bluuebunny/crossref_metadata_2025_split huggingface dataset:
„Daß auch zugleich die Gottseligkeit dadurch gebauet wird”︁ — Pietismus und Medizin in der ersten Hälfte des 18. Jahrhunderts
Authors: Helm Jürgen 
Published: September 2003

AbstractIn the beginning of the 18th century Halle Pietists tried to establish a specific approach to sickness and healing. They constructed close links between physical illness on the one hand and the religious concept of individual piety, penance and rebirth on the other. This ‚new’︁ pietist medicine largely depended on Georg Ernst Stahl's medical theory, which was not pietist in itself, but was adopted and simplified by pietist physicians. Although conclusive and rhetorically present in programmatic texts, pietist medicine turned out to be less influential on medical practice than expected.
Anthracene–BODIPY Cassettes: Syntheses and Energy Transfer
Authors: Wan Chi‐Wai , Burghart Armin , Chen Jiong , Bergström Fredrik , Johansson Lennart B.‐Å. , Wolford Matthew F. , Kim Taeg Gyum , Topp Michael R. , Hochstrasser Robin M. , Burgess Kevin 
Published: September 2003

AbstractCompounds based on the 4,4‐difluoro‐1,3,5,7‐tetramethyl‐4‐bora‐3a,4a‐diaza‐s‐indacene (BODIPY) framework are excellent fluorescent markers. When BODIPY dyes of this type are conjugated to functionalities that absorb at relatively short wavelengths, those functionalities can, in some molecules, transmit the absorbed energy to the BODIPY which then fluoresces. In such cases the BODIPY fragment acts as an acceptor while the other group serves as a donor. Energy transfer efficiencies in such donor–acceptor cassette systems must vary with the relative orientation of the two components, and with the structure of the linkers that attach them. This study was designed to probe these issues for the special case in which the linkers between the donor and acceptor fragments are conjugated. To do this, the cassettes3–10were prepared. Electrochemical studies were performed to provide insight into the degree of donor–acceptor conjugation in these systems. X‐ray Crystallographic studies on single crystals of compounds7and9revealed the favored conformations of the donor and acceptor fragments in the solid state. Absorption, fluorescence, and time‐resolved fluorescence spectra of the compounds were recorded, and quantum yields for the cassettes excited at the donorλmaxwere measured. Fluorescence steady‐state anisotropy data were determined for cassettes3and9to provide information about the mutual direction of the transition dipole moments.
Mechanistic Study of Bu2SnCl2‐Mediated Ring‐Opening Polymerization of ε‐Caprolactone by Multinuclear NMR Spectroscopy
Authors: Deshayes Gaëlle , Mercier Frédéric A. G. , Degée Philippe , Verbruggen Ingrid , Biesemans Monique , Willem Rudolph , Dubois Philippe 
Published: September 2003

AbstractThe ring‐opening polymerization (ROP) of ε‐caprolactone (CL) was carried out in toluene at 100 °C with n‐propanol (nPrOH) in the presence of Bu2SnCl2. It comes out that the molar mass of the polyester chains can be predicted from the initial monomer‐to‐alcohol molar ratio in accordance with a controlled ROP mechanism involving an O‐acyl cleavage of the monomer to selectively form (α‐propyloxy)(ω‐hydroxy)poly(ε‐caprolactone) chains. In order to gain fundamental understanding of the mechanistic factors governing the polyester chain growth, advanced 1H, 13C, and 119Sn NMR investigations were performed in situ in [D8]toluene, as well as with model solutions that contained Bu2SnCl2 and binary mixtures of the components at various concentrations and temperatures. This has enabled us to propose a mechanism in which Bu2SnCl2 behaves as a catalyst, while nPrOH is the actual initiator. It involves non‐aggregated, six‐coordinate Bu2SnCl2 complexes in which ligands exchange fast on the 119Sn NMR observational timescale, and the simultaneous interactions of CL and alcohol function in such a way that it favors insertion/propagation reactions over transesterification ones, up to high monomer conversion.
Synthesis of a New Polyfluorinated Vinylogue of Tetrathiafulvalene through 1,3‐Dipolar Cycloaddition of Ethyl β‐Bromoperfluorodithiocrotonate with Dimethyl Acetylenedicarboxylate
Authors: Timoshenko Vadim M. , Bouillon Jean‐Philippe , Chernega Alexander N. , Shermolovich Yuriy G. , Portella Charles 
Published: September 2003

AbstractThe ethyl ester of β‐bromoperfluorodithiocrotonic acid reacts with dimethyl acetylenedicarboxylate to give 1,4‐difluoro‐2,3‐bis(trifluoromethyl)‐but‐2‐ene‐1,4‐diylidene‐2,2′‐bis(4′,5′‐dicarbomethoxy‐1′,3′‐dithiole) (4), a new type of vinylogue of tetrathiafulvalene. The thermal transformations of this compound lead, depending on the temperature, to the formation of the cyclization products: 11,14‐difluoro‐2,3,8,9‐tetra(carbomethoxy)‐12,13‐bis(trifluoromethyl)‐1,4,7,10‐tetrathiadispiro[4.0.4.4]tetradeca‐2,8,11,13‐tetraene (8) or 5,8‐difluoro‐6,7‐bis(trifluoromethyl)‐2,3‐bis(carboxymethyl)‐1,4‐benzodithiine (11).
Synthesis, Solid‐State Structure, and Bonding Analysis of the Beryllocenes [Be(C5Me4H)2], [Be(C5Me5)2], and [Be(C5Me5)(C5Me4H)]
Authors: del Mar Conejo M. , Fernández Rafael , del Río Diego , Carmona Ernesto , Monge Angeles , Ruiz Caridad , Márquez Antonio M. , Fernández Sanz Javier 
Published: September 2003

AbstractThe beryllocenes [Be(C5Me4H)2] (1), [Be(C5Me5)2] (2), and [Be(C5Me5)(C5Me4H)] (3) have been prepared from BeCl2 and the appropriate KCp′ reagent in toluene/diethyl ether solvent mixtures. The synthesis of 1 is facile (20 °C, overnight), but generation of decamethylberyllocene 2 demands high temperatures (ca. 115 °C) and extended reaction times (3–4 days). The mixed‐ring beryllocene 3 is obtained when the known [(η5‐C5Me5)BeCl] is allowed to react with K[C5Me4H], once more under somewhat forcing conditions (115 °C, 36 h). The structures of the three metallocenes have been determined by low‐temperature X‐ray studies. Both 1 and 3 present η5/η1 geometries of the slip‐sandwich type, whereas 2 exhibits an almost regular, ferrocene‐like, sandwich structure. In the mixed‐ring compound 3, C5Me5 is centrally bound to beryllium and the η1‐C5Me4H ring bonds to the metal through the unique CH carbon atom. This is also the binding mode of the η1‐ring of 1. To analyze the nature of the bonding in these molecules, theoretical calculations at different levels of theory have been performed on compounds 2 and 3, and a comparison with the bonding in [Be(C5H5)2] has been made. As for the latter molecule, energy differences between the η5/η5 and the η5/η1 structures of 2 are very small, being of the order of a few kcal mol−1. Constrained space orbital variations (CSOV) calculations show that the covalent character in the bonding is larger for [Be(C5Me5)2] than for [Be(C5H5)2] due to larger charge delocalization and to increased polarizability of the C5Me5 fragment.
Synthetic, Reactivity, and Structural Studies on Half‐Sandwich (η5‐C5Me5)Be and Related Compounds: Halide, Alkyl, and Iminoacyl Derivatives
Authors: del Mar Conejo M. , Fernández Rafael , Carmona Ernesto , Andersen Richard A. , Gutiérrez‐Puebla Enrique , Monge M. Angeles 
Published: September 2003

AbstractThe half‐sandwich compounds [(η5‐C5Me5)BeX] (X=Cl, 1 a; Br, 1 b), readily prepared from the reaction of the halides BeX2 and M[C5Me5] (M=Na or K), are useful synthons for other (η5‐C5Me5)Be organometallic compounds, including the alkyl derivatives [(η5‐C5Me5)BeR] (R=Me, 2 a; CMe3, 2 b; CH2CMe3, 2 c; CH2Ph, 2 d). The latter compounds can be obtained by metathetical exchange of the halides 1 with the corresponding lithium reagent and exhibit NMR signals and other properties in accord with the proposed formulation. Attempts to make [(η5‐C5Me5)BeH] have proved fruitless, probably due to instability of the hydride toward disproportionation into [Be(C5Me5)2] and BeH2. The half‐sandwich iminoacyl [(η5‐C5Me5)Be(C(NXyl)Cp′)] and [(η5‐C5Me4H)Be(C(NXyl)Cp′)]3, 6 where Xyl=C6H3‐2,6‐Me2 and Cp′=C5Me5 or C5Me4H, are formed when the beryllocenes [Be(C5Me5)2], [Be(C5Me4H)2], and [Be(C5Me5)(C5Me4H)] are allowed to react with CNXyl. Isolation of three different iminoacyl isomers from the reaction of the mixed‐ring beryllocene [(η5‐C5Me5)Be(η1‐C5Me4H)] and CNXyl, namely compounds 5 a, 5 b, and 6, provides compelling evidence for the existence in solution of different beryllocene isomers, generated in the course of two very facile processes that explain the solution dynamics of these metallocenes, that is the 1,5‐sigmatropic shift of the Be(η5‐Cp′) unit around the periphery of the η1‐Cp′ ring, and the molecular inversion rearrangement that exchanges the roles of the two rings.
Synthesis of Five Generations of Redox‐Stable Pentamethylamidoferrocenyl Dendrimers and Comparison of Amidoferrocenyl‐ and Pentamethylamidoferrocenyl Dendrimers as Electrochemical Exoreceptors for the Selective Recognition of H2PO4−, HSO4−, and Adenosine 5′‐Triphosphate (ATP) Anions: Stereoelectronic and Hydrophobic Roles of Cyclopentadienyl Permethylation
Authors: Daniel Marie‐Christine , Ruiz Jaime , Blais Jean‐Claude , Daro Nathalie , Astruc Didier 
Published: September 2003

AbstractA family of five metallodendrimers with pentamethylamidoferrocenyl termini were synthesized from the DSM dendrimers Gn‐DAB‐dend‐(NH2)x (x=4, 8, 16, 32, 64) and characterized by standard techniques, including prominent molecular peaks (broad for x=64) in their MALDI‐TOF mass spectra. Oxidation of G4‐DAB‐dend‐(NHCOFc*)x (Fc*=C5H4FeCp*, Cp*=η5‐C5Me5) with SbCl5 in CH2Cl2 yields the stable 17‐electron pentamethylferrocenium analogue, which can be characterized by ESR and Mössbauer spectroscopy and reduced back to the initial FeII dendrimer, the cycle being carried out without decomposition. The cyclic voltammograms (CVs) of all dendrimers, recorded in CH2Cl2 or DMF, show a fully reversible ferrocenyl wave without adsorption. They are much cleaner than those of the parent ferrocenyl analogues previously synthesized and studied by Cuadrado et al. These properties allow much easier recognition and titration of H2PO4− and ATP2− by CV with the permethylated series than with the parent series. On the other hand, permethylation reduces the difference between the potentials recorded before and after titration. This is not crucial for H2PO4− and ATP2−, but it is for HSO4−, because of the weak interaction in this case. Thus recognition and titration in CH2Cl2 proceeds best with the parent series, and a positive dendritic effect is revealed by the appearance of a new wave whose difference in potential relative to the initial wave increases with increasing generation number. In DMF, recognition and titration are only possible with the permethylated series and are subject to a dramatic dendritic effect. Indeed, the titration is followed by only a shift of the initial wave with G1 and by the appearance of a new wave with G2 and G3. In conclusion, the permethylated dendrimers allow excellent recognition and titration of the oxoanions by CV due to the stereoelectronic stabilization of the 17‐electron form and their hydrophobic effect. The magnitude of the recognition and positive dendritic effects is very sensitive to the dendrimer structure and to the nature of the solvent. The recognition is of the strong‐interaction type (square scheme) between these dendrimers and ATP2− with a stoichiometry of 0.5 equiv ATP2− per ferrocenyl branch.
Crystal and Molecular Structure of Rubidium Peroxodicarbonate Rb2[C2O6]
Authors: Dinnebier Robert E. , Vensky Sascha , Jansen Martin 
Published: September 2003

AbstractWe report the crystal structure of rubidium peroxodicarbonate, which was synthesized by electrocrystallization at T=257 K, from laboratory X‐ray powder diffraction data. The compound crystallizes in the monoclinic space group P21/c with four formula units per unit cell and cell parameters of a=7.9129(1), b=10.5117(1), c=7.5559(1) Å, β=102.001(1)°, and V=614.75(1) Å3. The packing can be considered as a strongly distorted CsCl type of structure. The conformation of the peroxodicarbonate anion was found to be planar (C2h symmetry), in contrast to the staggered conformation of the peroxodicarbonate anion in the respective potassium peroxodicarbonate. The different conformation is attributed to packing effects.
Asymmetric Synthesis of Oxygen Heterocycles via Pd‐Catalyzed Dynamic Kinetic Asymmetric Transformations: Application to Nucleosides
Authors: Trost Barry M. , Brown Brian S. , McEachern Ernest J. , Kuhn Oliver 
Published: September 2003

AbstractRacemic butadiene and isoprene monoepoxide react with unsaturated alcohols in the presence of a chiral palladium catalyst and a boron co‐catalyst to give 3‐alkoxy‐4‐hydroxy‐1‐butene and 3‐alkoxy‐4‐hydroxy‐3‐methyl‐1‐butene, respectively, with excellent regio‐ and enantioselectivity in a dynamic kinetic asymmetric transformation whereby both enantiomers of the starting epoxides provide the same enantiomeric product. In the case of 2‐phenylbutadiene monoepoxide, easily available from phenacyl chloride and vinylmagnesium bromide, the reaction proceeds by kinetic resolution. A model to rationalize the result is presented. The bis‐olefin products are ideal substrates for the Ru catalyzed ring closing metathesis. In this way, five‐, six‐, and seven‐membered oxygen heterocycles are readily available enantiomerically pure. The value of this very simple two step process is demonstrated by the use of the five‐membered ring heterocycles to form unnatural and unusual nucleosides that cannot be easily accessed by other means. The sequence involves a Ru catalyzed isomerization of the initial 2,5‐dihydrofuran to a 2,3‐dihydrofuran followed by a selenium promoted addition of a pyrimidine or purine base. One advantage of this strategy is the easy access to either enantiomeric series, both of which have important biological applications.
CC versus CH Activation and versus Agostic CC Interaction Controlled by Electron Density at the Metal Center
Authors: Gandelman Mark , Shimon Linda J. W. , Milstein David 
Published: September 2003

AbstractBased on the PCN ligand 2, a remarkable degree of control over CC versus CH bond activation and versus formation of an agostic CC complex was demonstrated by choice of cationic [Rh(CO)n(C2H4)2−n] (n=0, 1, 2) precursors. Whereas reaction of 2 with [Rh(C2H4)2(solv)n]BF4 results in exclusive CC bond activation to yield product 5, reaction with the dicarbonyl precursor [Rh(CO)2(solv)n]BF4 leads to formation of the CH activated complex 9. The latter process is promoted by intramolecular deprotonation of the CH bond by the hemilabile amine arm of the PCN ligand. The mixed monocarbonyl monoethylene Rh species [Rh(CO)(C2H4)]BF4 reacts with the PCN ligand 2 to give an agostic complex 7. The CC activated complex 5 is easily converted to the CH activated one (9) by reaction with CO; the reaction proceeds by a unique sequence of 1,2‐metal‐to‐carbon methyl shift, agostic interaction, and CH activation processes. Similarly, the CC agostic complex 7 is converted to the same CH activated product 9 by treatment with CO.
Assembly of Hybrid Organic–Organometallic Materials through Mechanochemical Acid–Base Reactions
Authors: Braga Dario , Maini Lucia , Polito Marco , Mirolo Laurent , Grepioni Fabrizia 
Published: September 2003

AbstractManual grinding of the organometallic complex [Fe(η5‐C5H4COOH)2] with a number of solid bases, namely 1,4‐diazabicyclo[2.2.2]octane, C6H12N2, 1,4‐phenylenediamine, p‐(NH2)2C6H4, piperazine, HN(C2H4)2NH, trans‐1,4‐cyclohexanediamine, p‐(NH2)2C6H10, and guanidinium carbonate [(NH2)3C]2[CO3], generates quantitatively the corresponding adducts, [HC6H12N2][Fe(η5‐C5H4COOH)(η5‐C5H4COO)] (1), [HC6H8N2][Fe(η5‐C5H4COOH)(η5‐C5H4COO)] (2), [H2C4H10N2][Fe(η5‐C5H4COO)2] (3), [H2C6H14N2][Fe(η5‐C5H4COO)2]⋅2 H2O, (4⋅2 H2O), and [C(NH2)3]2[Fe(η5‐C5H4COO)2]⋅2 H2O, (5⋅2 H2O), respectively. Crystallization from methanol in the presence of seeds of the ground sample allows the growth of single crystals of these adducts; therefore we were able to determine the structures of the adducts by single‐crystal X‐ray diffraction. This information was used in turn to identify and characterize the polycrystalline materials obtained by the grinding process. In the case of [HC6N2H12][Fe(η5‐C5H4COOH)(η5‐C5H4COO)] (1), the base can be removed by mild treatment regenerating the starting dicarboxylic acid, while in all other cases decomposition is observed. The solid–solid processes described herein imply molecular diffusion through the lattice, breaking and reassembling of hydrogen‐bonded networks, and proton transfer from acid to base.
Multicomponent Coupling Reactions for Organic Synthesis: Chemoselective Reactions with Amide–Aldehyde Mixtures
Authors: Jacobi von Wangelin Axel , Neumann Helfried , Gördes Dirk , Klaus Stefan , Strübing Dirk , Beller Matthias 
Published: September 2003

AbstractThe acid‐catalyzed condensation chemistry of simple amides and aldehydes provides a highly prolific source of diverse reactants for irreversible follow‐up reactions. Amide–aldehyde mixtures have been successfully employed in multicomponent syntheses of N‐acyl α‐amino acids (via palladium‐catalyzed amidocarbonylation) and various cyclohexene, cyclohexadiene, and benzene derivatives (via the amide–aldehyde–dienophile (AAD) reaction).
Catalytic Asymmetric Allylation of Aldehydes and Related Reactions with Bis(((S)‐binaphthoxy)(isopropoxy)titanium) Oxide as a μ‐Oxo‐Type Chiral Lewis Acid
Authors: Hanawa Hideo , Uraguchi Daisuke , Konishi Shunsuke , Hashimoto Takuya , Maruoka Keiji 
Published: September 2003

AbstractA new, chiral bis‐TiIV oxide of type 3 has been designed and can be utilized for strong activation of aldehyde carbonyls, thereby allowing a new catalytic enantioselective allylation of aldehydes with allyltributyltin. The chiral bis‐TiIV catalyst (S,S)‐3 can be readily prepared either by treatment of bis(triisopropoxy)titanium oxide with (S)‐BINOL or by treatment of ((S)‐binaphthoxy)isopropoxytitanium chloride with silver(I) oxide. Treatment of hydrocinnamaldehyde with allyltributyltin under the influence of chiral bis‐TiIV oxide (S,S)‐3 generated in situ (10 mol %) in CH2Cl2 afforded an allylation product in 84 % yield and with 99 % ee. This asymmetric allylation with non‐racemic bis‐TiIV oxide 3 and partially resolved (S)‐BINOL shows a positive nonlinear effect in correlation of the enantiopurity of the allylation product with the ee of the (S)‐BINOL. Chiral bis‐TiIV oxide (S,S)‐3 can also be utilized for related reactions such as asymmetric methallylation and propargylation of aldehydes with high enantioselectivity. This asymmetric approach provides a very useful way of obtaining high reactivity and selectivity through the simple introduction of the MOM unit into the design of chiral Lewis acid catalysts.
Cover Picture: Assembly of Hybrid Organic–Organometallic Materials through Mechanochemical Acid–Base Reactions (Chem. Eur. J. 18/2003)
Authors: Braga Dario , Maini Lucia , Polito Marco , Mirolo Laurent , Grepioni Fabrizia 
Published: September 2003

AbstractThe cover picture shows schematically the preparation of a crystalline material by grinding (top) of the solid reagents or by crystallization by seeding (bottom) of a solution of the powder obtained from the mechanochemical process. Manual grinding of the organometallic complex [Fe(η5‐C5H4COOH)2] with a number of solid bases, namely 1,4‐diazabicyclo[2.2.2]octane, 1,4‐phenylenediamine, piperazine, trans‐1,4‐cyclohexanediamine and guanidinium carbonate generates quantitatively the corresponding adducts, [HC6H12N2][Fe(η5‐C5H4COOH)(η5‐C5H4COO)], [HC6H8N2][Fe(η5‐C5H4COOH)(η5‐C5H4COO)], [H2C4H10N2][Fe(η5‐C5H4COO)2], [H2C6H14N2][Fe(η5‐C5H4COO)2] ⋅ 2 H2O and [C(NH2)3]2[Fe(η5‐C5H4COO)2]⋅2 H2O, respectively. Crystallization from methanol in the presence of seeds of the ground sample allows to grow single crystals of the adducts, hence determination of the adduct structures by single crystal X‐ray diffraction. This, in turn, allows identification and characterization of the polycrystalline materials obtained by the grinding process. These solid‐solid processes imply molecular diffusion through the lattice and breaking and reassembling of hydrogen bonded networks and proton transfer from acid to base. For more details see the article by D. Braga, F. Grepioni et al. on p. 4362 ff.
Particle size of powders under hydrothermal conditions
Authors: Li Wen‐Jun , Shi Er‐Wei , Fukuda Tsuguo 
Published: September 2003

AbstractVarious non‐oxide (CuI, AgI, AgCl, PbS, CuS and ZnS) and oxide (ZnO, TiO2, SnO2, CeO2 and ZrO2) powders were prepared under hydrothermal conditions to investigate the effects of temperature, pH and precursors on the particle size of powders. It was found that the particle sizes of PbS, CuS and ZnS powders were much smaller than that of CuI, AgI and AgCl powders prepared under the same conditions. The particle sizes of TiO2, SnO2, CeO2 and ZrO2 powders are much smaller than that of ZnO powders prepared under the same conditions. It is concluded that the solution conditions have a certain effect on the particle size of powders under the hydrothermal conditions. The particle size of powders increased with the rising of temperature. Additional factors affecting the particle size were uncovered through studying the nucleation mechanism. The particle size was mainly related to the Madelung constant and the electric charge number of ions. Powders with smaller particle size resulted from systems that possessed the larger Madelung constant and ionic charge number. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of internal radiation on the heat transfer during growth of YAG single crystals by the Czochralski method
Authors: Galazka Z. , Schwabe D. , Wilke H. 
Published: September 2003

AbstractHeat and mass transfer taking place during growth of Y3Al5O12 (YAG) crystals by the Czochralski method, including inner radiation, is analyzed numerically using a Finite Element Method. For inner radiative heat transfer through the crystal the band approximation model and real transmission characteristics, measured from obtained crystals, are used. The results reveal significant differences in temperature and melt flow for YAG crystals doped with different dopands influencing the optical properties of the crystals. When radiative heat transport through the crystal is taken into account the melt‐crystal interface shape is different from that when the radiative transport is not included. Its deflection remains constant over a wide range of crystal rotation rates until it finally rapidly changes in a narrow range of rotation rates. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transmission spectra of crystals at elevated temperatures for the calculation of internal radiant heat transport during crystal growth – Part 2: Spectra of YAG:Cr, YVO4:Nd and the bandgap variation of various materials
Authors: Polity A. , Schwabe D. , Ackermann L. , Dupré K. 
Published: September 2003

AbstractThe transmission spectra in the range from 350 to 3500 nm of the two most complex materials with regard to radiant heat transport – YAG:Cr+4 and YVO4:Nd – are reported for temperatures between 25 and 1310 °C. The extreme shift of the short wavelength cut‐off (band gap) of YVO4:Nd with temperature is shown in comparison to that of some other materials. In YAG:Cr4+ we found a light‐induced absorption band near 2000 nm besides a strong reduction of the transmission in the visible and the near IR with increasing temperature. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)