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31.
Khan MS Al-Mandhary MR Al-Suti MK Al-Battashi FR Al-Saadi S Ahrens B Bjernemose JK Mahon MF Raithby PR Younus M Chawdhury N Kohler A Marseglia EA Tedesco E Feeder N Teat SJ 《Dalton transactions (Cambridge, England : 2003)》2004,(15):2377-2385
A series of protected and terminal dialkynes with extended pi-conjugation through a condensed aromatic linker unit in the backbone, 1,4-bis(trimethylsilylethynyl)naphthalene, 1,4-bis(ethynyl)naphthalene, 9,10-bis(trimethylsilylethynyl)anthracene, 9,10-bis(ethynyl)anthracene, have been synthesized and characterized spectroscopically. The solid-state structures of and have been confirmed by single crystal X-ray diffraction studies. Reaction of two equivalents of the complex trans-[Ph(Et(3)P)(2)PtCl] with an equivalent of the terminal dialkynes 1,4-bis(ethynyl)benzene and, in (i)Pr(2)NH-CH(2)Cl(2), in the presence of CuI, at room temperature, afforded the platinum(II) di-ynes trans-[Ph(Et(3)P)(2)Pt-C[triple bond, length as m-dash]C-R-C[triple bond, length as m-dash]C-Pt(PEt(3))(2)Ph](R = benzene-1,4-diyl; naphthalene-1,4-diyl and anthracene-9,10-diyl ) while reactions between equimolar quantities of trans-[((n)Bu(3)P)(2)PtCl(2)] and under similar conditions readily afforded the platinum(II) poly-ynes trans-[-((n)Bu(3)P)(2)Pt-C[triple bond]C-R-C[triple bond]C-](n)(R = naphthalene-1,4-diyl and anthracene-9,10-diyl ). The Pt(II) diynes and poly-ynes have been characterized by analytical and spectroscopic methods, and the single crystal X-ray structures of and have been determined. These structures confirm the trans-square planar geometry at the platinum centres and the linear nature of the molecules. The di-ynes and poly-ynes are soluble in organic solvents and readily cast into thin films. Optical spectroscopic measurements reveal that the electron-rich naphthalene and anthracene spacers create strong donor-acceptor interactions between the Pt(II) centres and conjugated ligands along the rigid backbone of the organometallic polymers. Thermogravimetry shows that the di-ynes possess a somewhat higher thermal stability than the corresponding poly-ynes. Both the Pt(II) di-ynes and the poly-ynes exhibit increasing thermal stability along the series of spacers from phenylene through naphthalene to anthracene. 相似文献
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Bautista-Sanchez A Kasselouri A Desroches MC Blais J Maillard P de Oliveira DM Tedesco AC Prognon P Delaire J 《Journal of photochemistry and photobiology. B, Biology》2005,81(3):154-162
Glucoconjugated analogues of the meta-hydroxyphenyl porphyrin (m-THPP) and meta-hydroxyphenyl chlorin (m-THPC) has been recently synthesized. The characteristics of their triplet states have been determined with regard to their involvement in the photodynamic (PDT) efficiency. In the case of porphyrin derivatives, triplet quantum yields (Phi(T)) were ranging from 0.42 to 0.55 and triplet life times (tau(T)) from 1 to 5 micros. High reaction rate constants (k(q)) with molecular oxygen (k(q): 1.2-1.6 x 10(9)s(-1)) have been found. The triplet lifetimes of chlorin derivatives were about four times higher than those of porphyrins whereas the Phi(T) and k(q) values remained quite similar. Singlet oxygen yields of glucosylated and non-glucosylated porphyrins and chlorins were not significantly different within experimental errors (Phi(Delta)((1)O(2)): 0.41-0.58). Furthermore, it has been shown that glucoconjugated photosensitizers could undergo associations with the methyl-beta-cyclodextrin (Me-beta-CD) which exhibit high triplet lifetimes and singlet oxygen yields ranging from 0.27 to 0.48. 相似文献
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In the present paper we consider f (R) gravity theories in the metric approach and we derive the equations of motion, focusing also on the boundary conditions. In such a way we apply the general equations to a first order perturbation expansion of the Lagrangian. We present a model able to fit supernovae data without introducing dark energy. 相似文献
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The first results are presented of calculations using a quite simple phenomenological model developed to simulate the cationic substitutions in Nd1+ x Ba2? x Cu3O7+ x /2?δ (Nd123). Although elementary concepts from statistical mechanics are used in the model, significant results have been obtained, such as the reconstruction of the substitution region limits and their dependence on temperature. Particularly interesting is the prediction of strong temperature dependence for the minimum substitution parameter, x min. 相似文献
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M.J.M. Pires M.S. Araújo Filho J.C.G. Tedesco J.D. Ardisson W.A.A. Macedo 《Journal of Physics and Chemistry of Solids》2014
Polycrystalline thin films usually present magnetic anisotropy resulting from a conjunction of textures, residual stresses, surface effects, and magnetic dipole distribution. The shape anisotropy, which is caused by the magnetic dipole distribution, is dominant in most of the cases, and it forces the occurrence of in-plane easy axes for the magnetization. Contrary to this common expectation, we have found predominant out-of-plane easy axes in a series of Fe–Ni thin films produced by DC sputtering. Films with different thicknesses, from 40 to 1000 nm, and different deposition temperatures have been tested and show similar results. These unusual characteristics are results of a particular columnar structure formed during the films growth. The magnetic characterization of the samples has been done by Mössbauer spectroscopy, magnetometry, and ferromagnetic resonance. The unusual anisotropy observed is not believed to be uniform along the film thickness. This interpretation comes from the comparison of the experimental results with hysteresis obtained by micromagnetic simulations. Five distinct configurations for the anisotropies have been simulated for this comparison. 相似文献
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M. A. L. Capri A. J. Gómez M. S. Guimaraes V. E. R. Lemes S. P. Sorella D. G. Tedesco 《The European Physical Journal C - Particles and Fields》2011,71(1):1-15
The construction of BRST invariant local operators with the quantum numbers of the lightest glueball states, J PC=0++,2++,0?+, is worked out by making use of an Euclidean confining renormalizable gauge theory. The correlation functions of these operators are evaluated by employing a confining gluon propagator of the Gribov type and shown to display a spectral representation with positive spectral densities. An attempt to provide a first qualitative analysis of the ratios of the masses of the lightest glueballs is also discussed. 相似文献
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Simone Aparecida Cicillini Ana Carolina Lemos Prazias Antonio Claudio Tedesco Osvaldo Antonio Serra Roberto Santana da Silva 《Polyhedron》2009,28(13):2766-2770
The photochemical, photophysical and photobiological studies of a mixture containing cis-[Ru(H-dcbpy−)2(Cl)(NO)] (H2-dcbpy = 4,4′-dicarboxy-2,2′-bipyridine) and Na4[Tb(TsPc)(acac)] (TsPc = tetrasulfonated phthalocyanines; acac = acetylacetone), a system capable of improving photodynamic therapy (PDT), were accomplished. cis-[Ru(H-dcbpy−)2(Cl)(NO)] was obtained from cis-[Ru(H2-dcbpy)2Cl2]·2H2O, whereas Na4[Tb(TsPc)(acac)] was obtained by reacting phthalocyanine with terbium acetylacetonate. The UV–Vis spectrum of cis-[Ru(H-dcbpy−)2(Cl)(NO)] displays a band in the region of 305 nm (λmax in 0.1 mol L−1 HCl)(π–π*) and a shoulder at 323 nm (MLCT), while the UV–Vis spectrum of Na4[Tb(TsPc)(acac)] presents the typical phthalocyanine bands at 342 nm (Soret λmax in H2O) and 642, 682 (Q bands). The cis-[Ru(H-dcbpy−)2(Cl)(NO)] FTIR spectrum displays a band at 1932 cm−1 (Ru–NO+). The cyclic voltammogram of the cis-[Ru(H-dcbpy−)2(Cl)(NO)] complex in aqueous solution presented peaks at E = 0.10 V (NO+/0) and E = −0.50 V (NO0/−) versus Ag/AgCl. The NO concentration and 1O2 quantum yield for light irradiation in the λ > 550 nm region were measured as [NO] = 1.21 ± 0.14 μmol L−1 and øOS = 0.41, respectively. The amount of released NO seems to be dependent on oxygen concentration, once the NO concentration measured in aerated condition was 1.51 ± 0.11 μmol L−1 The photochemical pathway of the cis-[Ru(H-dcbpy−)2(Cl)(NO)]/Na4[Tb(TsPc)(acac)] mixture could be attributed to a photoinduced electron transfer process. The cytotoxic assays of cis-[Ru(H-dcbpy-)2(Cl)(NO)] and of the mixture carried out with B16F10 cells show a decrease in cell viability to 80% in the dark and to 20% under light irradiation. Our results document that the simultaneous production of NO and 1O2 could improve PDT and be useful in cancer treatment. 相似文献
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Tedesco E Turner GW Harris KD Johnston RL Kariuki BM 《Angewandte Chemie (International ed. in English)》2000,39(24):4488-4491