Solvatochromic behaviour of cyclic dithioether-functionalized triphenylamine ligands and their mechano-responsive Cu(I) coordination polymers.

Cu(I)-based coordination polymers (CPs) are known as efficient emissive materials providing an eco-friendly and cost-effective platform for the development of various functional materials and sensors. In addition to the nature of the metal center, organic ligands also play a crucial role in controlling the emissive properties of coordination polymers. Herein, we report on the synthesis of dithiane- and dithiolane-substituted triphenylamine ligands L1 and L2. These ligands were found to be emissive both in the solid state and in solution. In addition, these ligands exhibit solvatochromic behaviour due to the twisted intramolecular charge transfer (TICT) phenomenon. Next, coordination behaviour of these ligands was explored with Cu(I)X salts (X = Br and Cl) and four new 1D coordination polymers [{Cu(µ2-X)2Cu}(µ2-L)]n, CP1 (X = Br, L = L1), CP2 (X = Cl, L = L1), CP3 (X = Br, L = L2), and CP4 (X = Cl, L = L2) were synthesized and crystallographically characterized. The emission behaviour of all the CPs suggests ligand-centered transitions. On mechanical grinding, emission maxima (λem) for CP1 and CP2 were blue-shifted, whereas for CP3 and CP4 red-shifts were observed. All CPs were found to emit at 448 nm with increased intensity after grinding. It is supposed that grinding is responsible for a change in the spatial arrangement (dihedral angles) of the phenyl groups of triphenylamine, causing the observed emission shifts. Furthermore, the higher emission intensity after grinding suggests the occurrence of a similar phenomenon as an aggregation-induced quenching in these CPs.

Electropolymerization of Pyrrole-Tailed Imidazolium Ionic Liquid for the Elaboration of Antibacterial Surfaces.

A strategy was developed to prepare antibacterial surfaces by electropolymerization of a pyrrole-functionalized imidazolium ionic liquid bearing an halometallate anion. The objective was to combine the antibacterial efficiency of polypyrrole (PPy) with those of the ionic liquid's components (cation and anion). For this, N-(1-methyl-3-octylimidazolium)pyrrole bromide monomer [PyC8MIm]Br was synthesized and coordinated to ZnCl2 affording [PyC8MIm]Br-ZnCl2. The antibacterial properties of [PyC8MIm]Br-ZnCl2 monomer were evaluated against Escherichia coli and Staphylococcus aureus by measurement of the minimum inhibitory concentration (MIC) values. This monomer presents higher activity against S. aureus (MIC = 0.098 µmol·mL-1) than against E. coli (MIC = 2.10 µmol·mL-1). Mixtures of pyrrole and the pyrrole-functionalized ionic liquid [PyC8MIm]Br-ZnCl2 were then used for the electrodeposition of PPy films on Fluorine-doped tin oxide (FTO) substrates. The concentration of pyrrole was fixed to 50 mM, while the concentration of [PyC8MIm]Br-ZnCl2 was varied from 5 to 100 mM. The efficient incorporation of the imidazolium cation and zinc halometallate anion into the films was confirmed by X-ray photoelectron spectroscopy (XPS) measurements. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements confirmed the homogeneity of the different films with structures that depend on the [PyC8MIm]Br-ZnCl2 concentration. The films' thickness determined by profilometry varies only slightly with the [PyC8MIm]Br-ZnCl2 concentration from 7.4 µm at 5 mM to 8.9 µM at 100 mM. The films become more hydrophilic with an increase of [PyC8MIm]Br-ZnCl2 concentration with water contact angles varying from 47° at the lowest concentration to 32° at the highest concentration. The antibacterial activities of the different PPy films were determined both by the halo inhibition method and by the colony forming units (CFUs) counting method over time against Gram-positive S. aureus and Gram-negative E. coli bacteria. Films obtained by incorporation of [PyC8MIm]Br-ZnCl2 showed excellent antibacterial properties, at least two times higher than those of neat PPy, validating our strategy. Furthermore, a comparison of the antibacterial properties of the films obtained using the same [PyC8MIm]Br-ZnCl2 concentration (50 mM) evidenced much better activity against Gram-positive (no bacterial survival within 5 min) than against Gram-negative bacteria (no bacterial survival within 3 h). Finally, the antibacterial performances over time could be tuned by the concentration of the employed pyrrole-functionalized ionic liquid monomer. Against E. coli, using 100 mM of [PyC8MIm]Br-ZnCl2, the bacteria were totally killed within a few minutes, using 50 mM, they were killed after 2 h while using 10 mM, about 20% of bacteria survived even after 6 h.

Silver-based coordination polymers assembled by dithioether ligands: potential antibacterial materials despite received ideas.

We report on the first examples on the antibacterial activity towards Gram-negative and Gram-positive bacteria of 2D silver-based coordination polymers obtained by self-assembly with acetylenic dithioether ligands. Their structure imparts a good stability that allows a sustainable release of Ag+ in the media.

Release kinetics of [lidocainium][ibuprofenate] as Active Pharmaceutical Ingredient-Ionic Liquid from a plasticized zein matrix in simulated digestion.

An in vitro approach is proposed to study the release of an Active Pharmaceutical Ingredient-Ionic Liquid (API-IL) from a natural biopolymer matrix based on zein, a maize storage protein. Zein can be processed in the molten state with 20 w% [Lidocainium][Ibuprofenate] added as API-IL also acting as plasticizer and potentially co-plasticized by glycerol. The thermal stability of the matrix is checked, as well as the in vivo biological activity of the API-IL confirming anesthetic and anti-inflammatory activities. Model tablets are thermomolded at 130 °C (∅20 mm, 0.2 mm thick) and submitted to simulated digestion based on the INFOGEST static protocol of gastrointestinal food digestion at 37 °C (2 h under gastric conditions followed by 2 h under intestinal ones). The release of the API-IL is evaluated by HPLC-UV to dissociate lidocainium, that shows a progressive release (35 % after 2 h and 60 % after 4 h digestion), from ibuprofenate, that is mainly released under intestinal conditions due to low solubility in acidic conditions. The monitoring of the tablets reveals release mechanisms based on diffusion without noticeable erosion of the matrix. These results demonstrate the interest of this thermoplastic material to provide a relevant drug delivery system.

2,2'-Ethylenebis(1,3-dithiane) as a polydentate µ2-, µ4- and µ5-assembling ligand for the construction of sulphur-rich Cu(I), Hg(II) and heterometallic Cu(I)/Hg(II) coordination polymers featuring uncommon network architectures.

With the aim to elaborate novel and inexpensive sulphur-rich materials featuring unusual network architectures, the coordination chemistry of the tetradentate thiaheterocycle 1,2-di(1,3-dithian-2-yl)ethane L1 ligand toward CuX and HgX2 salts was investigated. When L1 is reacted with CuI in a 1 : 1 ratio, a two-dimensional CP [{Cu(µ2-I)2Cu}(µ2-L1)]n (CP1) is formed, in which two out of four S atoms of L1 remain non-coordinated. Upon treatment of L1 with CuI in a 1 : 2 ratio, [{Cu(µ2-I)2Cu}(µ4-L1)]n (CP2) is obtained, in which each S atom of L1 coordinates to one copper centre forming a 2D layer. Raising the ligand-to-CuI ratio to 1 : 4 affords the 2D material [{Cu(µ4-I)(µ2-I)Cu}2(µ4-L1)]n (CP3), in which [Cu(µ4-I)(µ2-I)Cu]n ribbons are interconnected through µ4-bridging L1 ligands. Upon the reaction of L1 with CuBr in a 1 : 2 ratio, a 2D CP [{Cu(µ2-Br)}2(µ2-L1)(µ4-L1)0.5]n (CP4) is formed at room temperature and a 2D CP [{Cu(µ2-Br)}2(µ4-L1)]n (CP5) is obtained in refluxing propionitrile. In CP4 and CP5 Cu atoms are bridged by a single µ2-Br ligand giving rise to [Cu(µ2-Br)Cu]n ribbons but CP4 differs from CP5 from the metal to ligand ratio and the presence of non-coordinated S atoms. Employing a 1 : 3 ratio, a 1D ribbon [{Cu(µ2-Br)}3(MeCN)(µ4-L1)]n (CP6) is generated, that contains both tetrahedral and trigonal copper atoms. CP6 also presents two different L1 ligands that differ by the coordination mode of the sulphur atoms (S acting as 2 or as 4 electron-donor). With CuCl, a 2D network [{Cu(µ2-Cl)2Cu}(µ4-L1)]n (CP7) is generated. L1 coordinates also on HgX2 salts to yield CPs whose architecture depends on the ligand-to-metal ratio. The meander-shaped 1D CP [(HgI2)(µ2-L1)]n (CP8) and the linear 1D ribbons of CP9 and CP12 [(HgX2)(µ2-L1)]n (X = Br, Cl) result from treatment with L1 in a 1 : 1 ratio. In the case of HgBr2, using a 2 : 1 metal-to-ligand ratio, 1D polymeric [{BrHg(µ2-Br)2HgBr}(µ2-L1)] (CP10) is produced. HgI2 and HgBr2 have also been reacted with 2-methyl-1,3-dithiane L2 yielding the molecular complexes [{IHg(µ2-I)2HgI}(κ1-L2)2] (D1) and [HgBr2(κ1-L2)2] (M1). Two heterometallic 1D materials [{IHg(µ2-I)2HgI(µ2-I)2{Cu(RCN)2}2(µ2-L1)]n (CP13) and (CP14) result from the treatment of CP1 with HgI2 in MeCN or EtCN. Performing the reaction of CP1 with HgBr2 in acetonitrile produces the zwitterionic 2D material [Cu(MeCN)}(HgIBr2)(µ2-L1)1.5]n (CP15).

Crystal structures of 9-[bis-(benzyl-sulfan-yl)meth-yl]anthracene and of cyclo-dodeca-kis-(µ2-phenyl-methane-thiol-ato-κ2 S:S)hexa-palladium(6 Pd-Pd)-anthracene-9,10-dione (1/1).

The first title compound, C29H24S2, L1, represents an example of an anthracene-based functionalized di-thio-ether, which may be useful as a potential chelating or terminal ligand for coordination chemistry. This di-thio-acetal L1 crystallizes in the monoclinic space group P21/c. The phenyl rings of the benzyl groups and that of the anthracene unit form dihedral angles of 49.21 (4) and 58.79 (5)° and the crystal structure displays short C-H⋯π contacts. Surprisingly, when attempting to coordinate L1 to [PdCl2(PhCN)2], instead of the targeted chelate complex [PdCl2(κ2-L1)], a cleavage reaction leads to the formation of the centrosymmetric hexa-nuclear cyclic cluster of composition [Pd6(µ2-SCH2Ph)12] Pd6, or [Pd6(C7H7S)12]·C14H8O2. This tiara-shaped hexa-mer crystallizing in the triclinic space group P consists of six approximately square planar Pd(II)S4 centers, which are inter-connected through twelve µ2-bridging benzyl thiol-ate groups. The Pd⋯Pd contacts range from 3.0892 (2) to 3.1609 (2) Šand can be considered as weakly bonding. The unit cell of Pd6 contains also a co-crystallized anthracene-9,10-dione mol-ecule.

Crystal structure of the two-dimensional coordination polymer poly[di-µ-bromido-bis-(µ-tetra-hydro-thiophene)-dicopper(I)].

The polymeric title compound, [Cu2Br2(C4H8S)2] n , CP1, represents an example of a two-dimensional coordination polymer resulting from reaction of CuBr with tetra-hydro-thio-phene (THT) in MeCN solution. The two-dimensional layers consist of two different types of rhomboid-shaped dinuclear Cu(µ2-Br)2Cu secondary building units (SBUs); one with a quite loose Cu⋯Cu separation of 3.3348 (10) Šand a second one with a much closer inter-metallic contact of 2.9044 (9) Å. These SBUs are inter-connected through bridging THT ligands, in which the S atom acts as a four-electron donor bridging each Cu(µ2-Br)2Cu unit in a µ2-bonding mode. In the crystal, the layers are linked by very weak C-H⋯·Br hydrogen bonds with H⋯Br distances of 2.95 Å, thus giving rise to a three-dimensional supra-molecular network.

A drug delivery system obtained by hot-melt processing of zein plasticized by a pharmaceutically active ionic liquid.

Zein-based filaments containing 20 weight% [Lidocainium][Ibuprofenate] used as a doubly Active Pharmaceutical Ingredient-Ionic Liquid (API-IL) were obtained by extrusion at 130 °C. The plasticizing effect of the active ingredient on the zein amorphous matrix was assessed by differential scanning calorimetry, with a decrease in the glass transition temperature (Tg) from 77 °C, for the raw zein, to 53 °C. After storage under standard conditions (relative humidity 59%, 20 °C) the extrudates were rigid, with a high storage modulus (E') of about 3 GPa at ambient temperature. They had a main mechanical relaxation (Tα) beginning at 55 °C, leading to their flowing at temperatures above 130 °C, as determined by dynamic mechanical analysis, with E' below 1 MPa and tan δ above 1. Their structure was evaluated by wide angle X-ray scattering and NMR analysis was used to evaluate the API-IL stability after thermomechanical processing. Release experiments performed under simulated physiological conditions on filaments evidenced a release of 85% after 7 days immersion. These results demonstrate the advantage of using an API-IL as plasticizer of a resorbable biopolymer. The resulting material can be shaped by a continuous thermomechanical process and used as a drug delivery system.

Crystal structure of 2-[bis(benzylsulfanyl)methyl]-6-methoxyphenol.

The title compound, C22H22O2S2, 1, represents an example of an ortho-vanillin-based functionalized di-thio-ether, which could be useful as a potential chelating ligand or bridging ligand for coordination chemistry. This di-thio-acetal 1 crystallizes in the ortho-rhom-bic space group Pbca. The phenyl rings of the benzyl groups and that of the vanillin unit form dihedral angles of 35.38 (6) and 79.77 (6)°, respectively. The crystal structure, recorded at 100 K, displays both weak intra-molecular O-H⋯O and inter-molecular O-H⋯S hydrogen bonding.

Crystal structure of the coordination polymer catena-poly[[[(acetonitrile-κN)copper(I)]-µ3-1,3-dithiolane-κ3 S:S:S'] hexafluoridophosphate].

The polymeric title compound, [Cu2(C2H3N)2(C3H6S2)2](PF6)2, represents an example of a one-dimensional coordination polymer resulting from the reaction of [Cu(MeCN)4][PF6] with 1,3-di-thiol-ane. The cationic one-dimensional ribbon consists of two copper(I) centers each ligated by one aceto-nitrile mol-ecule and inter-connected through two bridging 1,3-di-thiol-ane ligands. One S-donor site of each ligand is κ1-bound to Cu, whereas the second S atom acts as a four-electron donor, bridging two Cu atoms in a κ4-bonding mode. The positive charge of each copper cation is compensated for by a hexa-fluorido-phosphate counter-ion. In the crystal, the polymer chains are linked by a series of C-H⋯F hydrogen bonds, forming a supra-molecular framework.

1,3-Dithianes as Assembling Ligands for the Construction of Copper(I) Coordination Polymers. Investigation of the Impact of the RC(H)S2C3H6 Substituent and Reaction Conditions on the Architecture of the 0D-3D Networks.

The parent compound 1,3-dithiane (L1) was reacted with CuI providing the 1D coordination polymer [{Cu(µ2-I)2Cu}(µ2-L1)2] n (CP1), an isostructural compound [{Cu(µ2-Br)2Cu}(µ2-L1)2] n (CP2) was isolated upon treatment of CuBr with L1. In contrast, treatment of L1 with CuCl results in the formation of 2D polymeric [{Cu(µ2-Cl)2Cu}(µ2-L1)] n (CP3), in which each sulfur atom acts as a 4-electron donor. The 1D compounds [{Cu(µ2-X)2Cu}(µ2-L2)2] n (CP7, X = Br, and CP8, X = Cl) resulting from treatment of 2-methyl-1,3 dithiane (L2) with CuBr and CuCl are isostructural with their CuI homologue [{Cu(µ2-I)2Cu}(µ2-L2)2] n (CP5), reported previously. Using CuCN, a 2D CP of composition [{Cu(µ2-CN)2Cu}(µ2-L2)2] n (CP9) has been isolated. Complexation of 2-isobutyl-1,3-dithiane (L3) on CuI generates a 2D material [{Cu3(µ3-I)(µ2-I)2(µ2-L3)2}] n (CP10), incorporating the usual trinuclear µ3-I-capped Cu clusters as SBUs, whereas 2D-polymeric compounds [{Cu(µ2-Br)2Cu}(µ2-L3)2] n (CP11) and [{Cu(µ2-Cl)2Cu}(µ2-L3)2] n (CP12) were obtained with CuBr and CuCl. Treatment of 2-Me3Si-1,3-dithiane (L4) with CuX yields the series [{Cu2(µ4-X)(µ2-X)}(µ2-L4)] n (CP13-CP15). With 2-phenyl-1,3-dithiane (L5), the outcome of the reaction with CuI depends on the reaction conditions. Reaction with CuI in MeCN provides a 1D ribbon [{Cu(µ2-I)2Cu}(MeCN)2(µ2-L5)2] n (CP16), whereas treatment of CuI with L5 in hot EtCN yields 2D-polymeric[{Cu3(µ3-I)(µ2-I)2(µ2-L5)2}] n (CP17). A reversible phase transition from triclinic P1̅ to monoclinic P21/ m is observed when recording the structure of CP16 at five different temperatures in the 100-300 K range. Ligand L6 containing a ferrocenyl function at the 2-position was also probed as organometallic dithioether ligand. Reaction of L6 with 1 equiv of CuI produces the 0D dinuclear complex [{Cu(µ2-I)2Cu}(η1-L6)2(MeCN)2] (D1), whereas treatment with 2 equiv of CuI affords the novel 1D CP [{Cu(µ3-I)2Cu}(µ-L6)] n (CP18), in which both S atoms of one L6 molecule span two copper centers of the infinite (CuI) n ribbon. Some selected results of thermal analyses and luminescence measurements are also presented.

Control of Structures and Emission Properties of (CuI) n 2-Methyldithiane Coordination Polymers.

A structurally unique and strongly luminescent nonporous 3D coordination polymer (CP) [Cu8I8(methyldithiane)4] n, CP3, has been prepared in a quasi-anticipated manner from 2-methyl-1,3-dithiane, L1, and CuI. This CP incorporates an unprecedented Cu8I8 cluster built upon two side-fused open cubanes. The crystal structure of CP3 has been determined at 100, 150, 200, 250, 300, 350, and 400 K to study the temperature dependence of the Cu···Cu distances. Two other topological 1D and 2D CPs isomers of formula [{Cu2I2}(L1)2] n featuring dinuclear {Cu2(µ2-I)2} rhomboids were also obtained independently by control of the reaction conditions. These two CPs convert into CP3 in hot PrCN, thus indicating that this latter material is the thermodynamic product. While CP1 and CP2 are not emissive, CP3 exhibits an intense luminescence due to the incorporation of the octanuclear Cu8I8 clusters as secondary building units within the network. The photophysical properties of CP3 have been investigated and rationalized by means of DFT and TDDFT computing. Furthermore, the thermal stability of these materials has been studied by ATG and DSC analyses. The Raman spectra of CP1-3 have been recorded in the solid state in the 50-500 cm-1 region.

Assembly of Coordination Polymers Using Thioether-Functionalized Octasilsesquioxanes: Occurrence of (CuX)n Clusters (X=Br and I) within 3D-POSS Networks.

For the first time, POSS-based coordination polymers (CPs) have been structurally characterized. These CPs were obtained in high yield via self-assembly reactions of thioether-functionalized polysilsesquioxanes with CuI salts under mild conditions. Single crystal analyses revealed the formation of 3D networks incorporating different secondary building units (SBUs) as connection nodes. The nature of the -SAr functionality allows a fine-tuning of the cluster nuclearity, that is, butterfly-shaped Cu2 X2 or closed cubane-type Cu4 I4 cores. As such, the resulting hybrid materials exhibit a combination of high thermal stability arising from the inorganic POSS core along with interesting luminescent properties conferred by the cubane cluster core. Furthermore, the occurrence of channels has been shown crystallographically in the case of the Cu4 I4 cluster containing CP.

Synthesis and characterization of polyaniline-silica composites: Raspberry vs core-shell structures. Where do we stand?

The synthesis of polyaniline-silica composites has been reinvestigated in view of the opposing results found in the literature. Firstly, we synthesized silica particles with tunable size using the Stöber process. These silica particles have been fully characterized before being used as solid support for the polymerization of aniline. This polymerization was performed according to a published procedure where the pH of the reaction mixture was below the pKa of aniline but at a value where the silica particles surface was still slightly negatively charged. The objective of this procedure was to favor electrostatic interactions between anilinium cations and the silica surface to lead to the formation of silica-polyaniline core-shell particles. Several sets of nanocomposites were prepared under different experimental conditions (oxidant/aniline ratio, silica concentration, temperature, silica particles diameters). The study evidenced that under all the conditions used the formation of core-shell nanoparticles is impossible. However, using different particle sizes, noticeable morphological differences were observed. The use of large silica particles led to the formation of non-uniform polyaniline-silica composites whereas the use of smaller particles always led to raspberry-like morphology as reported by other groups in highly acidic media. The difference in morphology led to different electrical properties with electrical conductivities measured at room temperature ranging from 1.6×10-3 to 2.5×10-5S cm-1.

Ultracompact x-ray dosimeter based on scintillators coupled to a nano-optical antenna.

We show that nano-optical antennas are capable of controlling the luminescence induced by the absorption of x rays into matter. The x-ray-excited luminescence from a tiny scintillation cluster coupled to a horn nano-optical antenna is highly directed and determined by the antenna's geometrical parameters. Directionality is sufficiently high to efficiently outcouple the x-ray-excited luminescence to a narrow single-mode optical fiber, thus enabling ultracompact fiber-integrated x-ray sensors. Our nano-optically driven approach offers the possibility of x-ray profiling and dosimetry in ultra-confined environments, opening up new avenues in the fields of x-ray imaging, as well as medical and industrial endoscopy. With this study, to the best of our knowledge, nano-optical antennas make a first key contribution to the development of x-ray sensing protocols and architectures.

Diacetylenes with Ionic-Liquid-Like Substituents: Associating a Polymerizing Cation with a Polymerizing Anion in a Single Precursor for the Synthesis of N-Doped Carbon Materials.

Imidazolium- and benzimidazolium-substituted diacetylenes with bromide or nitrogen-rich dicyanamide and tricyanomethanide anions were synthesized and used as precursors for the preparation of N-doped carbon materials. On pyrolysis under argon at 800 °C both halide precursors afforded graphite-like structures with nitrogen contents of about 8.5%. When the dicyanamide and tricyanomethanide precursors were thermolyzed at the same temperature, graphite-like structures were obtained that exhibit nitrogen contents in the range 17-20 wt%; thereby, the benefit of associating a polymerizing cation with a polymerizing anion in a single precursor was demonstrated. On pyrolysis at 1100 °C the nitrogen contents of the latter pyrolysates remain high (ca. 6 wt%). Adsorption measurements with krypton at 77 K indicated that the materials are nonporous. The highest electrical conductivity was observed for a pyrolysate with one of the lowest nitrogen contents, which also has the highest degree of graphitization. Thus, the quest for N-rich carbons with high electrical conductivities should include both maximization of the nitrogen content and optimization of the degree of graphitization. Crystallographic investigation of the precursors and spectroscopic characterization of the pyrolysates prepared by heating at 220 °C indicate that construction of the final carbon framework does not involve the intermediate formation of a polydiacetylene.

Surfactant behavior of ionic liquids involving a drug: from molecular interactions to self-assembly.

Aggregates formed in an aqueous medium by three ionic liquids CnMImIbu made up of 1-alkyl-3-methyl-imidazolium cation (n = 4, 6, 8) and ibuprofenate anion are investigated. Dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM), (1)H nuclear magnetic resonance measurements, and atom-scale molecular dynamics simulations are used to shed light on the main interactions governing the formation of the aggregates and their composition. At high concentration, mixed micelles are formed with a composition that depends on the imidazolium alkyl chain length. For the shortest alkyl chain, micelles are mainly composed of ibuprofenate anions with some imidazolium cations intercalated between the anions. Upon increasing the alkyl chain length, the composition of the aggregates gets enriched in imidazolium cations and aggregates of stoichiometric composition are obtained. Attractive interactions between these aggregates led to the formation of larger aggregates. As suggested by molecular simulations, these larger aggregates might constitute the early stage of phase separation. Transitions from micelles to vesicles or ribbons are observed due to dilution effects and changes in the chemical composition of the aggregates. We also show that aggregation can be probed using simple microscopic quantities such as radial distribution functions and average solvation numbers.

Drug delivery systems based on pharmaceutically active ionic liquids and biocompatible poly(lactic acid).

Poly(l-lactic acid) (PLLA) membranes containing pharmaceutically active ionic liquids (API-ILs) have been prepared by using a simple film casting from solvent evaporation method. Several sets of membranes were prepared from two different ionic liquids namely 1-methyl-3-butyl-imidazolium ibuprofenate (C4MImIbu) and lidocainium ibuprofenate (LidIbu) with different API-IL contents. Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Wide-Angle and Small-Angle X-ray Scattering (WAXS and SAXS) revealed the strong influence of both the IL nature and content on the morphology and the crystallinity of the resulting PLLA. At 20 weight%, LidIbu was shown to act as a plasticizer for PLLA and homogeneous membranes were obtained. In contrast, at the same IL content, phase separation occurred using C4MImIbu, resulting in the formation of porous PLLA. An increase of LidIbu content to 50 weight% results also in phase separation. 1H and 1H-13C CP-MAS NMR measurements evidenced the influence of different morphologies and crystallinities on IL mobility. C4MImIbu was found to be highly mobile whereas the mobility of LidIbu was content dependent. At low percent, low mobility was observed while at higher content, two populations with respectively high and low mobility were observed. These PLLA-IL membranes were further tested as drug delivery systems. In accordance with the morphology and mobility obtained, we demonstrated that release kinetics from PLLA membranes can be tuned by the nature and the content of API-ILs. Sustainable release kinetics were obtained with API-IL acting as a plasticizer while the fastest release was obtained with API-IL acting as a porogenic agent.

Surfactant properties of ionic liquids containing short alkyl chain imidazolium cations and ibuprofenate anions.

Interfacial tension, electrical conductivity, NMR self-diffusion and DLS experiments have been used to investigate the self-aggregation in water of ionic liquids associating an ibuprofenate anion and 1-alkyl-3-methylimidazolium [C(n)MIm](+) (n = 4, 6, 8) cations. Despite the short alkyl chain on imidazolium cations (n ≤ 8), these ionic liquids exhibit particularly low Critical Aggregation Concentrations (CAC), significantly lower than their parent 1-alkyl-3-methylimidazolium chloride salts. This behaviour is attributed to the formation of catanionic pairs between ibuprofenate and imidazolium.

Ionogels, ionic liquid based hybrid materials.

The current interest in ionic liquids (ILs) is motivated by some unique properties, such as negligible vapour pressure, thermal stability and non-flammability, combined with high ionic conductivity and wide electrochemical stability window. However, for material applications, there is a challenging need for immobilizing ILs in solid devices, while keeping their specific properties. In this critical review, ionogels are presented as a new class of hybrid materials, in which the properties of the IL are hybridized with those of another component, which may be organic (low molecular weight gelator, (bio)polymer), inorganic (e.g. carbon nanotubes, silica etc.) or hybrid organic-inorganic (e.g. polymer and inorganic fillers). Actually, ILs act as structuring media during the formation of inorganic ionogels, their intrinsic organization and physicochemical properties influencing the building of the solid host network. Conversely, some effects of confinement can modify some properties of the guest IL, even though liquid-like dynamics and ion mobility are preserved. Ionogels, which keep the main properties of ILs except outflow, while allowing easy shaping, considerably enlarge the array of applications of ILs. Thus, they form a promising family of solid electrolyte membranes, which gives access to all-solid devices, a topical industrial challenge in domains such as lithium batteries, fuel cells and dye-sensitized solar cells. Replacing conventional media, organic solvents in lithium batteries or water in proton-exchange-membrane fuel cells (PEMFC), by low-vapour-pressure and non flammable ILs presents major advantages such as improved safety and a higher operating temperature range. Implementation of ILs in separation techniques, where they benefit from huge advantages as well, relies again on the development of supported IL membranes such as ionogels. Moreover, functionalization of ionogels can be achieved both by incorporation of organic functions in the solid matrix, and by encapsulation of molecular species (from metal complexes to enzymes) in the immobilized IL phase, which opens new routes for designing advanced materials, especially (bio)catalytic membranes, sensors and drug release systems (194 references).