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A polymeric two-dimensional mixed-metal network. Crystal structure and magnetic properties of {[P(Ph)4][MnCr(ox)3]}
1994
Abstract The mixed-metal ferromagnet {[P(Ph) 4 ][MnCr(ox) 3 ]} n , where Ph is phenyl and ox is oxalate, has been prepared and a two-dimensional network structure, extended by Mn(II)-ox-Cr(III) bridges, has been determined from single crystal X-ray data. Crystal data: space group R 3 c , a = b =18.783(3), c =57.283(24) A, α=β=90, γ=120°, Z =24 (C 30 H 20 O 12 PCrMn). The magnetic susceptibility data obey the Curie-Weiss law in the temperature range 260–20 K with a positive Weiss constant of 10.5 K. The temperature dependence of the molar magnetization exhibits a magnetic phase transition at T c =5.9 K. The structure is discussed in relation to the strategy for preparing molecular based ferr…
<title>Coumarin fluorescent probes by electro-optical and laser spectrofluorimetry methods</title>
1997
Modified electro-optical absorption and emission methods were used to measure the dipole moments of six coumarin fluorescent probes (CU1, CU4, CU7, CU30, CU120, CU334) in the equilibrated ground, excited Franck-Condon and equilibrated excited states. The measurements were performed in cyclohexane and dioxane at room temperature. The equilibrated ground and excited states dipole measured by electro-optical methods are compared with those derived from other measurements techniques and from semiempirical calculations. Experiments and calculations performed in this work reveal a set of anomalous and interesting properties of CU7 and CU30 in solutions. The spectral dependence of some electro-opt…
Organic Materials for Non-Linear Optics: The 2D Approach
1998
Conventional organic molecules for applications in second-order non-linear optics are donor–acceptor substituted π systems that show only one intense charge-transfer (CT) transition. Thus, only a single element of the second-order polarizability tensor, β, is significant in these one-dimensional systems. The advantages and optimization strategies for two new classes of molecules with multiple CT transitions and two-dimensional second-order polarizability are reviewed. These are donor–acceptor substituted π systems that lack a dipole and have a molecular symmetry of C3 or higher, and dipolar molecules of symmetry C2v. A basic introduction to the field is also given.
ChemInform Abstract: Organic Materials for Non-Linear Optics: The 2D Approach
2010
Conventional organic molecules for applications in second-order non-linear optics are donor–acceptor substituted π systems that show only one intense charge-transfer (CT) transition. Thus, only a single element of the second-order polarizability tensor, β, is significant in these one-dimensional systems. The advantages and optimization strategies for two new classes of molecules with multiple CT transitions and two-dimensional second-order polarizability are reviewed. These are donor–acceptor substituted π systems that lack a dipole and have a molecular symmetry of C3 or higher, and dipolar molecules of symmetry C2v. A basic introduction to the field is also given.
Elektrooptische Emissionsuntersuchungen, III. Das Dipolmoment von trans-p-Dimethylamino-p′-nitrostilben im ersten angeregten Singulettzustand
1977
Aus elektrooptischen Emissions- und Absorptionsuntersuchungen in flussigen und glasig erstarrten Losungen kombiniert mit dielektrischen Untersuchungen konnten u. a. das Dipolmoment und die Polarisierbarkeitskomponente in Richtung des Dipolmoments von trans-p-Dimethylamino-p′-nitrostilben (DMANS) im ersten angeregten Singulettzustand bestimmt werden zu μ0a = (63 ± 5) · 10−30 Cm und α0az = (442 ± 65) · 10−40 CV−1 m2. Es zeigte sich, das die elektrooptischen Absorptions- und Emissionsuntersuchungen an DMANS in unpolaren Losungen zu einem konsistenten Satz von Dipolmomenten fuhren, das also die Aquilibrierung mit der Umgebung nach Anre-gung im unpolaren Cyclohexan keinen Einflus auf das permane…
Electronic structure of the glyoxalbis(2-hydroxyanil) (gha) ligand in [CoIII(gha)(PPh3)2]+: radical vs. non-radical states
2008
The synthesis, structure and spectroscopic properties of a complex salt [CoIII(gha)(PPh3)2][CoIICl3(PPh3)]·C2H5OH (1) are reported; gha = glyoxalbis(2-hydroxyanil). This is the first single crystal X-ray structure of a (gha)2− complex with a transition element. Though the determined bond parameters and UV-Vis spectroscopic data correlate well with a diradical description for the cation in 1, detailed electronic structure calculations using density functional theory confirm that [Co(gha)(PPh3)2]+ can be described as a closed shell singlet species which nevertheless displays an interesting electronic structure with significant electron transfer to the formally unoccupied LUMO of the square pl…
La responsabilità dei prestatori di servizi di condivisione di contenuti online.
2023
Il saggio analizza il recepimento della dir. 2019/790/UE, sul diritto d'autore e i diritti connessi nel mercato unico digitale. Lo studio si concentra sulle norme relative alla responsabilità dei prestatori di servizi di condivisione di contenuti on-line e le confronta con le disposizioni generali contenute nel Digital Services Act. The essay analyzes the transposition of dir. 2019/790/EU, on copyright and related rights in the digital single market. The study focuses on the liability rules of online content sharing service providers and compares them with the general provisions contained in the Digital Services Act.
Split-ticket voting in German Federal elections, 1953–90: an example of sophisticated balloting?
1999
Abstract Though the German electoral system has provided the opportunity of split-ticket voting since 1953, until now there has only been mere speculation concerning the rationality of ticket-splitting. In this paper we examine the rationality thesis empirically, using data provided by the official representative electoral statistics of the Federal Republic. Modifying the Downsian notion of rational voting, rational ticket-splitting is defined in terms of coalition building and of voters' expectations of the electoral success of candidates and parties. Applying this conceptual framework, it will be shown that the combinations of first and second votes actually chosen by a majority of the Ge…
Single-valued extension property at the points of the approximate point spectrum
2003
Abstract A localized version of the single-valued extension property is studied at the points which are not limit points of the approximate point spectrum, as well as of the surjectivity spectrum. In particular, we shall characterize the single-valued extension property at a point λ o ∈ C in the case that λoI−T is of Kato type. From this characterizations we shall deduce several results on cluster points of some distinguished parts of the spectrum.
Operators Which Do Not Have the Single Valued Extension Property
2000
Abstract In this paper we shall consider the relationships between a local version of the single valued extension property of a bounded operator T ∈ L ( X ) on a Banach space X and some quantities associated with T which play an important role in Fredholm theory. In particular, we shall consider some conditions for which T does not have the single valued extension property at a point λ o ∈ C .