23 research outputs found

    El Diario de Pontevedra : periódico liberal: Ano XVII Número 4808 - 1900 maio 23

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    The Perceptions About Medications-Diabetes 21 Questionnaire - Japanese version (PAM-D21-J). (PDF 61 kb

    NCN Pincer–Pt Complexes Coordinated by (Nitronyl Nitroxide)-2-ide Radical Anion

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    New pincer–Pt complexes coordinated by (nitronyl nitroxide)-2-ide radical anion were prepared as stable compounds in high yields. The structures of these Pt complexes and the oxidized complexes were unequivocally determined by spectral and crystal structure analyses. The oxidation potential of the nitronyl nitroxide moiety in these complexes was shifted in the negative direction by ∼0.6 V as a result of coordination to the Pt­(II) atom

    Trimeric Assembly of Dendritic Light-Harvesting Antenna with Two Kinds of Porphyrin Cores

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    A trimeric assembly of light-harvesting antennas was prepared using a copper-catalyzed Hüisgen 1,3-dipolar cycloaddition reaction between a dendrimer having a zinc diethynyldiphenylporphyrin core (ZnDEDPP) with two azide terminals and two equivalents of dendrimers having a zinc tetraphenylporphyrin core (ZnTPP) with one ethynyl terminal. The absorptions of the trimer appear in a longer-wavelength region compared to monomeric references in toluene; however, there is almost no shift in wavelength in 1,1,2,2-tetrachloroethane (TCE). Fluorescence spectra of the trimer show that the singlet energy transfer from ZnTPP to ZnDEDPP takes place more effectively in toluene than in TCE. These absorption and fluorescence studies are compatible with solvent-dependent conformation; the extended forms of the trimers are favored by solvation in polar TCE, and the folded conformation is stabilized by the attractive van der Waals and dipole–dipole interactions between the dendritic chains in nonpolar toluene

    NCN Pincer–Pt Complexes Coordinated by (Nitronyl Nitroxide)-2-ide Radical Anion

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    New pincer–Pt complexes coordinated by (nitronyl nitroxide)-2-ide radical anion were prepared as stable compounds in high yields. The structures of these Pt complexes and the oxidized complexes were unequivocally determined by spectral and crystal structure analyses. The oxidation potential of the nitronyl nitroxide moiety in these complexes was shifted in the negative direction by ∼0.6 V as a result of coordination to the Pt­(II) atom

    2,11-Dibromo-13,14-dimesityl-5,8-dioxapentaphene: A Stable and Twisted Polycyclic System Containing the <i>o</i>‑Quinodimethane Skeleton

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    A stable <i>o</i>-quinodimethane (<i>o</i>QDM) derivative, 2,11-dibromo-13,14-dimesityl-5,8-dioxapentaphene (<b>3</b>) was synthesized, and its structure and properties were investigated. The X-ray structural analysis showed a significantly twisted π-framework and a clear bond-length alternation in the central <i>o</i>QDM skeleton. Owing to the quinoidal conjugation, <b>3</b> exhibited a broad absorption band in the visible region (up to 700 nm) and amphoteric redox behavior. Furthermore, radical cation <b>3</b><sup>•+</sup> was isolated, and its electronic structure was elucidated by spectroscopic measurements

    Jonas Dryander to James Edward Smith

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    Believes Smith is right to include an index of the genera for "Flora Britannica" but that the English index should be at the end and approves of the title. [John] Sibthorp's plants have now been laid out in the herbarium

    NCN Pincer–Pt Complexes Coordinated by (Nitronyl Nitroxide)-2-ide Radical Anion

    No full text
    New pincer–Pt complexes coordinated by (nitronyl nitroxide)-2-ide radical anion were prepared as stable compounds in high yields. The structures of these Pt complexes and the oxidized complexes were unequivocally determined by spectral and crystal structure analyses. The oxidation potential of the nitronyl nitroxide moiety in these complexes was shifted in the negative direction by ∼0.6 V as a result of coordination to the Pt­(II) atom

    Construction of Snowflake-Shaped Dendritic Covalent Assemblies with Rigid Conjugated Networks

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    A convergent method for the construction of shape-persistent nanoscale assemblies with conjugated backbones was developed. The copper-free Sonogashira coupling reaction was successfully applied to the formation of multiple covalent connections between conjugated terminals (iodide substituted aryl groups) of AB<sub>2</sub>-type outer components and four conjugated terminals (acetylenic bonds) of an inner A<sub>4</sub>-type core dendrimer. The conjugated networks in the starting components are expanded during the assembly process to afford nanoscale dendritic conjugated networks of the type A<sub>4</sub>(AB<sub>2</sub>)<sub>4</sub>, which have a porphyrin core, and longer (3.9 or 4.5 nm) and shorter (1.6 nm) conjugated chains. Fluorescence measurements revealed that singlet energy is effectively transferred in the assemblies from peripheral benzyl ether units and conjugated chains to the free base porphyrin core

    Synthesis and Higher-Order Structure of Linear Dendrimeric Assemblies

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    A series of linear covalent assemblies of dendrimers with conjugated backbones were synthesized by means of an iterative divergent and convergent method in which copper-catalyzed acetylene–azide cycloaddition reactions were used to form flexible linkages. UV–vis and fluorescence spectra indicate that dendrimeric assemblies have a strong propensity to adopt folded conformations in which conjugated backbones adopt planar conformations. The folded conformation is stabilized by strong attractive van der Waals and dipole–dipole interactions between the dendrimers
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