TY  - JOUR
A1  - Fudickar, Werner
A1  - Metz, Melanie
A1  - Mai-Linde, Yasemin
A1  - Krüger, Tobias
A1  - Kelling, Alexandra
A1  - Sperlich, Eric
A1  - Linker, Torsten
T1  - Influence of functional groups on the ene reaction of singlet oxygen with 1,4-cyclohexadienes
JF  - Photochemistry and photobiology : the official journal of the American Society for Photobiology
N2  - The photooxygenation of 1,4-cyclohexadienes has been studied with a special focus on regio- and stereoselectivities. In all examples, only the methyl-substituted double bond undergoes an ene reaction with singlet oxygen, to afford hydroperoxides in moderate to good yields. We explain the high regioselectivities by a "large-group effect" of the adjacent quaternary stereocenter. Nitriles decrease the reactivity of singlet oxygen, presumably by quenching, but can stabilize proposed per-epoxide intermediates by polar interactions resulting in different stereoselectivities. Spiro lactams and lactones show an interesting effect on regio- and stereoselectivities of the ene reactions. Thus, singlet oxygen attacks the double bond preferentially anti to the carbonyl group, affording only one regioisomeric hydroperoxide. If the reaction occurs from the opposite face, the other regioisomer is exclusively formed by severe electrostatic repulsion in a perepoxide intermediate. We explain this unusual behavior by the fixed geometry of spiro compounds and call it a "spiro effect" in singlet oxygen ene reactions.
Y1  - 2021
U6  - https://doi.org/10.1111/php.13422
SN  - 0031-8655
SN  - 1751-1097
VL  - 97
IS  - 6
SP  - 1289
EP  - 1297
PB  - Wiley
CY  - Malden, Mass.
ER  - 
TY  - JOUR
A1  - Zabel, André
A1  - Winter, Alette
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Strauch, Peter
T1  - Tetrabromidocuprates(II)-Synthesis, Structure and EPR
JF  - International journal of molecular sciences
N2  - 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.
KW  - tetrabromidocuprate(II)
KW  - X-ray structure
KW  - electron paramagnetic resonance
KW  - copper(II)
Y1  - 2016
U6  - https://doi.org/10.3390/ijms17040596
VL  - 17
IS  - 4
PB  - MDPI
CY  - Basel
ER  - 
TY  - GEN
A1  - Zabel, André
A1  - Winter, Alette
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Strauch, Peter
T1  - Tetrabromidocuprates(II)-Synthesis, Structure and EPR
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 226 
KW  - tetrabromidocuprate(II)
KW  - X-ray structure
KW  - electron paramagnetic resonance
KW  - copper(II)
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-91470
ER  - 
TY  - GEN
A1  - Zehbe, Kerstin
A1  - Kollosche, Matthias
A1  - Lardong, Sebastian
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Taubert, Andreas
T1  - Ionogels based on poly(methyl methacrylate) and metal-containing ionic liquids
BT  - correlation between structure and mechanical and electrical properties
N2  - 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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 361 
KW  - microstructure
KW  - ionogels
KW  - ionic liquids
KW  - phase separation
KW  - mechanical properties
KW  - ionic conductivity
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-400607
ER  -