bluuebunny/crossref_metadata_2025_split huggingface dataset:
Active immunization with IL‐1 displayed on virus‐like particles protects from autoimmune arthritis
Authors: Spohn Gunther , Keller Iris , Beck Markus , Grest Paula , Jennings Gary T. , Bachmann Martin F. 
Published: February 2008

AbstractIL‐1 is an important mediator of inflammation and a major cause of tissue damage in rheumatoid arthritis (RA). Therapeutic administration of recombinant IL‐1 receptor antagonist (IL‐1Ra) is efficacious in reducing clinical symptoms of disease, but suffers from several drawbacks, including the need for frequent administrations of large amounts. Here, we show that immunization of mice with either IL‐1α or IL‐1β chemically cross‐linked to virus‐like particles (VLP) of the bacteriophage Qβ elicited a rapid and long‐lasting autoantibody response. The induced Ab efficiently neutralized the binding of the respective IL‐1 molecules to their receptors in vitro and their pro‐inflammatory activities in vivo. In the collagen‐induced arthritis model, both vaccines strongly protected mice from inflammation and degradation of bone and cartilage. Moreover, immunization with either vaccine showed superior efficacy than daily administrations of high amounts of IL‐1Ra. In the T and B cell‐independent collagen Ab transfer model, immunization with the IL‐1β vaccine strongly protected from arthritis, whereas immunization with the IL‐1α vaccine had no effect. Our results suggest that active immunization with IL‐1α, and especially IL‐1β conjugated to Qβ VLP, might become an efficacious and cost‐effective new treatment option for RA and other systemic IL‐1‐dependent inflammatory disorders.
Reductive Activation of tripod Metal Compounds: Identification of Intermediates and Preparative Application
Authors: Mautz Jürgen , Heinze Katja , Wadepohl Hubert , Huttner Gottfried 
Published: February 2008

Abstract[tripodCoCl2] {tripod = CH3C(CH2PPh2)3} when treated with KC8 in THF solution under an argon atmosphere produces a reactive species [“tripodCo0”] (A) which undergoes oxidative additions with stannanes, [tripodCo(H)2(SnBu3)] (4), formed, for example, by addition of Bu3SnH. Silanes, R3SiH, undergo the same type of reaction producing [tripodCo(H)2(SiR3)] (R = Et: 5a; R = Ph: 5b). The solid‐state structures of all the compounds [tripodCo(H)2(ER3)] (E = Si, R = Ph; E = Sn, R = Ph, Bu) are rather similar. While they contain six‐coordinate cobalt with the formal oxidation state of cobalt being +III the coordination geometry is not octahedral: the heteroelement E deviates from the position which it would have in octahedral coordination by around 40° while the other five ligands, three phosphorus and two hydrogen, have the expected interligand angles of around 90° and 180°, respectively. The deviation of the heteroelement E is such that it approaches the metal bonded hydrogen atoms leading to short H···E contacts of only about 190 pm (E = Si) and 230 pm (E = Sn), respectively. The generation of a reactive species [“tripodCo0”] (A) was transferred to the synthesis of a reactive tripodnickel(0) species by treating a THF solution of [(DME)NiBr2] with KC8 in the presence of tripod. This species reacts with two electron donor ligands L to produce the pseudo tetrahedral compounds [tripodNi(L)] {L = PPh3 (6), AsPh3 (7), cHexNC (8), tBuNC (9), C2H4 (10)}. The identity of the reactive nickel(0) species as unequivocally deduced from NMR experiments is [tripod4Ni3] (12). All compounds were characterised by the usual analytic techniques including X‐ray analysis where applicable.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Reductive Activation oftripodMetal Compounds: Preparative Application
Authors: Mautz Jürgen , Huttner Gottfried 
Published: February 2008

AbstractThetripodnickel(0) species [tripod4Ni3] (1) {tripod= CH3C(CH2PPPh2)3} is shown to undergo oxidative addition with disulfides or diselenides REER (E = S, Se, R =tBu, Ph) to produce [tripodNi(ER)] (2). Compounds2show pseudo tetrahedral coordination. They are paramagnetic with one unpaired electron per molecule. Their magnetic behaviour is almost that of an ideal Curie‐type magnet down to temperatures of 2 K. They undergo reversible one electron oxidation to the 16 valence electron species [tripodNi(ER)]+. The isoelectronic pseudo tetrahedral 16 valence electron cobalt species [tripodCo(ER)] (3) are obtained by reduction of CoCl2with KC8in the presence oftripodand subsequent reaction with REER (E = S, Se; R =tBu, Ph). They are paramagnetic with two unpaired electrons per molecule. They can be reversibly oxidised to the 15 valence electron compounds [tripodCo(ER)]+while their reduction to the 17 valence electron species [tripodCo(ER)]–, which would be isoelectronic to the stable compounds2, is not observed. Under appropriate conditions the reactions with REER do not result in the formation of3but yield [tripodCoECotripod] (4) by extrusion of sulfur and selenium from the substrate. Compounds4show a linear Co–E–Co framework with very short Co–E bonds (E = S: 205 pm; E = Se: 216 pm). They are members of a family of dimetallaheterocumulenic compounds [LnMEMLn] (E = main group element of groups III to VI) with a valence electron count of 36 electrons. Quantum chemistry predicts that the HOMO of such compounds should be a degenerated pair of mainly metal centred orbitals. Electrochemistry of4a, [tripodCoSCotripod], shows three quasi‐reversible oxidation steps in the range of –700 mV vs. SCE to 570 mV vs. SCE, which can be understood as metal centred oxidations. Three different types of crystals have been obtained for different types of pseudopolymorphs4a. The geometric parameters of the coordination compounds are almost equal in these pseudopolymorphic crystals. The real difference is the content of solvent molecules and, hence, the packing of the molecules. In the crystals of4acontaining no solvent the coordination compounds form close packed layers stacked on each other in an oblique way. In the crystals containing4a·DME a layer of solvent molecules separates each pair of layers of close packed molecules. In the crystal of4a·3DME a cuboctahedral cage of solvent molecules embedding each coordination compound separates the complex molecules from each other. The different types of crystals observed underpin the globular shape of4and the effective shielding power of thetripodligand. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis, Structure, and Optical Properties of a Contorted <110>‐Oriented Layered Hybrid Perovskite: C3H11SN3PbBr4
Authors: Li Yinyan , Zheng Guoli , Lin Jun 
Published: February 2008

AbstractThe <110>‐oriented perovskite is very rare in the hybrid perovskites family. In this work, an unusual layered <110>‐oriented hybrid perovskite, which is stabilized by a special organic ligand, 2‐(aminoethyl)isothiourea, has been obtained. This ligand combines a primary amine and a formamidine on the two ends of one molecule. Introduction of the special ligand brings about contorted inorganic sheets in the hybrid perovskite structure. The optical properties of the new <110>‐oriented perovskite were studied.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
New Germanium Complexes Containing Ligands Based on 4,6‐Di‐tert‐butyl‐N‐(2,6‐diisopropylphenyl)‐o‐iminobenzoquinone in Different Redox States
Authors: Piskunov Alexandr V. , Aivaz'yan Igor A. , Poddel'sky Andrey I. , Fukin Georgii K. , Baranov Evgenii V. , Cherkasov Vladimir K. , Abakumov Gleb A. 
Published: February 2008

AbstractThe exchange reaction of lithium o‐amidophenolate, (AP)Li2, derived from the reaction of 4,6‐di‐tert‐butyl‐N‐(2,6‐diisopropylphenyl)‐o‐iminobenzoquinone (imQ) with GeCl4 in hexane or thf leads to (AP)2Ge (1) (AP is a dianion of imQ). The latter was also obtained by the interaction of GeCl2·dioxane and (ISQ)Li in toluene (ISQ is a radical anion of imQ). The reaction of (AP)Li2 with GeCl2·dioxane in thf results in the formation of germylene 2, [(AP)Ge (2)], which reduces neutral imQ to give compound 1. The exposure of 1 in thf to anhydrous HCl in a 1:1 molar ratio leads to its o‐aminophenolato derivative, (AP)(APH)GeCl (3). Free imQ inserts into the Ge–H bond of (C6F5)3GeH in thf to give (C6F5)3Ge(APH) (4). It is another way of obtaining complexes with protonated ligands such as APH. Compound 3 can be easily oxidized by air to form the stable paramagnetic complex (AP)(ISQ)GeCl (5). Complexes 1 and 3–5 were structurally investigated by using single‐crystal X‐ray diffraction.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Gas‐Phase Generation and Electronic Structure Investigation of Oxidovanadium Triisocyanate, OV(NCO)3
Authors: Ge Maofa , Wang Weigang , Yin Shi , Della Védova Carlos O. 
Published: February 2008

AbstractOxidovanadium triisocyanate was generated from the heterogeneous reaction of gaseous vanadium trichloride oxide with silver cyanate and studied for the first time in the gas phase. The reaction processes were studied in situ by ultraviolet photoionization mass spectrometry combined with quantum chemical calculations and ultraviolet photoelectron spectrometry. The geometric and electronic structures were characterized and discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Coordination and Supramolecular Chemistry of New Bis‐bidentate Schiff‐Base Ligands
Authors: Isola Mauro , Balzano Federica , Liuzzo Vincenzo , Marchetti Fabio , Raffaelli Andrea , Uccello Barretta Gloria 
Published: February 2008

AbstractThe coordination chemistry of a series of bis‐bidentate Schiff‐base ligands with NiII and CuII has been investigated. The ligands contain two N,O‐bidentate chelating salicylaldiminato units attached to polymethylene or α,α′‐ortho‐xylidene central spacers, through ether linkages at the 3‐position of the salicyl moieties. In this paper we present a series of seven new complexes displaying several novel structural types, three of which are crystallographically characterized. Among others, the double‐stranded helicates with the metal ions in the trans‐square‐planar geometry are of particular interest. The ortho‐xylidene ligand H2L8, like the analogue H2L7 previously reported by us, forms dinuclear double‐stranded helicates stable both in the solid state and in solution; in the case of the ligands H2L1–6, the nuclearity and the structural motif of the related complexes depend on the number (n) of methylene units in the bridge. When n = 3, 4, thermodynamically stable products from their reaction with NiII and CuII are oligomeric or polymeric species, while under kinetic control novel supramolecular architectures become accessible. The NiII complexes of the ligands with n = 5, 6, 8 exist as dinuclear double‐stranded helicates in the solid state, while in solution they exhibit a monomer–dimer interconversion process, which has been studied using Diffusion Ordered Spectroscopy (DOSY). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Hydrogen Bonding and Lewis Acid–Base Interactions in the System Bis(pentafluorophenyl)borinic Acid / Methanol
Authors: Donghi Daniela , Maggioni Daniela , Beringhelli Tiziana , D'Alfonso Giuseppe , Mercandelli Pierluigi , Sironi Angelo 
Published: February 2008

AbstractMethanol does not significantly affect the position and the rate of the equilibrium between the monomeric (1m) and cyclic trimeric (1t) forms of bis(pentafluorophenyl)borinic acid, Ar2BOH (1, Ar = C6F5), in CD2Cl2 solution. This contrasts with what was previously observed in the presence of thf and is mainly due to the stabilization of the 1m·MeOH covalent adduct through the formation of the hydrogen‐bonded dimer [Ar2B(OH)(MeOH)]2 (7), characterized in solution and by single‐crystal X‐ray analysis. This dimer can be viewed as the intermediate in the conversion of 1 into its methyl ester 6 by fast proton transfer along the hydrogen bond, which transforms the 1m·MeOH adduct into the 6·H2O adduct. Extrusion of H2O by water scavengers drives the equilibrium toward ester 6. X‐ray analysis showed that, at variance with 1, ester 6 in the solid state is a monomer. Hindered rotation [ΔH# = 38(1) kJ mol–1, ΔS# = –35(6) J mol–1] around the B–OMe bond, due to O‐to‐B π‐donation, has been observed. This π‐donation lowers the Lewis acidity of 6, as shown by the thermal instability of its adducts with MeOH and thf. Water addition to 6 affords the dimeric adduct 7, in fast equilibrium with both 1m and 6, even at 183 K, as revealed by 2D EXSY analysis. Borinic acid itself can act as a water scavenger at low temperature, so that 6 is formed also in the early stages of the titration of 1 with MeOH. The other main initial product was the adduct [Ar2B(OH)]3·MeOH (3) containing a MeOH molecule bound within an octaatomic –B–O(H)–B–O(Me)–H···O(H)–B–O(H)– ring. Fast proton transfer along the strong hydrogen bond was revealed by 2D EXSY analysis. At variance with thf, the adduct containing MeOH exocyclically hydrogen‐bonded to 1t could be obtained in high concentration at 183 K only when due allowance for the kinetic requirements of the slow trimerization equilibrium was made.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Oxidative Addition of B–Br Bonds to Pd0: Synthesis and Structure of trans‐Bromo(boryl)palladium Complexes
Authors: Braunschweig Holger , Gruss Katrin , Radacki Krzysztof , Uttinger Katharina 
Published: February 2008

AbstractThe oxidative addition of several bromoboranes to the Pd0 species [Pd(PCy3)2] yielded the novel palladium boryl complexes trans‐[(Cy3P)2Pd(Br)(BCat)] (1) (Cat = 1,2‐dioxophenylene), trans‐[(Cy3P)2Pd(Br)(BCat′)] (2) (Cat′ = Cat‐4‐tBu) and trans‐[(Cy3P)2Pd(Br){B(X)X′}] {X = Br, X′ = NMe2 (3), Pip (4) (Pip = NC5H10), Mes (5) [Mes = 2,4,6‐(CH3)3C6H2]}. Compounds 1–5 were characterized by multinuclear NMR spectroscopy in solution; single crystals for X‐ray analyses were acquired from 2 and 3, which thus allowed comparison of the structural data. The few palladium boryl complexes published so far were obtained by σ‐bond metathesis; the oxidative addition of the corresponding bromoboranes to Pd0 has not yet been reported.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Supramolecular Isomerism in Coordination Polymers of Isophthalato‐Bridged MnII Complexes Using 4,4′‐Dipyridyl N,N′‐Dioxide
Authors: Manna Subal Chandra , Zangrando Ennio , Ribas Joan , Ray Chaudhuri Nirmalendu 
Published: February 2008

AbstractA one‐pot reaction of three components [MnII, isophthalate dianion (isop) and 4,4′‐dipyridyl N,N′‐dioxide (dpyo)] in water/methanol (1:1) causes self‐assembly resulting in two 3D supramolecular isomers of the same stoichiometry, {[Mn(isop)(H2O)2]·(dpyo)·(H2O)}n (colorless) (1) and {[Mn(isop)(H2O)(dpyo)0.5]·(dpyo)0.5·(H2O)2}n (pink) (2). Both isomers crystallize in the same crystal system (triclinic) and space group (P$\bar {1}$). The structural determination of 1 reveals an isophthalato‐bridged 1D coordination polymer, {[Mn(isop)(H2O)2]n, having 16‐ and 8‐membered rings where isophthalate acts simultaneously as chelating and bridging ligand connected to three metal centers. In isomer 2 the 1D chains transform to a 2D arrangement through bridging dpyo that replaces a water molecule at metal axial position. Both the crystal structures result in a 3D supramolecular network achieved through H‐bonding among the 1D (in 1) or 2D (in 2) coordination polymers with lattice water and dpyo molecules and also by means of π‐π interactions in 1. Low‐temperature magnetic measurement indicates antiferromagnetic interaction in both the isomers and the best fits are given by the exchange parameters J = –0.56 ± 0.02 cm–1, g = 2.01 ± 0.01 and R = 3.1 × 10–5 for 1 and J = –1.06 ± 0.03 cm–1, g = 2.01 ± 0.01 and R = 2.8 × 10–5 for 2.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Guanosine Analog with Respect to Z‐DNA Stabilization: Nucleotide with Combined C8‐Bromo and C2′‐Ethynyl Modifications
Authors: Nadler André , Diederichsen Ulf 
Published: February 2008

AbstractThe stabilization of left‐handed Z‐DNA double strands by chemical modifications is especially of interest regarding investigations of its biological role. Incorporation of modified nucleotide building blocks in DNA allows recognition studies under physiological conditions without the need for a Z‐DNA inducing environment. Approaches to enforce the Z‐DNA double helix using guanosine derivatives are the introduction of sterically demanding groups at guanine C8 or of 2′‐ribosyl substitutions determining the ribosyl conformation. 8‐Bromo‐2′‐ethynyl‐arabino‐deoxyguanosine was synthesized as phosphoramidite building block. Incorporated in suitable oligonucleotides the potential to induce the Z‐form DNA was investigated by CD spectroscopy. With a nucleotide containing the 8‐bromo and the 2′‐ethynyl group a synergistic effect of the two modifications was expected to provide stronger stabilization of Z‐DNA. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Design, Synthesis, and Spectral Luminescent Properties of a Novel Polycarbocyanine Series Based on the 2,2‐Difluoro‐1,3,2‐dioxaborine Nucleus
Authors: Zyabrev Konstantin , Doroshenko Andrey , Mikitenko Elena , Slominskii Yurii , Tolmachev Alexei 
Published: February 2008

AbstractThe natures of the chromophores in symmetric polymethine dyes derived from 2,2‐difluoro‐1,3,2‐dioxaborine have been investigated. Ab initio quantum chemical calculations demonstrated that the presence of dioxaborine end residues stabilizes the frontier levels of the corresponding polymethine dye and makes electron‐density distribution over the oxygen atoms in the chelate ring more even than in the analogous dye structure with boron‐free acyclic end groups. A series of novel symmetric polycarbocyanines and a tricarbocyanine series with variously bridged polymethine chromophores have been synthesized from hitherto unknown pyrimidino‐annelated dioxaborines. The absorption, fluorescence and 13C NMR spectroscopic data point to the polymethinic type of electron‐density distribution in the 2,2‐difluoro‐1,3,2‐dioxaborine polymethine dye molecules. The fundamental options for controlling the spectral properties of these dyes by modification of their polymethine chains have been evaluated. One of the new compounds synthesized is remarkable among the known open‐chain polymethine dyes for its record high fluorescence quantum yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
(E,E,E)‐4,4′‐Distyrylstilbenes – Synthesis, Photophysics, Photochemistry and Phase Behavior
Authors: Meier Herbert , Lifka Thorsten , Stalmach Ulf , Oehlhof Annette , Prehl Sabine 
Published: February 2008

AbstractThe fluorescence quantum yields F(n) of oligo[2,5‐bis(propyloxy)‐1,4‐phenylenevinylene]s (1b) reach for the trimer (n = 3) in solution a maximum of 86 %, which is almost twice as high as for the monomer (n = 1) and the octamer or undecamer (n = 8, 11). The latter represent the convergence limit of 46 %. 4‐Mono‐, 3,4‐di‐ or 3,4,5‐trisubstituted terminal phenyl rings in the trimers 6a–f do not lead to calamitic or phasmidic liquid crystals; however, 2,3,4‐trisubstitution with hexyloxy groups (6h) and even with OCH3 groups (6g) effects LC formation. Irradiation with energy‐rich UV light provokes a crosslinking of the originally conjugated chains. In the case of 6c, a chemo‐ and stereoselective [2π + 2π] photocycloaddition could be established as well.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Stereoselective Access to Substituted [(E)‐ or (Z)‐1‐(Trifluoromethyl)allyl]amines
Authors: Magueur Guillaume , Crousse Benoit , Bonnet‐Delpon Danièle 
Published: February 2008

AbstractHydrometallation reactions, for example, hydroboration and hydroalumination, on [1‐(trifluoromethyl)propargyl]amines lead stereoselectively to the corresponding [(Z)‐ and (E)‐1‐(trifluoromethyl)allyl]amines in good yields; (Z)‐ and (E)‐allylamines with a free amino group can be obtained in good yields and excellent enantioselectivities from the chiral propargylamines.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis of Non‐Natural Aromatic α‐Amino Acids by a Heck Reaction
Authors: Suhartono Marcel , Weidlich Markus , Stein Torsten , Karas Michael , Dürner Gerd , Göbel Michael W. 
Published: February 2008

AbstractAlkene 3, a TBS‐ and Cbz‐protected derivative of vinylglycinol, safely available from methionine, undergoes efficient Heck coupling reactions in high yields. The resulting products can be converted into enantiopure α‐amino acids with aromatic and heteroaromatic side‐chains. Compound 6a, a brightly fluorescent Fmoc‐protected pyrene amino acid is of special interest. Tripeptide 8a, composed of this building block and two arginines, binds to TAR, an RNA element regulating transcriptional efficiency in HIV, with a Kd value of 50 nM. This compound also inhibits a coupled cell‐free transcription‐translation assay (IC50 = 40 μM) and shows pronounced antibacterial activity against B. subtilis. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
A bivariate stochastic Gompertz diffusion model: statistical aspects and application to the joint modeling of the Gross Domestic Product and CO2 emissions in Spain
Authors: Gutiérrez R. , Gutiérrez‐Sánchez R. , Nafidi A. 
Published: February 2008

AbstractIn this paper we propose a bivariate stochastic Gompertz diffusion model as the solution for a system of two Itô stochastic differential equations (SDE) that are similar as regards the drift and diffusion coefficients to those considered in the univariate Gompertz diffusion model, which has been the object of much study in recent years. We establish the probabilistic characteristics of this model, such as the bivariate transition density, the bidimensional moment functions, the conditioned trend functions and in particular, the correlation function between each of the components of the model. We then go on to study the maximum likelihood estimation of the bidimensional drift and the diffusion matrix of the diffusion in question, proposing a computational statistical methodology for this purpose based on discrete observations over time, for both components of the model. By these means we are able to achieve the maximum likelihood estimation of the trend and correlation functions and thus establish a method for trend analysis, which we apply to the real case of two dependent variables, Gross Domestic Product (GDP) and CO2 emission in Spain, the joint dynamic evolution of which is modeled by the proposed Gompertz bidimensional model. This implementation is carried out on the basis of annual observations of the variables over the period 1986–2003. The application is a new methodology in environmental and climate change studies, and provides an alternative to other approaches of a more econometric nature, or those corresponding to the methodology of secular trends in Time Series. Copyright © 2008 John Wiley & Sons, Ltd.
Smoothing and bootstrapping the PROMETHEUS fire growth model
Authors: Garcia Tanya , Braun John , Bryce Robert , Tymstra Cordy 
Published: February 2008

AbstractThe PROMETHEUS model is a spatially explicit, deterministic fire growth model, praised for being beneficial in various aspects of fire management. Our goal is to build on this success, applying statistical smoothing to alleviate some computational difficulties and to increase accuracy; a pleasant by‐product is the opportunity to introduce stochasticity to the model using a residual‐based block bootstrap. Copyright © 2008 John Wiley & Sons, Ltd.