ORCID Profile
0000-0002-6188-3957
Current Organisation
KU Leuven
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Publisher: Wiley
Date: 28-01-2010
Abstract: A series of nitrile-functionalized ionic liquids were found to exhibit temperature-dependent miscibility (thermomorphism) with the lower alcohols. Their coordinating abilities toward cobalt(II) ions were investigated through the dissolution process of cobalt(II) bis(trifluoromethylsulfonyl)imide and were found to depend on the donor abilities of the nitrile group. The crystal structures of the cobalt(II) solvates [Co(C(1)C(1CN)Pyr)(2)(Tf(2)N)(4)] and [Co(C(1)C(2CN)Pyr)(6)][Tf(2)N](8), which were isolated from ionic-liquid solutions, gave an insight into the coordination chemistry of functionalized ionic liquids. Smooth layers of cobalt metal could be obtained by electrodeposition of the cobalt-containing ionic liquids.
Publisher: Wiley
Date: 20-01-2009
Abstract: The dissolution process of metal complexes in ionic liquids was investigated by a multiple-technique approach to reveal the solvate species of the metal in solution. The task-specific ionic liquid betainium bis(trifluoromethylsulfonyl)imide ([Hbet][Tf(2)N]) is able to dissolve stoichiometric amounts of the oxides of the rare-earth elements. The crystal structures of the compounds [Eu(2)(bet)(8)(H(2)O)(4)][Tf(2)N](6), [Eu(2)(bet)(8)(H(2)O)(2)][Tf(2)N](6) x 2 H(2)O, and [Y(2)(bet)(6)(H(2)O)(4)][Tf(2)N](6) were found to consist of dimers. These rare-earth complexes are well soluble in the ionic liquids [Hbet][Tf(2)N] and [C(4)mim][Tf(2)N] (C(4)mim = 1-butyl-3-methylimidazolium). The speciation of the metal complexes after dissolution in these ionic liquids was investigated by luminescence spectroscopy, (1)H, (13)C, and (89)Y NMR spectroscopy, and by the synchrotron techniques EXAFS (extended X-ray absorption fine structure) and HEXS (high-energy X-ray scattering). The combination of these complementary analytical techniques reveals that the cationic dimers decompose into monomers after dissolution of the complexes in the ionic liquids. Deeper insight into the solution processes of metal compounds is desirable for applications of ionic liquids in the field of electrochemistry, catalysis, and materials chemistry.
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8CC07092J
Abstract: A novel, reversible redox-active MRI probe, GdNR1, has been developed based on the biologically-inspired nicotinimidium redox switch.
Publisher: Proceedings of the National Academy of Sciences
Date: 27-06-2019
Abstract: During pregnancy, the placenta functions as surrogate fetal lungs, kidneys, and gut. Proper placental functioning is therefore paramount during embryonic development. Indeed, placental defects are highly prevalent in mouse mutants showing embryonic death. Here we validate a contrast agent that allows development of the intact placenta to be visualized using microfocus computed topography. This technique enables an initial 3D inspection of the overall placental structure and provides the possibility to quantify different compartments in the placenta. Moreover, the nondestructive nature of this contrast agent permits further histological processing of the same s le when defects are observed.
Publisher: American Chemical Society (ACS)
Date: 10-06-2011
DOI: 10.1021/JP2027675
Abstract: Two series of 1-alkylpyridinium and N-alkyl-N-methylpiperidinium ionic liquids functionalized with a nitrile group at the end of the alkyl chain have been synthesized. Structural modifications include a change of the alkyl spacer length between the nitrile group and the heterocycle of the cationic core, as well as adding methyl or ethyl substituents on different positions of the pyridinium ring. The anions are the bromide and the bis(trifluoromethylsulfonyl)imide ion. All the bis(trifluoromethylsulfonyl)imide salts as well as the bromide salts with a long alkyl spacer were obtained as viscous liquids at room temperature, but some turned out to be supercooled liquids. In addition, pyrrolidinium and piperidinium ionic liquids with two nitrile functions attached to the heterocyclic core have been prepared. The crystal structures of seven pyridinium bis(trifluoromethylsulfonyl)imide salts are reported. Quantum chemical calculations have been performed on model cations and ion pairs with the bis(trifluoromethylsulfonyl)imide anion. A continuum model has been used to take solvation effects into account. These calculations show that the natural partial charge on the nitrogen atom of the nitrile group becomes more negative when the length of the alkyl spacer between the nitrile functional group and the heterocyclic core of the cation is increased. Methyl or methoxy substituents on the pyridinium ring slightly increase the negative charge on the nitrile nitrogen atom due to their electron-donating abilities. The position of the substituent (ortho, meta, or para) has only a very minor effect on the charge of the nitrogen atom. The (15)N NMR spectra of the bis(trifluoromethylsulfonyl)imide ionic liquids were recorded with the nitrogen-15 nucleus at its natural abundance. The chemical shift of the (15)N nucleus of the nitrile nitrogen atom could be correlated with the calculated negative partial charge on the nitrogen atom.
Location: United States of America
No related grants have been discovered for Tatjana Parac-Vogt.