TY  - JOUR
A1  - Brinkmann, Pia
A1  - Köllner, Nicole
A1  - Merk, Sven
A1  - Beitz, Toralf
A1  - Altenberger, Uwe
A1  - Löhmannsröben, Hans-Gerd
T1  - Comparison of handheld and echelle spectrometer to assess copper in ores by means of laser-induced breakdown spectroscopy (LIBS)
JF  - Minerals
N2  - Its properties make copper one of the world’s most important functional metals. Numerous megatrends are increasing the demand for copper. This requires the prospection and exploration of new deposits, as well as the monitoring of copper quality in the various production steps. A promising technique to perform these tasks is Laser Induced Breakdown Spectroscopy (LIBS). Its unique feature, among others, is the ability to measure on site without sample collection and preparation. In this work, copper-bearing minerals from two different deposits are studied. The first set of field samples come from a volcanogenic massive sulfide (VMS) deposit, the second part from a stratiform sedimentary copper (SSC) deposit. Different approaches are used to analyze the data. First, univariate regression (UVR) is used. However, due to the strong influence of matrix effects, this is not suitable for the quantitative analysis of copper grades. Second, the multivariate method of partial least squares regression (PLSR) is used, which is more suitable for quantification. In addition, the effects of the surrounding matrices on the LIBS data are characterized by principal component analysis (PCA), alternative regression methods to PLSR are tested and the PLSR calibration is validated using field samples.
KW  - LIBS
KW  - copper-bearing minerals
KW  - UVR
KW  - PCA
KW  - PLSR
Y1  - 2023
U6  - https://doi.org/10.3390/min13010113
SN  - 2075-163X
VL  - 13
IS  - 1
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Dettmann, Sophie
A1  - Huittinen, Nina Maria
A1  - Nicolas, Jahn
A1  - Kretzschmar, Jerome
A1  - Kumke, Michael
A1  - Kutyma, Tamara
A1  - Lohmann, Janik
A1  - Reich, Tobias
A1  - Schmeide, Katja
A1  - Azzam, Salim Shams Aldin
A1  - Spittler, Leon
A1  - Stietz, Janina
T1  - Influence of gluconate on the retention of Eu(III), Am(III), Th(IV), Pu(IV), and U(VI) by C-S-H (C/S = 0.8)
JF  - Frontiers in Nuclear Engineering
N2  - The retention of actinides in different oxidation states (An(X), X = III, IV, VI) by a calcium-silicate-hydrate (C-S-H) phase with a Ca/Si (C/S) ratio of 0.8 was investigated in the presence of gluconate (GLU). The actinides considered were Am(III), Th(IV), Pu(IV), and U(VI). Eu(III) was investigated as chemical analogue for Am(III) and Cm(III). In addition to the ternary systems An(X)/GLU/C-S-H, also binary systems An(X)/C-S-H, GLU/C-S-H, and An(X)/GLU were studied. Complementary analytical techniques were applied to address the different specific aspects of the binary and ternary systems. Time-resolved laser-induced luminescence spectroscopy (TRLFS) was applied in combination with parallel factor analysis (PARAFAC) to identify retained species and to monitor species-selective sorption kinetics. ¹³C and ²⁹Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were applied to determine the bulk structure and the composition of the C-S-H surface, respectively, in the absence and presence of GLU. The interaction of Th(IV) with GLU in different electrolytes was studied by capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS). The influence of GLU on An(X) retention was investigated for a large concentration range up to 10⁻² M. The results showed that GLU had little to no effect on the overall An(X) retention by C-S-H with C/S of 0.8, regardless of the oxidation state of the actinides. For Eu(III), the TRLFS investigations additionally implied the formation of a Eu(III)-bearing precipitate with dissolved constituents of the C-S-H phase, which becomes structurally altered by the presence of GLU. For U(VI) sorption on the C-S-H phase, only a small influence of GLU could be established in the luminescence spectroscopic investigations, and no precipitation of U(VI)-containing secondary phases could be identified.
KW  - actinide
KW  - organic ligand
KW  - sorption
KW  - cementitious material
KW  - concrete
KW  - luminescence
Y1  - 2023
U6  - https://doi.org/10.3389/fnuen.2023.1124856
SN  - 2813-3412
VL  - 2
PB  - Frontiers Media
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Sperlich, Eric
A1  - Köckerling, Martin
T1  - The double cluster compound [Nb6Cl14(MeCN)(4)] [Nb6Cl14(pyz)(4)].6MeCN (Me: methyl, pyz: pyrazine) with a layered structure resulting from weak intermolecular interactions
JF  - Zeitschrift für Naturforschung
N2  - The synthesis and the crystal structure of the double cluster compound [Nb6Cl14(MeCN)(4)][Nb6Cl14(pyz)(4)]middot6CH(3)CN are described. The synthesis is based on a partial ligand exchange reaction, which proceeds upon dissolving [Nb6Cl14(pyz)(4)]middot2CH(2)Cl(2) in acetonitrile. The compound is built up of two discrete neutral cluster units, which consist of octahedra of Nb-6 atoms coordinated by 12 edge-bridging chlorido and two terminal chlorido ligands, and four acetonitrile ligands on one and four pyrazine ligands on the other cluster unit. Co-crystallized acetonitrile molecules are also present. The single-crystal structure determination has revealed a cluster arrangement in which the [Nb6Cl14(pyz)(4)] units are connected by (halogen) lone-pair-(pyrazine) pi interactions. These lead to chains of [Nb6Cl14(pyz)(4)] clusters. These chains are further connected to cluster layers by (nitrile-halogen) dipole-dipole interactions, in which the [Nb6Cl14(MeCN)(4)] and co-crystallized MeCN molecules are also involved. These cluster layers are arranged parallel to the crystallographic {011} plane.
KW  - cluster
KW  - crystal structure
KW  - dipole-dipole interaction
KW  - halide
KW  - lone-pair-pi interactions
KW  - niobium
Y1  - 2023
U6  - https://doi.org/10.1515/znb-2023-0001
SN  - 0932-0776
SN  - 1865-7117
VL  - 78
IS  - 5
SP  - 279
EP  - 283
PB  - De Gruyter
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Akampurira, Denis
A1  - Akala, Hoseah M.
A1  - Derese, Solomon
A1  - Heydenreich, Matthias
A1  - Yenesew, Abiy
T1  - A new C-C linked benzophenathridine-2-quinoline dimer, and the antiplasmodial activity of alkaloids from Zanthoxylum holstzianum
JF  - Natural product research
N2  - The CH2Cl2/MeOH (1:1) extract of Zanthoxylum holstzianum stem bark showed good antiplasmodial activity (IC50 2.5 +/- 0.3 and 2.6 +/- 0.3 mu g/mL against the W2 and D6 strains of Plasmodium falciparum, respectively). From the extract five benzophenanthridine alkaloids [8-acetonyldihydrochelerythrine (1), nitidine (2), dihydrochelerythine (3), norchelerythrine (5), arnottianamide (8)]; a 2-quinolone alkaloid [N-methylflindersine (4)]; a lignan [4,4 '-dihydroxy-3,3 '-dimethoxylignan-9,9 '-diyl diacetate (7)] and a dimer of a benzophenanthridine and 2-quinoline [holstzianoquinoline (6)] were isolated. The CH2Cl2/MeOH (1:1) extract of the root bark afforded 1, 3-6, 8, chelerythridimerine (9) and 9-demethyloxychelerythrine (10). Holstzianoquinoline (6) is new, and is the second dimer linked by a C-C bond of a benzophenanthridine and a 2-quinoline reported thus far. The compounds were identified based on spectroscopic evidence. Amongst five compounds (1-5) tested against two strains of P. falciparum, nitidine (IC50 0.11 +/- 0.01 mu g/mL against W2 and D6 strains) and norchelerythrine (IC50 value of 0.15 +/- 0.01 mu g/mL against D6 strain) were the most active.
KW  - Antiplasmodial
KW  - benzophenanthridine alkaloid
KW  - holstzianoquinoline;
KW  - rutaceae
KW  - Zanthoxylum holstzianum
Y1  - 2022
U6  - https://doi.org/10.1080/14786419.2022.2034810
SN  - 1478-6419
SN  - 1478-6427
VL  - 37
IS  - 13
SP  - 2161
EP  - 2171
PB  - Taylor & Francis
CY  - London [u.a.]
ER  - 
TY  - JOUR
A1  - Hu, Neng
A1  - Lin, Li
A1  - Metwalli, Ezzeldin
A1  - Bießmann, Lorenz
A1  - Philipp, Martine
A1  - Hildebrand, Viet
A1  - Laschewsky, André
A1  - Papadakis, Christine M.
A1  - Cubitt, Robert
A1  - Zhong, Qi
A1  - Müller-Buschbaum, Peter
T1  - Kinetics of water transfer between the LCST and UCST thermoresponsive blocks in diblock copolymer thin films monitored by in situ neutron reflectivity
JF  - Advanced materials interfaces
N2  - The kinetics of water transfer between the lower critical solution temperature (LCST) and upper critical solution temperature (UCST) thermoresponsive blocks in about 10 nm thin films of a diblock copolymer is monitored by in situ neutron reflectivity. The UCST-exhibiting block in the copolymer consists of the zwitterionic poly(4((3-methacrylamidopropyl)dimethylammonio)butane-1-sulfonate), abbreviated as PSBP. The LCST-exhibiting block consists of the nonionic poly(N-isopropylacrylamide), abbreviated as PNIPAM. The as-prepared PSBP80-b-PNIPAM(400) films feature a three-layer structure, i.e., PNIPAM, mixed PNIPAM and PSBP, and PSBP. Both blocks have similar transition temperatures (TTs), namely around 32 degrees C for PNIPAM, and around 35 degrees C for PSBP, and with a two-step heating protocol (20 degrees C to 40 degrees C and 40 degrees C to 80 degrees C), both TTs are passed. The response to such a thermal stimulus turns out to be complex. Besides a three-step process (shrinkage, rearrangement, and reswelling), a continuous transfer of D2O from the PNIPAM to the PSBP block is observed. Due to the existence of both, LCST and UCST blocks in the PSBP80-b-PNIPAM(400 )film, the water transfer from the contracting PNIPAM, and mixed layers to the expanding PSBP layer occurs. Thus, the hydration kinetics and thermal response differ markedly from a thermoresponsive polymer film with a single LCST transition.
KW  - block copolymer
KW  - dual thermoresponsive
KW  - kinetic water transfer
KW  - neutron
KW  - reflectivity
KW  - thin film
Y1  - 2022
U6  - https://doi.org/10.1002/admi.202201913
SN  - 2196-7350
VL  - 10
IS  - 3
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Bhattacharyya, Biswajit
A1  - Balischewski, Christian
A1  - Sperlich, Eric
A1  - Günter, Christina
A1  - Mies, Stefan
A1  - Kelling, Alexandra
A1  - Taubert, Andreas
T1  - N-Butyl Pyridinium Diiodido Argentate(I)
BT  - A One-Dimensional Ag-I Network with Superior Solid-State Ionic Conductivity at Room Temperature
JF  - Advanced materials interfaces
N2  - A new solid-state material, N-butyl pyridinium diiodido argentate(I), is synthesized using a simple and effective one-pot approach. In the solid state, the compound exhibits 1D ([AgI2](-))(n) chains that are stabilized by the N-butyl pyridinium cation. The 1D structure is further manifested by the formation of long, needle-like crystals, as revealed from electron microscopy. As the general composition is derived from metal halide-based ionic liquids, the compound has a low melting point of 100-101 degrees C, as confirmed by differential scanning calorimetry. Most importantly, the compound has a conductivity of 10(-6) S cm(-1) at room temperature. At higher temperatures the conductivity increases and reaches to 10(-4 )S cm(-1) at 70 degrees C. In contrast to AgI, however, the current material has a highly anisotropic 1D arrangement of the ionic domains. This provides direct and tuneable access to fast and anisotropic ionic conduction. The material is thus a significant step forward beyond current ion conductors and a highly promising prototype for the rational design of highly conductive ionic solid-state conductors for battery or solar cell applications.
KW  - AgI
KW  - ionic conductivity
KW  - Ionic liquids
KW  - thermal properties
Y1  - 2023
U6  - https://doi.org/10.1002/admi.202202363
SN  - 2196-7350
VL  - 10
IS  - 12
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Nchiozem-Ngnitedem, Vaderament-Alexe
A1  - Sperlich, Eric
A1  - Matieta, Valaire Yemene
A1  - Kuete, Jenifer Reine Ngnouzouba
A1  - Kuete, Victor
A1  - Omer, Ejlal A. A.
A1  - Efferth, Thomas
A1  - Schmidt, Bernd
T1  - Synthesis and bioactivity of isoflavones from ficus carica and some non-natural analogues
JF  - Journal of natural products : Lloydia
N2  - FicucariconeD (1) and its 4 '-demethyl congener 2 are isoflavones isolated from fruits of Ficus carica that share a 5,7-dimethoxy-6-prenyl-substituted A-ring. Both naturalproducts were, for the first time, obtained by chemical synthesisin six steps, starting from 2,4,6-trihydroxyacetophenone. Key stepsare a microwave-promoted tandem sequence of Claisen- and Cope-rearrangementsto install the 6-prenyl substituent and a Suzuki-Miyaura crosscoupling for installing the B-ring. By using various boronic acids,non-natural analogues become conveniently available. All compoundswere tested for cytotoxicity against drug-sensitive and drug-resistanthuman leukemia cell lines, but were found to be inactive. The compoundswere also tested for antimicrobial activities against a panel of eightGram-negative and two Gram-positive bacterial strains. Addition ofthe efflux pump inhibitor phenylalanine-arginine-beta-naphthylamide(PA beta N) significantly improved the antibiotic activity in mostcases, with MIC values as low as 2.5 mu M and activity improvementfactors as high as 128-fold.
KW  - Antimicrobial activity
KW  - Bacteria
KW  - Ethers
KW  - Flavonoids
KW  - Mixtures
Y1  - 2023
U6  - https://doi.org/10.1021/acs.jnatprod.3c00219
SN  - 0163-3864
SN  - 1520-6025
VL  - 86
IS  - 6
SP  - 1520
EP  - 1528
PB  - American Chemical Society
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Reitenbach, Julija
A1  - Geiger, Christina
A1  - Wang, Peixi
A1  - Vagias, Apostolos N.
A1  - Cubitt, Robert
A1  - Schanzenbach, Dirk
A1  - Laschewsky, André
A1  - Papadakis, Christine M.
A1  - Müller-Buschbaum, Peter
T1  - Effect of magnesium salts with chaotropic anions on the swelling behavior of PNIPMAM thin films
JF  - Macromolecules : a publication of the American Chemical Society
N2  - Poly(N-isopropylmethacrylamide) (PNIPMAM) is a stimuli responsive polymer, which in thin film geometry exhibits a volume-phase transition upon temperature increase in water vapor. The swelling behavior of PNIPMAM thin films containing magnesium salts in water vapor is investigated in view of their potential application as nanodevices. Both the extent and the kinetics of the swelling ratio as well as the water content are probed with in situ time-of-flight neutron reflectometry. Additionally, in situ Fourier-transform infrared (FTIR) spectroscopy provides information about the local solvation of the specific functional groups, while two-dimensional FTIR correlation analysis further elucidates the temporal sequence of solvation events. The addition of Mg(ClO4)2 or Mg(NO3)2 enhances the sensitivity of the polymer and therefore the responsiveness of switches and sensors based on PNIPMAM thin films. It is found that Mg(NO3)2 leads to a higher relative water uptake and therefore achieves the highest thickness gain in the swollen state.
Y1  - 2023
U6  - https://doi.org/10.1021/acs.macromol.2c02282
SN  - 0024-9297
SN  - 1520-5835
VL  - 56
IS  - 2
SP  - 567
EP  - 577
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - The multiple bond character of the carbon-boron bond in boron trapped N-heterocyclic carbenes (NHCs) and cyclic(alkyl)(amino) carbenes (CAACs) on the magnetic criterion
JF  - Tetrahedron
N2  - Geometry, 11B, 13C chemical shifts and the spatial magnetic properties (Through-Space NMR Shieldings -TSNMRS) of both cations and anions of boron-trapped N-heterocyclic carbenes (NHCs) and cyclic (alkyl)(amino)carbenes (CAACs) and of the corresponding diborane/diborene/diboryne dis-carbene adducts have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept; the TSNMRS results are visualized as iso-chemical-shielding surfaces (ICSS) of various size and direction. The ICSS of the TSNMRS (actually the anisotropy effects measurable in 1H NMR spectroscopy) are employed to qualify and quantify the present multiple bond character of the Carbene-Boron bond in the trapped NHCs and CAACs. Results are confirmed by bond length and 11B/13C chemical shift variations. Thus the partial multiple bond character of the Carbene-Boron bond cannot be expressed by the arrow of weak, much longer dative bonds and should be omitted as in other covalent lone pair-it or triel bonds. & COPY; 2023 Elsevier Ltd. All rights reserved.
KW  - NHCs
KW  - CAACs
KW  - Multiple NHC(CAAC)-Boron bonds
KW  - Through -space NMR
KW  - shieldings (TSNMRS)
KW  - NICS
KW  - Anisotropy effect
KW  - Ring current effect
Y1  - 2023
U6  - https://doi.org/10.1016/j.tet.2023.133469
SN  - 0040-4020
SN  - 1464-5416
VL  - 140
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Schlappa, Stephanie
A1  - Bressel, Lena
A1  - Reich, Oliver
A1  - Münzberg, Marvin
T1  - Advanced particle size analysis in high-solid-content polymer dispersions using photon density wave spectroscopy
JF  - Polymers
N2  - High-solid-content polystyrene and polyvinyl acetate dispersions of polymer particles with a 50 nm to 500 nm mean particle diameter and 12-55% (w/w) solid content have been produced via emulsion polymerization and characterized regarding their optical and physical properties. Both systems have been analyzed with common particle-size-measuring techniques like dynamic light scattering (DLS) and static light scattering (SLS) and compared to inline particle size distribution (PSD) measurements via photon density wave (PDW) spectroscopy in undiluted samples. It is shown that particle size measurements of undiluted polystyrene dispersions are in good agreement between analysis methods. However, for polyvinyl acetate particles, size determination is challenging due to bound water in the produced polymer. For the first time, water-swelling factors were determined via an iterative approach of PDW spectroscopy error (X-2) minimization. It is shown that water-swollen particles can be analyzed in high-solid-content solutions and their physical properties can be assumed to determine the refractive index, density, and volume fraction in dispersion. It was found that assumed water swelling improved the reduced scattering coefficient fit by PDW spectroscopy by up to ten times and particle size determination was refined and enabled. Particle size analysis of the water-swollen particles agreed well with offline-based state-of-the-art techniques.
KW  - emulsion polymerization
KW  - multiple light scattering
KW  - photon density wave
KW  - spectroscopy
KW  - particle sizing
KW  - swelling of polymers
Y1  - 2023
U6  - https://doi.org/10.3390/polym15153181
SN  - 2073-4360
VL  - 15
IS  - 15
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Mazarei, Elham
A1  - Penschke, Christopher
A1  - Saalfrank, Peter
T1  - Band gap engineering in two-dimensional materials by functionalization
BT  - Methylation of graphene and graphene bilayers
JF  - ACS Omega
N2  - Graphene is well-knownfor its unique combination of electricaland mechanical properties. However, its vanishing band gap limitsthe use of graphene in microelectronics. Covalent functionalizationof graphene has been a common approach to address this critical issueand introduce a band gap. In this Article, we systematically analyzethe functionalization of single-layer graphene (SLG) and bilayer graphene(BLG) with methyl (CH3) using periodic density functionaltheory (DFT) at the PBE+D3 level of theory. We also include a comparisonof methylated single-layer and bilayer graphene, as well as a discussionof different methylation options (radicalic, cationic, and anionic).For SLG, methyl coverages ranging from 1/8 to 1/1, (i.e.,the fully methylated analogue of graphane) are considered. We findthat up to a coverage theta of 1/2, graphene readily accepts CH3, with neighbor CH3 groups preferring trans positions. Above theta = 1/2, the tendency to accept further CH3 weakens and the lattice constant increases. The band gapbehaves less regularly, but overall it increases with increasing methylcoverage. Thus, methylated graphene shows potential for developingband gap-tuned microelectronics devices and may offer further functionalizationoptions. To guide in the interpretation of methylation experiments,vibrational signatures of various species are characterized by normal-modeanalysis (NMA), their vibrational density of states (VDOS), and infrared(IR) spectra, the latter two are obtained from ab initio moleculardynamics (AIMD) in combination with a velocity-velocity autocorrelationfunction (VVAF) approach.
KW  - Adsorption
KW  - Alkyls
KW  - Band structure
KW  - Electrical conductivity
KW  - Two dimensional materials
Y1  - 2023
U6  - https://doi.org/10.1021/acsomega.3c02068
SN  - 2470-1343
VL  - 8
IS  - 24
SP  - 22026
EP  - 22041
PB  - American Chemical Society
CY  - Washington
ER  -