 ABSTRACT: Recently we have discovered and optimized the first practical synthesis of non-fused pyrrole[3,2-b]pyrroles via domino reaction of aldehydes, primary amines, and butane-2,3-dione.1 Six bonds are formed in heretofore unknown tandem process, which gives rise to substituted pyrrole[3,2-b]pyrroles – the ‘missing link’ on the map of aromatic heterocycles. The parent 1,4-dihydro-pyrrolo[3,2-b]pyrroles served as building block to construct various π-expanded analogs including nitrogen-embedded buckybowl with inverse Stone–Thrower–Wales topology2 and diindolo[2,3-b:2',3'-f]pyrrolo[3,2-b]pyrroles. These compounds constitute the most electron-rich ladder-type heteroacenes known to date - EHOMO was  . . . Ler mais . . .

 ABSTRACT: There has been much interest recently in electrocatalytic water splitting for storing intermit-tent renewably-generated power (e.g. solar) as chemical fuels such as hydrogen.1 Conventional electrolysers usually require stable power inputs in order to operate effectively and safely and so may be unsuited to harnessing renewable power, which is often intermittent and diffuse. Decoupled electrolysis using suitable redox mediators2 allows oxygen and hydrogen production to be separated in both space and time. The advantages of this approach for harnessing intermittent power sources will be explained, such as the production of ultra-pure product gases3,4 and the potential benefits of using such a . . . Ler mais . . .

 ABSTRACT: In the 1970s the major global concern was the catastrophic predictions of the end of oil reserves. Today, these concerns have shifted to global warming, whose existence has become almost consensual. In this presentation we will recapitulate some important episodes of the tragic history that represents the struggle of man for energy, and raise some important questions that more than allow to predict the outcome of this story, will try to describe the different possible scenarios in which the next chapters will take place.

 ABSTRACT: Semiconductor electrodes have been investigated to convert solar energy for use in different applications of technological interest, such as water remediation[1]and solar fuels production.[2]Films of TiO2and WO3/TiO2deposited on stainless steel (SS) or glass covered with F-doped SnO2(FTO),irradiated by a solar simulator, were used foroxidation of ciprofloxacin (CIP) and amoxicillin(AMX) antibioticsin aqueous solutions by heterogeneous photocatalysis (HP). After inclusion of a Pt counter-electrode, application of an external bias or connection of the electrodes with a solar cell, whichresulted in an electrochemically assisted HP (EHP)configuration, enhanced in 30 % the efficiency for  . . Ler mais . . .

 ABSTRACT: Efficient solar-energy conversion relies on molecular-level control of charge transfer for organic electronics. Electromagnetic interactions, originating from the second strongest fundamental force in the universe, occur between charged particles. As electrostatic analogues of magnets, molecular electrets are dielectrics that contain ordered electric dipoles. Much like protein helices, anthranilamides, composed of non-native beta amino acids, possess intrinsic dipole moments originating from ordered amide and hydrogen bonds. Unlike the protein helices, however, anthranilamides have a backbone of directly linked aromatic moieties comprising pathways for highly efficient  . . . Ler mais . . .

 ABSTRACT: Metal-halide perovskites, with composition A+B2+X–3, have exerted one of the biggest impacts in the development of photovoltaics (PVs). The unique electronic structure of the [BX6]4– octahedrons ensures not only long exciton lifetimes, but also separate transport pathways for electrons and holes. The latter feature, along with the small exciton binding energy has made these perovskites practically the “perfect” materials for photovoltaics. The ionic bonding in the A+B2+X–3 crystalline structures is relatively weak, allowing for a certain level of plasticity of the metal-perovskite lattices. This softness of the ionic structure, along with the “looseness” of the large counterion, A+, is key for the benef. . . Ler mais . . .

 ABSTRACT: Currently,  there  has  been  a  lot  of  effort  in  developing  low-cost  solar  cells  using semiconductors  made  with  simple  processes,  in  contrast  to  silicon,  an  expensive semiconductor,  but  used  largely  today  in  solar  panels.  Methylammonium  lead  halide perovskite,mainly the CH3NH3PbI3structure demonstrateincredible performance with efficiency exceeding 23%.The deposition of the perovskite films is usually carried out by   solution-based   processes   using   spincoating   techniquesor   through   thermal evaporation. In  this  work new  methods  are  proposed using  alternatives  routes:  1)  from sputtered lead sulphidethin film, 2) lead sulphide(PbS) quantum dotsand 3)   . . . Ler mais . . .

 ABSTRACT: The quest for new technologies in the last decades has targets in all fields of knowledge. Progressively, the mankind has paid attention to the nanotechnology and its particularities. Build nanodevices is a key to obtain more efficient and versatile computers, and reduce the energy cost to do trivial activities, as send messages, compute solutions to problems, and store information. There exist a great number of ways to study and develop nanodevices or maybe idealize nanodevices through simulations. All these approaches ask for schemes that reduce the energy lost and provide better efficiency. In this presentation of 45 minutes, the nanotech . . . Ler mais . . .

 ABSTRACT: Anew  strategy  to  insert  small  amounts  of  active  Pt  atoms  in  an  inactive  Rh  matrix, forming nanoalloys dispersed in high surface area carbon (Black Pearls® -BP) results in  synergistic  materials  dotted  with  better  activity  to  CO2selective  formation  and robustness   toward   the   ethanol   oxidation   reaction   (EOR)   in   acid   media   when compared to the pure Pt materials. The results are discussed based on crystal lattice parameter   modifications   in   a   way   that   points   out   the   lattice   strain   and, consequently,  the  electronic  modification  into  Pt  sites  resulted  in  differences  such ethanol  adsorption  as ethoxide  molecules  andacetaldehyde  as  the  most  active reaction  intermediate . . Ler mais . . .

 ABSTRACT: The optical properties of amyloid staining dyes, such as ThioflavinT (ThT) and 3,3’-diethylthiacyanine iodide (THIA), make them immensely attractive for fluorescence-based applications. THIA and ThT are rotamer dyes,dissipatingenergy via multiple non-radiative pathways. It results in parallel excited-state transient conformational changes, most of which do not undergo radiative deactivation, i.e. they do not fluoresce.1These dyes have a strongaffinity for β-sheet proteins, such as amyloids and bacterial surface proteins.3Binding to proteins suppresses the degrees of torsional freedom of such rotameric dyes and prevents their non-radiative deactivation, increasing their fluorescence quantum  . . Ler mais . . .