1,366 research outputs found

    Neue Synthesestrategien zur Darstellung von Oxonitridocarbonaten und Nitridosilicaten

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    Synthesis, Structure, and Dynamics of Tris(η5-cyclopentadienyl)lanthanides and Bis(η5-cyclopentadienyl)[bis(trimethylsilyl)amido]cerium(III)

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    The crystal structures of tris(η5-cyclopentadienyl)lanthanides (Ln = Ce, Dy, Ho) have been determined using different X-ray diffraction methods. Cp3Ce and Cp3Ho (Cp = cyclopentadienyl) crystal data needed special solution and refinement methods, due to the occurrence of intrinsic twinning in these species. Our results do not agree with the previously published cell constants of Cp3Ho. The space group and unit cell parameters of Cp3Dy have been derived from powder diffraction experiments. High-resolution 13C solid-state NMR data of Cp3La are presented, giving evidence of the dynamics and bonding situation of the Cp ligands. Cp3Ce turned out to be a reactive reagent for the synthesis of bis(η5-cyclopentadienyl)[bis(trimethylsilyl)amido]cerium(III)

    Mixed Valence Europium Nitridosilicate Eu2SiN3

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    The mixed valence europium nitridosilicate Eu2SiN3 has been synthesized at 900°C in welded tantalum ampules starting from europium and silicon diimide Si(NH)2 in a lithium flux. The structure of the black material has been determined by single-crystal X-ray diffraction analysis (Cmca (no. 64), a=542.3(11) pm, b=1061.0(2) pm, c=1162.9(2) pm, Z=8, 767 independent reflections, 37 parameters, R1=0.017, wR2=0.032). Eu2SiN3 is a chain-type silicate comprising one-dimensional infinite nonbranched zweier chains of corner-sharing SiN4 tetrahedra running parallel [100] with a maximum stretching factor fs=1.0. The compound is isostructural with Ca2PN3 and Rb2TiO3, and it represents the first example of a nonbranched chain silicate in the class of nitridosilicates. There are two crystallographically distinct europium sites (at two different Wyckoff positions 8f) being occupied with Eu2+ and Eu3+, respectively. 151Eu Mössbauer spectroscopy of Eu2SiN3 differentiates unequivocally these two europium atoms and confirms their equiatomic multiplicity, showing static mixed valence with a constant ratio of the Eu2+ and Eu3+ signals over the whole temperature range. The Eu2+ site shows magnetic hyperfine field splitting at 4.2 K. Magnetic susceptibility measurements exhibit Curie-Weiss behavior above 24 K with an effective magnetic moment of 7.5 μB/f.u. and a small contribution of Eu3+, in accordance with Eu2+ and Eu3+ in equiatomic ratio. Ferromagnetic ordering at unusually high temperature is detected at TC=24 K. DFT calculations of Eu2SiN3 reveal a band gap of ∼0.2 eV, which is in agreement with the black color of the compound. Both DFT calculations and lattice energetic calculations (MAPLE) corroborate the assignment of two crystallographically independent Eu sites to Eu2+ and Eu3+

    Di-μ-tert-butanolato-bis­[bis­(η5-cyclo­penta­dien­yl)erbium(III)]

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    In the centrosymmetric title compound, [Er2(C5H5)4(C4H9O)2], each Er atom is in a distorted tetra­hedral coordination environment, coordinated by two cyclo­penta­dienyl rings and two tert-but­oxy groups, forming a dimeric complex bridged through the tert-but­oxy groups

    Post-War Institutional Shocks: The Divergence of Italian and Japanese Corporate Governance Models

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    After the first section, introducing some typical problems of family capitalism, the following three sections of the paper consider the ambiguity of the legal framework defining the modern corporation, the two way relation between technology and property rights and the different mechanisms by which the control of the firms can be transferred to new individuals. In the other sections we examine the different role that the American occupation has had in the two countries: in Italy it involved the definitive blessing and reinforcement of both State-owned corporations and family controlled pyramidal groups that had emerged during the fascist period, whereas in Japan it caused the end of the power of the great zaibatsu families. We will also consider how inter-firm share holding can promote (Japan) or inhibit (Italy) expansion of large corporations and the mechanisms that have made each model self- sustaining after the initial institutional shocks.

    Health conditions of inmates in Italy

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    Abstract Background Several studies have shown that prison is characterized by a higher prevalence of chronic diseases than unconfined settings. The aim of this study was to describe the characteristics and health of inmates, focusing on internal diseases. Methods We designed a specific clinical record using the Python programming language. We considered all of the diagnoses according to the ICD-9-CM. Results Of a total of 17,086 inmates, 15,751 were enrolled in our study (M = 14,835; F = 869), corresponding to 92.2% of the entire inmate population (mean age of 39.6 years). The project involved a total of 57 detention facilities in six Italian regions (for a total of 28% of all detainees in Italy), as counted in a census taken on February 3, 2014. From the entire study sample, 32.5% of prisoners did not present any disorders, while 67.5% suffered from at least one disease. The most frequent pathologies were psychiatric (41.3%), digestive (14.5%), infectious (11.5%), cardiovascular (11.4%), endocrine, metabolic, and immune (8.6%), and respiratory (5.4%). Conclusion The findings showed that a large number of detainees were affected by several chronic conditions such as hypertension, dyslipidemia and type 2 diabetes mellitus, with an unusually high prevalence for such a young population. Therefore, a series of preventive measures is recommended to strengthen the entire care process and improve the health and living conditions of prisoners

    Light: a rare reaction product

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    The production of visible light by chemical reactions constitutes interesting and fascinating phenomena and several reaction mechanisms are discussed to rationalize excited state formation. Most efficient chemiluminescence reactions are thought to involve one or more electron transfer steps and chemiexcitation is believed to occur by radical annihilation. A brief introduction to the general principles of light production and the main known chemiexcitation mechanisms will be given here. Subsequently, recent results on the mechanistic elucidation of efficient chemiluminescence systems, as the peroxyoxalate reaction, the induced decomposition of phenoxy-substituted 1,2-dioxetanes and the catalyzed decomposition of new a-peroxylactones will be discussed.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenadoria para o Aperfeiçoamento de Pessoal do Ensino Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
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