Thirteen N-butylpyridinium salts, including three monometallic [C 4 Py] 2 [MCl 4 ], nine bimetallic [C 4 Py] 2 [M 1Àx a M x b Cl 4 ]a nd one trimetallicc ompound [C 4 Py] 2 [M 1Ày-z a M y b M z c Cl 4 ](M = Co, Cu, Mn; x = 0.25, 0.50 or 0.75 and y = z = 0.33), were synthesized and their structure and thermala nd electrochemical properties were studied. All compoundsa re ionic liquids(ILs) with melting points between 69 and 93 8C. X-ray diffraction provest hat all ILs are isostructural. The conductivity at room temperature is be-tween1 0 À4 and1 0 À8 Scm À1 .S ome Cu-based ILs reach conductivities of 10 À2 Scm À1 ,w hichi s, however, probablyd ue to IL dec. This correlates with the opticalb andgap measurementsi ndicating the formation of large bandgap semiconductors.A te levated temperaturesa pproaching the melting points, the conductivities reach up to 1.47 10 À1 Scm À1 at 70 8C. The electrochemical stability windowso ft he ILs are between2.5 and 3.0 V.

Six N-alkylpyridinium salts [C n Py] 2 [MCl 4 ] (n = 4 or 12 and M = Co, Cu, Zn) were synthesized, and their structure and thermal properties were studied. The [C 4 Py] 2 [MCl 4 ] compounds are monoclinic and crystallize in the space group P2 1 /n. The crystals of the longer chain analogues [C 12 Py] 2 [MCl 4 ] are triclinic and crystallize in the space group P1. Above the melting tem-[a]5640 perature, all compounds are ionic liquids (ILs). The derivatives with the longer C12 chain exhibit liquid crystallinity and the shorter chain compounds only show a melting transition. Consistent with single-crystal analysis, electron paramagnetic resonance spectroscopy suggests that the [CuCl 4 ] 2ions in the Cubased ILs have a distorted tetrahedral geometry.

Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs.

New mesoporous silk fibroin (SF)/silica hybrids were processed via a one-pot soft and energy-efficient sol–gel chemistry and self-assembly from a silica precursor, an acidic or basic catalyst, and the ionic liquid 1-butyl-3-methylimidazolium chloride, acting as both solvent and mesoporosity-inducer. The as-prepared materials were obtained as slightly transparent-opaque, amorphous monoliths, easily transformed into powders, and stable up to ca. 300 °C. Structural data suggest the formation of a hexagonal mesostructure with low range order and apparent surface areas, pore volumes, and pore radii of 205–263 m2 g–1, 0.16–0.19 cm3 g–1, and 1.2–1.6 nm, respectively. In all samples, the dominating conformation of the SF chains is the β-sheet. Cytotoxicity/bioactivity resazurin assays and fluorescence microscopy demonstrate the high viability of MC3T3 pre-osteoblasts to indirect (≥99 ± 9%) and direct (78 ± 2 to 99 ± 13%) contact with the SF/silica materials. Considering their properties and further improvements, these systems are promising candidates to be explored in bone tissue engineering. They also offer excellent prospects as electrolytes for solid-state electrochemical devices, in particular for fuel cells.

New ionogels (IGs) were prepared by combination of a series of sulfonate-based ionic liquids (ILs), 1-methyl-3-(4-sulfobutyl)­imidazolium para-toluenesulfonate [BmimSO3H]­[pTS], 1-methyl-1-butylpiperidiniumsulfonate para-toluenesulfonate [BmpipSO3]­[pTS], and 1-methyl-3-(4-sulfobutyl) imidazolium methylsulfonate [BmimSO3H]­[MeSO3] with a commercial stereolithography photoreactive resin. The article describes both the fundamental properties of the ILs and the resulting IGs. The IGs obtained from the ILs and the resin show high ionic conductivity of up to ca. 0.7·10–4 S/cm at room temperature and 3.4·10–3 S/cm at 90 °C. Moreover, the IGs are thermally stable to about 200 °C and mechanically robust. Finally, and most importantly, the article demonstrates that the IGs can be molded three-dimensionally using stereolithography. This provides, for the first time, access to IGs with complex 3D shapes with potential application in battery or fuel cell technology.