bluuebunny/crossref_metadata_2025 huggingface dataset:
Needs Analysis and Training Model Design Competence of Residential Construction Workers has Local Wisdom Value
Authors: Utiarahman Arfan , Yahya Muhammad , Purnamawati
Published: January 2024

One of the goals of Construction Management is to effectively oversee the utilization of Human Resources in the execution of a construction project. Indonesia is among the key proponents of establishing the Economic Community integration. The government has undertaken various measures to align with the economic collaboration among the ten ASEAN nations, including the development of competent human resources. Thus far, training observations have been conducted without any provision of training or technical guidance for workers regarding a construction project that possesses local knowledge significance. The objective of this study is to analyze the requirements of the competency training model for residential construction workers that incorporate local wisdom values, and to develop the corresponding training model. This study employed the Research and Development approach to investigate the competency standards for building work executors that are associated with building construction and incorporate local wisdom values. The ADDIE development model (Analyze, Design, Development, Implementation, and Evaluation) was utilized to create the training model. Findings of the research the initial survey conducted on 30 workers revealed an average competence level of 30.9%, which falls within the category of weak competence according to local wisdom. Additionally, all workers (100%) expressed agreement in enhancing their competence in residential houses that embody local wisdom ideals. The competency training model was designed utilizing the ADDIE Research & Development Model, which consists of five components: model syntax, social system, reaction principle, support system, instructional impact, and accompanying impact. This model comprises a model book, teaching material modules, and books.
Effect of Spring Goshoerami Mulberry Leaf Extract on Second Commercial Cocoon Crop under Temperate Climatic Condition
Authors: Qadri S. Farth Iqbal , Ganie N. A. , Dar K. A. , Bashir Masarat
Published: January 2024

Nutrition plays an important role in silkworm rearing. It improves the growth, development, health and feed consumption, thereby improving the commercial traits. As reported, the mulberry leaf under Kashmir climatic condition during Summer/autumn season is nutritionally poor. In Kashmir Valley 90% of silkworm rearers mostly do rearing only once in a year i.e during spring season and lesser number of rearers goes for second rearing during summer/ autumn season because of less productivity and poor quality cocoon crops. Fortification of leaves by supplementing nutrients and using them for feeding the silkworm is a useful technique to increase their economic value. Several attempts have been made to enhance the cocoon yield and silk content through supplement of amino acids on mulberry leaf. However supplement of amino acids on mulberry leaf may not be economical and is not easily assessable to farmers. Silkworm, Bombyx mori L., is a monophagous insect that drives all required nutrients for its growth and development from mulberry leaf. Hence the present study was undertaken to study the efficacy of fortification of spring leaf extract of Goshoerami on growth and commercial traits of double hybrid FC1 (CSR6×CSR26) × FC2 (CSR2×CSR27) of silkworm Bombyx mori L. during second commercial rearing. The results showed, that application of aqueous extract of spring mulberry leaf fed silkworm larvae shows significantly higher in terms of body weight, cocoon weight, shell weight, yield and silk filament length in all the treatments over the control. However the highest body weight (44.143 g/10) mature larval, Single cocoon weight (1.967g), single shell weight (0.471g), shell ratio percentage (23.921 %) and silk filament length (1,159.66 mtr) were recorded at 10% fortification. In order to promote the use of spring leaf extract for fortification among the silkworm rearers further studies are required in consultation with Department of Sericulture of the U T of Jammu and Kashmir.
Garret Ranking of Constraints Perceived by Silkworm Rearers in Sericulture Enterprise
Authors: Choudhari S. D.  , Perke D. S.  , Pathrikar D. T.
Published: January 2024

The current investigation primarily delves into the challenges faced by sericulture growers in mulberry and cocoon production. Sericulture, a highly competitive and capital-intensive enterprise, is prevalent across rural and semi-urban areas in India. This industry not only contributes to household income but also generates employment opportunities for entire families, with women actively participating in various facets of sericulture activities. A multistage sampling design was employed to select districts, tehsils, villages, and sericulture growers for the study. Specifically, Beed, Parbhani, and Jalna districts were purposively chosen in the Marathwada region due to their significant sericulture production. Two tehsils from each district and four villages from each tehsil were then selected, resulting in a total of 24 villages with 240 sample respondents. The study utilized Garret's ranking technique to assess the constraints affecting the adoption of sericulture production. The study identified four key types of constraints in the examined area: economic, technical, marketing, and supply constraints. According to Garret's ranking, the primary economic constraint was the high cost of inputs, including FYM, planting material, and chemical fertilizers. In the realm of technical constraints, a lack of information about Uzi fly control emerged as the major hurdle. Marketing constraints were predominantly characterized by fluctuations in cocoon prices, ranking highest in prominence. Additionally, insufficient FYM availability was highlighted as a significant supply constraint.
National Surveillance Data on the Epidemiology of Meningitis in Niger, 2005 - 2020
Authors: Alkassoum S. I.  , Abdoulaye Z.  , Goni A.  , Amadou O.  , Djibo A.  , Emoud T.  , Ibrahim M. L.  , Adeossi E.
Published: January 2024

Background: Bacterial meningitis is a major public health problem, especially in low-income countries. We analyzed national surveillance data and isolates from Niger to describe the epidemiology of bacterial meningitis from 2005 to 2020.

Methods: We conducted a retrospective study of nationwide case-based surveillance data of all reported meningitis cases in Niger from 2005 to 2020. Modified case definition was used to classify the cases.

Results: A total of 47,953 suspected meningitis cases and 3,276 deaths (CFR=6.83%) were reported, corresponding to an incidence of 189.01 cases per 100,000 population. The male represented 55.41% ( sex-ratio male : female = 1.30) and 40.52% were 5 -14 y. A total of 29,998 cases were reported through RNL, of which 10,979 (36.60%) were confirmed, of which 6,149 (56.01%), were confirmed by culture. The predominant organism identified was N. meningitidis serogroup A (33.91%). All regions reported meningitis cases and a consistent and substantial reduction was seen in confirmed NmA cases, with no cases occurring in the country after the completion of mass campaigns. Nevertheless, other pathogen species and Nm variants, including NmX, NmC, and Streptococcus pneumoniae, have become more prevalent.

Conclusion: Increased surveillance of multiple serogroups throughout is necessary, as well as consideration of vaccination with combination vaccines rather than just using a single strain as is currently the case with NmA.
Musculoskeletal disorders in relation to age and occupation in Swedish construction workers
Authors: Holmström Eva , Engholm Göran
Published: September 2003

Background

Physical exposure load varies between trades in the construction industry. Our hypothesis is that the prevalence of MSD in a trade, reflects the level of physical exposure; the aim of the study was to describe MSD in relation to age and occupation within the industry.

Methods

The study is based on data from self‐administered questionnaires filled out by 85,191 males in the Swedish construction industry.

Results

Construction workers had higher age‐adjusted prevalence of MSD than foremen and office workers. In general prevalence rates increased steadily with age. Scaffolders showed the highest prevalence of MSD in all body locations. Elevated prevalence of neck disorders was found in crane operators, insulators, and painters, and of lower back and lower extremity disorders in roofers and floorers.

Conclusion

MSD increase with age. The variation between trades of MSD prevalence seems to correspond to the variation with respect to physical exposure. Am. J. Ind. Med. 44:377–384, 2003. © 2003 Wiley‐Liss, Inc.
Low levels of occupational exposure to arsenic and antimony: Effects on lysosomal glycohydrolase levels in plasma of exposed workers and in lymphocyte cultures
Authors: Goi Giancarlo , Bairati Chiara , Massaccesi Luca , Sarnico Michela , Pagani Anna , Lombardo Adriana , Apostoli Pietro
Published: September 2003

Background

Heavy metals have been shown to alter the mechanism and release of lysosomal enzymes. In the present study, the activities of lysosomal glycohydrolases were determined in order to evaluate the asymptomatic toxic effects of low levels of exposure to arsenic (As) and antimony (Sb) in art glass workers.

Methods

N‐acetyl‐β‐D‐glucosaminidase (NAG), β‐D‐glucuronidase (GCR), α‐ and β‐D‐galactosidase, α‐D‐glucosidase, and α‐D‐mannosidase were determined by a fluorimetric assay in the plasma of 26 art glass workers. Lymphocytes cultured in the presence of different species of As and Sb served as an in vitro model for the study of the protective action of selenium and zinc.

Results

No significant difference in the plasma levels of the various enzymes was detected in art glass workers or control subjects. The in vitro experiments demonstrated that secretion of lysosomal glycohydrolases was increased by Sb (225%) and decreased by As (57%) at the same concentration of elements (200 μg/L). The addition of bivalent selenium to the culture neutralized the effects of both metals, while zinc chloride did not show any protective effect.

Conclusions

As for the plasma glycohydrolases, no praecox signs of toxicity related to a low concentration of As and Sb was evident in art glass workers. This may be due to the antagonistic effects demonstrated by these two metals in vitro. Their different mechanism of action on release of glycohydrolases is being discussed. Am. J. Ind. Med. 44:405–412, 2003. © 2003 Wiley‐Liss, Inc.
Perceived and measured hearing ability in construction laborers and farmers
Authors: Kerr Madeleine J. , McCullagh Marjorie , Savik Kay , Dvorak Leah A.
Published: September 2003

Background

Construction and farming are characterized by small independently operated enterprises; few are included in hearing loss prevention programs. This study describes perceived and measured hearing ability among construction laborers and farmers in order to further the Healthy People 2010 goal to reduce noise‐induced hearing loss (NIHL).

Methods

Construction laborers (n = 147) and farmers (n = 150) had screening audiograms at their workplace and a farm show, respectively. The relationship of the audiograms with a one‐item measure of perceived hearing ability was explored using non‐parametric statistics.

Results

At the 4,000 Hz frequency, indicative of NIHL, a high percentage of both groups exhibited hearing loss greater than 25 dB: laborers 53%, farmers 67%. Perceived hearing ability was significantly worse (P < 0.05) for workers with a measured hearing loss. The sensitivities of perceived hearing loss compared to audiometry ranged from 0.30 to 0.72 suggesting that perceived hearing loss was not a good indicator of actual hearing loss in this sample.

Conclusions

The poor relationship between perceived and actual hearing loss in this study suggests that best practice requires inclusion of audiometric screening as part of a complete hearing loss prevention program. Future development of an improved instrument to measure perceived hearing ability may be useful in assessing this dimension of hearing. Am. J. Ind. Med. 44:431–437, 2003. © 2003 Wiley‐Liss, Inc.
Highly Functionalized Organomagnesium Reagents Prepared through Halogen–Metal Exchange
Authors: Knochel Paul , Dohle Wolfgang , Gommermann Nina , Kneisel Florian F. , Kopp Felix , Korn Tobias , Sapountzis Ioannis , Vu Viet Anh
Published: September 2003

Organomagnesium reagents occupy a central position in synthetic organic and organometallic chemistry. Recently, the halogen–magnesium exchange has considerably extended the range of functionalized Grignard reagents available for synthetic purposes. Functional groups such as esters, nitriles, iodides, imines, or even nitro groups can be present in a wide range of aromatic and heterocyclic organomagnesium reagents. Also various highly functionalized alkenyl magnesium species can be prepared. These recent developments as well as new applications of organomagnesium reagents in cross‐coupling reactions and amination reactions will be covered in this Review.
New Cyanopeptide‐Derived Low MolecularWeight Thrombin Inhibitors
Authors: Radau Gregor , Gebel Jana , Rauh Daniel
Published: September 2003

Thrombosis is the result of defective regulation of the hemostasis system. This cardiovascular disorder may lead to deep vein thrombosis, myocardial infarction, and stroke. The majority of current drug research is focused on finding inhibitors of thrombin — the global player in hemostasis. In our work, we emphasize investigation of the marine environment to yield new lead structures from marine organisms like blue‐green algae (cyanobacteria). This article deals with the design, syntheses, and inhibition tests of new lowmolecularweight thrombin inhibitors utilizing cyanopeptides, the secondarymetabolites of cyanobacteria with interesting biological activities, as new lead structures. Starting with aeruginosin 98‐B (2) as a lead structure, we have developed and synthesized new, selective acting inhibitors of thrombin (RA‐1001 and RA‐1002), which are suitable targets for further structure‐activity studies.
1‐N‐Substituted Thiocarbamoyl‐3‐phenyl‐5‐thienyl‐2‐pyrazolines: Synthesis and Evaluation as MAO Inhibitors
Authors: Gökhan Nesrin , Yeşilada Akgül , Uçar Gülberk , Erol Kevser , Bilgin A. Altan
Published: September 2003

Twelve new 1‐N‐substituted thiocarbomoyl‐3‐phenyl‐5‐thienyl‐2‐pyrazoline derivatives were synthesized and evaluated their for antidepressant, anxiogenic and mammalianmonoamine oxidase (MAO)‐A and Binhibitory activities by in vivo and in vitro tests. MAO was isolated and purified from the mitochondrial pellet of bovine liver homogenates and human platelets. All of the new compounds inhibited the total MAO activity of liver homogenates and the inhibition was found to be time‐dependent. Four compounds (3 i—3 l) inhibited MAO‐B selectively and irreversibly in a classical non‐competitive manner with IC50 values in the range of 22.00—91.50 μM. The rest of the compounds appeared to be non‐selective reversible inhibitors. Itwas suggested that the p‐methoxy group on the phenyl ring in the compounds increased the inhibitory effect and selectivity towardMAO‐B. The reversible and unselective inhibition of MAO by the remaining compounds was suggested to be related to their properties of actingability to act as both as substrate and inhibitor at the same time. However, none of the novel compounds showed antidepressant activity as expected suggesting formation of inactive metabolites. We conclude that the compounds appeared as which functioned as selective MAO‐B inhibitors might have promising features as therapeutic properties in the treatment of Parkinson disease. In vivo studies are needed to verify this hypothesis.
Contribution of Lateral Substituents in Symmetrical and Non‐symmetrical Heptane‐bisammonio Compounds to the Allosteric Stabilization of N‐methylscopolamine Binding to Muscarinic M2 Receptors
Authors: Staudt Markus , Tränkle Christian , Mohr Klaus , Holzgrabe Ulrike
Published: September 2003

Allosteric modulators are able to enhance or decrease the equilibrium binding of orthosteric agonists or antagonists. The treatment of Alzheimer's disease and the organophosphorus poisoning can take advantage of the enhancement of the ligand binding. Prerequisite is the formation of ternary complexes consisting of the receptor protein, the orthosteric ligand, e. g. N‐methylscopolamine (NMS), and the alloster optimized for the corresponding orthoster. In this study, heptane‐bisammonio compounds were optimized with regard to the orthosteric antagonist NMS. Comparing pairs of compounds characterized by phthalimides, cyclohexanedicarbonic acid imide and succinimides at both ends or a phthalimide at one end and either of the three imides at the other end stressed the importance of an aromatic moiety at both ends of the heptane‐bisammonio chain.
Syntheses of 2, 5‐Dialkylfuran and Tetrahydrofuran Carbinols and Their Cytotoxic Activity
Authors: Krauss Jürgen , Unterreitmeier Doris , Antlsperger Dorothee
Published: September 2003

2, 5‐Dialkylfuran and tetrahydrofuran compounds as structural elements of Annonaceae acetogenins like Asitrocinwere synthesized starting from furfural by Grignard reactions, lithiation of the furan ring and addition of aliphatic aldehydes. Hydrogenation of the furan rings over Pd‐catalyst gave the corresponding tetrahydrofurans. All resulting compounds showed no or rather less antimicrobial activity against grampositive, gram‐negative bacteria and fungi compared to tetracycline or clotrimazol but high cytotoxic activity against HL 60 cell line determined in the MTT assay.
Zur Pluralisierung im Luthertum des 17. Jahrhunderts und ihrer Bedeutung für die Deutungen von ‚Natur’︁
Authors: Trepp Anne‐Charlott
Published: September 2003

Building on methodological considerations in cultural history and historical anthropology, the following contribution proceeds from the concept of ‚nature’︁ rather than from ‚natural science’︁, with the former understood here as the object of culturally determined projections, values and practices. This ‚constructive’︁, practice‐oriented concept of nature exposes perceptions of and attitudes towards nature that, owing to the usual reduction of nature to natural science, would otherwise have remained hidden, but which may well be essential to its constitution. To a certain extent, the term ‚nature’︁ continues the terminological extension from ‚natural science’︁ to ‚natural philosophy’︁, but as a heuristic device it more strongly implies the significance of culturally mediated practices and dynamics. The essay raises the following questions: Which religious conceptions entered into which attitudes towards nature and which religious expectations and interpretive matrices were the motivating forces behind which studies of nature?

The figures within seventeenth‐century Lutheranism who shaped and promoted nature‐oriented attitudes and practices were not the ‚orthodox’︁ scholars more strongly tied to academic and controversialist theology, but rather reform‐oriented theologians critical of the church. In the context of the inner differentiation and pluralization of seventeenth‐century Lutheranism, these reform‐oriented groups not only inspired innovate theological projects but also assumed a leading role, along with liked‐minded Christian laypersons, in interpreting and studying ‚nature’︁.
„Daß auch zugleich die Gottseligkeit dadurch gebauet wird”︁ — Pietismus und Medizin in der ersten Hälfte des 18. Jahrhunderts
Authors: Helm Jürgen
Published: September 2003

In 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

Compounds 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

The 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

The 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

The 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

The 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

A 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

We 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

Racemic 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

Based 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

Manual 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

The 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

A 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

The 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

Various 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

Heat 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

The 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)
The influence of Yb3+ concentration on Yb:YAl3(BO3)4
Authors: Li J. , Wang J. Y. , Cheng X. F. , Hu X. B. , Wang X. Q.
Published: September 2003

The Yb:YAl3(BO3) 4 crystals with different Yb3+ doping concentration have been grown by the flux method. The lattice parameters and decomposition of the Yb:YAl3(BO3)4 crystal with different Yb3+ doping concentration were measured by X‐ray and DTA method. The transmission and fluorescence spectra of Yb3+:YAl3(BO3)4 crystal have been measured. The growth defects of YbxY1‐xAl3(BO3)4 crystals were also detected by using the chemical etching method. The results show that the ytterbium concentration influences these properties of Yb:YAl3(BO3)4. As the Yb3+ concentration increased, the crystal lattice parameter was decreased. At high doping level, the absorption peak concerned at about 980 nm shift to short wavelength. It is also found that the perfection of Yb:YAl3(BO3) 4 crystal with low Yb3+ doping concentration is better than that with high Yb3+ concentration. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, characterization and structural phase transition studies in trismethylammonium pentachloro barium dihydrate single crystals
Authors: Amirthaganesan G. , Kandhaswamy M. A. , Srinivasan V.
Published: September 2003

Single crystals of trismethylammonium pentachlorobarium dihydrate were grown by slow evaporation method at ambient temperature. The crystals were characterized through powder XRD, thermal, infrared and NMR spectral studies. While the powder XRD pattern confirms the crystallinity of the title compound, the TG indicates the removal of occluded and adsorbed water molecules from the crystal when it is heated up to 86 °C. The TG study also confirms the presence of two water molecules of crystallization which are dehydrated on heating the crystal between 107 °C and 150 °C. The anhydrous compound is found to be stable at least up to 900 °C. The DTA curve shows two endothermic dips corresponding to weight losses observed in the TG curve. The low temperature DSC study shows thermal anomalies during the heating and cooling cycles indicating both first and second order phase transitions. The high temperature DSC shows the stepwise dehydration indicating phase transitions at temperatures 103 °C and 145 °C. The characteristic vibrational frequencies due to methylammonium ion, BaCl5 and other groups are assigned based on FTIR spectra. The NMR spectrum confirms the presence of protons of the methyl group and water of crystallization in the compound. In this paper, an attempt is also made to understand the effect of methyl group on the phase transitions of the compound in comparison with a closely related compound, trisammoniumpentachloro barium dihydrate. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The crystal and molecular structure of bis(tetramethylammonium) hexamolybdate(VI)
Authors: Ghammami S.
Published: September 2003

The crystal structure of the title compound, C8H24N2Mo6O19 was determined by single crystal X‐ray diffraction technique. The crystals are trigonals, space group P‐3c1, with a = b = 10.0176(11) Å, c = 14.089(2) Å, γ = 120°, V = 1224.4(3) Å3, Z = 2. The structure was solved by direct methods and refined by least‐squares methods to a Final R = 0.0316 for 1114 observed reflections with I > 2σ(I). In hexamolybdate anion, six MoO6 distorted octahedra are fused together so that they all share a common vertex. O atoms are of three types: central, terminal and bridging, bonded to six, one and two Mo atoms, respectively. The crystallographic data of the structure was deposited with the Cambridge Data Center as No. CCDC 199679. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hypersilyl‐Substituted Complexes of Group 1 and 2 Metals: Syntheses, Structures and Use in Styrene Polymerisation
Authors: Feil Florian , Harder Sjoerd
Published: September 2003

Alkali and alkaline‐earth metal complexes with sterically demanding hypersilyl‐substituted cyclopentadienyl or fluorenyl ligands [hSi‐Cp or hSi‐Flu; hSi = (Me3Si)3Si] were prepared. The crystal structures of [Li(hSi‐Flu)(THF)2], [K(hSi‐Flu)(THF)], [Ca(hSi‐Flu)2(THF)2], [Sr(hSi‐Flu)2(THF)2] and [Ca(hSi‐Cp)2(THF)] were determined. All structures show the enormous steric bulk of the hypersilyl substituent, which either results in a reduction in the number of solvent molecules in the coordination sphere of the metal or in a distortion of the ligand‐metal interaction. Heteroleptic calcium and strontium complexes with a benzyl ligand (2‐Me2N‐α‐Me3Si‐benzyl) and a sterically demanding hSi‐Flu ligand were prepared and used as initiators in the polymerization of styrene. The polymers produced with the heteroleptic benzylcalcium initiator are enriched in syndiotactic sequences, although they show the same tacticities as polymers obtained with benzylcalcium initiators containing the less bulky Me3Si‐Flu ligand. Introduction of the bulky hypersilyl group in heteroleptic benzylstrontium initiators resulted in a slight increase of the syndiotacticity of the polymers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)