Superfluorinated Ionic Liquid Crystals Based on Supramolecular, Halogen-Bonded Anions

Unconventional ionic liquid crystals in which the liquid crystallinity is enabled by halogen-bonded supramolecular anions [CnF2n+1-I···I···I-CnF2n+1]- are reported. The material system is unique in many ways, demonstrating for the first time 1)ionic, halogen-bonded liquid crystals, and 2)imidazolium-based ionic liquid crystals in which the occurrence of liquid crystallinity is not driven by the alkyl chains of the cation

Tetrachloridocuprates(II)—Synthesis and Electron Paramagnetic Resonance (EPR) Spectroscopy

Ionic liquids (ILs) on the basis of metal containing anions and/or cations are of interest for a variety of technical applications e.g., synthesis of particles, magnetic or thermochromic materials. We present the synthesis and the results of electron paramagnetic resonance (EPR) spectroscopic analyses of a series of some new potential ionic liquids based on tetrachloridocuprates(II), [CuCl4]2−, with different sterically demanding cations: hexadecyltrimethylammonium 1, tetradecyltrimethylammonium 2, tetrabutylammonium 3 and benzyltriethylammonium 4. The cations in the new compounds were used to achieve a reasonable separation of the paramagnetic Cu(II) ions for EPR spectroscopy. The EPR hyperfine structure was not resolved. This is due to the exchange broadening, resulting from still incomplete separation of the paramagnetic Cu(II) centers. Nevertheless, the principal values of the electron Zeemann tensor (g║ and g┴) of the complexes could be determined. Even though the solid substances show slightly different colors, the UV/Vis spectra are nearly identical, indicating structural changes of the tetrachloridocuprate moieties between solid state and solution. The complexes have a promising potential e.g., as high temperature ionic liquids, as precursors for the formation of copper chloride particles or as catalytic paramagnetic ionic liquids

1,1'-Dithiolenes: the Good, the Not Bad, and the Ugly

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1,1'-Dithiolenes: the Good, the Not Bad, and the Ugly

A series of 1, 1'-dithiolate ligands were used in the attempted preparation of metal complexes. These bidentate sulphur ligands were subsequently used in aromatic nucleophilic substitution reactions giving rise to several novel organic donor molecules. The electrochemistry data of two of the donors and their subsequent use in the preparation of donor-acceptor compounds is presented. One donor-acceptor compound exhibited high room temperature conductivity (up to 900 S cm$\text{}^{-1}$) and remained metallic down to low temperature. One donor containing two tetrathiafulvalene units was studied by near infrared absorption spectroscopy. An intervalence transition in the monocation form of this donor was observed, indicating that it behaves as a class II mixed valence compound

INTERVALENCE TRANSITIONS IN MIXED-VALENCE BIS(TETRATHIAFULVALENE) COMPOUNDS

The series of new bis(tetrathiafulvalene) [bis(TTF)] compounds 10-12a,b have been synthetized with the TTF-like synthon 8a,b, previously used to prepare the pyrazine-fused bis(TTF) 7a,b. These compounds exhibit four reversible sequential one-electron oxidation steps, on the basis of cyclic voltammetry. For the cation radicals 7b(.+), 10(.+), and 12(.+), generated electrochemically, rather intense and broad bands in the near-IR region, specific of class II mixed valence compounds, were found. Theoretical calculations at the semiempirical AM1 level as well as at the ab-initio level indicated that these cation radicals are charge-distributions localized as related to mixed valence species. These calculations also allowed the low-energy absorption bands to be assigned to intervalence transitions; these transitions imply the existence of multiple low-lying excited states that are non-adiabatically coupled to the ground-state of these open-shell species