TY - JOUR A1 - Fernandes, C. A1 - Santos, I.C. A1 - Santos, I. A1 - Pietzsch, H.J. A1 - Kunstler, J.-U. A1 - Kraus, Werner A1 - Rey, A. A1 - Margaritis, N. A1 - Bourkoula, A. A1 - Chiotellis, A. A1 - Paravatou-Petsotas, M. A1 - Pirmettis, I. T1 - Rhenium and technetium complexes bearing quinazoline derivatives: progress towards a 99mTc biomarker for EGFR-TK imaging N2 - The quinazoline derivatives (3-chloro-4-fluorophenyl)quinazoline-4,6-diamine (2) and (3-bromophenyl)quinazoline-4,6-diamine (3) were labelled with 99mTc using the 4 + 1 mixed-ligand system [Tc(NS3)(CN-R)] and the tricarbonyl moiety fac-[Tc(CO)3]+. In the 4 + 1 approach the technetium(III) is stabilized by a monodentate isocyanide bearing a quinazoline fragment (L1, L2) and by the tetradentate tripodal ligand tris(2-mercaptoethyl)-amine (NS3). In the 4 + 1 approach, 99mTc-labelling was performed in a two-step procedure, the complexes [Tc(NS3)(L1)] (7a) and [Tc(NS3)(L2)] (8a) being obtained in about 50–70% yield. In the tricarbonyl approach, the fac-[Tc(CO)3]+ unit is anchored by two different monoanionic chelators bearing the quinazoline derivatives (3-chloro-4-fluorophenyl)quinazoline-4,6-diamine (2) and (3-bromophenyl)quinazoline-4,6-diamine (3). Both chelators have a N2O donor atom set, but one contains a pyrazolyl ring (L5H) and the other contains a pyridine unit (L6H). In both cases the conjugation of the quinazoline to the chelator was done through the secondary amine of the potentially tridentate and monoanionic chelators, the corresponding 99mTc-complexes (10a, 11a) being obtained in quantitative yield. The identities of the 99mTc-labelled quinazolines (7a, 8a, 10a, 11a) were confirmed by comparison with the HPLC profiles of the analogous Re compounds (7, 8, 10, 11). All these Re complexes were characterized by NMR and IR spectroscopy, elemental analysis and in some cases by MS and X-ray diffraction analysis. In vitro studies indicate that the quinazoline fragments, after conjugation to the cyano group (L1, L2) or to the pyrazolyl containing chelator (L5H), as well as the corresponding Re complexes (7, 8, 10) inhibit significantly the EGFR autophosphorylation and also inhibit A431 cell growth. These two effects were also found for the pyridine-containing chelator (L6H) and corresponding Re complex (11), although to a lesser extent. PY - 2008 DO - https://doi.org/10.1039/b802021c SN - 1477-9226 SN - 1477-9234 SN - 1364-5447 SP - 3215 EP - 3225 PB - RSC CY - Cambridge AN - OPUS4-17754 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Santos, S. A1 - Costa, C. A. E. A1 - Duarte, A. C. A1 - Scherer, H. W. A1 - Schneider, Rudolf A1 - Esteves, V. I. A1 - Santos, E. B. H. T1 - Influence of different organic amendments on the potential availability of metals from soil: A study on metal fractionation and extraction kinetics by EDTA N2 - The effects of long-term application of different organic amendments, as compared to mineral fertilizer, on Zn, Cu and Pb content and leachability in a luvisol derived from loess were assessed. The organic fertilizers, applied since 1962, were compost (COM) – from green organic household waste, sewage sludge (SLU) – from municipal water treatment facilities, farmyard manure (FYM) and the doses applied since 1997 were 90 t ha-1, 10 t ha-1 and 9 t ha-1, once in 3 years, respectively. The kinetics of metals extraction with 0.05 mol dm-3 EDTA at pH 6.0 has been studied. The two first-order reactions model was fitted to the kinetic data and allowed to distinguish two pools for each metal: a 'labile' fraction (Q1), quickly extracted with a rate constant k1, and a 'moderately labile' fraction (Q2), more slowly extracted, with a rate constant k2. Simultaneously, the pseudo-total metal contents in the soil samples were determined after digestion with aqua regia (3:1 HCl + HNO3). The obtained parameters Q1, k1, Q2, k2, for the kinetics of extraction of each metal in the three replicates of each fertilization mode, as well as the pseudo-total metal contents, were statistically analysed. COM and SLU application resulted in an increase of the total contents of Pb, Zn and Cu in soil. Further, the percentage of labile Zn and Pb also increased in consequence of the application of those amendments, particularly COM. The increase was more noticeable for Zn. FYM, despite not increasing the total content of Pb, Zn or Cu, did also have an effect on the leachability of Zn and Pb, increasing their labile fraction in soil. These results point to a potential risk of increasing metals mobility in soil, mainly Zn, associated to the use of organic amendments, particularly COM or SLU. KW - Compost KW - Sewage sludge KW - Soils KW - Metal mobility KW - EDTA KW - Kinetics PY - 2010 DO - https://doi.org/10.1016/j.chemosphere.2009.11.008 SN - 0045-6535 SN - 0366-7111 VL - 78 IS - 4 SP - 389 EP - 396 PB - Elsevier Science CY - Kidlington, Oxford AN - OPUS4-22187 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kniess, T. A1 - Fernandes, C. A1 - Santos, I. A1 - Kraus, Werner A1 - Spies, H. T1 - Silylated mixed-ligand rhenium complexes with the [PNS/S] donor atom set N2 - New oxorhenium complexes with 2-(diphenylphosphanyl)-N-(2-thioethyl)benzamide (H2PNS) and trimethyl-, triethyl- and triphenyl-hydroxyl silylated monodentate thiols are reported. These new complexes have been prepared by reacting [NnBu4][Re(O)Cl4] with the tridentate H2PNS and the corresponding silylated thiol at room temperature. The characterization of the complexes involved elemental analysis, 31P and 1H NMR spectroscopies and X-ray crystallographic analysis for the triethyl-silylated Re complex. KW - Crystal structure KW - Rhenium oxo mixed-ligands complexes PY - 2003 DO - https://doi.org/10.1016/S0020-1693(02)01486-X SN - 0020-1693 SN - 1873-3255 VL - 348 SP - 237 EP - 241 PB - Elsevier Sequoia CY - Lausanne AN - OPUS4-2552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Soares, J. X. A1 - Wegner, Karl David A1 - Ribeiro, D. S. M. A1 - Melo, A. A1 - Häusler, I. A1 - Santos, J. L. M. A1 - Resch-Genger, Ute T1 - Rationally designed synthesis of bright AgInS2/ZnS quantum dots with emission control N2 - In the blossoming field of Cd-free semiconductor quantum dots (QDs), ternary I–III–VI QDs have received increasing attention due to the ease of the environmentally friendly synthesis of high-quality materials in water, their high photoluminescence (PL) Quantum yields (QYs) in the red and near infrared (NIR) region, and their inherently low toxicity. Moreover, their oxygen-insensitive long PL lifetimes of up to several hundreds of nanoseconds close a gap for applications exploiting the compound-specific parameter PL lifetime. To overcome the lack of reproducible synthetic methodologies and to enable a design-based control of their PL properties, we assessed and modelled the synthesis of high-quality MPA-capped AgInS2/ZnS (AIS/ZnS) QDs. Systematically refined Parameters included reaction time, temperature, Ag:In ratio, S:In ratio, Zn:In ratio, MPA:In ratio, and pH using a design-of-experiment approach. Guidance for the optimization was provided by mathematical models developed for the application-relevant PL parameters, maximum PL wavelength, QY, and PL lifetime as well as the elemental composition in terms of Ag:In:Zn ratio. With these experimental data-based models, MPA:In and Ag:In ratios and pH values were identified as the most important synthesis parameters for PL Control and an insight into the connection of these parameters could be gained. Subsequently, the experimental conditions to synthetize QDs with tunable emission and high QY were predicted. The excellent agreement between the predicted and experimentally found PL features confirmed the reliability of our methodology for the rational design of high quality AIS/ZnS QDs with defined PL features. This approach can be straightforwardly extended to other ternary and quaternary QDs and to doped QDs. KW - Modelling KW - Nanoparticle KW - AIS KW - Semiconductor quantum dot KW - Design of experiment KW - Photoluminescence KW - Quantum yield KW - Surface chemistry KW - Synthesis KW - Lifetime PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510075 DO - https://doi.org/10.1007/s12274-020-2876-8 VL - 13 IS - 9 SP - 2438 EP - 2450 PB - Springer AN - OPUS4-51007 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Santos de Freitas, M. A1 - Araghi, R. R. A1 - Brandenburg, E. A1 - Leiterer, Jork A1 - Emmerling, Franziska A1 - Folmert, K. A1 - Gerling-Driessen, U. I. M. A1 - Bardiaux, B. A1 - Böttcher, C. A1 - Pagel, K. A1 - Diehl, A. A1 - v. Berlepsch, H. A1 - Oschkinat, H. A1 - Koksch, B. T1 - The protofilament architecture of a de novo designed coiled coil-based amyloidogenic peptide N2 - Amyloid fibrils are polymers formed by proteins under specific conditions and in many cases they are related to pathogenesis, such as Parkinson’s and Alzheimer’s diseases. Their hallmark is the presence of a β-sheet structure. High resolution structural data on these systems as well as information gathered from multiple complementary analytical techniques is needed, from both a fundamental and a pharmaceutical perspective. Here, a previously reported de novo designed, pH-switchable coiled coil-based peptide that undergoes structural transitions resulting in fibril formation under physiological conditions has been exhaustively characterized by transmission electron microscopy (TEM), cryo-TEM, atomic force microscopy (AFM), wide-angle X-ray scattering (WAXS) and solid-state NMR (ssNMR). Overall, a unique 2-dimensional carpet-like assembly composed of large coexisiting ribbon-like, tubular and funnel-like structures with a clearly resolved protofilament substructure is observed. Whereas electron microscopy and scattering data point somewhat more to a hairpin model of β-fibrils, ssNMR data obtained from samples with selectively labelled peptides are in agreement with both, hairpin structures and linear arrangements. KW - Amyloid KW - Elektronenmikroskopie PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458713 UR - https://www.sciencedirect.com/science/article/pii/S1047847718301333 DO - https://doi.org/10.1016/j.jsb.2018.05.009 SN - 1047-8477 VL - 203 IS - 3 SP - 263 EP - 272 PB - Elsevier AN - OPUS4-45871 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Santos, C.I.L. A1 - Machado, W.S. A1 - Wegner, Karl David A1 - Gontijo, L.A.P. A1 - Bettini, J. A1 - Schiavon, M.A. A1 - Reiss, P. A1 - Aldakov, D. T1 - Hydrothermal Synthesis of Aqueous-Soluble Copper Indium Sulfide Nanocrystals and Their Use in Quantum Dot Sensitized Solar Cells N2 - facile hydrothermal method to synthesize water-soluble copper indium sulfide (CIS) nanocrystals (NCs) at 150 degrees C is presented. The obtained samples exhibited three distinct photoluminescence peaks in the red, green and blue spectral regions, corresponding to three size fractions, which could be separated by means of size-selective precipitation. While the red and green emitting fractions consist of 4.5 and 2.5 nm CIS NCs, the blue fraction was identified as in situ formed carbon nanodots showing excitation wavelength dependent emission. When used as light absorbers in quantum dot sensitized solar cells, the individual green and red fractions yielded power conversion efficiencies of 2.9% and 2.6%, respectively. With the unfractionated samples, the efficiency values approaching 5% were obtained. This improvement was mainly due to a significantly enhanced photocurrent arising from complementary panchromatic absorption. KW - Aqueous quantum dot KW - Solar cells KW - CUINS2 nanocrystals KW - Colloidal semiconductor nanocrystals PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517983 DO - https://doi.org/10.3390/nano10071252 VL - 10 IS - 7 SP - 1252 PB - MDPI AN - OPUS4-51798 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lima, D.L.D. A1 - Schneider, Rudolf A1 - Scherer, H.W. A1 - Duarte, A.C. A1 - Santos, E.B.H. A1 - Esteves, V.I. T1 - Sorption-desorption behavior of atrazine on soils subjected to different organic long-term amendments N2 - Sorption of atrazine on soils subjected to three different organic amendments was measured using a batch equilibrium technique. A higher KF value (2.20 kg-1(mg L-1)-N) was obtained for soil fertilized with compost, which had a higher organic matter (OM) content. A correlation between the KFOC values and the percentage of aromatic carbon in OM was observed. The highest KFOC value was obtained for the soil with the highest aromatic content. Higher aromatic content results in higher hydrophobicity of OM, and hydrophobic interactions play a key role in binding of atrazine. On the other hand, the soil amended with farmyard manure had a higher content of carboxylic units, which could be responsible for hydrogen bonding between atrazine and OM. Dominance of hydrogen bonds compared to hydrophobic interactions can be responsible for the lower desorption capacity observed with the farmyard manure soil. The stronger hydrogen bonding can reduce the leaching of atrazine into drinking water resources and runoff to rivers and other surface waters. KW - Capillary electrophoresis KW - Atrazine KW - Sorption KW - Soil KW - Compost KW - Sewage sludge KW - Farmyard manure PY - 2010 DO - https://doi.org/10.1021/jf903937d SN - 0021-8561 SN - 1520-5118 VL - 58 IS - 5 SP - 3101 EP - 3106 PB - American Chemical Society CY - Columbus, Ohio AN - OPUS4-21108 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Filipe, O.M.S. A1 - Vidal, M.M. A1 - Scherer, H.W. A1 - Schneider, Rudolf A1 - Duarte, A. A1 - Esteves, V.I. A1 - Santos, E.B.H. T1 - Effect of long term organic amendments on adsorption-desorption of thiram onto a luvisol soil derived from loess KW - Thiram KW - Adsorption-desorption KW - Soil KW - Organic amendments PY - 2010 DO - https://doi.org/10.1016/j.chemosphere.2010.04.003 SN - 0045-6535 SN - 0366-7111 VL - 80 IS - 3 SP - 293 EP - 300 PB - Elsevier Science CY - Kidlington, Oxford AN - OPUS4-23196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -