bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioresolution and absolute configurations of chiral meta‐substituted diphenylmethanols as determined by x‐ray crystallographic and 1H NMR anisotropy methods
Authors: Kosaka Masashi , Sugito Takeo , Kasai Yusuke , Kuwahara Shunsuke , Watanabe Masataka , Harada Nobuyuki , Job Gabriel E. , Shvet Alex , Pirkle William H. 
Published: March 2003

Abstractmeta‐Substituted diphenylmethanols were enantioresolved by the method of chiral phthalic acid yielding enantiopure alcohols. Their absolute configurations were unambiguously determined by X‐ray crystallography of chiral phthalate esters and/or by the 1H NMR anisotropy method using 2‐methoxy‐2‐(1‐naphthyl)propionic acid. Chirality 15:324–328, 2003. © 2003 Wiley‐Liss, Inc.
Stereoselectivity in the oxidation of bufuralol, a chiral substrate, by human cytochrome P450s
Authors: Narimatsu Shizuo , Takemi Chie , Kuramoto Shino , Tsuzuki Daisuke , Hichiya Hiroyuki , Tamagake Keietsu , Yamamoto Shigeo 
Published: March 2003

AbstractBufuralol (BF), a nonselective β‐adrenoceptor blocking agent, has a chiral center in its molecule, yielding the enantiomers 1′R‐BF and 1′S‐BF. β‐Adrenoceptor blocking potency is much higher in 1′S‐BF than in 1′R‐BF. One of the metabolic pathways of BF is 1″‐hydroxylation of an ethyl group attached at the aromatic 7‐position forming a carbinol metabolite (1″‐hydroxybufuralol, 1″‐OH‐BF), and further oxidation (or dehydrogenation) produces a ketone metabolite (1‐oxobufuralol, 1″‐Oxo‐BF). Both 1″‐OH‐BF and 1″‐Oxo‐BF are known to have β‐adrenoceptor blocking activities comparable to or higher than those of the parent drug. The 1″‐hydroxylation introduces another chiral center into the BF molecule and four 1″‐OH‐BF diastereomers are formed from BF racemate in mammals, including humans, making elucidation of the metabolic profiles complicated. HPLC methods employing derivatization, reversed phase, or chiral columns have been developed to efficiently separate the four 1″‐OH‐BF diastereomers formed from BF enantiomers or racemate. Accumulated in vitro experimental results revealed that 1′R‐BF is a much more preferential substrate than 1′S‐BR for BF 1″‐hydroxylation in human liver microsomes. Kinetic studies using recombinant human cytochrome P450 (CYP) enzymes indicate that CYP2D6 serves as a major BF 1″‐hydroxylase and that CYP1A2 and CYP2C19 also contribute to BF 1″‐hydroxylation in human livers. This mini‐review summarizes the knowledge reported so far on the pharmacology of BF and its metabolites and the profiles of BF metabolism, especially focusing on the stereoselectivity in the oxidation of BF mainly in human livers and recombinant CYP enzymes. Chirality 15:333–339, 2003. © 2003 Wiley‐Liss, Inc.
Cover Picture: A Facile Synthesis of a Push‐Pull Mixed‐Ligand Pd‐Dithiolene Complex Containing the Et2timdt Ligand (Et2timdt = Monoreduced Diethylimidazolidine‐2,4,5‐trithione) (Eur. J. Inorg. Chem. 7/2003)
Authors: Aragoni M. Carla , Arca Massimiliano , Denotti Carla , Devillanova Francesco A. , Grigiotti Emanuela , Isaia Francesco , Laschi Franco , Lippolis Vito , Pala Luca , Slawin Alexandra M. Z. , Zanello Piero , Woollins J. Derek 
Published: March 2003

AbstractThe cover picture shows the X‐ray structure of [Pd(Et2timdt)Br2] (left; Et2timdt = diethylimidazolidine‐2,4,5‐trithione), obtained by treating the symmetrically substituted dithiolene [Pd(Et2timdt)2] with Br2 or IBr. This complex has been exploited as a starting material for the synthesis of the new mixed‐ligand, push‐pull dithiolene [Pd(Et2timdt)(mnt)] (mnt = maleonitriledithiolate), whose X‐ray molecular structure is depicted on the right. Details are discussed in the Short Communication by M. Arca et al. on p. 1291 ff.
Synthesis and Structure of Two New High Nuclearity Ru/Pt Mixed‐Metal Clusters
Authors: Johnson Brian F. G. , Hermans Sophie , Khimyak Tetyana 
Published: March 2003

AbstractThe reaction of the dianion [Ru5C(CO)14]2− with [PtCl2(MeCN)2] in the presence of silica yields [Ru5PtC(CO)16] (1) and the new compound [PPN]2[Ru10Pt2C2(CO)28] (2), while, in a related reaction, [Ru6C(CO)16]2− undergoes addition of [PtCl2(MeCN)2] to yield the cluster [Ru12PtC2(CO)32(MeCN)2] (3). The high nuclearity compounds 2 and 3 have been fully characterized and their structures determined by single crystal X‐ray analysis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Hydrothermal Synthesis and Characterization of Novel Lanthanide 2,2′‐Diphenyldicarboxylate Complexes
Authors: Wang Yi‐Bo , Zheng Xiang‐Jun , Zhuang Wen‐Juan , Jin Lin‐Pei 
Published: March 2003

AbstractLanthanide complexes with a one‐dimensional chain, [Ln2(dpdc)3(H2O)2]n [Ln = La (1), Pr (2), Eu (3), Tb (4); dpdc = 2,2′‐diphenyldicarboxylate] were obtained by hydrothermal reaction of lanthanide(III) chlorides and 2,2′‐diphenyldicarboxylic acid, and characterized by X‐ray diffraction. The crystal structure data reveal that they are isostructural. In the asymmetric unit, the two Ln3+ ions are both eight‐coordinate but they have different coordination environments. Lanthanide ions arranged in a zigzag manner are bridged by the dpdc ligands into a 1‐D chain, while the structure appears like a pinwheel viewed along the c axis. In these complexes, 2,2′‐diphenyldicarboxylate anions exhibit tetradentate and pentadentate coordination modes. A laser‐induced highresolution spectrum (resolution: 0.2 cm−1) of 3 was obtained, which shows two Eu3+ sites in 3. This is in agreement with the results of single‐crystal X‐ray diffraction studies of 3. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Low‐Valent Organobismuth Compounds with Intramolecular Coordination: cyclo‐R3Bi3, cyclo‐R4Bi4, RBi[W(CO)5]2, and R4Bi2 [R = 2‐(Me2NCH2)C6H4]
Authors: Balazs Lucia , Breunig Hans J. , Lork Enno , Silvestru Cristian 
Published: March 2003

AbstractThe cyclobismuthanes RnBin, [R = 2‐(Me2NCH2)C6H4; n = 3 (1a), 4 (1b)] have been synthesised by reduction of RBiCl2 with Na in liquid NH3 or by reaction of R2BiCl with LiAlH4 in Et2O. The reaction of 1a/b with W(CO)5·THF afforded the bismuthinidene complex RBi[W(CO)5]2 (2). R2BiCl reacts with Mg in THF to give the dibismuthane R4Bi2 (3). Single‐crystal X‐ray structure analyses of 1b, 2, and 3 reveal intramolecular coordination of the pendant CH2NMe2 groups to the bismuth atom. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Polypeptide Adsorption on a Synthetic Montmorillonite: A Combined Solid‐State NMR Spectroscopy, X‐ray Diffraction, Thermal Analysis and N2 Adsorption Study
Authors: Gougeon Régis D. , Soulard Michel , Reinholdt Marc , Miehé‐Brendlé Jocelyne , Chézeau Jean‐Michel , Dred Ronan Le , Marchal Richard , Jeandet Philippe 
Published: March 2003

AbstractTwo homopolypeptides, polylysine and polyglutamic acid, were adsorbed on a synthetic montmorillonite clay, in acidic medium. These organic‐inorganic complexes can be heated up to 110 °C without any degradation of the polypeptide. 1H‐13C CP‐MAS NMR spectra show that these polypeptides, which exhibit a mixture of α‐helical and random coil conformations in the bulk, tend to unfold and adopt a more extended random coil structure on adsorption on the phyllosilicate. The values of the basal spacing measured by X‐ray diffraction on dehydrated samples clearly indicate that in the presence of adsorbed polypeptide, the silicate layers do not collapse. The incorporation of polypeptide fragments within the interlayer space is also revealed by the decrease in the specific surface areas measured by N2‐adsorption BET experiments. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Assembly of Hydrogen‐Bonded Organic Layers with Macrocyclic Complexes Acting as Pillars
Authors: Suh Myunghyun Paik , Min Kil Sik , Ko Jung Woo , Choi Hye Jin 
Published: March 2003

AbstractNovel supramolecular networks of 2D {[Ni(cyclam)][C6H9(COOH)2(COO)]2}n(1) and 3D {[Ni(cyclam)][C6H3(OH)2(COO)]2}n(2) have been constructed by the self‐assembly of [Ni(cyclam)](ClO4)2withcis,cis‐1,3,5‐cyclohexanetricarboxylic acid (H3CTC) and 3,5‐dihydroxybenzoic acid (HDHB), respectively, in py/MeCN/H2O. In the crystal structure of1, each nickel(II) macrocyclic complex binds two H2CTC−ions at the axial sites. The coordinated H2CTC−ions form hydrogen bonds with one another, which results in organic bilayers having macrocyclic complexes as pillars. In the crystal structure of2, each nickel(II) macrocyclic complex binds two DHB−ions in thetransposition. Two free hydroxyl groups and one carbonyl oxygen atom of the coordinated DHB−ion are extensively hydrogen‐bonded with the DHB−ligand of the neighboring complexes, which results in a 3D network where 2D organic layers are linked by the macrocyclic complexes acting as pillars. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Five‐ and Six‐Membered Cobaltocycles with C,P‐Chelating Ligands through Regiospecific Cyclometalation of Mono(2‐Substituted) Triphenylphosphane
Authors: Klein Hans‐Friedrich , Beck Robert , Flörke Ulrich , Haupt Hans‐Jürgen 
Published: March 2003

AbstractCyclometalation in the aliphatic ring occurs in the reaction between [CoCH3(PMe3)4] and 5‐(diphenylphosphanyl)‐1,2,3,4‐tetrahydronaphthalene to give [{8‐(diphenylphosphanyl)‐1,2,3,4‐tetrahydronaphthyl‐(C1,P)}tris(trimethylphosphane)cobalt] (1), containing a five‐membered metallacycle as shown in the molecular structure. While 1‐(diphenylphosphanyl)naphthalene reacts accordingly, affording [{8‐(diphenylphosphanyl)naphthyl‐(C1,P)}tris(trimethylphosphane)cobalt] (2), 2‐(diphenylphosphanyl)biphenyl yields ortho‐metalated [{2‐(diphenylphosphanyl)‐3‐phenylphenyl‐(C1,P)}tris(trimethylphosphane)cobalt] (3), containing a four‐membered metallacycle. 1‐(Diphenylphosphanyl)‐8‐methylnaphthalene is metalated in the aliphatic substituent to form [{[8‐(diphenylphosphanyl)naphth‐1‐yl]methyl‐(C,P)}tris(trimethylphosphane)cobalt] (4). The molecular structure shows a trigonal‐bipyramidal configuration of the cobalt atom accommodating a six‐membered metallacycle. 2‐(Diphenylphosphanyl)styrene replaces two trimethylphosphane ligands to give [{2‐(diphenylphosphanyl)styrene‐(C,C‐η2,P)}methylbis(trimethylphosphane)cobalt] (5), avoiding metalation. Replacement of equatorial trimethylphosphane in compounds 1−3 by ethene gives π‐ethene complexes 6−8. In the molecular structure of 7 the C−C vector of the π‐ethene ligand is arranged in the equatorial plane of a trigonal bipyramid. Under 1 bar of CO, compound 2 forms a monocarbonyl complex 9, in which an equatorial carbonyl ligand is found in the molecular structure. Iodomethane transforms 2 into pentacoordinate [{2‐(diphenylphosphanyl)naphthyl‐(C1,P)}iodobis(trimethylphosphane)cobalt] (10) with retention of the metallacycle. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003
Towards an ontology for electronic transaction services
Authors: Adams Nick , Fraser John , Macintosh Ann , McKay‐Hubbard Andy 
Published: March 2003

AbstractIn this paper we present an ontology for transaction services built upon an established ontology for corporate knowledge called the Enterprise Ontology. We introduce the SmartGov platform for the ‘Smart’ deployment of online services for Public Authorities (PAs) whose requirement of a model of PAs has motivated the ontology, and describe our approach to constructing it. After presenting the ontology we then relate it to the pilot application areas in which the SmartGov platform will be trialed and evaluated. Copyright © 2003 John Wiley & Sons, Ltd.
Energies, structures, and electronic properties of molecules in solution with the C‐PCM solvation model
Authors: Cossi Maurizio , Rega Nadia , Scalmani Giovanni , Barone Vincenzo 
Published: March 2003

AbstractThe conductor‐like solvation model, as developed in the framework of the polarizable continuum model (PCM), has been reformulated and newly implemented in order to compute energies, geometric structures, harmonic frequencies, and electronic properties in solution for any chemical system that can be studied in vacuo. Particular attention is devoted to large systems requiring suitable iterative algorithms to compute the solvation charges: the fast multipole method (FMM) has been extensively used to ensure a linear scaling of the computational times with the size of the solute. A number of test applications are presented to evaluate the performances of the method. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 669–681, 2003
Dependence of the rate constants on the treatment of internal rotation modes: The reaction OH + CH3SH → CH3S + H2O as an example
Authors: Masgrau Laura , González–Lafont Àngels , Lluch José M. 
Published: March 2003

AbstractThe title reaction has been used as an example to test the importance of using a hindered rotor treatment instead of a harmonic oscillator model for calculating vibrational partition functions corresponding to low‐frequency internal rotation modes. First, a normal‐mode analysis according to the Ayala and Schlegel's algorithm has been used to identify the internal rotation modes of methanethiol and the transition state structure. Then, after calculation of the energy barrier for each internal rotation, the corresponding hindered rotor partition functions have been calculated following the CW scheme of Chuang and Truhlar. The results show that the anharmonic treatment produces a rather modest improvement of the rate constants at room temperature or below. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 701–706, 2003
Implementation of a general multireference configuration interaction procedure with analytic gradients in a semiempirical context using the graphical unitary group approach
Authors: Koslowski Axel , Beck Michael E. , Thiel Walter 
Published: March 2003

AbstractThe graphical unitary group approach has been applied in an efficient implementation of a general multireference configuration interaction (MRCI) method for use with small active molecular orbital spaces in a semiempirical framework. Gradients can be computed analytically for molecular orbitals from a closed‐shell or a half‐electron open‐shell Hartree‐Fock calculation. CPU times for single point energy and gradient calculations are reported. The code allows MRCI geometry optimizations of large molecules, as illustrated for the singlet ground state and the four lowest triplet states of fullerene C76. © 2003 Wiley Periodicals, Inc. J Comput Chem 6: 714–726, 2003
Prediction of protein secondary structure content by artificial neural network
Authors: Cai Yu‐Dong , Liu Xiao‐Jun , Chou Kuo‐Chen 
Published: March 2003

AbstractThe neural network method was applied to the prediction of the content of protein secondary structure elements, including α‐helix, β‐strand, β‐bridge, 310‐helix, π‐helix, H‐bonded turn, bend, and random coil. The “pair‐coupled amino acid composition” originally proposed by K. C. Chou [J Protein Chem 1999, 18, 473] was adopted as the input. Self‐consistency and independent‐dataset tests were used to appraise the performance of the neural network. Results of both tests indicated high performance of the method. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 727–731, 2003
The single‐vehicle routing problem with unrestricted backhauls
Authors: Süral Haldun , Bookbinder James H. 
Published: March 2003

AbstractSuppose that a private carrier delivers to a set of customers and also has a number of (optional) backhaul opportunities. It wants to choose the best of these, depending on the revenue generated, and insert them in a revised tour. This will be at an expense of deviation from the original tour, because, here, deliveries need not precede backhauls. The problem is to find the mixed tour whose net cost is the lowest, selecting the most profitable backhauls subject to the overall capacity. We thus generalize several other vehicle routing problems with backhauls. A mixed‐integer model is developed for the problem. It is based on Miller–Tucker–Zemlin subtour elimination constraints. We address several improvement techniques aimed at increasing computational tractability of the formulation. Computational results show that medium‐sized problems can be solved optimally in a reasonable time by using a general‐purpose commercial solver. © 2003 Wiley Periodicals, Inc.
Network flow models for designing diameter‐constrained minimum‐spanning and Steiner trees
Authors: Gouveia Luis , Magnanti Thomas L. 
Published: March 2003

AbstractWe formulate and computationally test several models for the Diameter‐Constrained Minimum Spanning and Steiner Tree Problems, which seek a least‐cost spanning or Steiner tree subject to a (diameter) bound imposed on the number of edges in the tree between any node pair. A traditional multicommodity flow model with a commodity for every pair of nodes was unable to solve a 20‐node and 100‐edge spanning tree problem after 1 week of computation. In contrast, the new models were able to optimality solve this problem in less than 1 second and larger problem instances with up to 100 nodes and 1000 edges. The largest model contains more than 250,000 integer variables and more than 125,000 constraints. The new models simultaneously find a directed tree with a central node or a central edge that serve as a source for the commodities in a multicommodity flow model with hop constraints. Our results demonstrate the power of using single‐sourcing combined with other reformulation techniques: directing the model and using hop‐indexed formulations. Enhancements improve the models when the diameter bound is odd (these situations are more difficult to solve). The linear programming relaxation of the best formulations discussed in this paper always give an optimal integer solution for two special, polynomially solvable cases of the problem. © 2003 Wiley Periodicals, Inc.
Voronoi cell finite difference method for the diffusion operator on arbitrary unstructured grids
Authors: Sukumar N. 
Published: March 2003

AbstractVoronoi cells and the notion of natural neighbours are used to develop a finite difference method for the diffusion operator on arbitrary unstructured grids. Natural neighbours are based on the Voronoi diagram, which partitions space into closest‐point regions. The Sibson and the Laplace (non‐Sibsonian) interpolants which are based on natural neighbours have shown promise within a Galerkin framework for the solution of partial differential equations. In this paper, we focus on the Laplace interpolant with a two‐fold objective: first, to unify the previous developments related to the Laplace interpolant and to indicate its ties to some well‐known numerical methods; and secondly to propose a Voronoi cell finite difference scheme for the diffusion operator on arbitrary unstructured grids. A conservation law in integral form is discretized on Voronoi cells to derive a finite difference scheme for the diffusion operator on irregular grids. The proposed scheme can also be viewed as a point collocation technique. A detailed study on consistency is conducted, and the satisfaction of the discrete maximum principle (stability) is established. Owing to symmetry of the Laplace weight, a symmetric positive‐definite stiffness matrix is realized which permits the use of efficient linear solvers. On a regular (rectangular or hexagonal) grid, the difference scheme reduces to the classical finite difference method. Numerical examples for the Poisson equation with Dirichlet boundary conditions are presented to demonstrate the accuracy and convergence of the finite difference scheme. Copyright © 2003 John Wiley & Sons, Ltd.
Crack identification of a planar frame structure based on a synthetic artificial intelligence technique
Authors: Shim Mun‐Bo , Suh Myung‐Won 
Published: March 2003

AbstractIt has been established that a crack has an important effect on the dynamic behaviour of a structure. This effect depends mainly on the location and depth of the crack. To identify the location and depth of a crack in a planar frame structure, a method is presented in this paper which uses a synthetic artificial intelligence technique, i.e. adaptive‐network‐based fuzzy inference system (ANFIS) solved via a hybrid learning algorithm (the backpropagation gradient descent and the least‐squares method) and continuous evolutionary algorithms (CEAs) solving single objective optimization problems with a continuous function and continuous search space efficiently are unified. With ANFIS and CEAs it is possible to formulate the inverse problem. ANFIS is used to obtain the input (the location and depth of a crack)–output (the structural eigenfrequencies) relation of the structural system. CEAs are used to identify the crack location and depth by minimizing the difference from the measured frequencies. We have tried this idea on 2D beam structures and the results are promising. Copyright © 2003 John Wiley & Sons, Ltd.
A new fixed‐point algorithm for hardening plasticity based on non‐linear mixed variational inequalities
Authors: Venini P. , Nascimbene R. 
Published: March 2003

AbstractMoving from the seminal papers of Han and Reddy, we propose a fixed‐point algorithm for the solution of hardening plasticity two‐dimensional problems. The continuous problem may be classified as a mixed non‐linear non‐differentiable variational inequality of the second type and is discretized by means of a truly mixed finite‐element scheme. One of the main peculiarities of our approach is the use of the composite triangular element of Johnson and Mercier for the approximation of the stress field. The non‐differentiability is coped with via regularization whereas the non‐linearity is approached with a fixed‐point iterative strategy. Numerical results are proposed that investigate the sensitivity of the approach with respect to the mesh size and the regularization parameter ε. The simplicity of the proposed fixed‐point scheme with respect to more classical return mapping approaches seems to represent one of the key features of our algorithm. Copyright © 2003 John Wiley & Sons, Ltd.
An arbitrary Lagrangian Eulerian finite‐element approach for fluid–structure interaction phenomena
Authors: Kuhl E. , Hulshoff S. , de Borst R. 
Published: March 2003

AbstractThe present contribution is concerned with the design of a family of consistent fluid–structure interaction algorithms based on a unique temporal and spatial discretization of the governing equations. The characterization of the moving fluid–structure interface is realized by means of the arbitrary Lagrangian Eulerian technique. The spatial discretization is performed with the finite‐element method, whereby either a first‐order upwind scheme or the classical second‐order upwind Petrov–Galerkin technique are used to discretize the linearized fluid equations while the standard Bubnov–Galerkin method is applied to the structural equations. In order to streamline coupling, the structure is discretized in a velocity‐based fashion. The temporal discretization of both the fluid and the structural equations is embedded in the generalized‐α framework by making use of classical Newmark approximations in time. To quantify the sources of error of the proposed algorithms, systematic studies in terms of the one‐dimensional piston model problem are presented. Copyright © 2003 John Wiley & Sons, Ltd.
A moving horizon technique for the simulation of automobile test‐drives
Authors: Gerdts M. 
Published: March 2003

AbstractThe test‐drive of an automobile along a given test‐course can be modeled by formulation of a suitable optimal control problem. For the numerical solution the optimal control problem is discretized by a direct shooting method and transformed into a finite dimensional nonlinear optimization problem. With increasing length of the test‐course, the dimension of the nonlinear optimization problem increases as well and its numerical solution becomes very difficult due to stability reasons. Therefore a moving horizon technique with reduced range of vision for the test‐driver is introduced. Instead of treating the complete test‐course, a comparatively short local sector is considered on which a corresponding local optimal control problem can be solved comfortably. The local solutions are then combined by suitable transient conditions. A numerical example with a realistic car model is given.