A trajectória do auto-retrato pintado na história da arte em Portugal : da emergência à afirmação do género, na contemporaneidade, 1470-1975

Tese de doutoramento, História (História da Arte), Universidade de Lisboa, Faculdade de Letras, 2015

Joaquim Rodrigo:a contínua reinvenção da pintura

Tese de doutoramento, História (História da Arte), Universidade de Lisboa, Faculdade de Letras, 2014

Solvation and axial ligation properties of (2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrinato)zinc(II)

he solvation of (2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrinato)zinc(II)[Zn(obtpp)], in twelve different solvents results in large red shifts of the B and Q bands of the porphyrin accompanied by enhanced absorbance ratios of the Q bands. These observations are ascribed to the destabilisation of the highest occupied molecular orbital a2u of the porphyrin arising from a flow of charge from the axial ligand to the porphyrin ring through the zinc(II) ion. The binding constants of adducts of [Zn(obtpp)] with neutral bases have been found to be an order of magnitude greater than those observed for the corresponding adducts of (5,10,15,20-tetraphenylporphyrinato)-zinc and vary in the order piperidine > imidazole > pyridine > 3-methylpyridine > pyridine-3-carbaldehyde. The enhanced binding constants and large spectral shifts are interpreted in terms of the electrophilicity of [Zn(obtpp)] induced by the electron-withdrawing bromine substituents in the porphyrin core. The structure of [Zn(obtpp)(PrCN)2] has been determined; it reveals six-co-ordinated zinc(II) with two long Zn–N distance [2.51(4), 2.59(3)Å]. The porphyrin is non-planar and displays a saddle-shaped conformation.

3,12-dinitro-5,10,15,20-tetraphenylporphyrin- an example of a twisted intramolecular charge-transfer system

he porphyrin ring in the title compound, 10,19-dinitro-2,7,12,17-tetraphenyl-21,22,23,24-tetraazapenta-cyclo[16.2.1.1(3,6).1(8,11).1(13,16)]tetracosa-1,3,5,7,9,11(23),-12,14,16,18(21),19-undecaene 0.5-dichloromethane solvate, C44H28N6O4.0.5CH2Cl2, adopts a saddle conformation with neighbouring pyrrole rings tilted with respect to each other. The two nitro groups are situated on alternate pyrrole rings and have their planes angled away from those of the pyrrole rings, thereby indicating that interaction between the porphyrin and nitro groups is slight.

Ligand 5,10,15,20-Tetra(N-methyl-4-pyridyl)porphine (TMPyP4) Prefers the Parallel Propeller-Type Human Telomeric G-Quadruplex DNA over Its Other Polymorphs

The binding of ligand 5,10,15,20-tetra(N-methyl-4-pyridyl)porphine (TMPyP4) with telomeric and genomic G-quadruplex DNA has been extensively studied. However, a comparative study of interactions of TMPyP4 with different conformations of human telomeric G-quadruplex DNA, namely, parallel propeller-type (PP), antiparallel basket-type (AB), and mixed hybrid-type (MH) G-quadruplex DNA, has not been done. We considered all the possible binding sites in each of the G-quadruplex DNA structures and docked TMPyP4 to each one of them. The resultant most potent sites for binding were analyzed from the mean binding free energy of the complexes. Molecular dynamics simulations were then carried out, and analysis of the binding free energy of the TMPyP4-G-quadruplex complex showed that the binding of TMPyP4 with parallel propeller-type G-quadruplex DNA is preferred over the other two G-quadruplex DNA conformations. The results obtained from the change in solvent excluded surface area (SESA) and solvent accessible surface area (SASA) also support the more pronounced binding of the ligand with the parallel propeller-type G-quadruplex DNA.

Synthesis and electrochemical characteristics of lanthanide complexes with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate

Four lanthanide complexes with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate were prepared and characterized by elemental analyses, LR, UV-Visible,H-1 NMR, XPS and molar conductance. The redox properties of the lutetium complex with 2-nitro-5,10,15,20-tetraphenylporphyrin and acetylacetonate in dichloromethane were studied by cyclic voltammetry.

5，10，15，20－四（对－山嵛酸乙酯－α－氧代苯基）卟啉LB膜结构研究

５，１０，１５，２０－四（对－山嵛酸乙酯－α－氧代苯基）卟啉ＬＢ膜结构研究王海水，曾广赋，谷淑珍，席时权（中国科学院长春应用化学研究所长春１３００２２）利用ＬＢ膜技术将分子组装成有序的分子单层或多层体系，研究膜内分子间相互作用和分子的结构，对了解结构...

5,10,15,20-四(对-乙酯苯基)卟啉LB膜的结构

对卟啉类化合物LB膜的结构、电性质和气敏性的研究已见报道。本文利用膜天平和UV-Vis分光光度计研究了标题化合物在气-液界面上的成膜特性、分子间相互作用和LB膜的结构。5,10,15,20-四(对-乙酯苯基)卟啉(TPEPP)由5,10,15,20-四(对-氰苯基)卟啉和乙醇酯化得到。元素分析测定值与计算值相符。λ(CHCl_3,nm):421,515,550,590,645;ν(KBr压

(5,10,15,20-Tetra(4-pyridil)porphinato)manganes(III) acetate modified by four mu(3)-oxo-triruthenium acetate clusters: synthesis, characterization, electrochemical behavior and catalytic activity

A novel supermolecule constituted by four mu(3)-oxo-triruthenium acetate clusters coordinated to manganese(III)-meso -tetra(4-pyridil)porphyrin acetate ([MnTPyP]CH3COO) has been synthesized. Characterization has been performed by UV-Vis and H-1 NMR spectroscopy. The electrochemical behavior (cyclic voltammetry and spectroelectrochemistry) in N,N'-dimethylformamide has been analyzed in terms of five redox processes: three related to peripheral clusters (Ru-IV,Ru-III,Ru-III/Ru-III,Ru-III,Ru-III/Ru-III,Ru-II,Ru-II) and two centered on the Mn-porphyrin core ((MnP)-P-III/(MnP)-P-II/(MnP2-)-P-II). A direct comparison has been performed between MnTCP and MnTPyP as catalysts for the cyclooctene and cyclohexane oxidation reactions. The improved selectivity exhibited by the supramolecular catalyst for cyclohexane oxidation has been ascribed to electronic effects on the oxomanganese(V) porphyrin species induced by the four peripheral clusters, in the formal (RuRuRuIII)-Ru-IV-Ru-III oxidation state. (C) 2000 Elsevier B.V. S.A. All rights reserved.

Biomimetic sensor based on 5,10,15,20-tetrakis(pentafluorophenyl)-21H,23H- porphyrin iron (III) chloride and MWCNT for selective detection of 2,4-D

Exploitation of the electronic properties of carbon nanotubes for the development of voltammetric and amperometric sensors to monitor analytes of environmental relevance has increased in recent years. This work reports the development of a biomimetic sensor based on a carbon paste modified with 5,10,15,20-tetrakis(pentafluorophenyl)-21H,23H-porphyrin iron (III) chloride (a biomimetic catalyst of the P450 enzyme) and multi-wall carbon nanotubes (MWCNT), for the sensitive and selective detection of the herbicide 2,4- dichlorophenoxyacetic acid (2,4-D). The sensor was evaluated using cyclic voltammetry and amperometry, for electrochemical characterization and quantification purposes, respectively. Amperometric analyses were carried out at -100 mV vs. Ag/AgCl(KClsat), using a 0.1 mol L-1 phosphate buffer solution at pH 6.0 as the support electrolyte. Under these optimized analytical conditions, the sensor showed a linear response between 9.9 × 10-6 and 1.4 × 10-4 mol L-1, a sensitivity of 1.8 × 104 (±429) μA L mol -1, and limits of detection and quantification of 2.1 × 10 -6 and 6.8 × 10-6 mol L-1, respectively. The incorporation of functionalized MWCNT in the carbon paste resulted in a 10-fold increase in the response, compared to that of the biomimetic sensor without MWCNT. In addition, the low applied potential (-100 mV) used to obtain high sensitivity also contributed to the excellent selectivity of the proposed sensor. The viability of the application of this sensor for analysis of soil samples was confirmed by satisfactory recovery values, with a mean of 96% and RSD of 2.1% (n = 3). © 2013 Elsevier B.V.