highly Sulfated Cyclodextrins for Enantiomeric Separation by Capillary Electrophoresis
Authors: Chen Fu‐Tai A. , Evangelista Ramon A.
Published: May 2015

Separation of enantiomeric pairs of compounds by capillary electrophoresis (CE) was performed using highly sulfated α‐, β‐ and γ‐cyclodextrins (HS‐CDs). CE analysis of the HS‐CDs using indirect absorbance detection showed that the new class of chiral selectors has substantially higher degrees of sulfation and narrower heterogeneity than those used in previous reports. Elemental analyses showed that the average number of sulfate groups per cyclodextrin was 11, 12, and 13, for HS‐α, β and γCD, respectively. Our earlier 13C NMR data of HS‐CDs were consistent with the structural assignment of complete sulfation at the C‐6 primary hydroxyl groups, greater than 70% sulfation at the C‐2 secondary hydroxyls and absence of substitution at the C‐3 hydroxyls. CE‐based chiral separations were performed using a generalized procedure with phosphate buffer (pH 2.5) containing 5% (w/v) HS‐CD in a 50 μm I.D. × 31 cm (total length) fused silica capillary. Quantitation of enantiomeric impurity of less than 1% was demonstrated for pseudoephedrine and phenylpropanolamine. The HS‐α, β and γCD complement each other by exhibiting different chiral selectivity. The combination of HS‐α, β and γCD resolved more than 140 chiral compounds of neutral, acidic and basic drugs with very different structural features. The HS‐CDs were synthesized under conditions of controlled sulfation to produce chiral reagents with consistent composition, making them excellent chiral selectors for capillary electrophoretic analysis of enantiomeric impurities.
The Leaving Group Effect in Free Radical SH2′ Reactions
Authors: Wu Yuh‐Wern , Tseng Ming‐Chung , Lu Cheng‐Yi , Chou Hsueh‐Hsun , Tseng Yeong‐Fuh , Hsieh Hui‐Joan
Published: May 2015

The relative rates of the leaving groups in free radical SH reactions have been determined. The order of the relative elimination rates of the leaving group is: I > Br (14) > SPh (2) > Cl (1) » OPh, SiMe3. This is consistent with the bond dissociation energy of the C‐X bond. The less the bond dissociation energy value is, the better the leaving group is.
Determination of Magnesium Ascorbyl Phosphate in Cosmetic Bleaching Products Using a Disposable Screen‐Printed Carbon Electrode
Authors: Shih Ying , Zen Jyh‐Myng
Published: May 2015

A preanodized screen‐printed carbon electrode is used for the determination of magnesium ascorbyl phosphate in cosmetic bleaching products. The preanodization process exhibits a marked enhancement of the current response of magnesium ascorbyl phosphate at the screen‐printed carbon electrode. The linear range is up to 240 (correlation coefficient = 0.999) in pH 2.0 citrate buffer with a detection limit (S/N = 3) of 0.33 μM. The electrode has the advantages of low cost and easy of handling and can be either disposable or reused since the renewal gives a good reproducible surface. Quantitative analysis was performed by the standard addition method for magnesium ascorbyl phosphate content in cosmetic products.
Studies on the Synthesis of New 3‐(3,5‐Diamino‐1‐substituted‐pyrazol‐4‐yl)azo‐thieno[2,3‐b]pyridines and 3‐(2‐Amino‐5,7‐disubstituted‐pyrazolo[1,5‐a]pyrimidine‐3‐yl)azothieno[2,3‐b]pyridines
Authors: Ho Yuh‐Wen
Published: May 2015

Coupling the diazonium salt of 3‐amino‐2‐cyano‐4,6‐dimethylthieno[2,3‐b]pyridine 1 with malononitrile 2 gave 2‐cyano‐3‐(hydrazonomalononitrile)‐4,6‐dimethylthieno[2,3‐b]pyridine 3 which then reacted with hydrazine compounds 4a‐4h to yield corresponding 2‐cyano‐3‐(3,5‐diamino‐1‐substituted‐pyrazol‐4‐yl)azo‐4,6‐dimethylthieno[2,3‐b]pyridines 5a‐5h. The 2‐cyano‐3‐(2‐amino‐5,7‐disubstituted‐pyrazolo‐[1,5‐a]pyrimidine‐3‐yl)azo‐4,6‐dimethylthieno[2,3‐b]pyridines 7a‐7f were obtained in good yield by the cyclocondensation reaction of 2‐cyano‐3‐(3,5‐diamino‐pyrazol‐4‐yl)azo‐4,6‐dimethylthieno[2,3‐b]pyridine 5a with the appropriate 1,3‐diketones 6a‐6f under acidic condition.
Siderophores and Iron‐Transport in Microorganisms
Authors: Pattus Franc , Abdallah Mohamed A.
Published: May 2015

Iron is an essential element in many biological systems, and in spite of its abundance (5% of the earth crust), its availability is dramatically limited by the very high insolubility of iron(III) at physiological pHs where the concentration of free iron(III) is less than 10−17 M, a value which is much too low to allow any possible growth to aerobic microorganisms.

Iron metabolization by the microorganisms necessitates generally the biosynthesis of low molecular weight compounds (300 to 2000 Da) called siderophores. These molecules which are generally excreted into the culture medium, chelate very strongly iron(III), solubilize it and transport it into the cells using an ATP‐dependent high affinity transport system.

For nearly fourty years, the structural studies on siderophores have shown a great diversity of structures for these iron‐chelating molecules synthesized by microorganisms. These structures are characterized by the presence of one, two and in most cases, three bidentate chelating groups, generally oxygenated, necessary for the formation of very stable hexacoordinated octahedric complexes between the siderophores and iron(III). These groups are generally either catecholates, or hydroxamates or hydroxyacids, but can be any other bidentate groups

In what follows several typical examples of siderophores belonging to each of these categories are given. It is clear that considering the very high number of siderophores having so many different structures so far isolated and characterized (more than 200), we have restricted this report to the most representative structures of each category, with a special emphasis to pyoverdins, the fluorescent peptidic siderophores of the fluorescent pseudomonads.

Similarly the siderophore‐mediated iron‐transport mechanisms of Gram‐negative bacteria described therafter will report mainly on those of Escherichia coli with a special emphasis to Pseudomonas when information is available.

The pyoverdin‐mediated iron‐transport in fluorescent pseudomonads implies biochemical mechanisms which involve signal and energy exchanges between the two membranes across the periplasmic space. The energy transduction mechanism in the case of the pyoverdin‐mediated active transport in P. aeruginosa has not been completely elucidated so far. Nevertheless from the data obtained for ferric enterobactin and ferrichrome in E. coli, it is plausible that a common mechanism of transport can take place for all the enterobacteria. The key element of this mechanism is protein TonB in E. coli, head of a series of TonB proteins having a very close structure and characterized in P. putida WCS358 and P. aeruginosa ATCC 156942. The striking similarities existing between the various iron‐transport steps in these different bacterial species is highly in favour of a common energy‐dependent siderophore‐mediated iron‐transport mechanism in microorganisms.
Piezoelectric Crystal Membrane Chemical Sensors Based on Fullerene and Macrocyclic Polyethers
Authors: Shih Jeng‐Shong
Published: May 2015

Various reusable and sensitive piezoelectric (PZ) quartz crystal membrane sensors with home‐made computer interfaces for signal acquisition and data processing were developed to detect organic/inorganic vapors and organic/inorganic/biologic species in solutions, respectively. Fullerene(C60), fullerene derivatives and artificial macrocyclic polyethers, e.g., crown ethers and cryptands, were synthesized and applied as coating materials on quartz crystals of the PZ crystal sensors. The oscillating frequency of the quartz crystal decreased due to the adsorption of organic or inorganic species onto coating material molecules on the crystal surface. The crown ether‐coated PZ crystal gas detector exhibited high sensitivity with a frequency shift range of 10–340 Hz/(mg/L) for polar organic gases, a short response time (< 2.0 min.), good selectivity, and good reproducibility. The Ag(I)/crptand22 and Ru(III) / crptand22 coated PZ gas detectors were also prepared for nonpolar organic vapors, e.g., alkynes and alkenes. The frequency shifts of the nonpolar PZ sensors were in the order: alkynes > alkenes > alkanes. A Ti(IV)/Cryptand22‐coated PZ crystal sensor was also developed to detect the inorganic air pollutants, e.g., CO and NO2. A piezoelectric gas sensor for both polar/nonpolar organic vapors based on C60‐cryptand22 was also prepared. The cryptand22‐coated PZ gas sensor was also employed as a GC detector for organic molecules. The cryptand22‐coated piezoelectric GC detectors compared well with the commercial thermal conductivity detector (TCD). The interaction between fullerene C60 and organic molecules was studied with a fullerene coated PZ gas detector. A multi‐channel PZ organic gas detector with PCA(Principal Component Analysis) and BPN (Back Propagation Neural) analysis methods was developed. Various liquid piezoelectric crystal sensors based on long‐chain macrocyclic polyethers, e.g., C10H21‐dibenzo‐16‐crown‐5, C18H37‐benzo‐15‐crown‐5, (C17CO)2‐cyptand22 and fullerene derivatives, e.g., C60‐NH‐cryptand22 and dibenzo‐16‐crown‐5‐C60, were also developed as HPLC detectors for metal ions, anions, and various organic compounds in solutions. The sensitive and highly selective PZ bio‐sensors based on enzymes, polyvinylaldehyde, polycinnaldehyde‐C60 and C60‐cryptand22 were developed to detect various biologic species, e.g., proteins, glucose, and urea. A quite sensitive EQCM (Electrochemical Quartz Crystal Micro‐balance) detection system was also developed for detection of trace heavy metal ions.
Theoretical Study Of β2,3‐Peptide Models
Authors: Wu Yun‐Dong , Wang De‐Ping
Published: May 2015

Conformational features of α,β‐disubstituted β2,3‐dipeptide models have been studied with quantum mechanics method. Geometries were optimized with the HF/6‐31G** method, and energies were evaluated with the B3LYP/6‐31G** method. Solvent effect was evaluated with the SCIPCM method. For (2S,3S)‐β2,3‐dipeptide model 1, a six‐membered‐ring hydrogen bonded structure is most stable. However, the conformation corresponding to the formation of the 14‐helix is only about 1.7 kcal/mol less stable in methanol solution, indicating that the 14‐helix is favored if a (2S,3S)‐β2,3‐polypeptide contains more than 5 residues. On the other hand, the conformation corresponding to the formation of β‐sheet is most stable for (2R,3S)‐β2,3‐dipeptide model 2, suggesting that this type of β‐peptides is intrinsically favored for the formation of β‐sheet secondary structure.
Computational Study of Vertical Ionization Potentials Using Density Functional Theory and Green's Function Methods
Authors: Hu Ching‐Han , Chong Delano P.
Published: May 2015

Over one hundred vertical ionization potentials (VIPs) were computed using density functional theory (DFT) and Green's function (GF) based methods. The DFT approaches include the unrestricted transition state (uTS) and unrestricted diffuse ionization (uDI) approximations using the Becke88‐Perdew86 exchange‐correlation functional. Green's function methods include the outer‐valence GF (OVGF) approach, the parametrized GF2 (pGF2), and the parametrized GF2 times screened interaction (pGW2) approximations. DFT computations of IPs using the uTS approximation was found to be nearly as accurate as those predicted using the elaborate OVGF method. The much more computationally efficient uDI approximation provides predictions of moderate accuracy and is recommended for computing IPs for larger molecules. We have observed that the average absolute deviations from a uDI calculation using poorer basis set (DZVP) and poorer geometry (AM1 optimization) is only slightly larger.
Determination of Molecular Weight of PDPS Modified Copolymers
Authors: Hwang Yeun‐Hsing , Yang Mei‐Hui
Published: May 2015

Molecular weight (MW) determinations of polydiphenylsiloxane‐co‐polydimethylsiloxane (PDPS/PDMS), polydiphenylsiloxane‐co‐polymethylphenylsiloxane (PDPS/PMPS) and polydiphenylsiloxane‐co‐polymethyl(3,3,3‐trifluoropropyl)siloxane (PDPS/PMFPS) statistical copolymers by gel permeation chromatography (GPC), GPC coupled differential viscometer (GPC‐DV) and light scattering (LS) techniques have been compared and discussed. The MW obtained by GPC‐DV in the PDPS/PDMS and the PDPS/PMPS series agreed with that obtained by LS very well. In PDPS/PDMS copolymers, it was found that the MW obtained by GPC was much lower than that obtained by GPC‐DV and LS, as Ph2SiO) content is higher than 50 mol%. In PDPS/PMFPS copolymers, the MW obtained by GPC was far different from that obtained by GPC‐DV and the deviation decreased with increasing Ph2SiO) mol%. The α values of the copolymers can be explained by the structure of the polymer in tetrahydrofuran (THF). Based on the relatively soluble copolymers, not only the differential refractive index increments (dn/dc) of PMPS, PDMS and PMFPS homopolymers but also that of the PDPS homopolymer in THF could be calculated by their corresponding copolymers.
Covalent Interaction of Ru(terpy)(tmephen)Cl+ with DNA: A Potential Ruthenium‐Based Anticancer Drug
Authors: Cheng Chien‐Chung , Lee Wen‐Li , Su Jyan‐Gwo , Liu Chen‐Lun
Published: May 2015

The use of ruthenium complexes in antitumor therapy was launched two decades ago. In view of their low toxicity and good selectivity for solid tumor metastasis, ruthenium complexes have great potential as alternative drugs to cisplatin in cancer chemotherapy. A series of monochloro ruthenium complexes, Ru(terpy) (NN)Cl+ (NN, bidentate nitrogen ligand), containing different electron‐donating groups were prepared. The reactivity towards the formation of Ru‐DNA adduct were revealed by gel mobility shift assay. Their DNA binding sites of Ru(terpy)(tmephen)Cl+ were located predominantly at the purine residues i.e., guanine and adenine, by terminating DNA elongation in vitro using PCR and primer extension techniques. Surprisingly, the ability of Ru(terpy)(tmephen)Cl+ to inhibit cell growth was found to be approximately two times better than that of a known cross‐linking agent, Ru(bpy)2Cl2. Therefore, the increase in liability of the chloro ligand was demonstrated to improve the reactivity of these ruthenium complexes towards the covalent bond formation in Ru‐DNA adducts and result also in a significant inhibition of cell growth. Based on our results, these ruthenium complexes modified with electron‐rich groups provide new consideration in the tune of ruthenium‐based drugs in cancer chemotherapy.
Copper(ll) Complexes of Diamino Diamide and Diamino Diamine in Aqueous Solution
Authors: Chao Min‐Shiun , Huang Shih‐Liang
Published: May 2015

In order to study the difference on the equilibrium, spectral properties of copper(II) complexes of diamino diamide and diamino diamine, new tetradentate ligands, 4,7‐dimethyl‐4,7‐diazadecanediamide (4,7‐N,N′‐Me2‐L‐2,2,2) and 1,10‐diamino‐4,7‐dimethyl‐4,7‐diazadecane (4,7‐N,N′‐Me2‐3,2,3‐tet), have been synthesized. Synthetic procedures for these new ligands are described. Their protonation constants have been determined potentiometrically in 0.10 MKC1 at 25.0°C. The formation of their copper(II) complexes have been investigated quantitatively by the potentiometric technique and by the measurement of their electronic spectra.
Studies with Polyfunctionally Substituted Heteroaromatics: The Reaction of Heterocyclic Enaminonitriles with α‐β‐Unsaturated Nitriles
Authors: Hussein A. M. , Hafez I. S. Abdel , Elnagdi M. H.
Published: May 2015

5‐Amino‐4‐cyano‐3‐phenylpyrazole (1) reacts with cinnamonitriles (2) to yield the pyrazolo[1,5‐a]pyrimidines (3). Also, 5‐amino‐4‐cyano‐1‐phenylpyrazole (4) reacts with cinnamonitriles (2) to yield the pyrazolo[3,4‐b]pyridine derivatives (5). In contrast to this reaction, enaminothiophene (6) reacts with cinnamonitriles (2) to yield compound (7) not (8). The enaminopyrane (9) reacts with cinnamonitriles (2) to yield (10). Finally we have attempted to add cinnamonitriles (2) to thiopyrane (13); only rearrangement and aromatization product (14) was isolated.
The Constituents of Lindera Glauca
Authors: Chang Yuh‐Chwen , Chang Fang‐Rong , Wu Yang‐Chang
Published: May 2015

Twenty‐eight compounds including seven alkaloids, (+)‐3‐chloro‐N‐formylnornantenine (1), (+)‐N‐formylnornantenine (2), (+)‐boldine (3), (+)‐norboldine (4), (‐)‐norboldine (5), lycicamine (6), and tetrahydroberberine (7); four flavonoids, kaempferol (8), kaempferol‐3‐O‐arabinoside (9), quercetin (10), and quercetin‐3‐O‐rhamnoside (11); one butanolide, akolactone A (12); one p‐quinone, 2,6‐dimethoxy‐p‐quinone (13); one cyclohex‐2‐en‐1‐one, blumenol A (14); six benzenoids, methylparaben (15), p‐hydroxybenzoic acid (16), vanillic acid (17), syringic acid (18), 3,4,5‐trimethoxybenzoic acid (19), and 3‐(3,4‐dihydroxyphenyl) propionic acid (20); one diterpene, phytol (21); one triterpene, squalene (22); six steroids, (3‐sitosterol (23), β‐sitostenone (24), stigmasta‐4,22‐dien‐3‐one (25), 6β‐hydroxy‐β‐sitostenone (26), 6β‐hydroxystigmasterone (27), and β‐sitosteryl‐D‐glucoside (28) were isolated from the aerial part of Lindera glauca. These compounds were characterized and identified by physical and spectral method. All compounds were isolated for the first time from this plant. Among them, (+)‐3‐chloro‐N‐formylnornantenine (1) is a new one.
Synthesis, Absorption Spectra Studies and Biological Activity of Some Novel Conjugated Dyes
Authors: El‐Aal R. M. Abd , Koraierm A. I. M.
Published: May 2015

Novel monomethine 2a‐f, dimethine 4a‐f and tetramethine 6a‐h cyanine dyes were prepared as conjugated dyes. Such dyes incorporating coumarin and/or quinoline derivatives 1a‐d. These dyes were synthesized to study their spectral behavior, solvatochromism and biological activity. These dyes are characterized by elemental analysis, IR, 1H NMR and mass‐spectra.
Analysis of Dichlorobenzene in Water by Solid‐Phase Microextraction
Authors: Liu Yah‐Ping , Ho Wu‐Hsiung
Published: May 2015

The solid‐phase microextraction (SPME) technique using a 100 μm film polydimethylsiloxane (PDMS) coated fiber has been examined with the aim to determine dichlorobenzene in aqueous samples. The feasibility of SPME‐GC‐ECD analysis has been evaluated. Absorption time of 30 min was selected and 1 min was long enough for complete desorption of the analytes in the injection port of the gas chromatograph. Linear ranges from 0.03 to 5 μg/L and method detection limits between 7 and 9 ng/L for dichlorobenzenes were obtained. The relative standard deviations were less than 12% for a spiking level of 3 μg/L. The proposed method was applied to determine dichlorobenzenes in spiked deionized water, ground water, and in industrial effluent samples.
Nickel(II) Complexes of N‐Alkyl‐Substituted Diamino Diamides in Aqueous Solution
Authors: Chao Min‐Shiun , Ou Chang‐Fang , Huang Shih‐Liang
Published: May 2015

In order to study the steric, inductive, and ring‐strain effects of diamino diamides on the equilibrium and spectral properties of nickel(II)‐diamino diamides complexes, four tetradentate ligands, 4‐methyl‐4,7‐diazadecanediamide(4‐Me‐L‐2,2,2), 4,7‐dimethyl‐4,7‐diazadecanediamide(4,7‐N,N'‐Me2‐L‐2,2,2), 4‐ethyl‐4,7‐diazadecanediamide (4‐Et‐L‐2,2,2), and 4‐methyl‐4,8‐diazaundecanediamide (4‐Me‐L‐2,3,2), have been synthesized. Their protonation constants have been determined potentiometrically in 0.1M KCl at 25.0°C The formation of their nickel(II)‐complexes and the Ni‐O to Ni‐N bond rearrangements at the two amide sites of these complexes have been investigated quantitatively by potentiometric and spectrophotometric techniques under the same conditions. Electronic spectra of the nickel(II)‐complexes of these ligands and their deprotonated species formed in aqueous solution were measured and discussed.
Determination of Organochlorine Pesticides in Milk by Electron Capture Capillary Gas Chromatography
Authors: Ho Wu‐Hsiung , Yu Li‐Jun
Published: May 2015

The goal of this study was to develop an analytical method to determine the organochlorine pesticides residues in milk. The samples were loaded onto the self‐packed diatomaceous earth columns, then eluted with 25 mL solvent mixture of n‐hexane‐acetone‐ethyl acetate (4+2+1, v/v/v). After collection and concentration, the extracts were cleaned up by the C18 solid‐phase extraction cartridges. Gas chromatograph/electron capture detector was used for determination. The average recoveries of milk which were spiked with 10 ng/mL of α‐BHC, lindane, heptachlor, dieldrin, p,p'‐DDD, and p,p'‐DDT were above 92%. Limits of detection between 0.5‐1.8 ng/mL were achieved.
Synthesis of Some 7H‐s‐Triazolo[3,4‐b]‐1,3,4‐thiadiazine Derivatives
Authors: Dong Heng‐Shan , Wei Kun , Wang Qing‐Lian , Quan Bin
Published: May 2015

The cyclization of 1‐amino‐2‐mercapto‐5‐[5‐methyl‐1‐(4‐methylphenyl)‐1,2,3‐triazol‐4‐yl]‐1,3,4‐triazole with various α‐haloketone in absolute ethanol yields 7H‐3‐[5‐methyl‐1‐(4‐methylphenyl)‐1,2,3‐triazol‐4‐yl]‐6‐substituted‐s‐triazolo[3,4‐b]‐1,3,4‐thiadiazines and their structures are established by elemental analysis, MS, IR and 1H NMR spectral data.
Diagram Technique for Nonlinear Optical Spectroscopy in the Fast Electronic Dephasing Limit
Authors: Fainberg B. D.
Published: May 2015

We show that applying the double‐sided Feynman diagrams to systems with fast electronic dephasing opens up new possibilities for using this technique in resonance nonlinear optical spectroscopy. The novel potentials are including non‐perturbative system‐bath interactions (non‐Markovian relaxation) and the summation of diagrams. The last procedure enables us to obtain new equations for a nonperturbative description of the light‐matter interaction.
Concentration Dependence of the Fifth‐Order Two‐Dimensional Raman Signal
Authors: Tominaga Keisuke , Yoshihara Keitaro
Published: May 2015

The concentration dependence of the fifth order two‐dimensional Raman signal intensity is reexamined. The instantaneous response of the fifth order signal comes from the fifth order susceptibility. The delayed response of the fifth order signal is consistent with a genuine fifth order Raman rather than a cascading process of the third order nonlinearity.
Ultrafast Coherent Control in the Electronic Ground State of a Molecule
Authors: Heid Mario , Chen Tao , Pausch Roman , Schwoerer Heinrich , Kiefer Wolfgang
Published: May 2015

We report on a coherent control experiment to selectively excite a well localized nuclear probability density in the electronic ground state of isolated, jet cooled potassium dimer molecules. The basic idea of this control scheme is to take advantage of the motion of a vibrational wave packet created in an intermediate excited electronic state, from which a Franck‐Condon window to the desired final state in the ground state emerges. To realize this concept we apply a resonant stimulated Raman process, in which the two involved laser pulses are separated by a time delay τ1 and their wavelengths are independently tunable. The method enables us to excite ground state vibrational wave packets, whereby the vibrational energy of the wave packet and the position of its generation along the internuclear separation coordinate of the ground state potential energy surface can in principle be freely chosen by the experimentalist. The results we present for the chosen model system K2 strongly support the idea that this control concept might be one possible approach to selectively populate a desired chemical reaction channel in the electronic ground state of a molecule.
Picosecond Vibrational Spectroscopy of Intermolecular Energy Transfer and Overtone Relaxation in Liquid Bromoform
Authors: Seifert G. , Patzlaff T. , Graener H.
Published: May 2015

Intermolecular energy transfer in liquid bromoform and d‐bromoform was investigated by help of picosecond IR and Raman spectroscopy. For a comprehensive interpretation of the corresponding results the study of C‐H bending overtone (2v4) relaxation was necessary; the effective vibrational lifetime of this vibrational mode was determined to T1 = 3±1 ps. For the intermolecular transfer a dominating process between the intramolecularly equilibrated C‐Br stretching modes v2 and v5 of CHBr3 and CDBr3 with a rate constant of 4·1010 s−1 was recognized. Other possible channels, particularly the one between the quasi resonant modes v1(C‐D) and 2v4(C‐H) were found to be negligible.
Ultrafast Charge Transfer Studied by Femtosecond IR‐Spectroscopy and ab Initio Calculations
Authors: Kummrow Andreas , Dreyer Jens , Chudoba Christian , Stenger Jens , Theodorus Erik , Nibbering Johannes , Elsaesser Thomas
Published: May 2015

Femtosecond vibrational spectroscopy is a versatile method to monitor excited state dynamics evolving in photochemical reactions. Applying high‐level calculations to analyze infrared absorption spectra allows to elucidate molecular structures of the transient compounds and to assign normal modes to the absorption lines. Striking differences in the experimental vibrational pattern of the locally excited states of 4‐(dimethylamino)benzonitrile (DMABN) and 4‐aminobenzonitrile (ABN) (dissolved in acetonitrile) are explained on the basis of planar and pyramidal structures obtained from ab initio complete‐active‐space self‐consistent‐field (CASSCF) calculations, giving evidence for a strong sensitivity of the molecular structure on modest changes in the substituents. Different models for the charge transfer state of DMABN are evaluated.
A Theoretical Analysis of Absorption Spectra and Dynamics of Photosynthetic Reaction Centers
Authors: Chang Chung‐Hung , Hayashi Michitoshi , Chang Railing , Liang Kuo‐Kan , Yang Tzyy‐Schiuan , Lin Sheng‐Hsien
Published: May 2015

In this work, we construct a microscopic model with which one can reconstruct all the experimentally observed characteristics of the RCs including temperature effects. For this purpose, we analyze the absorption spectra of Rb. sphaeroides RCs (R26 and R26. Phe‐a mutants). We apply the excitonic‐vibronic model with the displaced harmonic potential surface model for the nuclear freedoms and determine microscopic properties such as the electronic coupling constants, the vibrational frequencies, and the displacements among the potential surfaces of these electronic states. We also take into account inhomogeneity of RCs in our theoretical analysis. We introduce a thermal expansion model to treat temperature dependent peak shifts observed in the P band of the absorption spectra of the RCs. With the resulting information, we also calculate the rate constants of the dynamic processes occurring in RCs, determining the electronic coupling constants among the electronic states involved in electron transfer and electronic energy transfer of the RCs. Based on the excitonic‐vibronic model, we also investigate the mechanism of the direct path PB*H → P+B−H recently observed in YM210W mutant.
Generalized Redfield Theory and its Application to Transient Absorption Spectroscopies of Molecules in Condensed Phases
Authors: Yang Chen , Shuang Feng , Yan Yi Jing
Published: May 2015

We present a method of implementing the generalized Redfield theory on the calculation of femtosecond transient absorption spectrum of molecular systems in condensed phases. Numerical demonstration is carried out in a model Brownian molecular system involving two Morse potential surfaces. Intramolecular vibrational relaxation, its relation to the spectral density, its spectroscopic signature, and the temperature effect are analyzed.
Extraction Spectrophotometric Determination of Vanadium in Industrial Waste Water
Authors: Kamavisdar A. , Patel K. S.
Published: May 2015

A new and simple extraction spectrophotometric method for the determination of vanadium(V) with KIO4, N‐phenylbenzohydroxamic acid (PBHA) and crystal violet (CV), in industrial waste water samples is described. It is based on the extraction of mixed‐ligand complex V(V)‐IO4− ‐PBHA‐CV+ into chloroform solution over 2‐7 MHC1. The molar absorptivity of the complex is (7.20) × 1031 mol−1 cm−1 at λmax 535 nm. The detection limit of the method is 44 μg 1−1 V. The linearity of the calibration curve is followed up to 6 μgmL−1 in the organic solution with slope, intercept and correlation coefficient of 1.34 × 10−1, 6.7 × 10−3 and +0.99, respectively. This method enhances the sensitivity of the conventional PBHA method for the determination of vanadium, and is free from interferences of other metal ions commonly associated with vanadium. The method has been successfully tested for the determination of V in the industrial waste water samples.
Synthesis of Some New Fu Sed/Spiro of Benzoindole Derivatives and Their Biological Activity
Authors: Soleiman H. A. , Khalafallah A. K. , Abdelzaher H. M.
Published: May 2015

A series of fused and spiropyrazolones, pyrimidinthiones, thiazolidinones and β‐lactams incorporating benzoindole derivatives have been synthesised by cyclocondensation addition reaction and cycloaddition reaction of hydrazine hydrate, hydroxylamine, thiourea, mercapto acetic acid and monochloroacetyl chloride. The pre pared com pounds were tested for anti bacterial and fungicidal activity. Gram‐negative bacteria (Bacilluscereus), as well as the fun gus was used for this purpose. The biological assay was determined according to the filter paper disc method. Assay plates were incubated at 30°C one day for the bacteria and three days for the fun gus (British pharmacopoeia commisson, 1102m, London 1963). The test results show that the components have a strong and sat is factory effect.
Synthesis, Characterization and Reactions of 4‐Hydrazino‐2‐methylpyrimidino[4′5′:4,5]thiazolo[3,2‐a]benzimidazole
Authors: El‐Wareth Abd , Sarhan A. O.
Published: May 2015

4‐Hydrazino‐2‐methylpyrimidino[4′,5′:4,5]thiazolo[3,2‐a]benzimidazole (4) was obtained from hydrazinolysis of the 4‐chloro derivative 3 with hydrazine hydrate. The hydrazino derivative 4 was further cyclized to the corresponding pyrazole 5, pyrazolone 6 and 5‐methyl‐1,2,4‐triazolo[1″,5″:3′,4′]pyrimidino[5′,6′:5,4]‐thiazolo[3,2‐a]benzimidazole (9) and 5‐methy‐1,2,4‐triazolo[4″,3″:3′,4′]pyrimidino[5′,6′:5,4]thiazolo‐[3,2‐a]benzimidazole (10), respectively. The triazolo derivative 10 was isomerized to the triazolo derivative 9 under a variety of reaction conditions.
Flavonoid Aglycones and Indole Alkaloids from the Roots of Acacia Confusa
Authors: Lee Tzong‐Huei , Chou Chang‐Hung
Published: May 2015

From the methanolic extract of the roots of Acacia confusa Merr. (Leguminosae), (‐)‐2,3‐cis‐3,4‐cis‐4′‐methoxy‐3,3′,4,7,8‐pentahydroxyflavan (1), (‐)‐2,3‐cis‐3,4‐cis‐3,3′,4,4′,7,8‐hexahydroxyflavan (2), (‐)‐2,3‐trans‐3′,4′,7,8‐tetrahydroxydihydroflavonol (3), (+)‐catechin (4), (‐)‐epicatechin (5), 3′,4′,7,8‐tetrahydroxyflavonol (6) together with N‐methyltryptamine (7) and N,N‐dimethyltryptamine (8) were isolated, and their structures were established by analysis of their spectroscopic data. Among them, compound 1 was a new flavonoid. Additionally, the results of chromatographic bioassay on lettuce seeds indicated that compounds 7 and 8 exhibited significant phytotoxicity at a concentration lower than 14 mM.
Diamino‐Substituted Carbene Transfer between Transition Metal Ions
Authors: Chen Hsin‐Pei , Ku Rong‐Zhi , Liu Shiuh‐Tzung
Published: May 2015

Diamino‐carbene ligand transfer between various metalions is studied, particularly with Pd (II) to Rh(I), Rh(I) to Au(I). Reactions of various carbene complexes with AgPF6 result in the cleavage of the M=C bond to give the protonated carbene species, imidazolidin‐2‐ylidinium salt, indicating the presence of free carbene ligand in the reaction medium. When the carbene transfer process was carried out in tetrahydrofuran, the polymerization of tetrahydrofuran occurred.
Electrochemical Response of Polyaniline (PANI)/Thiokol Rubber (TR) Films in Cysteine Solution
Authors: Jia Zhenbin , Ding Keqiang , Zhao Qian , Cao Jianglin , Tong Ruting
Published: May 2015

The electrochemical character of polyaniline/thiokol rubber (PANI/TR) composite film on a Pt electrode was investigated in a cysteine sulphuric acid solution by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The significant change of the peak current and peak potential in the cyclic voltammograms was observed. The irreversible peaks of cyclic voltammetry for cysteine/cystine redox couple at a platinum electrode have turned into one pair of nearly reversible peaks at the above electrode; the reversibility of the redox couple has been greatly improved. We found that thiokol rubber could improve the electrocatalysis of the PANI film to the electrochemical reaction with S‐S bonds, as well as the adhesion of the PANI film to the Pt substrate. Several effective factors, such as the concentration of thiokol rubber in the nonaqueous electrodeposition solution, different potential scan rate, immersing time of the film electrode in the studied electrolyte were all taken into account.
Synthesis of C‐Butenyl Linked Disaccharides via Olefin Cross‐Metathesis
Authors: Lin Chang‐Ching , Subramanian Thangaiah , Hsu Tzu‐Sui , Fan Gang‐Ting , Lin Chun‐Cheng
Published: May 2015

Several C‐butenyl linked disaccharides were pre pared in high yields by olefin cross‐metathesis.
Synthesis, Acidity Constants and Tautomeric Structure of 7‐Arylhydrazono[1,2,4]Triazolo[3,4‐b][1,3,4]thiadiazines in Ground and Excited States
Authors: Shawali Ahmad S. , Zeid Ibrahim F. , Abdelkader Mahmoud H. , Elsherbini Alsayed A. , Altalbawy Farag M. A.
Published: May 2015

7‐Arylhydrazono[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazines 4 were synthesized from the reactions of 4‐amino‐5‐phenyl‐4H‐[1,2,4]triazole‐3‐thiol 2 and 2‐(2‐naphthyl)‐2‐oxoethanehydrazonoyl bromides 1 and their acid dissociation constants pK and pK*, in the ground and excited states, respectively, were determined. Both pK and pK* constants were correlated by Hammett equation. The pK and the spectral data presented indicate that the title compounds exist predominantly in the hydrazone tautomeric form.
Synthesis of Naturally Occurring Rubilactone, Mollugin, and Dihydromollugin of Rubia cordifolia
Authors: Ho Li‐Kang , Yu Hsi‐Jung , Ho Chen‐Ta , Don Ming‐Jaw
Published: May 2015

Rubilactone (1), dihydromollugin (2), and mollugin (3) are naturally occurring products found in Rubia cordifolia, which is a famous Chinese herb with anti tumor, viral inhibition and other activities. Synthetic studies were carried out in these naphthoic acid esters starting from 1,4‐dihydroxy‐2‐naphthoic acid. In this study, we finished the synthesis of rubilactone which has not been reported before and also synthesized dihydromollugin and mollugin with better yields with different approaches compared to those previously reported in the literature.
Dry Diazonium Nitrates from Aromatic Amines and Tributyl Phosphate‐NO2 Adduct
Authors: Zhang Qingzhi , Liu Xinming , Zhang Shensong , Zhang Jinming
Published: May 2015

Aromatic amines reacted with TBP‐NO2 adduct to give dry aryl diazonium nitrate in high purity and yield.
Time‐Resolved Extended X‐ray Absorption Fine Structure (EXAFS) Studies by Means of an Energy Dispersive Spectrometer
Authors: Oulianov Dmitri A. , Tomov Ivan V. , Lin Sheng H. , Rentzepis Peter M.
Published: May 2015

The structures formed during the photodicosiation of CBr4 in alcohol solution have been measured by means of a novel ultrafast time‐resolved x‐ray absorption fine structure (EXAFS) experimental system, suitable for the direct determination of ultrafast transient structures of molecules in the liquid and solid phase. The EXAFS spectra of the starting and final products of the reaction were measured and analyzed.
Concise Synthesis of Sibrafiban and Lamifiban, Two Non‐Peptide Fibrinogen Receptor (GPIIb/IIIa) Antagonists
Authors: Chang Meng‐Yang , Chen Shui‐Tein
Published: May 2015

The total synthesis of the non‐peptide fibrinogen receptor antagonists, sibrafiban (1) (Ro 48–3657) and lamifiban (2) (Ro 44–9883), is described. Both contain 4‐hydroxypiperidine unit and the same solid‐phase synthesis method was used as a key step. Connection of a secondary alcohol to the DHP‐resin, followed by iterative saponification and coupling sequences, provided novel drugs.