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91.
Magali A. Rodrigues Sérgio Brochsztain Teresa C. Barros Mauricio S. Baptista Mario J. Politi 《Photochemistry and photobiology》1999,70(1):35-39
Abstract— The effect of the protonation state of a novel aqueous soluble N,N'-di(2-phosphonoethyl)-l,4,5,8-naphthalene-diimide (DPN) on its spectroscopic properties is studied. In aqueous solution DPN depicts linear Lambert-Beer plots up to the solubility limits at pH 1.0, 7.1 and 10.1, in accordance with its solubilization as a monomer. A small increase in the extinction coefficients with pH is observed. Conversely a strong decrease in the fluorescence emission yields are observed with the increase in pH. These results are shown to originate from the distinct efficiencies of the intersystem crossing of DPN as a function of the net charge on the phosphono moieties. Accordingly, from the decrease in fluorescence emission, titration curves were obtained resulting in two pKa of –1.5 and 6.7 in agreement with the potentiometric analysis. In parallel monitoring the amount of heat deposited in the system shows an inverse pattern, that is, increase in the thermal tensing time-resolved signal with pH. Laser flash photolysis and thermal Iensing data in the absence and presence of oxygen show the interplay of an intersystem crossing process with the protonation state of the dye. The changes in protonation from neutral to two- and four-fold charged species are accompanied by an enhancing effect on the naphthalenediimide ring toward spin inversion (triplet formation) and consequently in different fluorescence yields 相似文献
92.
Synthesis of Modular “Inorganic–Organic–Inorganic” Polyoxometalates and Their Assembly into Vesicles
93.
Mauricio Arias Javier Concepción Irma Crivelli Alvaro Delgadillo Ramiro Díaz Angélica Francois Francisco Gajardo Rosa López Ana María Leiva Bárbara Loeb 《Chemical physics》2006
Different strategies to improve the excited state properties of polypyridinic complexes by varying ligand structure and molecular geometry are described. Bidentate and tetradentate ligands based on fragments as dipyrido[3,2-a:2′,3′-c]phenazine, dppz, and pyrazino[2,3-f][1,10]-phenanthroline, ppl, have been used. Quinonic residues were fused to these basic units to improve acceptor properties. Photophysical studies were performed in order to test theoretical predictions. 相似文献
94.
Mauricio Gomes Constantino Valdemar Lacerda Júnior Gil Valdo Jos Da Silva 《Journal of heterocyclic chemistry》2003,40(2):369-371
A new and efficient 2‐step synthesis of 3‐hydroxychromone is described. Commercially available chromone is converted to the corresponding epoxide which is rearranged with niobium pentachloride to 3‐hydroxychromone in 61% overall yield. 相似文献
95.
Gil V. J. da Silva Mauricio G. Constantino Cláudio F. Tormena R. Thomas Williamson Brian L. Marquez 《Magnetic resonance in chemistry : MRC》2007,45(3):282-282
The original article to which this Erratum refers was published in Magnetic Resonance in volume 45 issue 1. 相似文献
96.
Targeting the Two Oncogenic Functional Sites of the HPV E6 Oncoprotein with a High‐Affinity Bivalent Ligand
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97.
98.
Jarod Alper Tristram Bogart Mauricio Velasco 《Foundations of Computational Mathematics》2017,17(3):829-836
We prove that the determinantal complexity of a hypersurface of degree \(d > 2\) is bounded below by one more than the codimension of the singular locus, provided that this codimension is at least 5. As a result, we obtain that the determinantal complexity of the \(3 \times 3\) permanent is 7. We also prove that for \(n> 3\), there is no nonsingular hypersurface in \({\mathbb {P}}^n\) of degree d that has an expression as a determinant of a \(d \times d\) matrix of linear forms, while on the other hand for \(n \le 3\), a general determinantal expression is nonsingular. Finally, we answer a question of Ressayre by showing that the determinantal complexity of the unique (singular) cubic surface containing a single line is 5. 相似文献
99.
Mauricio ROMO 《数学年刊B辑(英文版)》2017,38(4):937-962
The author reviews some recent developments in Chern-Simons theory on a hyperbolic 3-manifold M with complex gauge group G.The author focuses on the case of G =SL(N,C) and M being a knot complement:M =S3 \ k.The main result presented in this note is the cluster partition function,a computational tool that uses cluster algebra techniques to evaluate the Chern-Simons path integral for G =SL(N,C).He also reviews various applications and open questions regarding the cluster partition function and some of its relation with string theory. 相似文献
100.
The authors describe the relationships between categories of B-branes in different phases of the non-Abelian gauged linear sigma model.The relationship is described explicitly for the model proposed by Hori and Tong with non-Abelian gauge group that connects two non-birational Calabi-Yau varieties studied by Rφdland.A grade restriction rule for this model is derived using the hemisphere partition function and it is used to map B-type D-branes between the two Calabi-Yau varieties. 相似文献