TY  - JOUR
A1  - Balischewski, Christian
A1  - Behrens, Karsten
A1  - Zehbe, Kerstin
A1  - Günter, Christina
A1  - Mies, Stefan
A1  - Sperlich, Eric
A1  - Kelling, Alexandra
A1  - Taubert, Andreas
T1  - Ionic liquids with more than one metal
BT  - optical and rlectrochemical properties versus d-block metal vombinations
JF  - Chemistry - a European journal
N2  - Thirteen N-butylpyridinium salts, including three monometallic [C4Py](2)[MCl4], nine bimetallic [C4Py](2)[(M1-xMxCl4)-M-a-Cl-b] and one trimetallic compound [C4Py](2)[(M1-y-zMyMz (c) Cl4)-M-a-M-b] (M=Co, Cu, Mn; x=0.25, 0.50 or 0.75 and y=z=0.33), were synthesized and their structure and thermal and electrochemical properties were studied. All compounds are ionic liquids (ILs) with melting points between 69 and 93 degrees C. X-ray diffraction proves that all ILs are isostructural. The conductivity at room temperature is between 10(-4) and 10(-8) S cm(-1). Some Cu-based ILs reach conductivities of 10(-2) S cm(-1), which is, however, probably due to IL dec. This correlates with the optical bandgap measurements indicating the formation of large bandgap semiconductors. At elevated temperatures approaching the melting points, the conductivities reach up to 1.47x10(-1) S cm(-1) at 70 degrees C. The electrochemical stability windows of the ILs are between 2.5 and 3.0 V.
KW  - bandgap
KW  - electrochemistry
KW  - ionic liquids
KW  - metal-containing ionic
KW  - liquids
KW  - tetrahalido metallates
Y1  - 2020
U6  - https://doi.org/10.1002/chem.202003097
SN  - 0947-6539
SN  - 1521-3765
VL  - 26
IS  - 72
SP  - 17504
EP  - 17513
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Balischewski, Christian
A1  - Bhattacharyya, Biswajit
A1  - Sperlich, Eric
A1  - Günter, Christina
A1  - Beqiraj, Alkit
A1  - Klamroth, Tillmann
A1  - Behrens, Karsten
A1  - Mies, Stefan
A1  - Kelling, Alexandra
A1  - Lubahn, Susanne
A1  - Holtzheimer, Lea
A1  - Nitschke, Anne
A1  - Taubert, Andreas
T1  - Tetrahalidometallate(II) ionic liquids with more than one metal
BT  - the effect of bromide versus chloride
JF  - Chemistry - a European journal
N2  - Fifteen N-butylpyridinium salts - five monometallic [C4Py](2)[MBr4] and ten bimetallic [C4Py](2)[(M0.5M0.5Br4)-M-a-Br-b] (M=Co, Cu, Mn, Ni, Zn) - were synthesized, and their structures and thermal and electrochemical properties were studied. All the compounds are ionic liquids (ILs) with melting points between 64 and 101 degrees C. Powder and single-crystal X-ray diffraction show that all ILs are isostructural. The electrochemical stability windows of the ILs are between 2 and 3 V. The conductivities at room temperature are between 10(-5) and 10(-6) S cm(-1). At elevated temperatures, the conductivities reach up to 10(-4) S cm(-1) at 70 degrees C. The structures and properties of the current bromide-based ILs were also compared with those of previous examples using chloride ligands, which illustrated differences and similarities between the two groups of ILs.
KW  - electrochemistry
KW  - ionic liquids
KW  - metal-containing ionic liquids;
KW  - N-butylpyridinium bromide
KW  - tetrahalidometallates
Y1  - 2022
U6  - https://doi.org/10.1002/chem.202201068
SN  - 1521-3765
VL  - 28
IS  - 64
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Balischewski, Christian
A1  - Choi, Hyung-Seok
A1  - Behrens, Karsten
A1  - Beqiraj, Alkit
A1  - Körzdörfer, Thomas
A1  - Gessner, Andre
A1  - Wedel, Armin
A1  - Taubert, Andreas
T1  - Metal sulfide nanoparticle synthesis with ionic liquids state of the art and future perspectives
JF  - ChemistryOpen
N2  - Metal sulfides are among the most promising materials for a wide variety of technologically relevant applications ranging from energy to environment and beyond. Incidentally, ionic liquids (ILs) have been among the top research subjects for the same applications and also for inorganic materials synthesis. As a result, the exploitation of the peculiar properties of ILs for metal sulfide synthesis could provide attractive new avenues for the generation of new, highly specific metal sulfides for numerous applications. This article therefore describes current developments in metal sulfide nano-particle synthesis as exemplified by a number of highlight examples. Moreover, the article demonstrates how ILs have been used in metal sulfide synthesis and discusses the benefits of using ILs over more traditional approaches. Finally, the article demonstrates some technological challenges and how ILs could be used to further advance the production and specific property engineering of metal sulfide nanomaterials, again based on a number of selected examples.
KW  - Ionic liquids
KW  - ionic liquid crystals
KW  - ionic liquid precursors
KW  - metal
KW  - sulfides
KW  - catalysis
KW  - electrochemistry
KW  - energy materials
KW  - LED
KW  - solar
KW  - cells
Y1  - 2021
U6  - https://doi.org/10.1002/open.202000357
SN  - 2191-1363
VL  - 10
IS  - 2
SP  - 272
EP  - 295
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Brietzke, Thomas Martin
A1  - Dietz, Thomas
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Bois, Juliana
A1  - Kelm, Harald
A1  - Reh, Manuel
A1  - Schmitz, Markus
A1  - Koerzdoerfer, Thomas
A1  - Leimkühler, Silke
A1  - Wollenberger, Ulla
A1  - Krueger, Hans-Joerg
A1  - Holdt, Hans-Jürgen
T1  - The 1,6,7,12-Tetraazaperylene Bridging Ligand as an Electron Reservoir and Its Disulfonato Derivative as Redox Mediator in an Enzyme-Electrode Process
JF  - Chemistry - a European journal
N2  - The homodinuclear ruthenium(II) complex [{Ru(l-N4Me2)}(2)(-tape)](PF6)(4) {[1](PF6)(4)} (l-N4Me2=N,N-dimethyl-2,11-diaza[3.3](2,6)-pyridinophane, tape=1,6,7,12-tetraazaperylene) can store one or two electrons in the energetically low-lying * orbital of the bridging ligand tape. The corresponding singly and doubly reduced complexes [{Ru(l-N4Me2)}(2)(-tape(.-))](PF6)(3) {[2](PF6)(3)} and [{Ru(l-N4Me2)}(2)(-tape(2-))](PF6)(2) {[3](PF6)(2)}, respectively, were electrochemically generated, successfully isolated and fully characterized by single-crystal X-ray crystallography, spectroscopic methods and magnetic susceptibility measurements. The singly reduced complex [2](PF6)(3) contains the -radical tape(.-) and the doubly reduced [3](PF6)(2) the diamagnetic dianion tape(2-) as bridging ligand, respectively. Nucleophilic aromatic substitution at the bridging tape in [1](4+) by two sulfite units gave the complex [{Ru(l-N4Me2)}(2){-tape-(SO3)(2)}](2+) ([4](2+)). Complex dication [4](2+) was exploited as a redox mediator between an anaerobic homogenous reaction solution of an enzyme system (sulfite/sulfite oxidase) and the electrode via participation of the low-energy *-orbital of the disulfonato-substituted bridging ligand tape-(SO3)(2)(2-) (E-red1=-0.1V versus Ag/AgCl/1m KCl in water).
KW  - electrochemistry
KW  - enzyme catalysis
KW  - N-ligands
KW  - redox-active ligands
KW  - ruthenium
Y1  - 2017
U6  - https://doi.org/10.1002/chem.201703639
SN  - 0947-6539
SN  - 1521-3765
VL  - 23
SP  - 15583
EP  - 15587
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Ilic, Ivan K.
A1  - Tsouka, Alexandra
A1  - Perovic, Milena
A1  - Hwang, Jinyeon
A1  - Heil, Tobias
A1  - Löffler, Felix
A1  - Oschatz, Martin
A1  - Antonietti, Markus
A1  - Liedel, Clemens
T1  - Sustainable cathodes for Lithium-ion energy storage devices based on tannic acid-toward ecofriendly energy storage
JF  - Advanced sustainable systems
N2  - The use of organic materials with reversible redox activity holds enormous potential for next-generation Li-ion energy storage devices. Yet, most candidates are not truly sustainable, i.e., not derived from renewable feedstock or made in benign reactions. Here an attempt is reported to resolve this issue by synthesizing an organic cathode material from tannic acid and microporous carbon derived from biomass. All constituents, including the redox-active material and conductive carbon additive, are made from renewable resources. Using a simple, sustainable fabrication method, a hybrid material is formed. The low cost and ecofriendly material shows outstanding performance with a capacity of 108 mAh g(-1) at 0.1 A g(-1) and low capacity fading, retaining approximately 80% of the maximum capacity after 90 cycles. With approximately 3.4 V versus Li+/Li, the cells also feature one of the highest reversible redox potentials reported for biomolecular cathodes. Finally, the quinone-catecholate redox mechanism responsible for the high capacity of tannic acid is confirmed by electrochemical characterization of a model compound similar to tannic acid but without catecholic groups.
KW  - biomass
KW  - electrochemistry
KW  - energy storage
KW  - redox chemistry
KW  - sustainability
KW  - tannic acid
Y1  - 2020
U6  - https://doi.org/10.1002/adsu.202000206
SN  - 2366-7486
VL  - 5
IS  - 1
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Kapernaum, Nadia
A1  - Lange, Alyna
A1  - Ebert, Max
A1  - Grunwald, Marco A.
A1  - Häge, Christian
A1  - Marino, Sebastian
A1  - Zens, Anna
A1  - Taubert, Andreas
A1  - Gießelmann, Frank
A1  - Laschat, Sabine
T1  - Current topics in ionic liquid crystals
JF  - ChemPlusChem
N2  - Ionic liquid crystals (ILCs), that is, ionic liquids exhibiting mesomorphism, liquid crystalline phases, and anisotropic properties, have received intense attention in the past years. Among others, this is due to their special properties arising from the combination of properties stemming from ionic liquids and from liquid crystalline arrangements. Besides interesting fundamental aspects, ILCs have been claimed to have tremendous application potential that again arises from the combination of properties and architectures that are not accessible otherwise, or at least not accessible easily by other strategies. The current review highlights recent developments in ILC research, starting with some key fundamental aspects. Further subjects covered include the synthesis and variations of modern ILCs, including the specific tuning of their mesomorphic behavior. The review concludes with reflections on some applications that may be within reach for ILCs and finally highlights a few key challenges that must be overcome prior and during true commercialization of ILCs.
KW  - electrochemistry
KW  - ionic liquid crystals
KW  - mesogen mesophases
KW  - self-assembly
KW  - X-ray diffraction
Y1  - 2021
U6  - https://doi.org/10.1002/cplu.202100397
SN  - 2192-6506
VL  - 87
IS  - 1
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Kapp, A.
A1  - Beissenhirtz, Moritz Karl
A1  - Geyer, F.
A1  - Scheller, F.
A1  - Viezzoli, Maria Silvia
A1  - Lisdat, Fred
T1  - Electrochemical and sensorial behavior of SOD mutants immobilized on gold electrodes in aqueous/organic solvent mixtures
JF  - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2  - A cysteine mutant of a monomeric human Cu, Zn-SOD (Glycine 61, Serine 142) has been immobilized directly on gold electrodes using the thiol groups introduced. The electrochemical behavior of the surface confined protein was studied in mixtures of aqueous buffer and DMSO up to an organic solvent content of 60%. The formal potential was found to be rather independent of the DMSO content. However, half peak width increased and the redoxactive amount clearly decreased with raising DMSO content. In addition, the kinetics of the heterogeneous electron transfer became slower; but still a quasireversible electrochemical conversion of the mutant SOD was feasible. Thus, the electrodes were applied for sensorial superoxide detection. At a potential of +220 mV vs. Ag/AgCl advantage was taken of the partial oxidation reaction of the enzyme. A defined superoxide signal was obtained in solutions up to 40% DMSO. The sensitivity of the mutant electrodes decreased linearly with the organic solvent content in solution but was still higher compared to conventional cyt.c based sensors. At DMSO concentrations higher than 40% no sensor response was detected.
KW  - SOD
KW  - mutants
KW  - gold electrodes
KW  - DMSO
KW  - electrochemistry
Y1  - 2006
U6  - https://doi.org/10.1002/elan.200603620
SN  - 1040-0397
VL  - 18
SP  - 1909
EP  - 1915
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Knoche, Lisa
A1  - Lisec, Jan
A1  - Schwerdtle, Tanja
A1  - Koch, Matthias
T1  - LC-HRMS-Based identification of transformation products of the drug salinomycin generated by electrochemistry and liver microsome
JF  - Antibiotics
N2  - The drug salinomycin (SAL) is a polyether antibiotic and used in veterinary medicine as coccidiostat and growth promoter. Recently, SAL was suggested as a potential anticancer drug. However, transformation products (TPs) resulting from metabolic and environmental degradation of SAL are incompletely known and structural information is missing. In this study, we therefore systematically investigated the formation and identification of SAL derived TPs using electrochemistry (EC) in an electrochemical reactor and rat and human liver microsome incubation (RLM and HLM) as TP generating methods. Liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS) was applied to determine accurate masses in a suspected target analysis to identify TPs and to deduce occurring modification reactions of derived TPs. A total of 14 new, structurally different TPs were found (two EC-TPs, five RLM-TPs, and 11 HLM-TPs). The main modification reactions are decarbonylation for EC-TPs and oxidation (hydroxylation) for RLM/HLM-TPs. Of particular interest are potassium-based TPs identified after liver microsome incubation because these might have been overlooked or declared as oxidated sodium adducts in previous, non-HRMS-based studies due to the small mass difference between K and O + Na of 21 mDa. The MS fragmentation pattern of TPs was used to predict the position of identified modifications in the SAL molecule. The obtained knowledge regarding transformation reactions and novel TPs of SAL will contribute to elucidate SAL-metabolites with regards to structural prediction.
KW  - salinomycin
KW  - ionophore antibiotics
KW  - transformation product
KW  - electrochemistry
KW  - rat
KW  - human liver microsomes
KW  - HRMS
Y1  - 2022
U6  - https://doi.org/10.3390/antibiotics11020155
SN  - 2079-6382
VL  - 11
IS  - 2
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Kotthoff, Lisa
A1  - Lisec, Jan
A1  - Schwerdtle, Tanja
A1  - Koch, Matthias
T1  - Prediction of transformation products of monensin by electrochemistry compared to microsomal assay and hydrolysis
JF  - Molecules
N2  - The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for animal health, food, and environmental matters. The active agent Monensin (MON) belongs to the ionophore antibiotics and is widely used as a veterinary drug against coccidiosis in broiler farming. However, no electrochemically (EC) generated TPs of MON have been described so far. In this study, the online coupling of EC and mass spectrometry (MS) was used for the generation of oxidative TPs. EC-conditions were optimized with respect to working electrode material, solvent, modifier, and potential polarity. Subsequent LC/HRMS (liquid chromatography/high resolution mass spectrometry) and MS/MS experiments were performed to identify the structures of derived TPs by a suspected target analysis. The obtained EC-results were compared to TPs observed in metabolism tests with microsomes and hydrolysis experiments of MON. Five previously undescribed TPs of MON were identified in our EC/MS based study and one TP, which was already known from literature and found by a microsomal assay, could be confirmed. Two and three further TPs were found as products in microsomal tests and following hydrolysis, respectively. We found decarboxylation, O-demethylation and acid-catalyzed ring-opening reactions to be the major mechanisms of MON transformation.
KW  - transformation products
KW  - monensin
KW  - veterinary drugs
KW  - electrochemistry
KW  - hydrolysis
KW  - LC/HRMS
Y1  - 2019
U6  - https://doi.org/10.3390/molecules24152732
SN  - 1420-3049
VL  - 24
IS  - 15
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Kotthoff, Lisa
A1  - O'Callaghan, Sarah-Louise
A1  - Lisec, Jan
A1  - Schwerdtle, Tanja
A1  - Koch, Matthias
T1  - Structural annotation of electro- and photochemically generated transformation products of moxidectin using high-resolution mass spectrometry
JF  - Analytical and bioanalytical chemistry : a merger of Fresenius' journal of analytical chemistry, Analusis and Quimica analitica
N2  - Moxidectin (MOX) is a widely used anthelmintic drug for the treatment of internal and external parasites in food-producing and companion animals. Transformation products (TPs) of MOX, formed through metabolic degradation or acid hydrolysis, may pose a potential environmental risk, but only few were identified so far. In this study, we therefore systematically characterized electro- and photochemically generated MOX TPs using high-resolution mass spectrometry (HRMS). Oxidative electrochemical (EC) TPs were generated in an electrochemical reactor and photochemical (PC) TPs by irradiation with UV-C light. Subsequent HRMS measurements were performed to identify accurate masses and deduce occurring modification reactions of derived TPs in a suspected target analysis. In total, 26 EC TPs and 59 PC TPs were found. The main modification reactions were hydroxylation, (de-)hydration, and derivative formation with methanol for EC experiments and isomeric changes, (de-)hydration, and changes at the methoxime moiety for PC experiments. In addition, several combinations of different modification reactions were identified. For 17 TPs, we could predict chemical structures through interpretation of acquired MS/MS data. Most modifications could be linked to two specific regions of MOX. Some previously described metabolic reactions like hydroxylation or O-demethylation were confirmed in our EC and PC experiments as reaction type, but the corresponding TPs were not identical to known metabolites or degradation products. The obtained knowledge regarding novel TPs and reactions will aid to elucidate the degradation pathway of MOX which is currently unknown.
KW  - veterinary drug
KW  - moxidectin
KW  - transformation products
KW  - electrochemistry
KW  - photochemistry
KW  - LC
KW  - HRMS
Y1  - 2020
U6  - https://doi.org/10.1007/s00216-020-02572-1
SN  - 1618-2642
SN  - 1618-2650
VL  - 412
IS  - 13
SP  - 3141
EP  - 3152
PB  - Springer
CY  - Heidelberg
ER  -