TY  - JOUR
A1  - Machumi, Francis
A1  - Yenesew, Abiy
A1  - Midiwo, Jacob O.
A1  - Heydenreich, Matthias
A1  - Kleinpeter, Erich
A1  - Tekwani, Babu L.
A1  - Khan, Shabana I.
A1  - Walker, Larry A.
A1  - Muhammad, Ilias
T1  - Antiparasitic and anticancer carvotacetone derivatives of Sphaeranthus bullatus
JF  - Natural product communications : an international journal for communications and reviews
N2  - The CH2Cl2-MeOH (1:1) extract of the aerial parts of Sphaeranthus bullatus, an annual herb native to tropical East Africa, showed activity against chloroquine sensitive D6 (IC50 9.7 mu g/mL) and chloroquine resistant W2 (IC50 15.0 mu g/mL) strains of Plasmodium falciparum. Seventeen secondary metabolites were isolated from the extract through conventional chromatographic techniques and identified using various spectroscopic methods. The compounds were evaluated for their in vitro antiplasmodial, antileishmanial and anticancer activities revealing activity of four carvotacetone derivatives, namely 3-acetoxy-7-hydroxy-5-tigloyloxycarvotacetone (1) 3,7-dihydroxy-5-tigloyloxycarvotacetone (2), 3-acetoxy-5,7-dihydroxycarvotacetone (3) and 3,5,7-trihydroxycarvotacetone (4); with antiplasmodial IC50 values of 1.40, 0.79, 0.60 and 3.40 mu g/mL, respectively, against chloroquine sensitive D6 strains of P. falciparum; antiplasmodial activity of IC50 2.00, 0.90, 0.68 and 2.80 mu g/mL respectively, against chloroquine resistant W2 strains of P. falciparum, antileishmanial IC50, values of 0.70, 3.00, 0.70 and 17.00 mu g/mL, respectively, against the parasite L. donovanii promastigotes, and anticancer activity against human SK-MEL, KB, BT-549 and SK-OV-3 tumor cells, with IC50 values between <1.1 - 5.3 mu g/mL, for 1-3. In addition, cytotoxic effects of the active compounds were evaluated against monkey kidney fibroblasts (VERO) and pig kidney epithelial cells (LLC-PK11). The structures of carvotacetone derivatives were determined by ID and 2D NMR spectroscopy; the absolute stereochemical configuration of 3-acetoxy-7-hydroxy-5-tigloyloxycarvotacetone (I) was determined as 3R, 4R, 5S by circular dichroism, specific rotation, H-1 NMR and 2D NMR ROESY and NOESY experiments.
KW  - Sphaeranthus bullatus
KW  - Asteraceae
KW  - Antiplasmodial
KW  - Antileishmanial
KW  - Anticancer
KW  - Carvotacetones
Y1  - 2012
SN  - 1934-578X
VL  - 7
IS  - 9
SP  - 1123
EP  - 1126
PB  - NPC
CY  - Westerville
ER  - 
TY  - JOUR
A1  - Induli, Martha
A1  - Cheloti, Michael
A1  - Wasuna, Antonina
A1  - Wekesa, Ingrid
A1  - Wanjohi, John M.
A1  - Byamukama, Robert
A1  - Heydenrich, Matthias
A1  - Makayoto, Moses
A1  - Yenesew, Abiy
T1  - Naphthoquinones from the roots of Aloe secundiflora
JF  - Phytochemistry letters
N2  - Two new naphthoquinones, 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione and 5,8-dihydroxy-3-methoxy-2-methylnaphthalene-1,4-dione, were isolated from the roots of Aloe secundiflora together with the known compounds chrysophanol, helminthosporin, isoxanthorin, ancistroquinone C, aloesaponarins I and II, aloesaponols I and II, laccaic acid D methyl ester and asphodelin. The structures were elucidated based on spectroscopic evidence. This appears to be the first report on the occurrence of naphthoquinones in the genus Aloe. Aloesaponarin I and 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione showed anti-bacterial activity against Mycobacterium tuberculosis with MIC values of 21-23 mu g/mL in the Microplate Alamar Blue Assay (MABA) and Low Oxygen Recovery Assay (LORA); 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione also showed cytotoxicity against the Vero cell line (IC50 = 10.2 mu g/mL).
KW  - Aloe secundiflora
KW  - Asphodelaceae
KW  - Roots
KW  - Naphthoquinone
KW  - 5-Hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione 5,8-Dihydroxy-3-methoxy-2-methylnaphthalene-1,4-dione
KW  - Anthraquinone
KW  - Aloesaponarin I
KW  - Mycobacterium tuberculosis
Y1  - 2012
U6  - https://doi.org/10.1016/j.phytol.2012.04.014
SN  - 1874-3900
VL  - 5
IS  - 3
SP  - 506
EP  - 509
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Gumula, Ivan
A1  - Heydenreich, Matthias
A1  - Derese, Solomon
A1  - Ndiege, Isaiah O.
A1  - Yenesew, Abiy
T1  - Four isoflavanones from the stem bark of Platycelphium voense
JF  - Phytochemistry letters
N2  - From the stem bark of Platycelphium voense (Leguminosae) four new isoflavanones were isolated and characterized as (S)-5,7-dihydroxy-2 ',4 '-dimethoxy-3 '-(3 ''-methylbut-2 ''-enyl)-isoflavanone (trivial name platyisoflavanone A), (+)-5,7,2 '-trihydroxy-4 '-methoxy-3 '-(3 ''-methylbut-2 ''-enyl)-isoflavanone (platyisoflavanone B), 5,7-dihydroxy-4 '-methoxy-2 ''-(2 '''-hydroxyisopropyl)-dihydrofurano-[4 '',5 '':3 ',2 ']-isoflavanone (platyisoflavanone C) and 5,7,2 ',3 ''-tetrahydroxy-2 '',2 ''-dimethyldihydropyrano-[5 '',6 '':3 ',4 ']-isoflavanone (platyisoflavanone D). In addition, the known isoflavanones, sophoraisoflavanone A and glyasperin F; the isoflavone, formononetin; two flavones, kumatakenin and isokaempferide; as well as two triterpenes, betulin and beta-amyrin were identified. The structures were elucidated on the basis of spectroscopic evidence. Platyisoflavanone A showed antibacterial activity against Mycobacterium tuberculosis in the microplate alamar blue assay (MABA) with MIC = 23.7 mu M, but also showed cytotoxicity (IC50 = 21.1 mu M) in the vero cell test.
KW  - Platycelphium voense
KW  - Stem bark
KW  - Leguminosae
KW  - Isoflavanones
KW  - Platyisoflavanone
KW  - Mycobacterium tuberculosis
Y1  - 2012
U6  - https://doi.org/10.1016/j.phytol.2011.11.012
SN  - 1874-3900
VL  - 5
IS  - 1
SP  - 150
EP  - 154
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Munzke, Dorit
A1  - Saunders, John
A1  - Omrani, Hengameh
A1  - Reich, Oliver
A1  - Loock, Hans-Peter
T1  - Modeling of fiber-optic fluorescence probes for strongly absorbing samples
JF  - Applied optics
N2  - The dynamic range of fiber-optic fluorescent probes such as single fibers and fiber bundles is calculated for strongly absorbing samples, such as process liquids, foodstuffs, and lubricants. The model assumes an excitation beam profile based on a Lambertian light source and uses analytical forms of the collection efficiency, followed by an Abel transformation and numerical integration. It is found that the effect of primary absorption of the excitation light and secondary absorption of the fluorescence is profound. For fiber bundles and bifurcated fiber probes, the upper accessible concentration limit is roughly given by the absorption length of the primary and secondary absorption. Fluorescence detectors that are placed at right angles to the excitation beam axis or collinear to the beam axis are equally strongly affected by secondary absorption. A probe in which the same fiber is used for excitation and for collection of the fluorescence emerges as the fiber probe with the largest accessible concentration range.
Y1  - 2012
U6  - https://doi.org/10.1364/AO.51.006343
SN  - 1559-128X
SN  - 2155-3165
VL  - 51
IS  - 26
SP  - 6343
EP  - 6351
PB  - Optical Society of America
CY  - Washington
ER  - 
TY  - JOUR
A1  - Ruiz, Salome Vargas
A1  - Hass, Roland
A1  - Reich, Oliver
T1  - Optical monitoring of milk fat phase transition within homogenized fresh milk by Photon Density Wave spectroscopy
JF  - International dairy journal
N2  - Photon Density Wave (PDW) spectroscopy was applied for temperature dependent monitoring of melting and crystallization of milk fat within homogenized fresh milk. As an in-line process analytical technique, PDW spectroscopy quantifies continuously the optical properties of turbid material, providing an insight into its structural processes. Here, the measured absorption coefficients reflect temperature as well as fat content of milk and the reduced scattering coefficients probe physical changes of the light scattering fat droplets and casein micelles. Thermal processing reveals breakpoints within the temperature trend of the reduced scattering coefficient of fat containing milk. Found at 16 degrees C and 24 degrees C while cooling and heating, respectively, they are associated to the phase transitions of milk fat. Continuous isothermal measurement of the optical coefficients showed that the crystallization process requires several hours. The strongly changing reduced scattering coefficient implies that the thermal history of milk will have a major impact on any method based on light scattering as quantitative analytical technique.
Y1  - 2012
U6  - https://doi.org/10.1016/j.idairyj.2012.03.012
SN  - 0958-6946
VL  - 26
IS  - 2
SP  - 120
EP  - 126
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Wöhl-Bruhn, Stefanie
A1  - Badar, Muhammad
A1  - Bertz, Andreas
A1  - Tiersch, Brigitte
A1  - Koetz, Joachim
A1  - Menzel, Henning
A1  - Müller, Peter P.
A1  - Bunjes, Heike
T1  - Comparison of in vitro and in vivo protein release from hydrogel systems
JF  - Journal of controlled release
N2  - Hydrogel systems based on hydroxyethyl starch-polyethylene glycol methacrylate (HES-P(EG)(6)MA) or hydroxyethyl starch methacrylate (HES-MA) were used to assess the protein release behavior. Here, we analyzed the in vitro release of FITC-anti-human antibodies incorporated in either HES-P(EG)(6)MA or HES-MA hydrogel delivery systems in PBS or human serum. In addition, hydrogel disks and microparticles prepared from the two polymers were subcutaneously implanted in BALB/c mice. The in vivo release of FITC-IgG was non-invasively monitored by an in vivo imaging system (IVIS 200) over a time period of up to 3 months. The imaging system allowed to asses individual animals over time, therefore only a small number of animals was required to obtain high quality data. The reduction in fluorescence intensity at the site of administration was compared to in vitro release profiles. These investigations demonstrated a sustained release from HES-MA hydrogel disks compared to rapidly degrading HES-P(EG)(6)MA disks and microparticles. The sustained release from HES-MA disks could be further optimized by using increased polymer concentrations. Human serum as in vitro release medium reflected better the in vivo release from HES-P(EG)(6)MA systems than PBS, suggesting that the presence of organic substances like proteins or lipids may play a significant role for the release kinetics.
KW  - In vivo imaging system (IVIS)
KW  - Hydrogel disks
KW  - Hydrogel microparticles
KW  - Release
KW  - In vivo-in vitro correlation
KW  - Hydroxyethyl starch (HES)
Y1  - 2012
U6  - https://doi.org/10.1016/j.jconrel.2012.05.049
SN  - 0168-3659
VL  - 162
IS  - 1
SP  - 127
EP  - 133
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Koeth, Anja
A1  - Tiersch, Brigitte
A1  - Appelhans, Dietmar
A1  - Gradzielski, Michael
A1  - Cölfen, Helmut
A1  - Koetz, Joachim
T1  - Synthesis of Core-Shell Gold Nanoparticles with Maltose-Modified Poly(Ethyleneimine)
JF  - Journal of dispersion science and technology
N2  - The synthesis of ultrafine gold nanoparticles in presence of maltose-modified hyperbranched poly(ethyleneimines) (PEI) is described. The polymer acted as both a reducing and stabilising agent in the particle formation process. The nanoparticles were characterized by means of dynamic light scattering (DLS), transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), small-angle x-ray scattering (SAXS), and small-angle neutron scattering (SANS). The mechanism of nanoparticle formation can be described in two steps. The reduction process of the Au3+ ions located in the inner coil region of the hyperbranched PEI led to the formation of a compact gold core, and is accompanied by a collapse of the polymer coil. Therefore, in the subsequent reduction process a gold-polymer hybrid shell is formed. By using the PEI of higher molar mass, core-shell gold nanoparticles of about 3.6 nm size with a more narrow size distribution and special fluorescence behavior could be synthesized.
KW  - Gold nanoparticles
KW  - gold-polymer hybrid shell
KW  - maltose-modified poly(ethyleneimine)
Y1  - 2012
U6  - https://doi.org/10.1080/01932691.2010.530084
SN  - 0193-2691
VL  - 33
IS  - 1-3
SP  - 52
EP  - 60
PB  - Taylor & Francis Group
CY  - Philadelphia
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Shainyan, Bagrat A.
A1  - Kirpichenko, Svetlana V.
A1  - Shlykov, Sergei A.
T1  - Structure and Conformational Properties of 1,3,3-Trimethyl-1,3-Azasilinane : Gas Electron Diffraction, Dynamic NMR, and Theoretical Study.
Y1  - 2012
SN  - 1089-5639
ER  - 
TY  - THES
A1  - Mucic, Nenad
T1  - Thermodynamics, kinetics and rheology of surfactant adsorption layers at water/oil interfaces
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Debatin, Franziska
T1  - Eine isoretikulare Serie mikroporöser, metall-organischer Netzwerke basierend auf 2-substituierten Imidazolat-4-amid-5-imidaten und Zink- oder Cobalt-Zentren: Synthesen, Strukturen und Eigenschaften
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Dorff, Giselher
T1  - Eigenschaftsverbesserung von Polylactid durch Copolymerisation mit anderen Thermoplasten
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Bettenbühl, Mario
T1  - Microsaccades: symbols in fixational eye movements
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Rojas Carillo, Oscar Mario
T1  - Versatile uses of halogen-free Ionic Liquids for the formulation of non-aqueous microemulsion and synthesis of gold nanoparticles
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Suslova, Elena N.
A1  - Kleinpeter, Erich
T1  - Conformational analysis of 4,4-dimethyl-1-(trifluoromethylsulfonyl)-1,4-azasilinane and 2,2,6,6-tetramethyl-4- (trifluoromethylsulfonyl)-1,4,2,6-oxazadisilinane
N2  - 4,4-Dimethyl-1-(trifluoromethylsulfonyl)-1,4-azasilinane 1 and 2,2,6,6-tetramethyl-4-(trifluoromethylsulfonyl)- 1,4,2,6-oxazadisilinane 2 were studied by variable temperature dynamic 1H, 13C, 19F NMR spectroscopy and theoretical calculations at the DFT (density functional theory) and MP2 (Moller-Plesset 2) levels of theory. Both kinetic (barriers to ring inversion) and thermodynamic data (frozen conformational equilibria) could be obtained for the two compounds. The computations revealed two minima on the potential energy surface for molecules 1 and 2 corresponding to the rotamers with the CF3SO2 group directed inward and outward the ring, the latter being 0.20.4 kcal/mol (for 1) and 1.1 kcal/mol (for 2) more stable than the former. The vibrational calculations at the DFT and MP2 levels of theory give the values of the free energy difference Delta G degrees for the 'inward' reversible arrow 'outward' equilibrium consistent with those determined from the experimentally measured ratio of the rotamers. The structure of crystalline compound 2 was ascertained by X-ray diffraction analysis.
Y1  - 2012
ER  - 
TY  - JOUR
A1  - Lazareva, Nataliya F.
A1  - Albanov, Alexander I.
A1  - Shainyan, Bagrat A.
A1  - Kleinpeter, Erich
T1  - Synthesis and conformational properties of substituted 1,4,2-oxazasilinanes: low temperature NMR study and quantum chemical calculations
Y1  - 2012
UR  - http://www.sciencedirect.com/science/article/pii/S0040402011018321
U6  - https://doi.org/10.1016/j.tet.2011.11.077
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Stojanovic, Milovan
A1  - Markovic, Rade
A1  - Baranac-Stojanovic, Marija
T1  - Synthesis of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions
N2  - Syntheses of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions incorporating heteroatom-based nucleophiles have been examined and discussed. The formation of (5,6)-membered systems was feasible with all nucleophiles tried (O, S and N), while the closing of the five-membered ring was restricted to O- and S-nucleophiles. The closure of a four-membered ring failed. Instead, the bicyclic (5,6)-membered acetal derivative and the tricyclic system with an eight-membered central ring were obtained from the substrates containing O and S nucleophilic moieties, respectively. The reaction outcome and stereochemistry are rationalized using quantum chemical calculations at B3LYP/6-31G(d) level. The exclusive cis-stereoselectivity in the formation of (5,6)- and (5,5)-membered systems results from thermodynamic control, whereas the formation of the eight-membered ring was kinetically controlled.
Y1  - 2012
SN  - 1477-0520
ER  - 
TY  - THES
A1  - Kuke, Stefanie
T1  - Lanthanoide(III) in Komplexen mit niedermolekularen Säuren : Spektroskopische Betrachtung kompexer- spezifischer Löschmechanis,men in Eu(III)- und TB(III)-Komplexen
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Steinbrück, Dörte
T1  - Faseroptische Sauerstoff- und ph-Sensorik mittels Phasenmodulationsspektroskopie
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Hahn, Simone
T1  - Extration von Hexachloroplatinat(IV) mit phoshorylierten Merrifield-Harzen aus salzsauren Lösungen
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Kleinpeter, Erich
T1  - Conformational preferences of Si-Ph,H and Si-Ph,Me silacyclohexanes and 1,3-thiasilacyclohexanes : Additivity of conformational energies in 1,1-disubstituted heterocyclohexanes
N2  - The conformational equilibria of 1-phenyl-1-silacyclohexane 1, 3-phenyl-1,3-thiasilacyclohexane 2, 1-methyl-1- phenyl-1-silacyclohexane 3, and 3-methyl-3-phenyl-1,3-thiasilacyclohexane 4 have been studied for the first time by low temperature C-13 NMR spectroscopy at 103 K. Predominance of the equatorial conformer of compound 1 (Ph-eq/Ph-ax=78%:22%) is much less than in its carbon analog, phenylcyclohexane (nearly 100% of Ph-eq). And in contrast to 1-methyl-1- phenylcyclohexane, the conformers with the equatorial Ph group are predominant for compounds 3 and 4: at 103 K, Ph-eq/Ph- ax ratios are 63%:37% (3) and 68%:32% (4). As the Si-C bonds are elongated with respect to C-C bonds, the barriers to ring inversion are only between 5.2-6.0 (ax -> eq) and 5.4-6.0 (eq -> ax) kcal mol(-1). Parallel calculations at the DFT and MP2 level of theory (as well as the G2 calculations for compound 1) show qualitative agreement with the experiment. The additivity/nonadditivity of conformational energies of substituents on cyclohexane and silacyclohexane derivatives is analyzed. The geminally disubstituted cyclohexanes containing a phenyl group show large deviations from additivity, whereas in 1-methyl-1-phenyl-1-silacyclohexane and 3-methyl-3-phenyl-1,3-thiasilacyclohexane the effects of the methyl and phenyl groups are almost additive. The reasons for the different conformational preferences in carbocyclic and heterocyclic compounds are analyzed using the homodesmotic reactions approach.
Y1  - 2012
UR  - http://www.sciencedirect.com/science/article/pii/S0040402011016620 (25.11.2013)
SN  - 0040-4020
ER  - 
TY  - THES
A1  - Schneider, Julia
T1  - Characterisation of single and multibubble cavitation through analysis of molecular, atomic and ionic line emissions
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Kupstat, Annette
T1  - Förster resonance energy transfer (FRET)-based detection of molecular binding interactions - from fundamental research to application in life science
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Heydenreich, Matthias
A1  - Koch, Andreas
A1  - Linker, Torsten
T1  - Synthesis and NMR spectroscopic conformational analysis of esters of 4-hydroxy-cyclohexanone-the more polar the molecule the more stable the axial conformer
N2  - The esters of 4-hydroxy-cyclohexanone and a series of carboxylic acids R-COOH with R of different electronic and steric influence (R=Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, sec-Bu, t-Bu, CF3, CH2Cl, CHCl2, CCl3, CH2Br, CHBr2, and CBr3) were synthesized and the conformational equilibria studied by 1H and 13C NMR spectroscopy at 103 K and at 295 K, respectively. The geometry of optimized structures of the axial/equatorial chair conformers was computed at the ab initio MO and DFT levels of theory. Only one preferred conformation was obtained for the axial and the equatorial conformer as well. When comparing the conformational equilibria of the cyclohexanone esters with those of the corresponding cyclohexyl esters a certain polarity contribution of the cyclohexanone framework was revealed, which is independent of the substituent effects and increases the stability of the axial conformers by a constant amount.
Y1  - 2012
SN  - 0040-4020
ER  - 
TY  - THES
A1  - von Rüsten-Lange, Maik
T1  - Improving Hemocompatibility of poly(ether imide) by surface functionalization with polyethers
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Techen, Anne
T1  - Fluoreszenzspektroskopische Untersuchungen von Arzneimittel-Träger-Wechselwirkungen am Beispiel von Xanthenfarbstoff-markierten CTAB-Mizellen
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Flehr, Roman
T1  - Design and development of novel three color-FRET systems in synthetic peptides and oligonucleotides
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Geißler, Daniel
T1  - Multiplexing in homogenen FRET-Immunoassays : Detektion von Lungenkrebs-Tumormarkern mittels zeitaufgelöster Laserspektoskopie durch Förster-Resonanzenergietransfer (FRET)
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Su, Fangzheng
T1  - Graphitic carbon nitride as a metal-free catalyst for photosynthesis, Amine oxidation and base-mediated reactions
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Lahn, Mattes
T1  - Investigation of ion concentrations in biological tissue using FLIM and 2P-microscopy
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Neuvonen, Kari
A1  - Neuvonen, Helmi
A1  - Koch, Andreas
T1  - Taft equation in the light of NBO computations : Introduction of a novel polar computational substituent constant scale for alkyl groups
Y1  - 2012
SN  - 2210-271X
ER  - 
TY  - THES
A1  - Pick, Charlotte Hildegard
T1  - Die Photo-Dehydro-Diels-Alder-Reaktion als potentielle Methode zur Ligandendarstellung: Untersuchungen zur atropselektiven Synthese von Biarylen und Synthese von Naphthylpryridinen
Y1  - 2012
SN  - 978-3-8439-0337-0
PB  - Dr. Hut
CY  - München
ER  - 
TY  - THES
A1  - Glatzel, Stefan
T1  - Cellulose based transition metal nano-composites : structuring and development
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Ast, Sandra
T1  - Integration of the 1,2,3-Triazole "Click" motif as a potent signalling element into metal ion responsive fluorescent probes for physiological cations
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Lazareva, Nataliya F.
A1  - Shainyan, Bagrat A.
A1  - Schilde, Uwe
A1  - Chipania, Nina N.
T1  - Synthesis, Molecular Structure, Conformational Analysis, and Chemical Properties of Silicon-Containing Derivatives of Quinolizidine
Y1  - 2012
SN  - 0022-3263
ER  - 
TY  - THES
A1  - Möllnitz, Kristian
T1  - Synthese und Untersuchung von molekularen Stäben basierend auf Oligospiroketalen
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Junginger, Mathias
T1  - Interface-controlled calcium phosphate mineralization
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Marmodée, Bettina
T1  - Fluorenscence Line-Narrowing-Spektroskopie zur Charakterisierung von Eu(III) in Komplexen mit kleinen organischen Liganden
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - GEN
A1  - Krehl, Stefan
T1  - Entwicklung von Ruthenium-katalysierten Tandem-Reaktionssequenzen
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Wilke, Antje
T1  - Synthese und Charakterisierung von mesoporösen Polymernetzwerken
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Xie, Zai-Lai
T1  - Functional materials in metal-containing ionic liquids
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - THES
A1  - Luzi, Manja
T1  - Kinetic studies of mixed gas hydrates
Y1  - 2012
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - Spatial magnetic properties subject to lone pair and pi electron delocalization in benzenoid and quinoid structures : are quinoid tautomers really nonaromatic?
N2  - The spatial magnetic properties, through-space NMR shieldings (TSNMRS), of benzenoid and quinoid tautomeric structures such as benzodifurantrione and phenazine-type molecules have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept of Paul von Rague Schleyer and visualized as iso- chemical-shielding surfaces (ICSS) of various size and direction. The TSNMRS values were employed to quantify and visualize the partial aromaticity of the studied compounds. In the case of the surprisingly more stable quinoid tautomers, the aromaticity-synonymous with stability due to the conjugation of p electrons and lone pairs-was not found to be particularly reduced.
Y1  - 2012
SN  - 1551-7004
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Modarresi-Alam, Ali Reza
A1  - Inaloo, Iman Dindarloo
T1  - Synthesis of primary thiocarbamates by silica sulfuric acid as effective reagent under solid-state and solution conditions
N2  - A simple and efficient method for the conversion of alcohols and phenols to primary O-thiocarbamates and S- thiocarbamates in the absence of solvent (solvent-free condition) using silica sulfuric acid (SiO2OSO3H) as a solid acid is described. The products are easily distinguished by IR, NMR and X-ray data. X-ray data of the compounds reveal a planar trigonal orientation of the NH2 nitrogen atom with the partial C,N double-bond character and the CS or CO groups in synperiplanar position with CarylO and CalkylS moieties, respectively. Moreover, the OCSNH2 group which is perpendicular to the plane of the benzene ring in 1c and the central thiocarbamate SCONH2 group in 2b are essentially planar.
Y1  - 2012
SN  - 0022-2860
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
T1  - Are lithium and sodium salts of N-(2-hydroxyphenyl)-salicylaldimine aromatic metalla-hetero[10]annulenes? An answer given by spatial magnetic properties (through space NMR shieldings-TSNMRS)
N2  - The spatial magnetic properties (through space NMR shieldings-TSNMRS) of the enol tautomer of N-(2- hydroxyphenyl)-salicylaldimine, the lithium and sodium salts in comparison with cyclodecapentaene and pyrano[2,3- b]pyrrole were studied to answer this question.
Y1  - 2012
SN  - 1463-9076
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Branac-Stojanovi, Marija
A1  - Koch, Andreas
T1  - Is the Conventional Interpretation of the Anisotropic Effects of CC Double Bonds and Aromatic Rings in NMR Spectra in Terms of the -Electron Shielding/Deshielding Contributions Correct?
N2  - Based on the nucleus-independent chemical shift (NICS) concept, isotropic magnetic shielding values have been computed along the three Cartesian axes for ethene, cyclobutadiene, benzene, naphthalene, and benzocyclobutadiene, starting from the molecular/ring center up to 10;Å away. These through-space NMR spectroscopic shielding (TSNMRS) values, which reflect the anisotropic effects, have been broken down into contributions from localized- and canonical molecular orbitals (LMOs and CMOs); these contributions revealed that the proton NMR spectroscopic chemical shifts of nuclei that are spatially close to the C=C double bond or the aromatic ring should not be explained in terms of the conventionally accepted ;-electron shielding/deshielding effects. In fact, these effects followed the predictions only for the antiaromatic cyclobutadiene ring.
Y1  - 2012
SN  - 1521-3765
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Balci, Kubilay
A1  - Yapar, G.
A1  - Akkaya, S.
A1  - Akyuz, S.
A1  - Koch, Andreas
T1  - A conformational analysis and vibrational spectroscopic investigation on 1,2-bis(o-carboxyphenoxy) ethane molecule
N2  - The minima on the potential energy surface of 1,2-bis(o-carboxyphenoxy) ethane (CPE) molecule in its electronic ground state were searched by a molecular dynamics simulation performed with MM2 force field. For each of the found minimum-energy conformers, the corresponding equilibrium geometry, charge distribution, HOMO-LUMO energy gap, force field, vibrational normal modes and associated IR and Raman spectral data were determined by means of the density functional theory (DFT) based electronic structure calculations carried out by using B3LYP method and various Pople- style basis sets. The obtained theoretical data confirmed the significant effects of the intra- and inter-molecular hydrogen bonding interactions on the conformational structure, force field, and group vibrations of the molecule. The same data have also revealed that two of the determined stable conformers, both of which exhibit pseudo-crown structure, are considerably more favorable in energy to the others and accordingly provide the major c ntribution to the experimental spectra of CPE. In the light of the improved vibrational spectral data obtained within the "SQM FF" methodology and "Dual Scale Factors" approach for the monomer and dimer forms of these two conformers, a reliable assignment of the fundamental bands observed in the experimental room-temperature IR and Raman spectra of the molecule was given, and the sensitivities of its group vibratb20s to conformation, substitution and dimerization were discussed.
Y1  - 2012
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Schainyan, Bagrat A.
A1  - Kirpichenko, Svetlane V.
T1  - Synthesis and conformational properties of 1,3-dimethyl-3-phenyl-1,3-azasilinane : low temperature dynamic NMR and computational study
N2  - 1,3-Dimethyl-3-phenyl-1,3-azasilinane was synthesized and its conformational behavior was studied by the low temperature NMR spectroscopy and quantum chemical calculations. The compound was shown to exist as an equilibrium mixture of the PhaxMeeq and PheqMeax chair conformers with the N-methyl substituent in equatorial position. The barrier to ring inversion was also determined.
Y1  - 2012
SN  - 1551-7004
ER  - 
TY  - JOUR
A1  - Awad, Duha Jawad
A1  - Koch, Andreas
A1  - Mickler, Wulfhard
A1  - Schilde, Uwe
A1  - Strauch, Peter
T1  - EPR spectroscopy of 4, 4 '-Bis(tert-butyl)-2, 2 '-bipyridine-1, 2-dithiolatocuprates(II) in host lattices with different coordination geometries
JF  - Zeitschrift für anorganische und allgemeine Chemie
N2  - A series of new heteroleptic MN2S2 transition metal complexes with M = Cu2+ for EPR measurements and as diamagnetic hosts Ni2+, Zn2+, and Pd2+ were synthesized and characterized. The ligands are N2 = 4, 4'-bis(tert-butyl)-2, 2'-bipyridine (tBu2bpy) and S2 =1, 2-dithiooxalate, (dto), 1, 2-dithiosquarate, (dtsq), maleonitrile-1, 2-dithiolate, or 1, 2-dicyanoethene-1, 2-dithiolate, (mnt). The CuII complexes were studied by EPR in solution and as powders, diamagnetically diluted in the isostructural planar [NiII(tBu2bpy)(S2)] or[PdII(tBu2bpy)(S2)] as well as in tetrahedrally coordinated[ZnII(tBu2bpy)(S2)] host structures to put steric stress on the coordination geometry of the central CuN2S2 unit. The spin density contributions for different geometries calculated from experimental parameters are compared with the electronic situation in the frontier orbital, namely in the semi-occupied molecular orbital (SOMO) of the copper complex, derived from quantum chemical calculations on different levels (EHT and DFT). One of the hosts, [NiII(tBu2bpy)(mnt)], is characterized by X-ray structure analysis to prove the coordination geometry. The complex crystallizes in a square-planar coordination mode in the monoclinic space group P21/a with Z = 4 and the unit cell parameters a = 10.4508(10) angstrom, b = 18.266(2) angstrom, c = 12.6566(12) angstrom, beta = 112.095(7)degrees. Oxidation and reductions potentials of one of the host complexes, [Ni(tBu2bpy)(mnt)], were obtained by cyclovoltammetric measurements.
KW  - 1
KW  - 2-Dithiosquarate
KW  - 1
KW  - 2-Dithiooxalate
KW  - 1
KW  - 2-Dicyanoethene-1
KW  - 2-dithiolate
KW  - 4
KW  - 4'-Bis(tert-butyl)-2
KW  - 2'-bipyridine
KW  - X-ray structure
KW  - EPR
KW  - Copper
KW  - Nickel
KW  - Zinc
Y1  - 2012
U6  - https://doi.org/10.1002/zaac.201100517
SN  - 0044-2313
VL  - 638
IS  - 6
SP  - 965
EP  - 975
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Primus, Philipp-A.
A1  - Kumke, Michael Uwe
T1  - Flash photolysis study of complexes between salicylic acid and lanthanide ions in water
JF  - The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment & general theory
N2  - In the natural environment humic substances (HS) represent a major factor determining the speciation of metal ions, e.g., in the context of radionuclide migration. Here, due to their intrinsic sensitivity and selectivity, spectroscopic methods are often applied, requiring a fundamental understanding of the photophysical processes present in such HS-metal complexes. Complexes with different metal ions were studied using 2-hydroxybenzoic acid (2HB) as a model compound representing an important part of the chelating substructures in HS. In flash photolysis experiments under direct excitation of 2HB in the absence and the presence of different lanthanide ions, the generation and the decay of the 2HB triplet state, of the phenoxy radical, and of the solvated electron were monitored. Depending on the lanthanide ion different intracomplex processes were observed for these transient species including energy migration to and photoreduction of the lanthanide ion. The complexity of the intracomplex photophysical processes even for small molecules such as 2HB underlines the necessity to step-by-step approach the photochemical reactivity of HS by using suitable model compounds.
Y1  - 2012
U6  - https://doi.org/10.1021/jp2043575
SN  - 1089-5639
VL  - 116
IS  - 4
SP  - 1176
EP  - 1182
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Tolstikova, Ljudmila L.
A1  - Schilde, Uwe
T1  - Simple methods for the preparation of N-triflyl guanidines and the structure of compounds with the CF3SO2N=C-N fragment
JF  - Journal of fluorine chemistry
N2  - Two novel and simple approaches to N-triflyl guanidines are elaborated. Owing to very strong conjugation the formally double C=N bond of TIN=C(NHR)(2) is longer than the formally single N-C bonds. Energetic effect of the triflylgroup on the conjugation in the N-C=N moiety is estimated to be >= 150 kcal/mol.
KW  - N-triflyl guanidines
KW  - Synthesis
KW  - Structure
KW  - X-ray
KW  - MP2 calculations
Y1  - 2012
U6  - https://doi.org/10.1016/j.fluchem.2011.12.004
SN  - 0022-1139
VL  - 135
IS  - 1
SP  - 261
EP  - 264
PB  - Elsevier
CY  - Lausanne
ER  -