Tiago A. Fernandes

Copper(II) Coordination Polymers Self-Assembled from Aminoalcohols and Pyromellitic Acid: Highly Active Precatalysts for the Mild Water-Promoted Oxidation of Alkanes

Three novel water-soluble 2D copper(II) coordination polymers-[{Cu2(μ2-dmea)2(H2O)}2(μ4-pma)]n·4nH2O (1), [{Cu2(μ2-Hedea)2}2(μ4-pma)]n·4nH2O (2), and [{Cu(bea)(Hbea)}4(μ4-pma)]n·2nH2O (3)-were generated by an aqueous medium self-assembly method from copper(II) nitrate, pyromellitic acid (H4pma), and different aminoalcohols [N,N-dimethylethanolamine (Hdmea), N-ethyldiethanolamine (H2edea), and N-benzylethanolamine (Hbea)]. Compounds 2 and 3 represent the first coordination polymers derived from H2edea and Hbea. All the products were characterized by infrared (IR), electron paramagnetic resonance (EPR), and ultraviolet-visible light (UV-vis) spectroscopy, electrospray ionization-mass spectroscopy (ESI-MS(±)), thermogravimetric and elemental analysis, and single-crystal X-ray diffraction (XRD), which revealed that their two-dimensional (2D) metal-organic networks are composed of distinct dicopper(II) or monocopper(II) aminoalcoholate units and μ4-pyromellitate spacers. From the topological viewpoint, the underlying 2D nets of 1-3 can be classified as uninodal 4-connected layers with the sql topology. The structures of 1 and 2 are further extended by multiple intermolecular hydrogen bonds, resulting in three-dimensional (3D) hydrogen-bonded networks with rare or unique topologies. The obtained compounds also act as highly efficient precatalysts for the mild homogeneous oxidation, by aqueous H2O2 in acidic MeCN/H2O medium, of various cycloalkanes to the corresponding alcohols and ketones. Overall product yields up to 45% (based on cycloalkane) were attained and the effects of various reaction parameters were investigated, including the type of precatalyst and acid promoter, influence of water, and substrate scope. Although water usually strongly inhibits the alkane oxidations, a very pronounced promoting behavior of H2O was detected when using the precatalyst 1, resulting in a 15-fold growth of an initial reaction rate in the cyclohexane oxidation on increasing the amount of H2O from ∼4 M to 17 M in the reaction mixture, followed by a 2-fold product yield growth.

Rethinking pathways to democracy: civil society in Portugal and Spain, 1960s–2000s

This article argues that patterns of civil society in post-authoritarian democracies are the result of divergent pathways to democracy. Through a comparison between contemporary Portugal and Spain, it is shown that revolutionary pathways to democracy have a positive impact on the self-organizing capabilities of popular groups. Two mechanisms contribute to this. First, the fact that the masses are the key actor in the revolutionary process results in greater legal recognition and institutional embeddedness between civil society organizations and the state. Second, as a consequence of changes in the social and economic structure, revolutions engender more inclusive democracies. This all leads to greater opportunities and resources for the civic action of the common people during the subsequent democratic regime.

Direct Reductive Deoxygenation of Aryl Ketones Catalyzed by Oxo‐Rhenium Complexes

The first methodology for the direct reductive deoxygenation of ketones catalyzed by high‐valent oxo‐rhenium complexes by using a silane as reducing agent is described. The systems PhSiH3/[ReOCl3(SMe2)(OPPh3)] (2 mmol/5 mol %) and PhSiH3/[ReOCl3(PPh3)2] (2 mmol/5 mol %) proved to be efficient for the deoxygenation of aryl ketones, producing selectively the corresponding alkane, or a mixture of alkane and alkene derivatives with the alkane as the major product.

New aqua-soluble dicopper(II) aminoalcoholate cores for mild and water-assisted catalytic oxidation of alkanes

Two new dicopper(II) aminoalcoholate compounds, namely a discrete 0D complex [{Cu(Hdea)(H2dea)}2(μ2-H2pma)]·3H2O (1) and a 1D coordination polymer [Cu2(μ2-H2tea)2(μ2-nda)]n·2nH2O (2), were self-assembled from copper(II) nitrate, an aminoalcohol {diethanolamine (H2dea) or triethanolamine (H3tea)} and carboxylic acid {pyromellitic (H4pma) or 2,6-naphthalenedicarboxylic (H2nda)} building blocks. Both products were isolated as stable and water-soluble microcrystalline solids and fully characterized by IR spectroscopy, ESI-MS(±), elemental analysis and single-crystal X-ray diffraction, revealing distinct types of dicopper(II) units. The structures of 1 and 2 are further extended by intermolecular hydrogen bonds giving rise to 3D or 2D H-bonded nets with a pcu and sql topology, respectively. Both compounds act as efficient pre-catalysts for the mild homogeneous oxidation, by aqueous H2O2 in MeCN/H2O medium, of different cycloalkanes to the corresponding cyclic alcohols and ketones, which are obtained in up to 34% total yields (based on alkanes). The influence of various reaction parameters such as the amount and type of pre-catalyst and acid promoter, solvent composition and substrate scope were investigated, which also show that the oxidation of cycloalkanes and the activity of a catalytic system can be restarted upon addition of new portions of oxidant and substrate. Besides, an unusual promoting role of water was found when using both pre-catalysts 1 and 2. The bond-, regio- and stereoselectivity parameters were established using different alkane substrates, supporting a free radical oxidation mechanism. The model 1/H+/H2O2 and 2/H+/H2O2 solutions were investigated by ESI-MS(±), allowing us to propose some possible catalytically active species.

Authoritarian Regimes and Pro-Democracy Semi-Oppositions: The End of the Portuguese Dictatorship (1968-1974) in Comparative Perspective

This article discusses the conditions of failure and success of pro-democracy semi-oppositions to authoritarian regimes through a comparative study of the last phase of the Portuguese authoritarian regime (1968–1974). It specifies and reformulates Juan Linzs concept of semi-opposition. In Portugal, contrary to Linzs argument, the moderate pro-democracy semi-oppositions participated in the regimes electoral moments and tended to take the greatest possible advantage of these periods so as to discredit the regime and to demonstrate that it could not be transformed from within. In order to make sense of this paradox, scholars should look at the institutional legacies and frameworks of authoritarian regimes. Specifically, we argue that the Portuguese semi-opposition failed because the institutional heritage of the Estado Novo, at the moment of the leadership succession, provided no opportunities for a reformist democratizing coalition to assert itself and promoted instead the radicalization of the semi-opposition. Paradoxically, it was the more liberal institutional framework of the regime that made a political change guided by the democratic semi-opposition impracticable.

Dioxomolybdenum Complexes as Excellent Catalysts for the Deoxygenation of Aryl Ketones to Aryl Alkenes

This work describes a new methodology for the selective deoxygenation of aryl ketones to the corresponding aryl alkenes catalyzed by dioxomolybdenum complexes using silanes as reducing agents. The best results were obtained with the system PhSiH3/MoO2Cl2(H2O)2 (5–10 mol %), which was very efficient for the deoxygenation of a large variety of aryl ketones to alkenes in excellent yields. This new methodology has the advantages of using an inexpensive, environmentally friendly, easily prepared, and air‐stable catalyst in ether solution.

Self-assembly generation, structural features, and oxidation catalytic properties of new aqua-soluble copper(II)-aminoalcohol derivatives

Self-assembly reactions of copper(II) nitrate with aminoalcohols {bis(2-hydroxyethyl)amino-tris(hydroxymethyl)methane (H5bis-tris) or 1,3-bis(tris(hydroxymethyl)methylamino)propane (H6bis-tris-propane)} as main N,O-building blocks, and isonicotinic acid (Hinic) or sodium azide (NaN3) as ancillary ligand sources resulted in two new copper(II) compounds [{Cu(H4.5bis-tris)(inic)}2](NO3)·2H2O (1) and [Cu(H5bis-tris-propane)(N3)]·2H2O (2). The obtained products were isolated as stable microcrystalline solids and fully characterized including by single-crystal X-ray diffraction, which disclosed the six-coordinate copper(II) centers with distorted octahedral {CuN2O4} or {CuN3O3} environments. The structures of 1 and 2 feature the formation of complex 3D H-bonded networks that were topologically classified as cbs-3,4-Cmmm-2 and sxd underlying nets, respectively. Both compounds 1 and 2 are soluble in water (S25 °C ≈ 6–12 mg mL−1) and act as efficient homogeneous catalysts for the mild and acid-promoter-free oxidation, by aqueous hydrogen peroxide, of C5–C8 cycloalkanes (cyclopentane, cyclohexane, cycloheptane, and cyclooctane) to give the corresponding cyclic alcohols and ketones. The influence of various reaction parameters (time, solvent composition, loading of substrate, oxidant, and catalyst, presence of a radical trap), bond- and regioselectivity features, and substrate scope were investigated and discussed in detail. A notable feature of the present catalysts concerns their high activity without the requirement for any promoter or co-catalyst, resulting in up to 46% total product yields based on cycloalkane.

Measuring Political Participation in Southern Europe: The Varieties of Democracy Approach

Most schools of democratic theory consider political participation to have a positive impact in deepening democracy. Political participation makes democracies more accountable and freer, as well as creating more engaged, civic minded and public spirited citizens. It has been observed that in regimes where citizens lack capacity for self-organization and political engagement this contributes to a lower quality of their democratic regimes and institutions.Moreover, this connection is even more vital in democratizing settings and new democracies, like the Southern European countries of Portugal, Spain, and Greece. Research has shown that in democracies that emerged after a long experience of authoritarianism there will be a lower capacity for mobilization of citizens. Democratic regimes may became established, with the minimal requirements (freedom of the press, civil and political liberties, a functioning party system, free and fair elections), but they will have a lower quality because there will be very weak attachments of citizens to its institutions. After the euphoria of participation during the transition, desencanto (disenchantment, disappointment) settles in, estranging citizen’s from the democratic process. Contrary to older democracies, where political participation tended to grow steadily after the transition and for decades, in new democracies the high levels of participation of the transition give place to very weak levels of participation. Even more troubling, new democracies are also characterized by strong inequalities in participation, which affect especially popular groups and the poor, but also the middle classes.