We present a new concept for the design of a polymeric conducting material that combines the chemical versatility of an organic salt ( ionic liquid) with the morphological versatility of a biopolymer ( gelatin); the resulting 'ion jelly' can be applied in electrochemical devices, such as batteries, fuel cells, electrochromic windows or photovoltaic cells.

The synthesis of a new oxaaza macrocyclic ligand, L, derived from O-1,O-7-bis(2-formylphenyl)-1,4,7-trioxaheptane and tren containing an amine terminal pendant arm, and its metal complexation with alkaline earth (M = Ca2+, Sr2+, Ba2+), transition (M = Co2+, Ni2+, Cu2+, Zn2+, Cd2+), post-transition (M = Pb2+), and Y3+ and lanthanide (M = La3+, Er3+) metal ions are reported. Crystal structures of [H2L](ClO4)(2).3H(2)O, [PbL](ClO4)(2), and [ZnLCl](ClO4).H2O are also reported. In the [PbL] complex, the metal ion is located inside the macrocyclic cavity coordinated by all N4O3 donor atoms while, in the [ZnLCI] complex, the metal ion is encapsulated only by the nitrogen atoms present in the ligand. pi-pi interactions in the [H2L](ClO4)(2).3H(2)O and [PbL](ClO4)(2) structures are observed. Protonation and Zn2+, Cd2+, and Cu2+ complexation were studied by means of potentiometric, UV-vis, and fluorescent emission measurements. The 10-fold fluorescence emission increase observed in the pH range 7-9 in the presence of Zn2+ leads to L as a good sensor for this biological metal in water solution.

The formation of Eu(III) nanoparticles in borosilicate sol-gels and the glass formation heat treatment effect on those particles were studied using luminescence techniques. The presence of the particles was observed using transmission electron microscopy (TEM) images followed by analysis with energy dispersive X-ray spectroscopy (EDS). These experiments showed the presence of particles with a large quantity of europium and chlorine and only small amounts of oxygen with sizes ranging from 30 to 100 nm. Heat treatment at 400, 600, and 800 degrees C lead to glass samples in which those particles were no longer observed. Steady-state and time-resolved luminescence techniques allowed a detailed study of Eu(III) photophysics in sot-gel and glass samples. In sol-gel matrices, the (5)D(0) -> (7)F(0) transition is very weak, hinting at Eu(III) species experiencing a rather symmetric crystal field. The (5)D(0) -> (7)F(2) transition intensity is not very strong, which according to a Judd-Ofelt analysis indicates low interaction with the anions present in the sol-gel matrices. This picture reverses after heat treatment, indicating a replacement of chloride anions with oxygen as preferential ligands of Eu(III). Time-resolved luminescence shows in a more detailed way these aspects. Sol-gel samples display nonexponential kinetics, which are attributed to Eu(III) species present in the nanoparticles surface (bound to oxygen) and Eu(III) in the core of the nanoparticles (bound to chloride). Glass samples display single-exponential luminescence decays, in which the decay constant approaches the values calculated for the radiative rate constant with Judd-Ofelt analysis. It is concluded that, in sol-gel, mechanisms like electron-phonon coupling suppress the Eu(III) luminescence, which disappear as soon as the nanoparticles are disrupted after heat treatment.

In this work, coloured glasses were produced based on the synthesis of gold and silver nanoparticles by the sol-gel process having in mind their application in art works. Gold and silver were used separately or as a mixture by varying the mole fractions in order to get a range of colours from yellow to red. The gold and silver nanoparticles were prepared by the reduction of tetrachloroauric acid and silver nitrate with sodium citrate in aqueous solutions which were further introduced in the sol-gel system. Attention was focused on the thermal treatment of the sol-gel samples. Different temperatures were used in order to determine their influence on the obtained colour. The glasses were characterized by UV-Vis absorption spectroscopy and the size of the nanoparticles was examined by transmission electron microscopy (TEM). The range of colours mentioned above is obtained either by preparing nanoparticles of each metal and mixing them or by preparing nanoparticles from solutions containing initially ions of both metals. In the former case, two surface plasmon resonance (SPR) bands were observed for temperatures below 200 degrees C while higher temperatures promote the formation of alloys between the Ag and Au nanoparticles. In the latter case, only one SPR band is observed and the nanoparticle size distribution is narrower. The results were explained by nanoparticle aggregation promoted by temperature. Glasses containing only Ag did not present the typical yellow colour above 300 degrees C but it was shown that the colour could be stabilized if Au was added in small amounts (Au/Ag molar ratio 0.1). (C) 2010 Elsevier B.V. All rights reserved.

By using monochromatic light the ability of semiconductor-free nanoporous carbons to convert the low-energy photons from the visible spectrum into chemical reactions (i.e. phenol photooxidation) is demonstrated. Data shows that the onset wavelength of the photochemical activity can be tuned by surface functionalization, with enhanced visible-light conversion upon introducing N-containing groups.