Mössbauer Spectroscopy and X-ray Diffraction Study of 57Fe-Labeled Tetrachloroferrate(III)-Based Magnetic Ionic Liquids

Four 57Fe-labeled tetrachloroferrates(III) of organic cations (1-butyl-3-methylimidazolium, 1-allyl-3-methylimidazolium, 1-methyl-1-propylpyrrolidinium, tetraphenylphosphonium) were examined by temperature-dependent Mössbauer spectroscopy. The hyperfine and dynamic parameters of the iron(III) site were determined. Single crystal X-ray diffraction data of [Ph4P][FeCl4] were collected at four temperatures (295, 223, 173, and 123 K), and the dynamics of the iron atom inferred from the Mössbauer data and the single crystal Ui,j parameters have been compared

Melchior Schmid,... / H. I. Schottenberger fec.

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Synthesis and characterisation of organometallic imidazolium compounds that include a new organometallic ionic liquid

New imidazolium salts, 1-(prop-2-ynyl)-3-vinyl-3H-imidazol-1-ium bromide, 1a, the tetraphenylborate, 1b, and hexafluorophosphate, 1c, salts of 1a and 3-allyl-1-(prop-2-ynyl)-3H-imidazol-1-ium bromide, 2a, containing alkene and alkyne groups for derivatisation were prepared from commercially available starting materials and fully characterised. New organometallic imidazolium salts, [{μ2-HCCCH2N=C(H)N(CH=CH2) CH=CH}Co2(CO)6]X [X- = BF4-, B(C6H5)4- or PF6-], 3a, 3b or 3c, and [{μ2-HCCCH2N=C(H)N(CH2CH=CH2) CH=CH}Co2(CO)6]BF4, 4a, and a new organometallic ionic liquid, [{μ2-HCCCH2 N=C(H)N(CH2CH=CH2)CH=CH}Co2(CO)6] PF6, 4b, were isolated by reacting 1a-c or 2a with Co2 (CO)8. The compound 4b, the first ionic liquid bearing an organometallic moiety covalently attached to the cation, melts reversibly at 75-77°C without decomposition. The imidazolium protons in 1b and 3b are shielded in the 1H NMR as a result of π-interaction with the phenyl rings of the tetraphenyl-borate anion. The cation-anion contacts (C-H ⋯ π ∼ 2.6 Å) observed in the molecular structure of 3b in the solid state are also maintained in solution, as evidenced in NOE NMR experiments. The molecular structures of 3b and 3c show an alkyne unit bonded to a Co2(CO)6 fragment with the C≡C bond perpendicular to the Co-Co bond.Articl

Temperature and moisture dependent powder X ray diffraction studies of kanemite NaSi2O4 OH x 3H 2 O

The high temperature and moisture dependent behaviour of synthetic kanemite NaSi2O4 OH 3H2O or SKS 10 has been studied by in situ powder X ray diffraction. Heating experiments in the range between ambient temperatures and 250 C confirm earlier investigations that the dehydration of kanemite occurs in two steps. According to our results the two different reactions start at amp; 8764;30 and 75 C. The dehydration products have the following compositions NaSi2O4 OH H2O monohydrate and NaSi2O4 OH , respectively. The crystal structures of both phases have been solved at ambient conditions ab initio from laboratory powder diffraction data using samples that have been carefully dehydrated at 60 and 150 C, respectively, and refined subsequently by the Rietveld method. Both compounds belong to the group of single layer silicates based on Si2O4 OH sheets. The sodium cations are located between the tetrahedral sheets and are surrounded by oxygen atoms from silicate anions and or water molecules. Depending on the dehydration step the coordination numbers of the alkali ions vary between six kanemite and five NaSi2O4 OH . Kanemite and its two dehydration products show structural similarities which are discussed in detail. Moisture dependent diffraction studies at ambient temperatures indicate that kanemite is stable between 10 and at least 90 relative humidity. Below the lower threshold a transformation to the monohydrate phase was observed. Dehydration and rehydration as a function of humidity is reversible. However, this process is combined with a significant loss of crystallinity of the sample

Synthesis and characterisation of organometallic imidazolium compounds that include a new organometallic ionic liquid.

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A cytotoxic bis(carbene)gold(I) complex of ferrocenyl complexes: Synthesis and structural characterisation

The N-heterocyclic carbene (NHC) precursors 1-[(E)-2-butenyl]-3-(4- ferrocenylphenyl)imidazolium bromide (2) and 1-[(E)-2-butenyl]-3-(4- ferrocenylphenyl)imidazolium tetrafluoroborate (3) were derived from 1-(4-ferrocenylphenyl)imidazole. Ferrocenyl complex 3 reacts with Ag 2O and chloro(dimethylsulfide)gold(i) in the presence of tetraethylammonium chloride to produce the mixed metal species bis{1-[(E)-2-butenyl]-3-(4-ferrocenylphenyl)-2H-imidazol-2-ylidene}gold(i) tetrafluoroborate (4). Single crystal X-ray structure analyses of 1, 3 and 4 indicate that the NCHN-hydrogen in 3 is hydrogen bonded to the BF 4- anion [C(H1)⋯F, 3.265(4) Å], as is also reflected in the position of its 1H NMR chemical shift. Cytotoxicity studies show that complex 4 is selective for cancer cells and active against the tumour cell lines Jurkat and MCF 7. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.The N-heterocyclic carbene (NHC) precursors 1-[(E)-2-butenyl]-3-(4- ferrocenylphenyl)imidazolium bromide (2) and 1-[(E)-2-butenyl]-3-(4- ferrocenylphenyl)imidazolium tetrafluoroborate (3) were derived from 1-(4-ferrocenylphenyl)imidazole. Ferrocenyl complex 3 reacts with Ag 2O and chloro(dimethylsulfide)gold(i) in the presence of tetraethylammonium chloride to produce the mixed metal species bis{1-[(E)-2-butenyl]-3-(4-ferrocenylphenyl)-2H-imidazol-2-ylidene}gold(i) tetrafluoroborate (4). Single crystal X-ray structure analyses of 1, 3 and 4 indicate that the NCHN-hydrogen in 3 is hydrogen bonded to the BF 4- anion [C(H1)⋯F, 3.265(4) Å], as is also reflected in the position of its 1H NMR chemical shift. Cytotoxicity studies show that complex 4 is selective for cancer cells and active against the tumour cell lines Jurkat and MCF 7. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.ArticleArticl

Phase-out-compliant fluorosurfactants

Expedient alkylations of 1-methyl-3H-imidazole-2-thione, a pharmaceutical active ingredient available in bulk quantities, provide high yield access to numerous protonated, or quaternized imidazoliums with chemospecific attachment of the fluoroponytail at the 2-mercapto functionality. The deprotonated primary target products represent valuable nitrogen heterocyclic bases, capable of further substitution, and salt or complex formation. Specific physicochemical characteristics that are relevant for phase and surface responsive behavior, e.g. critical micelle concentration, oleophobicity, depression of the aqueous surface tension, foam formation, emulsification of microgranular PTFE, are investigated for selected representatives and compared to the properties of common fluorosurfactants and ionic liquids. Remarkably, it is found that halogen bonding between iodide counterions of respective polyfluoroalkylmethimazolium systems and 1-iodoperfluoroalkanes, serving as the σ-hole partner of the halides, greatly affectthe solubility profile of the resulting molecular adducts. Single-crystal X-ray structure determinations are carried out across the new fluorous substance classes. Strikingly, the helical arrangement of fluorine atoms along the chains typically encountered in polyfluorinated compounds is not found as the prevailing conformation. Rather, they are outnumbered by structural motifs exhibiting the rare zig-zag (linear alkane-like) chain conformation. Key derivatives are also subjected to preliminary ecotoxicological testing.Peer reviewe