@article{ZehbeKolloscheLardongetal.2016, author = {Zehbe, Kerstin and Kollosche, Matthias and Lardong, Sebastian and Kelling, Alexandra and Schilde, Uwe and Taubert, Andreas}, title = {Ionogels Based on Poly(methyl methacrylate) and Metal-Containing Ionic Liquids: Correlation between Structure and Mechanical and Electrical Properties}, series = {International journal of molecular sciences}, volume = {17}, journal = {International journal of molecular sciences}, publisher = {MDPI}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms17030391}, pages = {16}, year = {2016}, abstract = {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.}, language = {en} } @article{ZabelWinterKellingetal.2016, author = {Zabel, Andr{\´e} and Winter, Alette and Kelling, Alexandra and Schilde, Uwe and Strauch, Peter}, title = {Tetrabromidocuprates(II)-Synthesis, Structure and EPR}, series = {International journal of molecular sciences}, volume = {17}, journal = {International journal of molecular sciences}, number = {4}, publisher = {MDPI}, address = {Basel}, doi = {10.3390/ijms17040596}, pages = {14}, year = {2016}, abstract = {Metal-containing ionic liquids (ILs) are of interest for a variety of technical applications, e.g., particle synthesis and materials with magnetic or thermochromic properties. In this paper we report the synthesis of, and two structures for, some new tetrabromidocuprates(II) with several "onium" cations in comparison to the results of electron paramagnetic resonance (EPR) spectroscopic analyses. The sterically demanding cations were used to separate the paramagnetic Cu(II) ions for EPR measurements. The EPR hyperfine structure in the spectra of these new compounds is not resolved, due to the line broadening resulting from magnetic exchange between the still-incomplete separated paramagnetic Cu(II) centres. For the majority of compounds, the principal g values (g|| and gK) of the tensors could be determined and information on the structural changes in the [CuBr4]2- anions can be obtained. The complexes have high potential, e.g., as ionic liquids, as precursors for the synthesis of copper bromide particles, as catalytically active or paramagnetic ionic liquids.}, language = {en} } @misc{ZabelWinterKellingetal.2016, author = {Zabel, Andr{\´e} and Winter, Alette and Kelling, Alexandra and Schilde, Uwe and Strauch, Peter}, title = {Tetrabromidocuprates(II)-Synthesis, Structure and EPR}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-91470}, pages = {14}, year = {2016}, abstract = {Metal-containing ionic liquids (ILs) are of interest for a variety of technical applications, e.g., particle synthesis and materials with magnetic or thermochromic properties. In this paper we report the synthesis of, and two structures for, some new tetrabromidocuprates(II) with several "onium" cations in comparison to the results of electron paramagnetic resonance (EPR) spectroscopic analyses. The sterically demanding cations were used to separate the paramagnetic Cu(II) ions for EPR measurements. The EPR hyperfine structure in the spectra of these new compounds is not resolved, due to the line broadening resulting from magnetic exchange between the still-incomplete separated paramagnetic Cu(II) centres. For the majority of compounds, the principal g values (g|| and gK) of the tensors could be determined and information on the structural changes in the [CuBr4]2- anions can be obtained. The complexes have high potential, e.g., as ionic liquids, as precursors for the synthesis of copper bromide particles, as catalytically active or paramagnetic ionic liquids.}, language = {en} } @article{ZabelWinterKellingetal.2016, author = {Zabel, Andre and Winter, Alette and Kelling, Alexandra and Schilde, Uwe and Strauch, Peter}, title = {Tetrabromidocuprates(II)-Synthesis, Structure and EPR}, series = {International journal of molecular sciences}, volume = {17}, journal = {International journal of molecular sciences}, publisher = {MDPI}, address = {Basel}, issn = {1422-0067}, doi = {10.3390/ijms17040596}, pages = {14}, year = {2016}, abstract = {Metal-containing ionic liquids (ILs) are of interest for a variety of technical applications, e.g., particle synthesis and materials with magnetic or thermochromic properties. In this paper we report the synthesis of, and two structures for, some new tetrabromidocuprates(II) with several "onium" cations in comparison to the results of electron paramagnetic resonance (EPR) spectroscopic analyses. The sterically demanding cations were used to separate the paramagnetic Cu(II) ions for EPR measurements. The EPR hyperfine structure in the spectra of these new compounds is not resolved, due to the line broadening resulting from magnetic exchange between the still-incomplete separated paramagnetic Cu(II) centres. For the majority of compounds, the principal g values (g|| and g(perpendicular to)) of the tensors could be determined and information on the structural changes in the [CuBr4](2-) anions can be obtained. The complexes have high potential, e.g., as ionic liquids, as precursors for the synthesis of copper bromide particles, as catalytically active or paramagnetic ionic liquids.}, language = {en} } @article{WessigGerngrossFreyseetal.2016, author = {Wessig, Pablo and Gerngross, Maik and Freyse, Daniel and Bruhn, P. and Przezdziak, Marc and Schilde, Uwe and Kelling, Alexandra}, title = {Molecular Rods Based on Oligo-spiro-thioketals}, series = {The journal of organic chemistry}, volume = {81}, journal = {The journal of organic chemistry}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/acs.joc.5b02670}, pages = {1125 -- 1136}, year = {2016}, abstract = {We report on an extension of the previously established concept of oligospiroketal (OSK) rods by replacing a part or all ketal moieties by thioketals leading to oligospirothioketal (OSTK) rods. In this way, some crucial problems arising from the reversible formation of ketals are circumvented. Furthermore, the stability of the rods toward hydrolysis is considerably improved. To successfully implement this concept, we first developed a number of new oligothiol building blocks and improved the synthetic accessibility of known oligothiols, respectively. Another advantage of thioacetals is that terephthalaldehyde (TAA) sleeves, which are too flexible in the case of acetals can be used in OSTK rods. The viability of the OSTK approach was demonstrated by the successful preparation of some OSTK rods with a length of some nanometers.}, language = {en} } @article{StrauchKossmannKellingetal.2016, author = {Strauch, Peter and Kossmann, Alexander and Kelling, Alexandra and Schilde, Uwe}, title = {EPR on bis(1,2-dithiosquarato)cuprate(II) in the bis(1,2-dithiosquarato)nickelate(II) host lattice - structure and spectroscopy}, series = {Chemical papers}, volume = {70}, journal = {Chemical papers}, publisher = {De Gruyter}, address = {Berlin}, issn = {0366-6352}, doi = {10.1515/chempap-2015-0154}, pages = {61 -- 68}, year = {2016}, abstract = {EPR spectroscopy is a well suited analytical tool to monitor the electronic situation around paramagnetic metal centres as copper(II) and therefore the structural influences on the paramagnetic ion. 1,2-Dithiosquaratometalates are available by direct synthesis from metal salts with dipotassium-1,2-dithiosquarate and the appropriate counter cations. Synthesis and characterisation of bis(benzyltributylammonium)1,2-dithiosquaratonickelate(II), (BzlBu(3)N)(2)[Ni(dtsq)(2)], and bis(benzyltributylammonium)1,2-dithiosquaratocuprate(II), (BzlBu(3)N)(2)[Cu(dtsq)(2)], with benzyltributylammonium as the counter ion is reported and the X-ray structures of two complexes, (BzlBu(3)N)(2)[Ni(dtsq)(2)] and (BzlBu(3)N)(2)[Cu(dtsq)(2)], are presented. Both complexes, crystallising in the monoclinic space group P2(1)/c, are isostructural with only small differences in the coordination sphere due to the different metal ions. The diamagnetic nickel complex is therefore well suited as a host lattice for the paramagnetic Cu(II) complex to measure EPR for additional structural information. (c) 2015 Institute of Chemistry, Slovak Academy of Sciences}, language = {en} } @article{SteeplesKellingSchildeetal.2016, author = {Steeples, Elliot and Kelling, Alexandra and Schilde, Uwe and Esposito, Davide}, title = {Amino acid-derived N-heterocyclic carbene palladium complexes for aqueous phase Suzuki-Miyaura couplings}, series = {New journal of chemistry}, volume = {40}, journal = {New journal of chemistry}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1144-0546}, doi = {10.1039/c5nj03337c}, pages = {4922 -- 4930}, year = {2016}, abstract = {In this work, three ligands produced from amino acids were synthesized and used to produce five bis- and PEPPSI-type palladium-NHC complexes using a novel synthesis route from sustainable starting materials. Three of these complexes were used as precatalysts in the aqueous-phase Suzuki-Miyaura coupling of various substrates displaying high activity. TEM and mercury poisoning experiments provide evidence for Pd-nanoparticle formation stabilized in water.}, language = {en} } @misc{SteeplesKellingSchildeetal.2016, author = {Steeples, Elliot and Kelling, Alexandra and Schilde, Uwe and Esposito, Davide}, title = {Amino acid-derived N-heterocyclic carbene palladium complexes for aqueous phase Suzuki-Miyaura couplings}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394488}, pages = {4922 -- 4930}, year = {2016}, abstract = {In this work, three ligands produced from amino acids were synthesized and used to produce five bis- and PEPPSI-type palladium-NHC complexes using a novel synthesis route from sustainable starting materials. Three of these complexes were used as precatalysts in the aqueous-phase Suzuki-Miyaura coupling of various substrates displaying high activity. TEM and mercury poisoning experiments provide evidence for Pd-nanoparticle formation stabilized in water.}, language = {en} } @article{SchildeKellingUmbreenetal.2016, author = {Schilde, Uwe and Kelling, Alexandra and Umbreen, Sumaira and Linker, Torsten}, title = {Crystal structures of three bicyclic carbohydrate derivatives}, series = {Acta crystallographica Section E ; Crystallographic communications}, volume = {72}, journal = {Acta crystallographica Section E ; Crystallographic communications}, number = {12}, publisher = {IUCR}, address = {Chester}, issn = {2056-9890}, doi = {10.1107/S2056989016018727}, pages = {1839 -- 1844}, year = {2016}, abstract = {The title compounds, [(1R,3R,4R,5R,6S)-4,5-bis(acetyloxy)-7-oxo-2-oxabicyclo- [4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acetyloxy-7- hydroxyimino-2-oxobicyclo[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and [(3aR,5R,6R,7R,7aS)-6,7-bis(acetyloxy)-2-oxooctahydropyrano[3,2-b]pyrrol-5- yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives. They can easily be synthesized in a few steps from commercially available glycals. As a result of the ring strain from the four-membered rings in (I) and (II), the conformations of the carbohydrates deviate strongly from the ideal chair form. Compound (II) occurs in the boat form. In the five-membered lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair conformation. As a result of the distortion of the sugar rings, the configurations of the three bicyclic carbohydrate derivatives could not be determined from their NMR coupling constants. From our three crystal structure determinations, we were able to establish for the first time the absolute configurations of all new stereocenters of the carbohydrate rings.}, language = {en} } @misc{SchildeKellingUmbreenetal.2016, author = {Schilde, Uwe and Kelling, Alexandra and Umbreen, Sumaira and Linker, Torsten}, title = {Crystal structures of three bicyclic carbohydrate derivatives}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-100833}, pages = {6}, year = {2016}, abstract = {The title compounds, [(1R,3R,4R,5R,6S)-4,5-bis­(acet­yloxy)-7-oxo-2-oxabi­cyclo[4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acet­yloxy-7-hy­droxy­imino-2-oxobi­cyclo­[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and [(3aR,5R,6R,7R,7aS)-6,7-bis­(acet­yloxy)-2-oxo­octa­hydro­pyrano[3,2-b]pyrrol-5-yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives. They can easily be synthesized in a few steps from commercially available glycals. As a result of the ring strain from the four-membered rings in (I) and (II), the conformations of the carbohydrates deviate strongly from the ideal chair form. Compound (II) occurs in the boat form. In the five-membered lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair conformation. As a result of the distortion of the sugar rings, the configurations of the three bicyclic carbohydrate derivatives could not be determined from their NMR coupling constants. From our three crystal structure determinations, we were able to establish for the first time the absolute configurations of all new stereocenters of the carbohydrate rings.}, language = {en} }