bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses and Structures of Molybdenum, Tungsten, and Manganese Complexes of a Cyclic Thiourea, [M(CO)5(SC3N2Me4)] (M = Mo, W) and [{CpMn(CO)2}2(μ‐SC3N2Me4)]
Authors: Saito Kazuya , Kawano Yasuro , Shimoi Mamoru 
Published: May 2007

AbstractPhotolysis of [CpMn(CO)3] in the presence of 1,3,4,5‐tetramethylimidazoline‐2‐thione, SC3N2Me4 (1), produced a thione‐bridged dinuclear complex, [{CpMn(CO)2}2(μ‐SC3N2Me4)] (2). Compound 2 shows unprecedented geometry of the Mn–S–Mn framework, featuring a pyramidal sulfur atom and long Mn···Mn distance. Photoreaction of [M(CO)6] (M = Mo, W) with 1 afforded mononuclear complexes [M(CO)5(SC3N2Me4)] [M = Mo (3), W (4)]. In compounds 2–4, the C–S bond of the thione ligand is stretched on coordination because of the polarization of the metal–ligand linkage. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
(Phthalocyaninato)copper(II) Complexes Fused with Different Numbers of 15‐Crown‐5 Moieties – Synthesis, Spectroscopy, Supramolecular Structures, and the Effects of Substituent Number and Molecular Symmetry
Authors: Sheng Ning , Zhang Yuexing , Xu Hui , Bao Meng , Sun Xuan , Jiang Jianzhuang 
Published: May 2007

AbstractSymmetrical (phthalocyaninato)copper(II) complexes Cu(Pc′) [Pc′ = Pc(15C5), Pc(opp‐15C5)2, Pc(adj‐15C5)2, Pc(15C5)3; Pc = unsubstituted phthalocyaninate, Pc(15C5) = 2,3‐(15‐crown‐5)phthalocyaninate, Pc(opp‐15C5)2 = 2,3,16,17‐bis(15‐crown‐5)phthalocyaninate, Pc(adj‐15C5)2 = 2,3,9,10‐bis(15‐crown‐5)phthalocyaninate, Pc(15C5)3 = 2,3,9,10,16,17‐tris(15‐crown‐5)phthalocyaninate] (2–5) have been prepared by the reaction of corresponding heteroleptic bis(phthalocyaninato)europium complexes Eu(Pc)(Pc′) [Pc′ = Pc(15C5), Pc(opp‐15C5)2, Pc(adj‐15C5)2, Pc(15C5)3, Pc(15C5)4; Pc = unsubstituted phthalocyaninate] with Cu(OAc)2 in dry dmf at 100 °C. For the purpose of comparative studies, the symmetrical counterparts CuPc (1) and CuPc(15C5)4 [Pc(15C5)4 =2,3,9,10,16,17,24,25‐tetrakis(15‐crown‐5)phthalocyaninate](7) have also been prepared. These monomeric complexes have been characterized by spectroscopic methods in addition to elemental analysis. Having a series of closely related phthalocyanines with a different number and/or disposition of 15‐crown‐5 groups at the peripheral positions, the effects of 15‐crown‐5 substituent number and molecular symmetry on the electronic absorption spectra, infra‐red (IR) spectra, and supramolecular structure formation induced by K+ ions have been investigated. Systematic studies on the formation of dimeric supramolecular structures of the series of monomers 2–6 reveal and confirm the previously proposed two‐step three‐stage process of K+‐induced dimerization of phthalocyanines with three or four 15‐crown‐5 moieties.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Coordination Assemblies of Metallacyclic, Prismatic and Tubular Molecular Architectures Based on the Non‐rigid Ligands
Authors: Chen Chun‐Long , Zhang Jian‐Yong , Su Cheng‐Yong 
Published: May 2007

AbstractThis microreview covers recent advances in the assembly of coordination molecular architectures showing cyclic, prismatic and tubular structures based on the semi‐rigid or flexible ligands. Four assembly routes are outlined depending on the symmetry interactions between specific ligands and metal ions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Generation of [2×2] Grid Metallosupramolecular Architectures from Preformed Ditopic Bis(acylhydrazone) Ligands and through Component Self‐Assembly
Authors: Cao Xiao‐Yu , Harrowfield Jack , Nitschke Jonathan , Ramírez Juan , Stadler Adrian‐Mihail , Kyritsakas‐Gruber Nathalie , Madalan Augustin , Rissanen Kari , Russo Luca , Vaughan Gavin , Lehn Jean‐Marie 
Published: May 2007

AbstractDitopic bis(acylhydrazone) ligands, derived from the reactions of carbohydrazides with 2‐phenylpyrimidine‐4,6‐dicarbaldehyde and designed for grid formation with octahedrally coordinating transition‐metal ions, exhibit a varied coordination chemistry depending upon the degree of their deprotonation. The neutral acylhydrazones are relatively poor ligands and are seemingly involved in multiple, labile complexation equilibria varying with the solvent and the particular metal salt in solution; nevertheless, grid complexes of different forms can be isolated in the solid state. Although only limited study has been made of the singly deprotonated ligands, grid species appear to be much more readily isolated. With the doubly deprotonated ligands, grid formation is strongly favoured in both the solution and solid states. As a consequence, the grid structures form spontaneously in the presence of a base by self‐assembly from their components without need to preform the ditopic ligands. Extensive structural studies have been carried out both to establish the grid structures and to analyse the nature of the supramolecular interactions possible for neutral and charged grid species. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Differential effects of obesity on acetoacetyl‐CoA synthetase gene in rat adipose tissues
Authors: Yamasaki Masahiro , Hasegawa Shinya , Kitani Tetsuya , Hidai Kensuke , Fukui Tetsuya 
Published: May 2007

AbstractIn order to investigate the physiological role of the ketone body‐utilizing enzyme acetoacetyl‐CoA synthetase (AACS) in obesity‐induced metabolic derangements, we examined the mRNA levels of AACS and other lipogenic enzymes in white adipose tissues (WAT) in the different types of obesity, genetic (Zucker fatty) and high‐fat diet (HFD)‐induced obesity. Plasma ketone body levels and gene expression levels of AACS and acetyl‐CoA carboxylase‐2 (ACC‐2) in WAT were lower in Zucker fatty rats than in lean rats. On the contrary, in HFD‐induced obese rats, these levels were increased. Moreover, AACS mRNA expression was affected only in subcutaneous WAT by each type of obesity. Our data suggest that AACS mRNA expression is related to obesity‐induced alteration of plasma ketone body levels, and that AACS in subcutaneous WAT plays an important role in the regulation of lipogenesis and ketone body utilization in various obese conditions.
Are natural antioxidants better – and safer – than synthetic antioxidants?
Authors: Pokorný Jan 
Published: May 2007

AbstractAntioxidants are necessary in the Western diet as it is rich in polyenoic fatty acids, which are easily oxidized with formation of free radicals that are harmful if present in higher amounts. Consumers prefer natural antioxidants to synthetic antioxidants, mainly for emotional reasons. The common Western daily diet contains about 1 g natural antioxidants even if no natural antioxidants have been added for lipid stabilization. Their main sources are cereals, fruits, vegetables, and beverages. Only a part of the natural antioxidants is absorbed and used as free‐radical scavengers in vivo. Natural antioxidants should be added to food in larger amounts than synthetic antioxidants as they are less active, but the actual activity depends very much on particular conditions and food composition. Nevertheless, the addition of additional antioxidants is still negligible in comparison with the dietary supply of native antioxidants. The safety limits of natural antioxidants are mostly not known, but they are hardly safer than synthetic antioxidants. The best protection would be to replace high‐polyenoic oils in the diet with high‐oleic oils, and to use alternative methods of food protection against autoxidation.
Stereoselective Synthesis of 2‐Deoxy‐2‐phenylselenenyl Glycosides from Furanoses: Implication of the Phenylselenenyl Group in the Stereocontrolled Preparation of 2‐Deoxy‐ribo‐ and 2‐Deoxy‐xylo‐oligosaccharides
Authors: Boutureira Omar , Rodríguez Miguel A. , Benito David , Matheu M. Isabel , Díaz Yolanda , Castillón Sergio 
Published: May 2007

AbstractA series of 2‐deoxy‐2‐phenylselenenyl‐1‐thioglycosides were evaluated as a class of glycosyl donors that provide access to 2‐deoxyglycosides from furanoses. This short synthetic route involves olefination, selenonium ion mediated 6‐endo cyclization and glycosylation reactions. The cyclization reaction proceeds with complete regio‐ and stereoselectivity, which are enhanced by employing 3,4‐O‐isopropylidene as a cyclic bifunctional protecting group. The implication of the phenylselenenyl group at C‐2 in the stereocontrolled preparation of 2‐deoxyoligosaccharides is discussed. Its presence gives some insights into the likely pathway of glycosylation reactions by using 2‐deoxy‐2‐phenylselenenyl‐1‐thioglycosyl donors in comparison with the previously described 2‐deoxy‐2‐iodo derivatives. We also demonstrated that the glycosylation of 2‐deoxy‐2‐phenylselenenyl‐1‐thioglycosides is highly substrate dependent, as well as particularly effective in providing 2‐deoxy‐2‐phenylselenenyl‐β‐D‐gulo‐ and ‐β‐D‐allo‐glycosides. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of (S)‐Nonacosan‐10‐ol, the Major Component of Tubular Plant Wax Crystals
Authors: Dommisse Aarnoud , Wirtz Jennifer , Koch Kerstin , Barthlott Wilhelm , Kolter Thomas 
Published: May 2007

Abstract(S)‐Nonacosan‐10‐ol [(+)‐Ginnol] is the main component of the tubular wax aggregates, which are found on many plant leaves. To investigate the role of this lipid for the formation of super hydrophobic self‐cleaning plant surfaces, both enantiomers of the title compound were prepared in six steps. Key steps are the resolution of the allylation product of decanal with (R)‐O‐methylmandelic acid, and a chain elongation by cross metathesis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Development in Synthesis, Electrochemistry, LB Moieties of Phenothiazine Based Units
Authors: Doskocz Jacek , Sołoducho Jadwiga , Cabaj Joanna , Łapkowski Mieczysław , Golba Sylwia , Palewska Krystyna 
Published: May 2007

AbstractA convenient and higher yielding synthetic route to N‐alkyl‐bis(thiophene)phenothiazine derivatives is reported and their aggregation, electrochemical properties and polymerization are characterized. The key step in the synthesis of this group of compounds has been the Stille type coupling reaction between the N‐alkyldibromophenothiazine and tin derivatives of thiophene as the best way for preparation of conjugated N‐alkylphenothiazine derivatives. For this group of compounds we also present an electrochemical polymerization effect and widely adopted approach to prepare structurally ordered thin, electroconducting films by Langmuir–Blodgett technique.
Electroaddressable Selective Functionalization of Electrode Arrays: Catalytic NADH Detection Using Aryl Diazonium Modified Gold Electrodes
Authors: Harper Jason C. , Polsky Ronen , Dirk Shawn M. , Wheeler David R. , Brozik Susan M. 
Published: May 2007

AbstractWe report the application of 4‐nitrophenyl diazonium modified electrodes towards the electrochemical detection of NADH. Selective activation of individual electrodes on a 5 element array by electro‐addressable conversion of nitro groups to amines and subsequent EDC/NHS crosslinking to the NADH oxidant, pyrroloquinoline quinone (PQQ), is demonstrated. Inactivated electrodes retained nitro functionality and were protected against non‐specific adsorption and mild chemical reactions. Electrodeposition conditions were used to control nitrophenyl film thickness and showed that while increased film thickness leads to greater functionalization density of PQQ, it also results in decreased electron transfer kinetics. The electrodeposition protocol can therefore serve as a method to control electrode functionalization density and film electron transfer kinetics. We believe this simple technique for selective electrode functionalization may facilitate the development of next generation multianalyte electrochemical sensors.
Acetylcholinesterase Immobilization on 3‐Mercaptopropionic Acid Self Assembled Monolayer for Determination of Pesticides
Authors: Pedrosa Valber A. , Caetano Josiane , Machado Sergio A. S. , Freire Renato S. , Bertotti Mauro 
Published: May 2007

AbstractStudies on the immobilization of acetylcholinesterase onto a SAM gold electrode and the use of the fabricated biosensor for the determination of carbaryl and parathion are presented. The influence of pH, ionic strength, enzyme loading and concentration of glutaraldehyde on the response of the biosensor was investigated . The amperometric biosensor developed in this study provided linearity to parathion and carbaryl in the 2.0 a 30.0×10−6 mol L−1 concentration range. The detection limits under the optimum working conditions were found to be 9.3 μg L−1 for parathion and 9.0 μg L−1 for carbaryl. The enzyme electrode was found to be stable for 7 days.
Anodic Stripping Voltammetry Using a Vibrating Electrode
Authors: Chapman Conrad S. , van den Berg Constant M. G. 
Published: May 2007

AbstractThis work proposes a vibrating microwire electrode as working electrode in stripping voltammetry. The vibration was found to maintain a constant and thin (1–2 μm) diffusion layer during the deposition step. The electrode vibration eliminated the need for external stirring of the solution, thus facilitating in situ detection in the environment. The vibration was effected by fixing a low‐voltage (3 V), asymmetric, electrical rotor to the working electrode (a gold microwire of either 5 or 25 μm). The sensitivity of the vibrated electrode was ca. 22×greater than stationary. Measurements of copper (4 nM) by anodic stripping voltammetry using the vibrating electrode had a low standard deviation (1% for n=6) indicating that the diffusion layer had only minor variability. The agitation mechanism was unaffected by water moving at >2 m s−1 and by water pressure equivalent to a depth of >40 m, indicating its suitability for in situ measurements. The vibrating probe was used for in situ detection of copper by anodic stripping voltammetry to a depth of 6 m. Using a 5 min deposition time, the limit of detection for labile copper was 38 pM.
A Versatile System for Arbitrary Function Large‐Amplitude Fourier Transformed Voltammetry
Authors: Wang Lishi , Huang Xinjian 
Published: May 2007

AbstractA novel low‐cost instrument for arbitrary function large‐amplitude Fourier transformed voltammetry was developed. Description of both hardware and software was given in detail in this paper. A micro‐control‐unit (MCU) in combination with a field programmable gate array (FPGA) was designed to act as the controller of the instrument. Profiting from the built‐in USB2.0 standard interface of the MCU, vast amount of data to/from the high resolution digital‐to‐analog converter (DAC)/analog‐to‐digital converter (ADC) then could be exchanged with computer in real‐time, instead of being temporarily stored at the capacity limited memory of the instrument which always restricted the length of sampling time and the size of the collected data set. In the [Fe(CN)6]4+/3+ system, by superimposing a sinusoidal waveform with an amplitude of 120 mV onto a triangular potential and then applying to a macro electrode through the instrument, voltammograms up to the eighth harmonic could be well resolved by FT‐IFT method. Excellent agreement was attained with Bond's similar experiment [Anal. Chem. 76 (2004) 3619] in respect of the shape and relative peak height of each harmonic. With the simply structured instrument, stable performance, flexible and versatile function was achieved. Arbitrary forms of AC perturbation which may not necessarily be sinusoidal or square‐wave or other regular formed periodic signal could be synthesized and superimposed onto a DC potential as the excitation signal with this instrument. Some more useful electrode process information was expected to unveil by utilizing the FT‐IFT algorithm to dissect the response signal.
Voltammetry as an Alternative Tool for Trace Metal Detection in Peloid Marine Sediments
Authors: Ciglenečki Irena , Bura‐Nakić Elvira , Inzelt György 
Published: May 2007

AbstractHere was demonstrated for the first time a possible application of abrasive stripping voltammetry in the direct measurement of trace metals in anoxic, sulfidic marine sediments (peloid mud) from a small and shallow (0.2–1 m) marine lagoon in Central Dalmatia, Croatia. Trace amounts of sample compounds are transferred to the graphite electrode surface and electrochemical reduction or oxidation processes are followed by the cyclic voltammetry in seawater or 0.55 M NaCl as electrolyte. After a preelectrolysis at potentials ranging from −1.0 to −1.5 V (vs. SCE) a well‐defined anodic stripping peak corresponding to the oxidation of metal deposits generated at deposition potentials is obtained around −0.74 V (vs. SCE). The same samples were studied by anodic stripping voltammetry at the Hg electrode and inductively coupled plasma‐mass spectrometer (ICP‐MS). ICP‐MS showed higher concentrations of trace metals such as Al, Fe, Mo, Mn. A relatively high concentration of reduced sulfur species (RSS) (10−3 M) is determined electrochemically in porewater of the peloid mud, indicating that the magnitude of metal enrichment in the sediments is probably controlled by precipitation with sulfide.
Fast Simultaneous Adsorptive Stripping Voltammetric Determination of Ni(II) and Co(II) at Lead Film Electrode Plated on Gold Substrate
Authors: Tyszczuk Katarzyna , Korolczuk Mieczyslaw 
Published: May 2007

AbstractA fast adsorptive stripping voltammetric procedure for simultaneous determination of Ni(II) and Co(II) in the presence of nioxime as a complexing agent at an in situ plated lead film electrode was described. The time of determination of these ions was shortened due to the application of gold as a substrate for lead film. At gold substrate lead film formation and accumulation of Ni(II) and Co(II) complexes with nioxime proceeds simultaneously. To obtain a stable signals for both ions a simple procedure of activation of the electrode was proposed. Calibration graphs for an accumulation time of 20 s were linear from 5×10−9 to 1×10−7 mol L−1 and from 5×10−10 to 1×10−8 mol L−1 for Ni(II) and Co(II), respectively. The procedure with the application of a lead film electrode on a gold substrate was validated in the course of Ni(II) and Co(II) determination in certified reference materials.
Comparison of DNA Hybridization at Rotating and Heated Gold Disk Electrodes
Authors: Peter Jörg , Reske Thomas , Flechsig Gerd‐Uwe 
Published: May 2007

AbstractThis paper reports about the influence of temperature, hybridization time and convection upon the detection of osmium tetroxide bipyridine‐labeled target oligonucleotides at rotating gold disk (RDE) and heated low temperature co‐fired ceramics (LTCC) gold disk electrodes. We used mixed self‐assembled monolayers of hexathiol‐linked probe oligonucleotides and mercaptohexanol on the gold surface of the electrodes for the hybridization detection of the labeled targets by means of square‐wave voltammetry. Due to protective strands, the osmium tetroxide‐modified target strands were still able to hybridize with the immobilized probe strands. The hybridization of such osmium tetroxide bipyridine‐modified target strands with thiol‐linked probe strands immobilized on gold yielded large reversible square‐wave‐voltammetric signals. Rotation speed and, hence, mass transport due to convection has only marginal effects. On the other hand, temperature affects greatly the hybridization step as indicated by both heated LTCC electrode in cold and RDE in warm hybridization solution. Calculated detection limits of 3.6 and 3.1 nM targets at the RDE and the LTCC electrode, respectively, have been almost the same at both types of electrodes. Applying an appropriate temperature during hybridization is more important than mechanically enhanced mass transport.
Electroanalytical Determination of Some Phenolic Acids by High‐Performance Liquid Chromatography at Gold Electrodes
Authors: Casella Innocenzo G. , Colonna Chiara , Contursi Michela 
Published: May 2007

AbstractThe electrochemical and amperometric behavior of a gold electrode was investigated towards the oxidation of several common phenolic acids in neutral phosphate solutions. Au electrodes show an appreciable stability and reproducibility of the amperometric signals by using a constant applied potential of 1.0 V vs. Ag/AgCl. Separations of selected phenolic acids using a reverse phase C18 analytical column with a mobile phase containing 10 mM NaH2PO4 plus 10 mM Na2HPO4 (pH 7) and methanol as organic modifier, are achieved isocratically in less than 30 min. The detection limits at the level of nmol/L and linear ranges of four‐five orders of magnitude are generally achieved. The proposed chromatographic strategy coupled with the electrochemical detection at the Au electrode was successful tested for the quantitative determination of phenolic acids in beer, red wine and brandy with good sensitivity and recovery.
Room Temperature Ionic Liquid Carbon Nanotube Paste Electrodes: Overcoming Large Capacitive Currents Using Rotating Disk Electrodes
Authors: Kachoosangi Roohollah Torabi , Wildgoose Gregory G. , Compton Richard G. 
Published: May 2007

AbstractThe voltammetric response of graphite or carbon nanotube paste electrodes, which incorporate the room temperature ionic liquid, N‐butyl‐N‐methyl pyrrolidinium bis(trifluoromethylsulfonyl) imide or [C4mpyrr][NTf2], (RTIL‐CNTPE and RTIL‐CPE respectively) as the binder, towards anionic, cationic and neutral redox probes is examined and compared to conventional paste electrodes which use mineral oil as the binder. The RTIL paste electrodes are found to suffer from very large background currents due to capacitive charging. This is exacerbated further when CNTs are combined with RTILs in the paste. The large charging currents obscure any Faradaic processes of interest, especially at low analyte concentrations. By employing steady state voltammetry at a rotating disk electrode made of the RTIL pastes this problem can be overcome. This allows the electroanalytical properties of these interesting electrode substrates, which combine the attractive properties of CNTs with RTILs to be further explored and developed.
Characterization of transferrin glycoforms in human serum by CE‐UV and CE‐ESI‐MS
Authors: Sanz‐Nebot Victoria , Balaguer Elvira , Benavente Fernando , Neusüß Christian , Barbosa José 
Published: May 2007

AbstractHuman transferrin (Tf) is a model glycoprotein for congenital disorders of glycosylation (CDG) diagnosis. In the last few years, new CE‐UV methods for intact Tf glycoforms analysis have been developed using nonvolatile BGEs and organic modifiers. However, the use of these BGEs does not allow the coupling of these procedures with electrospray MS (ESI‐MS). In this study, a new CE‐UV separation method of Tf glycoforms is developed, using a double‐layer stable coating and a volatile BGE based on ammonium acetate. The separation method is optimized using standard Tf and their potential is demonstrated applying the method to the analysis of sera Tf from healthy individuals and CDG patients. The CE‐UV separation method has been coupled to ESI‐MS detection. Main parameters such as sheath liquid composition are optimized in order to obtain a good sensitivity. The CE‐ESI‐MS method has also been used in serum samples obtaining the separation of the different proteins present in serum and partial separation of Tf glycoforms. Different mass spectra and deconvoluted molecular masses were obtained for each sialoform, allowing unequivocal glycoform identification.