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This work reports on the development of bending actuators based on poly(l-lactic acid) (PLLA)/ionic liquid (IL) blends, through the incorporation of 40% wt. of the 1-ethyl-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim][TFSI]) IL. The films, obtained by solvent casting at room temperature and 50 &deg, C, were subjected to several post-thermal treatments at 70, 90, 120 and 140 &deg, C, in order to modify the crystallinity of the films. The influence of the drying temperature and of [Emim][TFSI] blending on the morphological, structural, mechanical and electrical properties of the composite materials were studied. The IL induced the formation of a porous surface independently of the processing conditions. Moreover, the [Emim][TFSI] dopant and the post-thermal treatments at 70 &deg, C promoted an increase of the degree of crystallinity of the samples. No significant changes were observed in the degree of crystallinity and Young Modulus for samples with thermal treatment between 70 and 140 &deg, C. The viability of the developed high ionic conductive blends for applications as soft actuators was evaluated. A maximum displacement of 1.7 mm was achieved with the PLLA/[Emim][TFSI] composite prepared at 50 &deg, C and thermally treated at 140 &deg, C, for an applied voltage of 10 Vpp, at a frequency of 100 mHz. This work highlights interesting avenues for the use of PLLA in the field of actuators.

The development of materials that can help overcome the current limitations in energy storage and consumption is a pressing need. Recently, we developed non-Newtonian nanofluids based on non-toxic, carbon nanoparticles (NPs), carbon dots (Cdots) functionalized with ionic liquids. Here, we wanted to prove that these new nanofluids are, not only interesting as possible electrolytes, but also as new organic/inorganic hybrid separators. As such, we developed an entrapment method using poly(vinyl alcohol) (PVA). Indeed, the highly conductive Cdots were successfully retained inside the membrane even upon the application of several wetting/drying cycles. Moreover, the morphological characteristics did not change upon wetting/drying cycles and remained constant for more than four months. These nanofluids could be an interesting approach to tackle some of the current problems in the fields of solid-state batteries, and energy storage, among others.

Battery separators based on silk fibroin (SF) have been prepared aiming at improving the environmental issues of lithium-ioh, batteries. SF materials with three different morphologies were produced: membrane films (SF-F), sponges prepared by lyophilization (SF-L) and: electrospuri membranes (SF-E). The latter Materials presented a suitable porons,three-dimensional microstructure and were soaked with a I M LiPF6 electrolyte: The ionic conductivities for SF-L and SF-E were 1.00 and 0.32 mS cm(-1) at 20 degrees C, respectively. A correlation between the fraction "of beta-sheet conformations and the ionic conductivity was observed. The electrochemical performance of the SF-based materials was evaluated by incorporating them in cathodic half-cells with C-LiFePO4. The discharge capacities of SF-L and SF-E were 126 and 108 mA h g(-1), respectively, at the C/Iirate and 99 and 54 mA h g(-1), respectively, at the 2C-rate. Furthermore, the capacity retention and capacity fade of the SF-L membrane after 50 cycles at the 2C-rate were 72 and 5%, respectively. These electrochemical results show that a high percentage of beta-sheet conformations, were of prime importance to guarantee excellent cycling performance. This work demonstrates that SP-based membranes are appropriate separators for the production of environmentally friendlier lithium-ion batteries., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, ULD/QUI/00686/2013 and ULD/QUI/00686/2016. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013, PEst-OE/QUI/UI0616/2014, and LUMECD (POCI-01-0145-FEDER-016884 and PTDC/CTM-NAN/0956/2014), grants SFRH/BPD/87759/2012 (R.F.P.P.), and SFRH/BPD/112547/2015 (C.M.C.). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK program., info:eu-repo/semantics/publishedVersion

Amine-functionalized bridged silsesquioxanes (BSs) were synthesized from bis[(3-trimethoxysilyl)propyl] amine via a solvent-mediated route. BS-1 and BS-2 were obtained at neutral pH with sub- and stoichiometric amounts of water, respectively, and high tetrahydrofuran content. BS-3 was prepared with hyperstoichiometric water concentration, high tetrahydrofuran content, and hydrochloric acid. BS-4 was synthesized with hyperstoichiometric water concentration, high ethanol content, and sodium hydroxide. BS-1 and BS-2 were produced as transparent films, whereas BS-3 and BS-4 formed white powders. Face-to-face stacking of flat or folded lamellae yielded quasi-hydrophobic platelets with emission quantum yields of 0.05 ± 0.01 (BS-1 and BS-2) or superhydrophilic onion-like nanoparticles with exciting emission quantum yields of 0.38 ± 0.03 (BS-3) and 0.33 ± 0.04 (BS-4), respectively. The latter two values are the largest ever reported for amine-functionalized siloxane-based hybrids lacking aromatic groups. Fast Grotthus proton hopping between = [Formula: see text]/ = NH groups (BS-3) and = N-/ = NH groups (BS-4), promoted by H+ and OH- ions, respectively, and aided by short amine-amine contacts provided by the onion-like morphology, account for this unique optical behavior., This work was supported by Fundacao para a Ciencia e a Tecnologia (FCT)/MEC and FEDER (contracts UID/QUI/00616/2013, POCI-01-0145-FEDER-007491, and UID/Multi/00709/2013) and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement, project UniRCell (Ref. SAICTPAC/0032/2015, POCI-01-0145-FEDER-016422), and project LUMECD (Ref. PTDC/CTM/NAN/0956/20149 and POCI-01-0145-FEDER-016884). RP and MC acknowledge FCT for grants SFRH/BPD/87759/2012 and SFRH/BD/118466/2016, respectively. SN also acknowledges FCT for grants SFRH/BPD/63152/2009 and Post-PhD Fellowship of LUMECD project. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT-Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement.

In the quest for solutions to enhance the safety and sustainability of energy storage devices, Bombyx mori silkworm cocoons are proposed as separators for lithium (Li)‐ion batteries obtained literally from nature, and employed directly in a device. The suitability of the cocoons is evaluated in Li‐ion batteries using two different electrolytes: a mixture of lithium hexafluorophosphate (LiPF6), ethylene carbonate (EC), and dimethyl carbonate (DMC), and the ionic liquid (IL) 1‐ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([Emim]TFSI). Li/C–LiFePO4 half cells comprising the EC–DMC–LiPF6 electrolyte present excellent cycling performance, with a discharge capacity up to 86 mAh g−1 and a capacity retention up to 81% after 50 cycles at C rate. Values of 66 mAh g−1 at C/5 and 85% result with [Emim]TFSI, respectively. Separator/electrolyte interactions during battery cycling lead to a decrease of the degree of crystallinity of the cocoon silk fibers, and, in the presence of EC–DMC–LiPF6, to a concomitant increase of the concentration of free PF6− ions. The self‐extinguishing ability of silkworm cocoons represents an additional benefit to batteries, providing fire risk reduction or even suppression. This bio‐inspired work paves the way toward the fabrication of environmentally friendlier separators for next‐generation sustainable and safer Li‐ion batteries., R.F.P.P. and R.G. contributed equally to this work. This work was supported by National funds by Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, UID/QUI/00686/2013 and UID/QUI/00686/2016. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects POCI-01-0145-FEDER-028157 PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013, PEst-OE/QUI/UI0616/2014, and grants SFRH/BPD/87759/2012 (R.F.P.P.), SFRH/BPD/112547/2015 (C.M.C.), and UniRCell project (SAICTPAC/0032/2015 and POCI-01-0145-FEDER-016422). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) and from the Basque Government Industry Department under the ELKARTEK and HAZITEK programs. The authors thank F. A. Almeida Paz (CICECO-Instituto de Materiais de Aveiro, Aveiro, Portugal) for recording the XRD patterns., info:eu-repo/semantics/publishedVersion

Ionic liquids (ILs) have attracted tremendous interest in the last decades. This is due to their high chemical variability and their interesting and useful chemical, physical, and biological properties. The current chapter provides an overview on the use and the potential of ILs for biopolymer dissolution and processing, for chemical modification of biopolymers in ILs, and on the use of ILs for the fabrication of biocompatible materials and composites from renewable resources.

Designing novel multifunctional materials from natural resources is a challenging goal that has increasingly attracted researchers. Recently, the great potential of silk fibers has been recognized. The target readers for this review are researchers from different backgrounds (i.e., non-specialists in silk research) with special interests on the physical–chemical characterization of silk fibers, since their knowledge is crucial for the improvement of existent silk-based biomaterials and the basis for the development of new products. Examples of usual applications of Bombyx mori silk fibers are given and some of the most recent and exciting progress in new technological fields, is presented.

Luminescent solar concentrators (LSCs) appear as candidates to enhance the performance of photovoltaic (PV) cells and contribute to reduce the size of PV systems, decreasing, therefore, the amount of material needed and thus the cost associated with energy conversion. One way to maximize the device performance is to explore near-infrared (NIR)-emitting centers, resonant with the maximum optical response of the most common Si-based PV cells. Nevertheless, very few examples in the literature demonstrate the feasibility of fabricating LSCs emitting in the NIR region. In this work, NIR-emitting LSCs are reported using silicon 2,3-naphthalocyanine bis(trihexylsilyloxide) (SiNc or NIR775) immobilized in an organic-inorganic tri-ureasil matrix (t-U(5000)). The photophysical properties of the SiNc dye incorporated into the tri-ureasil host closely resembled those of SiNc in tetrahydrofuran solution (an absolute emission quantum yield of ∼0.17 and a fluorescence lifetime of ∼3.6 ns). The LSC coupled to a Si-based PV device revealed an optical conversion efficiency of ∼1.5%, which is among the largest values known in the literature for NIR-emitting LSCs. The LSCs were posteriorly coupled to a Si-based commercial PV cell, and the synergy between the t-U(5000) and SiNc molecules enabled an effective increase in the external quantum efficiency of PV cells, exceeding 20% in the SiNc absorption region.

Green electrolytes composed of kappa-carrageenan (κ-Cg), 1-butyl-3-methyl-1H-imidazolium chloride ([Bmim]Cl) ionic liquid, and glycerol (Gly) are prepared in aqueous solution using a simple, clean, fast and low-cost procedure. A flexible membrane incorporating 50% wt [Bmim]Cl and 50% wt Gly with respect to κ-Cg exhibits the highest ionic conductivity values (8.47 ×10−4/2.45 × 10−3 S cm−1 at 20/66 °C, under anhydrous conditions, and 5.49 × 10−2/0.186 S cm−1 at 30/60 °C, at a relative humidity of 98%). Tests of room temperature air/hydrogen fuel cells incorporating κ-Cg, κ-Cg/Gly, and κ-Cg/Gly/[Bmim]Cl membranes demonstrate that these predominantly protonic conductors electrolytes are particularly well suited for the design and fabrication of eco-friendly electrochemical devices whose operation does not require the flow of gases and does not lead to water formation. These new materials have excellent application prospects in high performance (flexible) energy storage devices (supercapacitors and batteries) and electrochromic devices., This work was supported by National Funds by FCT—Foundation for Science and Technology—and by FEDER funds through the POCI— COMPETE 2020—Operational Programme Competitiveness and Internationalisation in Axis I – Strengthening research, technological development and innovation (POCI-01-0145-FEDER-007491, FCOMP01-0124-FEDER-037271, Pest-OE/QUI/UI0616/2014, Pest-C/QUI/UI0686/2013, PEst-OE/SAU/UI0709/2014, UID/CTM/50011/2013,UID/ Multi/00709/2013 and LUMECD project (POCI-01-0145- FEDER-016884 and PTDC/CTM-NAN/0956/2014)), project UniRCell (Ref. SAICTPAC/0032/2015, POCI-01-0145-FEDER-016422), by COST Action MP1202880 “Rational design of hybrid organic–inorganic interfaces” and by the Portuguese National NMR Network (RNRMN). S.C.N. acknowledge FCT for grants, Post-Ph.D. Fellowship of LUMECD project and SFRH/BPD/63152/2009. R.F.P.P., N.S., and F.M.F. acknowledge FCT for grants (SFRH/BPD/87759/2012, SFRH/ BD/89670/2012, and IF/01174/2013, respectively)., info:eu-repo/semantics/publishedVersion

International audience; The copper-catalyzed alkyne azide cycloaddition (CuAAC) reaction was combined with sol-gel reactions for the production of bridged silsesquioxanes (BSs) in which hexyl and icosanyl chains are pendant and anchored on a single position to a triazole ring. The influence of the alkyl chain length on the structure of the BSs, represented by the notation Cn/ siloxane (where n = 6 and 20), was examined. The C20/siloxane hybrid is a hydrophobic material that exhibits a hierarchically structured lamellar bilayer organization, a texturecomposed of microplates of nanometer thickness, and a reversible time-independent order/disorder phase transition (onset at 60 °C). The driving forces for self-assembly are van der Waals interactions between the icosanyl chains and π-π interactions between the triazole rings. In the essentially amorphous C6/siloxane hybrid, the latter contribution promotesthe genesis of a pre-lamellar phase similar to that found in C20/siloxane.

The design of new advanced materials and technologies is essential for the development of smart windows for the next generation of energy‐efficient buildings. Here, it is demonstrated that the functionalization of glucose‐derived carbon dots with 1‐butyl‐3‐methylimidazolium chloride results in a self‐standing, water‐soluble, viscous, reusable nanofluid with self‐improving conductivity, thermotropy around 30–40 °C, and ultraviolet blocking ability. Its synthesis is straightforward, clean, fast, and cheap. At 36 °C (hot summer day), a sun‐actuated thermotropic (TT) device incorporating a 95% w/w nanofluid aqueous solution exhibits a transmittance variation (ΔT ) of 9% at 550/1000 nm, which is amplified to 47/31% via the surface plasmon resonance effect. An integrated self‐healing system enabling independent sun‐actuated TT and voltage‐actuated electrochromic (EC) operation is also produced. The low‐energy EC device offers bright hot and dark cold modes (ΔT = 68/64%), excellent cycling stability, unprecedented coloration efficiency values (−1.73 × 106/−1.67 × 106 cm2 C−1 (coloring) and +1.12 × 107/+1.08 × 107 cm2 C−1 (bleaching) at ±2.5 V), and impressive memory effect. The disruptive design and sustainable synthesis of the new nanofluid proposed here will foster the agile development of novel products with improved ecological footprint., This research was funded by the National Funds by Foundation for Science and Technology (FCT) and by the FEDER funds through POCI-COMPETE 2020-Operational Programme Competitiveness and Internationalization in Axis I: Strengthening research, technological development and innovation (UID/QUI/00616/2013, UID/QUI/50006/2019, UID/Multi/00709/2013, UID/QUI/00313/2019, UID/CTM/50025, POCI-01-0145-FEDER-007491, POCI-01-0145-FEDER-007688, UID/CTM/50025, POCI-01-0145-FEDER-016884, PTDC/CTM-NAN/0956/2014, SAICT/PAC/0032/2015, POCI-01-0145-FEDER-016422, and NORTE-01-0145-FEDER-030858). R.F.P.P. acknowledges FCT-MCTES for SFRH/BPD/87759/2012 grant. R. Rego and M. Fernandes (UTAD, Vila Real) and E. Pereira (FCUP, Porto) are acknowledged for their assistance.

The protic ionic liquid (PIL) N-butylimidazolium trifluoromethanesulfonate ([BIm][TfO]) was obtained for the first time and incorporated into a sol-gel derived di-ureasil matrix with a concentration of X = 5, 10 and 30 %, where X is the ratio of the mass of PIL per mass of poly(oxyethylene) (POE). Four years after their synthesis, the resulting quasi-anhydrous electrolytes remained amorphous, homogeneous, flexible and thermally stable below 200 ºC. SEM/EDS data revealed the presence of the PIL at the surface of the xerogels with X > 5 %, demonstrating that this type of morphological characterization is mandatory to avoid misleading ionic conductivity values. The highest ionic conductivity was produced in the washed sample with X = 30 % (3.5 x10-5 and 2.1x10-3 S cm-1 at 25 and 170 ºC, respectively). The present family of electrolytes yielded higher conductivities than the N-ethylimidazolium trifluoromethanesulfonate-based analogues introduced earlier by our group and may be thus considered as promising candidates for applications in fuel cells., Fundação para a Ciência e a Tecnologia (FCT) and when applicable by FEDER under the PT2020 Partnership Agreement for financial support (contracts PTDC/CTM - BPC/112774/2009, UID/Multi/00709/2013, PEst - C/QUI/ UI0686/2013, PEst - OE/QUI/UI0616/2014 and FCT UID/CTM/50011/2013 ) and COST Action MP1202

Transparent monoliths of urea cross-linked tripodal siloxane-based hybrids, named tri-ureasils, were prepared by the sol–gel process, using a wide concentration range of hydrochloric acid catalyst (1.0 × 10–3 ≤ [HCl] ≤ 2.0 M). The gelation time of the monoliths was controlled by varying the amount of water (2.2 and 22.2 mmol) and HCl (between 4.0 × 10–5 and 8.0 × 10–2 mmol) incorporated. Their local structure was characterized by X-ray diffraction, 29Si and 13C nuclear magnetic resonance, mid-infrared and ultraviolet/visible absorption spectroscopy, and photoluminescence in steady-state and time resolved modes. The effect of [HCl] in the enhancement of the emission quantum yield was quantified. Although all the hybrids display emission at room temperature in the blue spectral region, it was observed that maximum and constant quantum yield values of 0.13 ± 0.01 are achieved for 0.01 ≤ [HCl] ≤ 0.1 M.

The influence of 1-ethyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium chloride, 1-butyl-1-methylpyrrolidinium chloride, 1-ethyl-3-methylimidazolium tetrafluoroborate and 3-(2-hydroxyethyl)-1-methylimidazolium tetrafluoroborate ionic liquids (ILs) on the morphology and structure of CaCO3 has been investigated in an ethanolic medium by using calcium chloride and ammonium carbonate as the calcium and carbon sources, respectively. Syntheses were carried out at 9 °C and room temp. at different IL concentrations and CO32–/Ca2+ molar ratios. No polymorph selectivity was detected, and calcite was the sole crystalline form obtained under all the considered reactions conditions. In the case of the BF4–-based ILs, anion decomposition occurred, which led to the formation of fluorite. Low temperature reduced the precipitation rate. With the ILs employed, the morphology of CaCO3 has been finely tailored: calcite microcubes, microframes and microboxes with potential application in drug delivery, as well as nanocubes and nanocorn-like objects were produced with Cl–-based ILs; with BF4–-based ILs, hierarchically structured materials, in which calcite coexists with fluorite, and complex and intricate shapes were produced, such as nanostructured microspheres, nanostructured calla-lily-like and ice-cream-ball-like micro-objects.

In Press; available online 10 November 2011, Sol-gel derived KCF3SO3-doped di-urethane cross-linked poly(ε-caprolactone) (PCL(530))/siloxane ormolytes with ∞ > n ≥ 0.5 (n indicates the number of (C(=O)(CH2)5O) repeat units per K+ ion) have been studied. Xerogel samples with n ≥ 1 are thermally stable up to 235 ºC. A minor proportion of PCL crystallites occur in some dilute-to-concentrated samples. At n ≤ 4 a crystalline PCL(530)/siloxane-KCF3SO3 complex with unknown stoichiometry emerges. At n ≤ 2 this complex coexists with pure salt. At temperatures higher than 40 ºC the composition which exhibits the highest ionic conductivity is n = 21. “Free” anions, weakly coordinated CF3SO3- ions, contact ion pairs and several higher ionic aggregates emerge in all the samples. The K+ ions bond to the oxygen atoms of the carbonyl groups of the urethane and ester groups, of the PCL (530) ether chain and of the triflate ions at all salt concentrations. The ormolytes were successfully used in the production of prototype electrochromic devices (ECDs) that exhibit low switching time and good open circuit memory.. The ECD incorporating the ormolyte with n = 21 displays an average transmittance in the visible region of ca. 55 % in the colored state and 76 % in the bleached state., Fundação para a Ciência e Tecnologia (FCT)

Two structurally different but chemically similar families of alkyl/siloxane mono-amidosil hosts, represented by m-A(x) [where x = 14 or 8 represents the number of CH 2 groups of the pendant alkyl chains directly bonded to the carbonyl group of the amide cross-link] have been doped with a wide range of concentrations of Eu(CF 3 SO 3 ) 3 . Mono-amidosils mA(x) n Eu(CF 3 SO 3 ) 3 with n ≥ 10 (where n is the molar ratio of carbonyl groups per Eu 3+ ion) have been analyzed. The mA(8) n Eu(CF 3 SO 3 ) 3 mono-amidosils are transparent and amorphous films, in which the alkyl chains adopt gauche conformations. In contrast, the m-A(14) n Eu(CF 3 SO 3 ) 3 mono-amidosils are solid powders; here the lamellar bilayer hierarchical structure of m-A(14) coexists with a new lamellar phase in which the Eu 3+ ions are bonded to carbonyl oxygen atoms of the amide groups. At n = 10 the hydrogen-bonded associations formed are highly ordered and considerably stronger than those found in the less concentrated hybrids and in the nondoped matrices. "Free" and weakly coordinated triflate ions occur in all the mono-amidosil samples. The hybrids are white light emitters (maximum quantum yield: 0.08±0.01), presenting a broad emission band in the blue/purplish-blue spectral region (ascribed to the hybrid host) superimposed on the 5 D 0 → 7 F 0-4 Eu 3+ intra-4f 6 transitions. Two Eu 3+ local coordination sites (named A and B) have been discerned in both systems. Site A is attributed to weakly coordinated Eu 3+ /CF 3 SO 3 - ion pairs, whereas site B involves Eu 3 , coordination to the oxygen atoms of the C=O groups, of the CF 3 SO 3 ions and of the water molecules. For site B, the long-range order of the hybrid host induces distinct features in the energy of the 5 D 0 → 7 F 0-4 transitions, the 5 D 0 lifetime and the degree of covalency of the Eu 3+ -first-ligand bonds.

In the present work we report the unusual role played by a sol-gel derived di-urethane cross-linked poly(oxyethylene) (POE)/siloxane (di-urethanesil, d-Ut(600)) hybrid matrix in the immobilization of the β-diketonate aquocomplex Eu(btfac)3(H2O)2 (btfac− is 4,4,4-trifluoro-1-phenyl-2,4-butanedionate) and in the quasi preservation in the hybrid of the 5D0 quantum efficiency q(5D0) value displayed by this complex in the isolated state (0.12 versus 0.18, respectively). We demonstrate that the d-Ut(600) framework acts as an inert (although optically active) support towards Eu(btfac)3(H2O)2, enabling Eu3+ sensitization by the btfac− ligands and energy transfer between the hybrid host excited states and the lanthanide intra-4f6 levels, while the number of Eu3+-coordinated water molecules remains constant. We also provide evidence that the incorporation of the Eu(btfac)3phen (phen is 1,10-phenantroline) complex into the same hybrid matrix is disadvantageous from the 5D0 quantum efficiency standpoint, because of the severe steric hindrance that emerges between the POE chains of the host structure and the bulky phen molecules, leading to the expulsion of these ligands from the Eu3+ first coordination sphere and to their replacement by two water molecules. As a consequence, embedding of Eu(btfac)3phen in d-Ut(600) results in a significant reduction of the q(5D0) value of the isolated complex (from 0.47 to 0.16). The behaviour observed in the presence of this bidentate chelating ligand correlates well with the practically identical q(5D0) values and number of Eu3+-coordinated water molecules (ca. 2) estimated for the two hybrids.

Organic−inorganic hybrids containing methacrylic acid (McOH, CH2═C(CH3)COOH)) modified zirconium tetrapropoxide, Zr(OPrn)4, classed as di-ureasil−zirconium oxo-cluster hybrids, have been prepared a...

The luminescence properties of composites made of two conjugated luminescent polymers and two europium complexes are presented. We show that the electroluminescence spectra of these composites depend both on the energy transfer involving the host polymer and the ligands of the europium complexes and on the charge localisation effects which can be rationalised in terms of the energetic position of the frontier levels of the polymer and of the Eu-complex.

A thermally activated photoluminescence memory effect, induced by a reversible order-disorder phase transition of the alkyl chains, is reported for highly organized bilayer alkyl/siloxane hybrids (see figure; left at room temperature, right at 120 degrees C). The emission energy is sensitive to the annihilation/formation of the hydrogen-bonded amide-amide array displaying a unique nanoscopic sensitivity (ca. 150 nm).

This work discusses quantitatively the energy transfer mechanism that occurs in the white-light emission of sol−gel derived amine- and amide-functionalized hybrids. The white-light photoluminescence (PL) results from a convolution of the emission originated in the NH/CO groups of the organic/inorganic cross-links with electron-hole recombinations occurring in the siloxane nanoclusters, both emissions typical of donor−acceptor pairs. Two model compounds that reproduce separately the two hybrid's emissions were synthesized and characterized by X-ray diffraction, 29Si/1H/13C magic-angle spinning NMR, diffuse reflectance, Fourier transform−IR, and photoluminescence spectroscopy to support their use as organic and inorganic structural models for the two counterparts of the hybrids. The comparison between the lifetimes of the two emissions of the inorganic and organic model compounds with those of the hybrids, the Arrhenius dependence with temperature of the siliceous-related lifetime in the hybrids, and the no...

New polymer electrolytes (PEs) based on chitosan and three ionic liquid (IL) families ([C2mim][CnSO3], [C2mim][CnSO4] and [C2mim][diCnPO4]) were synthesized by the solvent casting method. The effect of the length of the alkyl chain of the IL anion on the thermal, morphological and electrochemical properties of the PEs was studied. The solid polymer electrolytes (SPE) membranes were analyzed by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), polarized optical microscopy (POM), atomic force microscopy (AFM), complex impedance spectroscopy (ionic conductivity) and cyclic voltammetry (CV). The obtained results evidenced an influence of the alkyl chain length of the IL anion on the temperature of degradation, birefringence, surface roughness and ionic conductivity of the membranes. The DSC, XRD and CV results showed independency from the length of the IL-anion-alkyl chain. The PEs displayed an predominantly amorphous morphology, a minimum temperature of degradation of 135 °C, a room temperature (T = 25 °C) ionic conductivity of 7.78 × 10−4 S cm−1 and a wide electrochemical window of ∼ 4.0 V., This work was supported by FEDER through the COMPETE Program and by Fundação para a Ciência e a Tecnologia (FCT) in the framework of the Strategic Projects PEST-C/QUI/UI0686/2013, PEst-OE/SAU/UI0709/2014 and UID/Multi/00709/2013, UID/Multi/04551/2013, projects PTDC/QUI/117340/2010 and COST Action MP1202 “Rational design of hybrids organic inorganic interfaces”, grants SRFH/BD/90366/2012 (R.L.) and SFRH/BPD/63152/2009 (S.C. Nunes) and FCT Investigator contract (J.M.S.S.E.). The authors are also indebted to CNPq, FAPESP and CAPES for the financial support given to this research. M.M. Silva acknowledges Fundação Luso- Americana (FLAD) and CNPq (PVE grant 406617/2013-9), for the mobility grant provided by these institutions.

Fourier transform mid-IR and Raman spectroscopies were extensively used to examine cation/polymer and cation/cross-link interactions, as well as hydrogen bonding, in Eu3+-doped sol–gel derived organic/inorganic materials (monourethanesils). The hybrid framework of these xerogels contains short methyl end capped polyether segments covalently bonded to a siliceous backbone through urethane groups. The cations were incorporated as europium triflate, Eu(CF3SO3)3. Samples with compositions ∞ > n ≥ 10 (where n indicates the ratio of (OCH2CH2) moieties per lanthanide ion) were investigated. The spectral data obtained provided unequivocal evidence that the cations coordinate exclusively to the urethane carbonyl oxygen atoms in compounds with 400 ≥ n ≥ 50. The participation of the ether oxygen atoms of the polymer chains in the Eu3+ complexation process is initiated at n = 30. The presence of a crystalline phase was detected at n = 10. The variation of the glass transition temperature of the monourethanesils studied with salt concentration is in perfect agreement with these claims. The beginning of the Eu3+–polyether interaction is accompanied by a breakdown of the hydrogen bonded aggregates of the matrix, as confirmed by photoluminescence spectroscopy.

Fourier transform mid-IR and Raman spectroscopies were employed to investigate the anionic local surrounding in sol-gel derived organic/inorganic materials-monourethanesils-incorporating europium triflate, Eu(CF 3 SO 3 ) 3 . The hybrid framework of these xerogels contains short methyl end capped polyether segments grafted to a siliceous network through urethane cross-links. Samples with compositions ∞ > n ≥ 10 (where n indicates the ratio of (OCH 2 CH 2 ) moieties per lanthanide ion) were examined. The spectral data obtained provide conclusive evidence of the presence of free and weakly coordinated CF 3 SO 3 - ions located in two distinct sites in the whole range of salt concentration analyzed. At n = 30 and 10, along with these species, two new anionic configurations, assigned to contact ion pairs and cross-link separated ions pairs, emerge. Two-dimensional correlation spectroscopic analysis allowed to clarify the number of components present in two critical bands containing strongly overlapped spectral profiles. The number of anionic environments found in the m-Ut(750) n Eu(CF 3 SO 3 ) 3 family confirms the rich coordinating possibilities offered by polymer systems incorporating trivalent triflate salts.

The aggregation, gelation, and aging of urea-cross-linked siloxane−poly(oxyethylene) nanohybrids [(U600)n] containing two different amounts of europium triflate initially dissolved in an ethanol−wa...

The combination of the glycine-derivative supramolecular salt 4,6-bis(carboxymethylamino)-2-oxo-2,3-dihydro-1,3,5-triazin-1-ium chloride (H(2)bodt center dot HCl) and lanthanide(III) chloride hydrates under hydrothermal conditions (120 degrees C, 48 h) led to the formation of a family of isotypical materials formulated as [Ln(bodt)(Hbodt)] [where Ln(3+) = La3+ (1), (La0.95Eu0.05)(3+) (2) and (La0.95Tb0.05)(3+) (3)]. The synthesis of the novel precursor H(2)bodt center dot HCl is detailed. The structures of H(2)bodt center dot HCl and its intermediate compound were unveiled by single-crystal X-ray diffraction and characterized by standard liquid-state techniques. The crystallographic details of compound 1 were unveiled in the monoclinic P2/c space group by using single-crystal X-ray diffraction, with the crystal structure of 1 comprising a one-dimensional (1)(infinity)[La(bodt)(Hbodt)] coordination polymer. All polymeric materials were fully characterized by FT-IR, electron microscopy (SEM and EDS), powder X-ray diffraction, and elemental and thermogravimetric analyses. The photoluminescent properties of 1 and of the mixed-lanthanide materials 2 and 3 were investigated at ambient and low temperatures. An excited-state intermolecular proton transfer (ESPT) process, induced by intermolecular hydrogen-bonding interactions, is proposed to account for the observed anomalous emission and excitation spectra of 1. Aiming at providing an in-depth understanding of the emission (fluorescence and phosphorescence) properties of the ligand, time-dependent density functional theory (TD-DFT) calculations were also performed.

Luminescent solar concentrators (LSCs) are devices comprising a transparent matrix embedding optically active centres that absorb the incident radiation, which is re-emitted at a specific wavelength and transferred by total internal reflection to photovoltaic (PV) cells located at the edges of the matrix. Organic-inorganic hybrids incarcerating trivalent lanthanide ions (Ln(3+)) are a very promising class of materials for addressing the required challenges in the LSC design to improve solar energy harvesting and, then, PV energy conversion. This feature article offers a general overview of the potential of down-shifting-based Ln(3+)-containing organic-inorganic hybrids for the development of the area with special focus on (i) optically active layer design, (ii) energy conversion mechanisms, (iii) performance and geometry and (iv) figures of merit in PV cell enhancement. Finally, a prospective outlook on future progress, e.g. optically active centre alignment, geometry optimization and building integration, is provided. The use of Ln(3+)-containing hybrids in LSCs is at an infant initial research step and considerable basic knowledge is still needed to enable prototypes to become a commercial reality.

Hybrid organic/inorganic networks doped with europium triflate, Eu(CF 3 SO 3 ) 3 , have been prepared by the sol-gel method and characterized by conductivity and thermal analysis techniques. The electrolyte films produced were obtained as transparent, amorphous monoliths with encouraging optical characteristics and moderate bulk conductivities.

The thermal, morphological and conducting properties of macromolecular organic-inorganic networks synthesized by the sol-gel process and containing a wide concentration range of europium trifluoromethanesulfonate, Eu(CF 3 SO 3 ) 3 , have been investigated. The hybrid matrix, U(2000), of these materials, classed as ureasils, includes a siliceous backbone and short polyether-based segments. The link between these components is made by urea bridges. The behaviour of the doped ureasils is significantly better than that of previously characterized electrolytes based on poly(ethylene oxide), PEO. The essentially amorphous character of the hybrid host contributes to an improved transparency and moderate conductivities of certain electrolytes at room temperature (ca. 5×10 –6 Ω –1 cm –1 ). DSC, XRD and FTIR measurements show that the formation of a high-melting crystalline complex results from the coordination of the Eu 3+ ions by the ether oxygens of the organic moieties at composition n=5 [where n represents the molar ratio of (OCH 2 CH 2 ) units per Eu 3+ ion]. The results obtained for samples with n≥20 suggest that in this range of composition the principal effect of the polyether chains is to exert a plasticizing influence, as the coordination of the cations by the urea linkages is favored.

A lamellar bilayer hierarchically structured amide cross-linked alkyl/siloxane hybrid matrix (mono-amidosil, m-A(14)) was doped with a wide concentration range of potassium triflate (KCF3SO3), magnesium triflate (Mg(CF3SO3)2), and europium triflate (Eu(CF3SO3)3). In the K(+)-, Mg(2+)-, and Eu(3+)-based samples with n ≥ 5, 20, and 60 (where n is the molar ratio of amide C═O groups per cation), respectively, the original lamellar structure of m-A(14) coexists with a new lamellar phase with lower interlamellar distance. The texture of the mono-amidosils doped with K(+), Mg(2+), and Eu(3+) ions mimics cabbage leaves, foliated schist, and sea sponges, respectively. In the three series of materials, the cations bond to the oxygen atoms of the amide carbonyl groups. The amide-amide hydrogen-bonded array of m-A(14) is less perturbed by the inclusion of KCF3SO3 and Mg(CF3SO3)2 than by the incorporation of Eu(CF3SO3)3. The degree of ionic association is low for n ≥ 20. The cations coordinate to the oxygen atoms of the triflate ions, forming contact ion pairs at higher salt content. In the Mg(CF3SO3)2- and Eu(CF3SO3)3-containing materials with n = 5 and 10, respectively, crystalline salt is formed. The structural changes undergone by the alkyl chains of selected mono-amidosils in a heating/cooling cycle are reversible, are time-independent, and exhibit two distinct hysteresis domains, one associated with the order/disorder phase transition of the original lamellar bilayer structure of m-A(14) and the second one associated with the order/disorder phase transition of the new lamellar bilayer structure formed in the presence of the salts.

13 pages; International audience; A new family of lamellar bilayer hierarchically structured mono-urethane cross-linked alkyl/siloxanes designated as mono-alkyl-urethanesils and represented by the notation m-Ut(CY)-ac, with Y = 14, 16 and 22 (where Y is the number of carbon atoms of the pendant polymer chains and ac is acid catalyzed) was prepared by the sol-gel process and self-assembly routes. The compounds were obtained as solid powders and are thermally stable up to 250 C. The alkyl chains adopt essentially all-trans conformations and are interdigitated. The degree of interpenetration depends non-linearly on the chain length. The intrincate morphology of the samples mimicks cabbage leaves or the desert rose. The present system allowed us to conclude that the nature of the cross-link exerts a key role on the properties of this sort of silsesquioxanes. The hydrogen bonded array in the monoalkyl- urethanesils is considerably weaker than that formed in the analogue mono-amidosil m-A(14) incorporating alkyl chains with 15 carbon atoms. The order/disorder phase transition temperatures of the mono-alkyl-urethanesils with Y = 14 and 16 are lower than that of m-A(14), making the former samples mechanically more resistant to consecutive heating/cooling cycles. The frequency of conformationalsensitive infrared modes of m-Ut(C16)-ac exhibit hysteresis behaviour during cooling after undergoing the order/disorder phase transition, but, unlike m-A(14), the latter transition, although reversible, is apparently time-independent. The hybrids display an efficient emission at room temperature in the blue-green spectral region with a maximum emission quantum yield value of 0.11 ± 0.01 (excited at 350-380 nm), which is of the same order of magnitude of that reported for m-A(14).

A new family of biodegradable polymer/bioactive glass (BG) composite materials has emerged based on the availability of nano-sized bioactive particles. Such novel biocomposites can have enhanced performance, in terms of mechanical properties and bioactivity, and they can be designed to be used in bone regeneration approaches. In this work, membranes of chitosan (CTS) and chitosan with bioactive glass (BG) both micron and nano sized particles (CTS/μBG, CTS/nBG, respectively) were prepared by solvent casting. Microstructural and mechanical properties were evaluated in order to compare the effects of the incorporation of micro (μBG) and nano (nBG) particles in the chitosan matrix. In vitro bioactivity tests were performed to characterize the apatite layer that is formed on the surface of the material after being immersed in simulated body fluid (SBF). The biomineralization process on the biomaterials was also followed using non-conventional dynamic mechanical analysis (DMA), both online and offline. In such DMA experiments, the change in the storage modulus, E′, and the loss factor, tan δ, were measured as a function of the immersion time in SBF. The results demonstrated that CTS/nBG membranes possess enhanced mechanical properties and higher bioactivity in comparison with the CTS/μBG membranes. Such results suggest the potential of nBG for the development of bioactive composites for bone regeneration applications., This work was financially supported by Foundation for Science and Technology (FCT) by the projects PTDC/QUI/69263/2006, PTDC/CTM-BPC/112774/2009 and, through the scholarship SFRH/BD/64601/2009 granted to Sofia G. Caridade. The authors acknowledge Dr D. Mohn and Prof. W. Stark (Em Zurich) for providing the nBG particles used.

The present work is focused on gelatin-based electrolytes doped with a range of concentration of zinc triflate (Zn(CF3SO3)2). The transparent-thin-film samples have been represented by the notation GelatinnZn(CF3SO3)2, where n represents the zinc triflate salt concentration in the electrolyte membranes from 0.00 wt% to 10.93 wt% . The samples have been characterized by conductivity measurements, thermal analysis, cyclic voltammetry, X-ray diffraction (XRD), polarized optical microscopy (POM) and scanning electron microscopy (SEM). The gelatin-based electrolytes were also tested as ionic conductors in electrochromic devices with the glass/ITO/WO3/gelatin-based electrolyte/CeO2-TiO2/ITO/glass configuration.

We report on a new thermochromic material containing a europium complex for thermal sensing through its fluorescence response to temperature. The ratio between the strong luminescence peak of europium (III) and a side band emission is employed as a new probe for optical sensing of temperature. The ratio is observed to follow an Arrhenius-type dependence with temperature. Based on these results we developed a thermal probe based on a segment of luminescent thermometer optically cemented to the tip of a PMMA fibre. Tecnología Electrónica

In the present work Fourier Transform infrared and Raman spectroscopy were used to characterize the cation/polymer, cation/cross-link, cation/anion and hydrogen bonding interactions in hybrid electrolytes composed of lithium tetrafluoroborate (LiBF4) and di-urea cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks (di-ureasils) designated as d-(2000) and d-U(600) and incorporating polyether chains with ca. 40.5 and 8.5 oxyethylene repeat units, respectively. Samples with ∞ > n ≥ 2.5 (where n, composition, is the molar ratio of CH2CH2O units per Li+ ion) were analyzed. In both di-ureasil systems over the whole range of salt content examined the Li+ ions bond to the ether oxygen atoms of amorphous POE chains and to BF4- ions forming ion contact pairs. Spectroscopic evidences and SEM images confirm the presence of a crystalline POE/LiBF4 complex of unknown stoichiometry at n < 20 and 25, respectively. Ionic association is particularly important in the case of the d-U(600)-based materials, as a result of the presence of strong hydrogen-bonded aggregates that prevent the establishment of Li+/urea carbonyl oxygen atom interactions., Fundação para a Ciência e a Tecnologia (FCT)

Research on organic–inorganic hybrid materials containing trivalent lanthanide ions (Ln3+) is a very active field that has rapidly shifted in the last couple of years to the development of eco-friendly, versatile and multifunctional systems, stimulated by the challenging requirements of technological applications spanning domains as diverse as optics, environment, energy, and biomedicine. This tutorial review offers a general overview of the myriad of advanced Ln3+-based organic–inorganic hybrid materials recently synthesised, which may be viewed as a major innovation in areas of phosphors, lighting, integrated optics and optical telecommunications, solar cells, and biomedicine.

International audience; The final morphology of the lamellar silsesquioxane produced from the (EtO)3Si(CH2)3NHC(¼O)NH(CH2)12NHC(¼O)NH(CH2)3Si(OEt)3 (P12) precursor using an acidcatalyst and a large excess of water was changed from rigid platelets (L12) to micro-objects that resemble sea sponges (L12D) upon simple mixing with dimethylsulfoxide (dmso). The microstructural modifications observed were ascertained by several techniques. A mechanism for the morphology tuning based on the polarity of the solvent mixture is proposed.

Diurea cross-linked bridged silsesquioxanes (BSs) C(10)C(11)C(10) derived from organosilane precursors, including decylene chains as side spacers and alkylene chains with variable length as central spacers (EtO)(3)Si- (CH(2))(10)-Y(CH(2))(n)-Y-(CH(2))(10)-Si(OEt)(3) (n = 7, 9-12; Y = urea group and Et = ethyl), have been synthesized through the combination of self-directed assembly and an acid-catalyzed sol gel route involving the addition of dimethylsulfoxide (DMSO) and a large excess of water. This new family of hybrids has enabled us to conclude that the length of the side spacers plays a unique role in the structuring of alkylene-based BSs, although their morphology remains unaffected. All the samples adopt a lamellar structure. While the alkylene chains are totally disordered in the case of the C(10)C(7)C(10) sample, a variable proportion of all-trans and gauche conformers exists in the materials with longer central spacers. The highest degree of structuring occurs for n = 9. The inclusion of decylene instead of propylene chains as side spacers leads to the formation of a stronger hydrogen-bonded urea-urea array as evidenced by two dimensional correlation Fourier transform infrared spectroscopic analysis. The emission spectra and emission quantum yields of the C(10)C(n)C(10) Cm materials are similar to those reported for diurea cross-linked alkylene-based BSs incorporating propylene chains as side spacers and prepared under different experimental conditions. The emission of the C(10)C(n)C(10) hybrids is ascribed to the overlap of two distinct components that occur within the urea cross-linkages and within the siliceous nanodomains. Time-resolved photoluminescence spectroscopy has provided evidence that the average distance between the siliceous domains and the urea cross-links is similar in the C(10)C(n)C(10) BSs and in oxyethylene-based hybrid analogues incorporating propylene chains as side spacers (diureasils), an indication that the longer side chains in the former materials adopt gauche conformations. It has also allowed us to demonstrate for the first time that the emission features of the urea-related component of the emission of alkylene-based BSs depend critically on the length of the side spacers.

Research on organic-inorganic hybrid materials containing trivalent lanthanide ions (Ln(3+)) is a very active field that has rapidly shifted in the last couple of years to the development of eco-friendly, versatile and multifunctional systems, stimulated by the challenging requirements of technological applications spanning domains as diverse as optics, environment, energy, and biomedicine. This tutorial review offers a general overview of the myriad of advanced Ln(3+)-based organic-inorganic hybrid materials recently synthesised, which may be viewed as a major innovation in areas of phosphors, lighting, integrated optics and optical telecommunications, solar cells, and biomedicine.

Interest in lanthanide-containing organic-inorganic hybrids has grown considerably during the last decade, with the concomitant fabrication of materials with tunable attributes offering modulated properties. The potential of these materials relies on exploiting the synergy between the intrinsic characteristics of sol-gel derived hosts (highly controlled purity, versatile shaping and patterning, excellent optical quality, easy control of the refractive index, photosensitivity, encapsulation of large amounts of isolated emitting centers protected by the host) and the luminescence features of trivalent lanthanide ions (high luminescence quantum yield, narrow bandwidth, long-lived emission, large Stokes shifts, ligand-dependent luminescence sensitization). Promising applications may be envisaged, such as light-emitting devices, active waveguides in the visible and near-IR spectral regions, active coatings, and bio-medical actuators and sensors, opening up exciting directions in materials science and related technologies with significant implications in the integration, miniaturization, and multifunctionalization of devices. This review provides an overview of the latest advances in Ln(3+)-containing siloxane-based hybrids, with emphasis on the different possible synthetic strategies, photoluminescence features, empirical determination.

The title compound, C(12)H(18)N(6)O(6), was synthesized via nucleophilic substitution by reacting 2,4,6-trichloro-1,3,5-triazine with glycine methyl ester hydro-chloride in reflux (dried toluene) under anhydrous atmosphere. Individual mol-ecules self-assemble via strong N-H⋯O hydrogen bonds into supra-molecular double tapes running parallel to the [010] crystallographic direction. The close packing of supra-molecular tapes is mediated by geometrical reasons in tandem with a number of weaker N-H⋯O and C-H⋯N hydrogen-bonding inter-actions.

International audience; Urea-based bis-silylated bipyridine (bpy) organic–inorganic hybrids incorporating different lanthanide (Ln3+) ions (Eu3+, Gd3+, Tb3+ or Eu3+/Tb3+) were obtained by the sol–gel process. The structure and the emission characteristics of the hybrids were ascertained using X-ray diffraction, nuclear magnetic resonance, Fourier transform infrared spectroscopy, photoluminescence, and quantum yield measurements. The hybrids feature both the emission of the host and the Eu 3+ and/or Tb3+ transitions allowing a fine-tuning of the color from the blue to the red, orange, or green spectral regions. Bpy-to-Ln3+ and Tb3+-to-Eu3+ energy transfer mechanisms are demonstrated and the hybrids present slightly distinct Ln3+ coordination spheres due to the different bpy/Ln3+ ratios.

International audience; The bridged silsesquioxane precursor (EtO)3Si(CH2)3NH(C=O)NH-(CH2)12-NH(C=O)NH-(CH2)3 Si(OEt)3, combining polymerizable silylated groups, urea functionalities, and alkyl chains, undergoes fluoride (F-)-catalyzed sol-gel reactions in the presence or absence of EuCl3 . 6H2O. Supramolecular self-assembly of the growing structure relies primarily on the establishment of strong and ordered hydrogen bonding interactions. In the case of the Eu3+-containing hybrids the lanthanide ions play a totally unparallel dual-role acting simultaneously as structure directing agents and structural probes to sense locally morphological alterations. In the early stages of the synthesis, while a fraction of the Eu3+ ions promotes the formation of a unidirectional urea-urea hydrogenbonded array, the remaining ions coordinate to silanol (Si-OH) groups inhibiting the growth of the siloxane network and yielding small anisotropic flakes (∼200 nm long). These are subsequently assembled on the micrometer scale in a brick-like tile-to-tile arrangement that ends up with the formation of fibers or twisted bundles (3.0-4.0 μm long and 0.5-1.0 μm wide). At higher Eu3+ concentrations, Eu3+-based ionic interfiber cross-links hinder the solvent flow and force adjacent fibers to adopt a bow-tie form (3.0-4.0 μm long and 3.0 μm wide at the tips). The hybrids are room temperature multiwavelength emitters because of the convolution of the hybrids' intrinsic emission and the Eu3+ intra-4f6 transitions. The photoluminescence features (5D0_7F0 energy, 5D0 quantum efficiency, number of coordinated water molecules, and experimental intensity parameters) as a function of the Eu3+ content and acidic- and F--catalyzed conditions used in the synthesis are compared to address the effect of the morphology in the photoluminescence features of the hybrid materials.

Variable chain length di-urethane cross-linked poly(oxyethylene) (POE)/siloxane hybrid networks were prepared by application of a sol-gel strategy. These materials, designated as di-urethanesils (represented as d-Ut(Y’), where Y’ indicates the average molecular weight of the polymer segment), were doped with lithium triflate (LiCF3SO3). The two host hybrid matrices used, d-Ut(300) and d-Ut(600), incorporate POE chains with approximately 6 and 13 (OCH2CH2) repeat units, respectively. All the samples studied, with compositions ∞ > n ≥ 1 (where n is the molar ratio of (OCH2CH2) repeat units per Li+),, are entirely amorphous. The di-urethanesils are thermally stable up to at least 200 ºC. At room temperature the conductivity maxima of the d-Ut(300)- and d-Ut(600)-based di-urethanesil families are located at n = 1 (approximately 2.0x10-6 and 7.4x10-5 Scm-1, respectively). At about 100 ºC, both these samples also exhibit the highest conductivity of the two electrolyte systems (approximately 1.6x10-4 and 1.0x10-3 Scm-1, respectively). The d-Ut(600)-based xerogel with n = 1 displays excellent redox stability., Fundação para a Ciência e a Tecnologia (FCT)

The title compound, C6H6Cl2N4O2, was prepared by the nucleophilic substitution of 2,4,6-trichloro-1,3,5-triazine by glycine methyl ester hydrochloride, and was isolated from the reaction by using flash chromatography. The crystal structure at 150 K reveals the presence two crystallographically independent molecules in the asymmetric unit which differ in the orientation of the pendant methoxycarbonyl group. Each molecular unit is engaged in strong and highly directional N—H...N hydrogen-bonding interactions with a symmetry-related molecule, forming supramolecular dimers which act as the synthons in the crystal packing.