@article{ZehmFudickarHansetal.2008, author = {Zehm, Daniel and Fudickar, Werner and Hans, Melanie and Schilde, Uwe and Kelling, Alexandra and Linker, Torsten}, title = {9,10-Diarylanthracenes as molecular switches : syntheses, properties, isomerisations and their reactions with singlet oxygen}, issn = {0947-6539}, year = {2008}, abstract = {A series of 9,10-diarylanthracenes with various substituents at the ortho positions have been synthesised by palladium-catalysed cross-coupling reactions. Such compounds exhibit interesting physical properties and can be applied as molecular switches. Despite the high steric demand of the substituents, products were formed in moderate-to-good yields. In some cases, microwave conditions further improved yields. Bis-coupling afforded two isomers (syn and anti) that do not interconvert at room temperature. These products were easily separated and their relative stereochemistries were unequivocally assigned by NMR spectroscopy and X-ray analysis. The syn and anti isomers exhibit different physical properties (e.g., melting points and solubilities) and interconversion by rotation around the aryl-aryl axis commences at <100 °C for fluoro-substituted diarylanthracenes and at >300 °C for alkyl- or alkoxy-substituted diarylanthracenes. The reactions with singlet oxygen were studied separately and revealed different reactivities and reaction pathways. The yields and reactivities depend on the size and electronic nature of the substituents. The anti isomers form the same 9,10-endoperoxides as the syn species, occasionally accompanied by unexpected 1,4-endoperoxides as byproducts. Thermolysis of the endoperoxides exclusively yielded the syn isomers. The interesting rotation around the aryl-aryl axis allows the application of 9,10-diarylanthracenes as molecular switches, which are triggered by light and air under mild conditions. Finally, the oxygenation and thermolysis sequence provides a simple, synthetic access to a single stereoisomer (syn) from an unselective coupling step.}, language = {en} } @article{KleinpeterKochSahooetal.2008, author = {Kleinpeter, Erich and Koch, Andreas and Sahoo, Himansu S. and Chand, Dillip Kumar}, title = {Anisotropic effect of the nitrate anion-manifestation of diamagnetic proton chemical shifts in the 1H NMR spectra of NO3-coordinated complexes}, doi = {10.1016/j.tet.2008.03.063}, year = {2008}, abstract = {The anisotropic effect of the planar nitrate anion NO3- has been ab initio calculated employing the Nucleus- Independent Chemical Shift (NICS) concept of von Ragu{\´e} Schleyer and visualized as Iso-Chemical-Shielding Surfaces (ICSSs) of various (de)shieldings. Complexation-induced shifts in the 1H NMR spectra of nitrate/metal complexes or nitrate/receptor supramolecules can be separated now into anisotropic influences of the suitably coordinated nitrate anions and effects originating from differential sources.}, language = {en} } @article{RukungaMuregiOmaretal.2008, author = {Rukunga, G. M. and Muregi, F. W. and Omar, S. A. and Gathirwa, J. W. and Muthaura, C. N. and Peter, Martin G.}, title = {Anti-plasmodial activity of the extracts and two sesquiterpenes from Cyperus articulatus}, issn = {0367-326X}, year = {2008}, abstract = {Two sesquiterpenes, corymbolone and mustakone, isolated from the chloroform extract of the rhizomes of Cyperus articulatus, exhibited significant anti-plasmodial properties. Mustakone was approximately ten times more active than corymbolone against the sensitive strains of the Plasmodium falciparum.}, language = {en} } @phdthesis{Stark2008, author = {Stark, Arne Henning}, title = {CCD based ellipsometric light scattering}, pages = {xv, 99, XVI S.: Ill., graph. Darst.}, year = {2008}, language = {en} } @phdthesis{Stark2008, author = {Stark, Arne Henning}, title = {CCD based ellipsometric light scattering}, address = {Potsdam}, pages = {99 S., vi-xv, : graph. Darst.}, year = {2008}, language = {en} } @phdthesis{Schwarz2008, author = {Schwarz, Guntram}, title = {Charakterisierung von Eigenschaften und Struktur Metallo-supramolekularer Funktionseinheiten}, address = {Potsdam}, pages = {156 S.: Ill., garph. Darst.}, year = {2008}, language = {de} } @phdthesis{Schwarz2008, author = {Schwarz, Guntram}, title = {Charakterisierung von Eigenschaften und Struktur Metallo-supramolekularer Funktionseinheiten}, address = {Potsdam}, pages = {155 S., : graph. Darst.}, year = {2008}, language = {de} } @phdthesis{Vergin2008, author = {Vergin, Annika}, title = {Charakterisierung von Metallosupramolekularen Polyelektrolyten mittels analytischer Ultrazentrifugation}, address = {Potsdam}, pages = {94 S.}, year = {2008}, language = {de} } @article{MarangReillerEidneretal.2008, author = {Marang, Laura and Reiller, Pascal E. and Eidner, Sascha and Kumke, Michael Uwe and Benedetti, Marc F.}, title = {Combining spectroscopic and potentiometric approaches to characterize competitive binding to humic substances}, doi = {10.1021/Es702858p}, year = {2008}, abstract = {In an area that contains high concentrations of natural organic matter, it is expected that it plays an important role on the behavior of rare earth elements (REE), like europium, and of trivalent actinides. Competitive interactions with H+, inorganic species, major cations, e.g. Ca(II) or Mg(II), could influence these metals transport and bioavailability. Competitive experiments between cations, which can bind differently to humic substances and Eu3+,will bring an improved understanding of the competitive mechanisms. The aim of this study is to acquire data for Eu(III)/Cu(II) and Eu(III)/Ca(II) competitive binding to a sedimentary originated humic acid (Gorleben, Germany). The NICA-Donnan parameters for Ca2+, Cu2+, and Eu3+ obtained from competitive binding experiments using Ca2+ or Cu2+ ion selective electrodes were used to model time-resolved laser fluorescence spectroscopy (TRLFS) measurements. Eu3+ and Cu2+ are in direct competition for the same type of sites,whereas Ca2+ has an indirect influence through electrostatic binding.}, language = {en} } @article{StarkeKammerGrunwaldetal.2008, author = {Starke, Ines and Kammer, Stefan and Grunwald, Nicolas and Schilde, Uwe and Holdt, Hans-J{\"u}rgen and Kleinpeter, Erich}, title = {Complexation of diazaperylene and bisisoquinoline with transition metal ions in the gas phase studied by electrospray ionization mass spectrometry}, year = {2008}, abstract = {The complex formation of the ligands 1,12-diazaperylene (dap), 1,1-bisisoquinoline (bis), 2,2-bipyridine (bpy) and 1,10-phenanthroline (phen) with transition metal ions (M = Fe, Co, Ni, Cu, Zn, Ru, Os, Re, Pd, Pt, Ag and Cd) in the gas phase has been studied by electrospray ionization mass spectrometry. With the exception of Ru, Os, Fe, Ni and Cu, singly charged complexes [MLn]+ (n = 1,2) were observed. The complexes of dap and bis with Ru, Os, Fe and Ni ions, and the mixed ligand complexes with bpy and phen, are preferably of the doubly charged type [ML3]2+. In addition, collision- induced dissociation (CID) measurements were employed to evaluate the relative stabilities of these complexes. The CID experiments of mixed-ligand complexes which contain both dap and phen or dap and bpy exhibit preferential elimination of bpy, indicating that bpy is a weaker ligand than phen and dap.}, language = {en} } @article{SchaeferBungNest2008, author = {Sch{\"a}fer-Bung, Boris and Nest, Mathias}, title = {Correlated dynamics of electrons with reduced 2-electron density matrices}, year = {2008}, abstract = {We present an approach to the correlated dynamics of many-electron systems. We show, that the two-electron reduced density matrix (2RDM) can provide a suitable description of the real time evolution of a system. To achieve this, the hierarchy of equations of motion must be truncated in a practical way. Also, the computational effort, given that the 2RDM is represented by products of two-electron determinants, is discussed, and numerical model calculations are presented.}, language = {en} } @article{HahnKellingSchildeetal.2008, author = {Hahn, Simone and Kelling, Alexandra and Schilde, Uwe and Holdt, Hans-J{\"u}rgen}, title = {Crystal structure of bis(2-ethylthiomethylpyridine)platinum(II) hexachloroplatinate, [Pt(C8H11NS)2][PtCl6]}, issn = {1433-7266}, doi = {10.1524/ncrs.2008.0216}, year = {2008}, abstract = {C16H22Cl6N2Pt2S2, orthorhombic, Pbca (no. 61), a = 15.5660(8) angstrom, b = 17.4892(9) angstrom, c = 18.161 (1) angstrom, V = 4944. 1 angstrom(3), Z = 8, R-gt(F) = 0.030, wR(ref)(F-2) = 0.055, T = 210 K.}, language = {en} } @article{ShainyanSuslovaSchilde2008, author = {Shainyan, Bagrat A. and Suslova, Elena N. and Schilde, Uwe}, title = {Crystal structures and theoretical calculations of trans -2,4,4-trimethyl-4-silathiane 1-oxide and 4,4-dimethyl- 4-silathiane 1,1-dioxide}, issn = {1040-0400}, year = {2008}, abstract = {The crystal and molecular structures of trans-2,4,4-trimethyl-4-silathiane 1-oxide 1 and 4,4-dimethyl-4- silathiane 1,1-dioxide 2 were determined by single crystal X-ray diffraction. Both compounds have the chair conformation with the 2-Me and the S=O group in compound 1 occupying the equatorial positions. The DFT (B3LYP/6-311G(d,p)) and MP2 (MP2/6-311G(d,p)) theoretical calculations nicely reproduce the X-ray experimental geometry. The obtained results are discussed in connection with the electronic and structural properties of the compounds.}, language = {en} } @article{KleinpeterKochShainyan2008, author = {Kleinpeter, Erich and Koch, Andreas and Shainyan, Bagrat A.}, title = {Cyclobutadiene dianion derivatives : Planar 4c,6e or three-dimensional 6c,6e aromaticity?}, doi = {10.1016/j.theochem.2008.05.027}, year = {2008}, abstract = {The spatial magnetic properties (Through Space NMR Shieldings - TSNMRS) of two cyclobutadiene derivatives (2 and 5) and of a number of cyclobutadiene dianion derivatives (3, 4 and 6-8) have been calculated by the GIAO perturbation method employing the Nucleus-Independent Chemical Shift (NICS) concept of P. v. Ragu{\´e} Schleyer, and visualized as Iso-Chemical-Shielding Surfaces (ICSS) of various size and direction. TSNMRS values can be successfully employed to quantify and visualize the (anti)aromaticity of the compounds studied and to discuss the influence of Li+ complexation to cyclobutadiene dianion (4a, 7 and 8) on planar 4c,6e or three-dimensional 6c,6e aromaticity.}, language = {en} } @article{OliverLunnUrbanczykWochniaketal.2008, author = {Oliver, Sandra N. and Lunn, John Edward and Urbanczyk-Wochniak, Ewa and Lytovchenko, Anna and van Dongen, Joost T. and Faix, Benjamin and Schm{\"a}lzlin, Elmar and Fernie, Alisdair R. and Schm{\"a}elzlin, E. and Geigenberger, Peter}, title = {Decreased expression of cytosolic pyruvate kinase in potato tubers leads to a decline in pyruvate resulting in an in vivo repression of the alternative oxidase}, doi = {10.1104/pp.108.126516}, year = {2008}, abstract = {The aim of this work was to investigate the effect of decreased cytosolic pyruvate kinase (PKc) on potato (Solanum tuberosum) tuber metabolism. Transgenic potato plants with strongly reduced levels of PKc were generated by RNA interference gene silencing under the control of a tuber-specific promoter. Metabolite profiling showed that decreased PKc activity led to a decrease in the levels of pyruvate and some other organic acids involved in the tricarboxylic acid cycle. Flux analysis showed that this was accompanied by changes in carbon partitioning, with carbon flux being diverted from glycolysis toward starch synthesis. However, this metabolic shift was relatively small and hence did not result in enhanced starch levels in the tubers. Although total respiration rates and the ATP to ADP ratio were largely unchanged, transgenic tubers showed a strong decrease in the levels of alternative oxidase (AOX) protein and a corresponding decrease in the capacity of the alternative pathway of respiration. External feeding of pyruvate to tuber tissue or isolated mitochondria resulted in activation of the AOX pathway, both in the wild type and the PKc transgenic lines, providing direct evidence for the regulation of AOX by changes in pyruvate levels. Overall, these results provide evidence for a crucial role of PKc in the regulation of pyruvate levels as well as the level of the AOX in heterotrophic plant tissue, and furthermore reveal that these parameters are interlinked in vivo.}, language = {en} } @article{TiseanuGessnerKumkeetal.2008, author = {Tiseanu, Carmen and Geßner, Andre and Kumke, Michael Uwe and Parvulescu, V.}, title = {Dehydration and rehydration effects on the photoluminescence properties of terbium-exchanged MFI type materials}, doi = {10.1016/j.jnoncrysol.2007.11.017}, year = {2008}, language = {en} } @article{LaudienRiebeBeitzetal.2008, author = {Laudien, Robert and Riebe, Daniel and Beitz, Toralf and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Detection of explosive related nitroaromatic compounds (ERNC) by laser-based ion mobility spectrometry}, isbn = {978-0-8194-7348-6}, year = {2008}, language = {en} } @phdthesis{Lutz2008, author = {Lutz, Jean-Fran{\c{c}}ois}, title = {Development of versatile chemical platforms to access new generations of "smart" polymer materials}, address = {Potsdam}, pages = {104 S.}, year = {2008}, language = {en} } @article{OPUS4-10587, title = {DFT-GIAO-NBO and 13C NMR study of the delta-syn-axial effect in 2,4-disubstituted adamantanes}, issn = {0749-1581}, doi = {10.1002/Mrc.2333}, year = {2008}, abstract = {Six groups of diastereomeric 2,4-disubstituted adamantanes were studied with DFT-GIAO-NBO (natural orbital analysis) methods. The calculated 13C chemical shifts reproduce well the experimental data. It was found that among all diastereomers, those bearing substituents in -syn-axial positions showed the largest overall deshielding, i.e. the sum of all 13C chemical shifts [;;(13C)] was the greatest and also had the highest delocalization contribution to the molecular energy evaluated with NBO. The higher delocalization energy is proposed to be the origin of the deshielding -syn-axial effect}, language = {en} } @article{NeuvonenFulopNeuvonenetal.2008, author = {Neuvonen, Helmi and Fulop, Ferenc and Neuvonen, Kari and Koch, Andreas and Kleinpeter, Erich}, title = {Electronic effects of heterocyclic ring systems as evaluated with the aid of 13C and 15N NMR chemical shifts and NBO analysis}, doi = {10.1002/Poc.1271}, year = {2008}, abstract = {The electronic effects of the 5- and 6-membered heterocyclic rings on the C=N-N unit of five different hydrazone derivatives of pyridine-2-, -3- and -4-carbaldehydes, pyrrole-2-carbaldehyde, furan-2- and -3-carbaldehydes and thiophene-2- and -3-carbaldehydes have been studied with the aid of 13C and 15N NMR measurements together with the natural bond orbital (NBO) analysis. As model compounds are used the corresponding substituted benzaldehyde derivatives. The polarization of the C=N unit of the hydrazone functionality of the heteroaryl derivatives occurs in an analogous manner with that of phenyl derivatives. The electron-withdrawing heteroaryl groups destabilize and the electron-donating groups stabilize the positive charge development at the CN carbon while the effect on the negative charge development is opposite. The 15N NMR chemical shift of the C=N and C=N-N nitrogens and the NBO charges at C=N-N unit can be correlated with the replacement substituent constants of the heteroaryl groups. 13C NMR shifts of the C=N carbon of N,N- dialkylhydrazones of the heteroarenecarbaldehydes can be correlated with a dual parameter equation possessing the polar substituent constant ;* of the heteroaryl group and the electronegativity of the heteroatom as variables.}, language = {en} } @book{KleinpeterKlodKoch2008, author = {Kleinpeter, Erich and Klod, Sabrina and Koch, Andreas}, title = {Endohedral and external through-space shieldings of the fullerenes C50, C60, C60-6, C70, and C70-6- visualization of (Anti)aromaticity and their effects on the chemical shifts of encapsulated nuclei}, doi = {10.1021/jo702316h}, year = {2008}, abstract = {Endohedral and external through-space NMR shieldings (TSNMRS) and the magnetic susceptibilities of the fullerene carbon cages of C50, C60, C60-6, C70, and C70-6 were assessed by ab initio molecular orbital calculations. Employing the nucleus-independent chemical shift (NICS) concept, these TSNMRS were visualized as isochemical shielding surfaces (ICSS) and were applied to quantitatively estimate either the aromaticity or the anti-aromaticity on the fullerene surface pertaining to the five- or six-membered ring moieties and the shielding of any nuclei enclosed within the carbon cages. Differences between the NICSs calculated at the center of the fullerene carbon cages and the experimental chemical shifts of encapsulated NMR-active nuclei as well as experimental shieldings observed for different encapsulated nuclei were able to be understood readily for the first time.}, language = {en} } @article{TsukamotoHaebelValencaetal.2008, author = {Tsukamoto, Junko and Haebel, Sophie and Valenca, Gustavo P. and Peter, Martin G. and FRanco, Telma T.}, title = {Enzymatic direct synthesis of acrylic acid esters of mono- and disaccharides}, issn = {0268-2575}, year = {2008}, abstract = {Background: There is an increased need to replace materials derived from fossil sources by renewables. Sugar- cane derived carbohydrates are very abundant in Brazil and are the cheapest sugars available in the market, with more than 400 million tons of sugarcane processed in the year 2007. The objective of this work was to study the prepn. of sugar acrylates from free sugars and free acrylic acid, thus avoiding the previous prepn. of protected sugar derivs., such as glycosides, or activated acrylates, such as vinyl acrylate. Results: Lipase catalyzed esterification of three mono- and two disaccharides with acrylic acid, in the presence or absence of mol. sieves was investigated. The reactions were monitored by high-performance liq. chromatog. (HPLC) and the products were analyzed by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry. The main products are mono- and diacrylates, while higher esters are formed as minor products. The highest conversion to sugar acrylates was obsd. for the D-glucose and D- fructose, followed by D-xylose and D-maltose. Mol. sieves had no pronounced effect on the conversion. Conclusions: A feasible method is described to produce and to characterize sugar acrylates, including those contg. more than two acrylate groups. The process for prodn. of these higher esters could potentially be optimized further to produce mols. for crosslinking in acrylate polymn. and other applications. The direct enzymic esterification of free carbohydrates with acrylic acid is unprecedented. [on SciFinder (R)].}, language = {en} } @article{TiseanuKumkeParvulescuetal.2008, author = {Tiseanu, Carmen and Kumke, Michael Uwe and Parvulescu, Vasile Ion and Geßner, Andre and Gagea, Bogdan and Martens, Johan}, title = {Europium(3+) : an efficient luminescence probe for the Si to Al ratio and silylation effect in the microporous- mesoporous Zeogrid materials}, doi = {10.1021/Jp711337h}, year = {2008}, language = {en} } @article{MondalBhuniaBaburinetal.2008, author = {Mondal, Suvendu Sekhar and Bhunia, Asamanjoy and Baburin, Igor A. and J{\"a}ger, Christian and Kelling, Alexandra and Schilde, Uwe and Seiert, Gotthard and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {Gate effects in a hexagonal zinc-imidazolate-4-amide-5-imidate framework with flexible methoxy substituents and CO2 selectivity}, doi = {10.1039/C3CC42156B}, year = {2008}, abstract = {A new imidazolate-4-amide-5-imidate based MOF, IFP-7, is generated, having flexible methoxy groups, which act as molecular gates for guest molecules. This allows highly selective CO2 sorption over N2 and CH4 gases.}, language = {en} } @article{OliveiraelGueddariMoerschbacheretal.2008, author = {Oliveira, Enio N. and el Gueddari, Nour E. and Moerschbacher, Bruno M. and Peter, Martin G. and Franco, Telma T.}, title = {Growth of phytopathogenic fungi in the presence of partially acetylated chitooligosaccharides}, issn = {0301-486X}, year = {2008}, abstract = {Four phytopathogenic fungi were cultivated up to six days in media contg. chitooligosaccharide mixts. differing in av. DP and F A. The three different mixts. were named Q3 (which contained oligosaccharides of DP2-DP10, with DP2-DP7 as main components), Q2 (which contained oligosaccharides of DP2-DP12, with DP2-DP10 as main components) and Q1 (which derived from Q2 and contained oligomers of DP5-DP8 with hexamer and a heptamer as the main components). The novel aspect of this work is the description of the effect of mixts. of oligosaccharides with different and known compn. on fungal growth rates. The growth rate of Alternaria alternata and Rhizopus stolonifer was initially inhibited by Q3 and Q2 at higher concns. Q1 had a growth stimulating effect on these two fungi. Growth of Botrytis cinerea was inhibited by Q3 and Q2, while Q1 had no effect on the growth of this fungus. Growth of Penicillium expansum was only slightly inhibited by higher concns. of sample Q3, while Q2 and Q1 had no effect. The inhibition of growth rates or their resistance toward chitooligosaccharides correlated with the absence or presence of chitinolytic enzymes in the culture media, resp. [on SciFinder (R)]}, language = {en} } @article{BaranacStojanovicTatarKleinpeteretal.2008, author = {Baranac-Stojanovic, Marija and Tatar, Jovanan and Kleinpeter, Erich and Markovic, Rade}, title = {High-Yield Synthesis of Substituted and Unsubstituted Pyridinium Salts Containing a 4-Oxothiazolidine Moiety}, year = {2008}, abstract = {A new series of unsubstituted and substituted pyridinium salts bearing a 4-oxothiazolidinyl moiety has been prepared by an efficient rearrangement of 2-(1-bromoalkylidene)thiazolidin-4-ones. The process in based on three steps, namely carbon-bromine cleavage, bromine transfer, and substitution, each induced by pyridine or its derivatives, acting as base and reactant.}, language = {en} } @article{RothLoehmannsroebenKelzetal.2008, author = {Roth, Martin M. and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Kelz, A. and Kumke, Michael Uwe}, title = {innoFSPEC : fiber optical spectroscopy and sensing}, isbn = {978-0-819-47228-1}, year = {2008}, language = {en} } @article{ScheweSchmaelzlinWalz2008, author = {Schewe, Bettina and Schmaelzlin, Elmar and Walz, Bernd}, title = {Intracellular pH homeostasis and serotonin-induced pH changes in Calliphora salivary glands : the contribution of V-ATPase and carbonic anhydrase}, year = {2008}, language = {en} } @article{BringmannMutanyattaComarMaksimenkaetal.2008, author = {Bringmann, Gerhard and Mutanyatta-Comar, Joan and Maksimenka, Katja and Wanjohi, John M. and Heydenreich, Matthias and Brun, Reto and M{\"u}ller, Werner E. G. and Peter, Martin G. and Midiwo, Jacob O. and Yenesew, Abiy}, title = {Joziknipholones A and B : the first dimeric phenylanthraquinones, from the roots of Bulbine frutescens}, issn = {0947-6539}, year = {2008}, abstract = {From the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and -anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P- configuration (i.e., with the acetyl portions below the anthraquinone plane) at both axes in the case of joziknipholone A, whereas in joziknipholone B, the knipholone part was found to be M-configured. Joziknipholones A and B are active against the chloroquine resistant strain K1 of the malaria pathogen, Plasmodium falciparum, and show moderate activity against murine leukemic lymphoma L5178y cells.}, language = {en} } @phdthesis{Wacker2008, author = {Wacker, Philipp}, title = {Konformationsanalyse meso-substituierter Porphyrine mittels NMR-Spektroskopie und quantenchemischer Berechnungen}, address = {Potsdam}, pages = {112, A36 : graph. Darst.}, year = {2008}, language = {de} } @phdthesis{Wacker2008, author = {Wacker, Philipp}, title = {Konformationsanalyse meso-substituierter Porphyrine mittels NMR-Spektroskopie und quantenchemischer Berechnungen}, address = {Potsdam}, pages = {112 S., A36: Ill., graph. Darst.}, year = {2008}, language = {de} } @article{UhlemannDuvinageSchilde2008, author = {Uhlemann, Jacqueline and Duvinage, Brigitte and Schilde, Uwe}, title = {Kontexte und Kompetenzen : Komplexverbindungen experimentell erkunden}, issn = {1617-5638}, year = {2008}, language = {de} } @article{CharbonniereHildebrandt2008, author = {Charbonni{\`e}re, Loic J. and Hildebrandt, Niko}, title = {Lanthanide complexes and quantum dots : a bright wedding for resonance energy transfer}, year = {2008}, abstract = {In this microreview we describe the principle of Forster resonance energy transfer (FRET) occurring between closely spaced energy-donor and -acceptor molecules. The theoretical treatment is depicted in relation with the data extractable from spectroscopic measurements. We present the specific case of semiconductor nanocrystals (or quantum dots QDs) as energy donors in FRET experiments and a particular emphasis is put on the specific advantages of these fluorophores with regard to both their exceptional photophysical properties and their nanoscopic morphology. In a following section, the special attributes of luminescent lanthanide complexes (LLCs) are outlined with illustrations of properties such as their characteristic emission spectra, long-lived luminescence, and large "Stokes shift". Finally, the successful combination of LLCs and QDs in FRET experiments is demonstrated, showing the unrivaled benefits of this singular marriage, opening doors for energy transfer at very large distances and excellent sensitivity of detection within the frame of time-resolved fluoroimmunoassays. ((C) Wiley-VCH Verlag GmbH \& Co. KGaA, 69451 Weinheim, Germany, 2008).}, language = {en} } @article{StarkeSchusterFulopetal.2008, author = {Starke, Ines and Schuster, Ildikk{\´o} and Fulop, Ferenc and Kleinpeter, Erich}, title = {Mass spectra of tetrahydroisoquinoline-fused 1,3,2-O,N,P- and 1,2,3-O,S,N-heterocycles: influence of ring size and fusion, of present heteroatoms, substituent effects and of the stereochemistry on fra}, year = {2008}, abstract = {The electron ionization (EI) mass spectra of a variety of stereoisomeric tricyclic 1,3,2-oxazaphosphino[4,3- a]isoquinolines (1-4), 1,2,3-oxathiazino[4,3-a]isoquinoline-4-oxides (5-7) and the -4,4-dioxides (8-10) of oxazaphospholo- and oxathiazolo[4,3-a]- (11, 12, 15 and 16) and -[3,4-b]isoquinolines (13, 14 and 17) were recorded. Ring size and fusion, the different heteroatoms (P and S) and substituents on the ring systems strongly influence the mass spectra. In addition, mass spectra of the stereoisomers of compounds 1, 2 and 13, 14 revealed stereochemically relevant differences which are not observed for the other pairs of isomers. Copyright © 2008 John Wiley \& Sons, Ltd.}, language = {en} } @article{HaebelHejaziFrohbergetal.2008, author = {Haebel, Sophie and Hejazi, Mahdi and Frohberg, Claus and Heydenreich, Matthias and Ritte, Gerhard}, title = {Mass spectrometric quantification of the relative amounts of C6 and C3 position phosphorylated glucosyl residues in starch}, issn = {0003-2697}, year = {2008}, abstract = {The quantification of phosphate bound to the C6 and C3 positions of glucose residues in starch has received increasing interest since the importance of starch phosphorylation for plant metabolism was discovered. The method described here is based on the observation that the isobaric compounds glucose-6-phosphate (Glc6P) and glucose-3- phosphate (Glc3P) exhibit significantly different fragmentation patterns in negative ion electrospray tandem mass spectrometry (MS/MS). A simple experiment involving collision-induced dissociation (CID) MS2 spectra of the sample and the two reference substances Glc3P and Glc6P permitted the quantification of the relative amounts of the two compounds in monosaccharide mixtures generated by acid hydrolysis of starch. The method was tested on well-characterized potato tuber starch. The results are consistent with those obtained by NMR analysis. In contrast to NMR, however, the presented method is fast and can be performed on less than 1 mg of starch. Starch samples of other origins exhibiting a variety of phosphorylation degrees were analyzed to assess the sensitivity and robustness of the method.}, language = {en} } @phdthesis{Doench2008, author = {D{\"o}nch, Ingo}, title = {Mechanische Eigenschaften von Polyelektrolyt-Multilagen bei verschiedenen Ladungsdichten und Hydrationszust{\"a}nden}, address = {Potsdam}, pages = {129 S. : Ill., graph. Darst.}, year = {2008}, language = {de} } @article{GeisslerButlinHilletal.2008, author = {Geißler, Daniel and Butlin, Nathaniel G. and Hill, Diana and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Hildebrandt, Niko}, title = {Multiplexed diagnostics and spectroscopic ruler applications with terbium to quantum dots FRET}, issn = {1605-7422}, year = {2008}, language = {en} } @article{RaschKumkeLoehmannsroeben2008, author = {Rasch, Claudia and Kumke, Michael Uwe and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Mykotoxine in Getreide spektroskopisch erfassen}, year = {2008}, language = {de} } @article{ShainyanUshakovTolstikovaetal.2008, author = {Shainyan, Bagrat A. and Ushakov, Igor A. and Tolstikova, Ljudmila L. and Koch, Andreas and Kleinpeter, Erich}, title = {N-Trifyl substituted 1,4-diheterocyclohexanes{\`u}stereodynamics and the Perlin effect}, year = {2008}, abstract = {The stereodynamic behaviour of 1-(trifluoromethylsulfonyl)piperidine 1, 4-(trifluoromethylsulfonyl)morpholine 2, 1,4-bis(trifluoromethylsulfonyl)piperazine 3 and 4-(trifluoromethylsulfonyl)thiomorpholine 1,1-dioxide 4 was studied by low-temperature 1H, 13C and 19F NMR spectroscopies. In acetone solution, compounds 1, 2 and 4 were found to exist as mixtures of two conformers in the ratio of 4:1, 4:1 and 8:1, respectively, differing by orientation of the CF3 group with respect to the ring. Compound 3 exists as a mixture of three conformers in the ratio of 3:28:69 also differing by the orientation of the two CF3 groups. Unlike the previously studied N-trifyl substituted 1,3,5-triheterocyclohexanes, the preferred conformers of compound 1 and of 1,4-diheterocyclohexanes 2-4 are those with the CF3 group directed outward from the ring, which is caused by intramolecular interactions of the oxygen atoms of the CF3SO2N groups with the equatorial hydrogens in the ;-position. B3LYP/6-311+G(d,p) calculations of the energy, geometry and NMR parameters corroborate the experimental data. The calculated Perlin effects for all conformers of compounds 1-4 as well as those measured for the major conformers of compounds 3 and 4 were analyzed by the use of the NBO analysis.}, language = {en} } @article{MeshcheryakovMoskalikKellingetal.2008, author = {Meshcheryakov, Vladimir I. and Moskalik, Mikail Yu. and Kelling, Alexandra and Schilde, Uwe and Ushakov, Igor A. and Shainyan, Bagrat A.}, title = {Oxymethylation of trifluoromethanesulfonamide with paraformaldehyde in ethyl acetate}, issn = {1070-4280}, doi = {10.1134/S1070428008020206}, year = {2008}, abstract = {Acid-catalyzed reaction of trifluoromethanesulfonamide with paraformaldehyde in ethyl acetate led to the formation of oxymethylated products that did not form in the reaction carried out in sulfuric acid. Following products were obtained: 5-trifluoromethylsulfonyl-1,3-dioxazinane, 3,7-bis-(trifluoromethylsulfonyl)-1,5,3,7-dioxadiazocane, and a complex of trifluoromethanesulfonamide with 2,4,8,10-tetraoxospiro[5,5]undecene, 1:1. The spiroring resulted from the cyclization of pentaerythritol under the action of formaldehyde. The pentaerythritol formed in its turn by oxymethylation of the methyl group of ethyl acetate with paraformaldehyde followed by the reduction of the COOEt group into CH2 OH by the formaldehyde.}, language = {en} } @article{SieboldKorabikSchildeetal.2008, author = {Siebold, Matthias and Korabik, Maria and Schilde, Uwe and Mrozinski, Jerzy and Strauch, Peter}, title = {Pentanuclear heterobimetallic 3d-4f complexes of Ln2M3-type - structure and magnetism}, issn = {0366-6352}, year = {2008}, abstract = {From a series of pentanuclear, heterobimetallic complexes of the general composition [{Ln(H2O)n}2{Ni(dto)2}3] · xH2O, four complexes (Ln = Gd(III) with n = 4; Ln = Dy(III), Ho(III), or Er(III), with n = 5; x = 9-12; dto = 1,2- dithiooxalate) were studied due to their large magnetic moments (up to 14.65 B.M.). The magnetic properties of these complete series were measured at room temperature and the temperature dependent magnetic properties of the complexes Gd2Ni3, Dy2Ni3, Ho2Ni3, and Er2Ni3 were studied at room temperature down to 1.8 K. Whereas the intramolecular metal- metal distances were rather long (Ni1-Ni2: 11.0-11.5 {\AA}; Ln-Ni: 6.0-6.3 {\AA}), relatively short intermolecular metal-metal distances (Ni1-Ni2;: 3.5 {\AA}; Er-Er;: 6.0 {\AA}) were found in the crystal lattice, giving rise to weak intermolecular metal-metal interactions. These weak spin interactions were also supported by the EPR spectrum of a powdered sample of the diamagnetically undiluted Gd2Ni3 complex.}, language = {en} } @article{TiseanuGessnerKumkeetal.2008, author = {Tiseanu, Carmen and Geßner, Andre and Kumke, Michael Uwe and Gagea, Bogdan and Parvulescu, Vasile Ion and Martens, Johan}, title = {Photoluminescence spectra and dynamics of lanthanide-doped microporous materials}, doi = {10.1016/j.jlumin.2007.10.018}, year = {2008}, abstract = {A series of terbium- and europium-exchanged microporous-mesoporous zeolite Socony Mobil Five (MFI)-type materials such as Zeotile-1 and Zeogrid with varying Si/Al ratios was investigated using FTIR, PXRD, adsorption- desorption isotherms of N-2 at 77 K and time-resolved luminescence spectroscopy. Silylation of the lanthanides-exchanged Zeotile-1 and Zeogrid with hexadecyl trimethoxysilanes via post-synthesis grafting was also studied. The results showed that the lanthanide's photoluminescence spectra and decays were modified due to silylation. The different silylation effects in Zeotile-1 and Zeogrid were correlated with the textural properties of the investigated materials. (C) 2007 Elsevier B.V. All rights reserved.}, language = {en} } @article{TiseanuLorenzFonfriaParvulescuetal.2008, author = {Tiseanu, Carmen and Lorenz-Fonfria, Victor A. and Parvulescu, Vasile Ion and Geßner, Andre and Kumke, Michael Uwe}, title = {Photoluminescence study of terbium-exchanged ultrastable Y zeolites: Number of species, photoluminescence decays and decay-associated spectra}, doi = {10.1063/1.2966304}, year = {2008}, language = {en} } @article{SteinbrueckRaschKumke2008, author = {Steinbr{\"u}ck, D{\"o}rte and Rasch, Claudia and Kumke, Michael Uwe}, title = {Photophysics of Ochratoxin A in aqueous solution}, year = {2008}, language = {en} } @article{KleinpeterBoelkeFrank2008, author = {Kleinpeter, Erich and B{\"o}lke, Ute and Frank, Andrea}, title = {Polar substituent effect of the ester group on conformational equilibria of O-mono-substituted cyclohexanes{\`u}the para-substituent effect in cyclohexyl benzoates}, doi = {10.1016/j.tet.2008.07.024}, year = {2008}, abstract = {Together with the nonsubstituted reference compound, para-methoxy- and para-nitro cyclohexyl benzoates have been synthesized and their conformational equilibria studied by low temperature NMR spectroscopy and theoretical DFT calculations. The free energy differences ;G° between axial and equatorial conformers were examined with respect to polar substituent influences on the conformational equilibrium of O-mono-substituted cyclohexane.}, language = {en} } @phdthesis{Lutter2008, author = {Lutter, Stefanie}, title = {Polymermodofizierte Mikroemulsionen als Pr{\"a}gematrix f{\"u}r die Nanopartikelbildung}, address = {Potsdam}, pages = {132 S., Anhang I-XIII, : graph. Darst.}, year = {2008}, language = {de} } @article{CherstvyMetzler2008, author = {Cherstvy, Andrey G. and Metzler, Ralf}, title = {Population splitting, trapping, and non-ergodicity in heterogeneous diffusion processes}, doi = {10.1039/C3CP53056F}, year = {2008}, abstract = {We consider diffusion processes with a spatially varying diffusivity giving rise to anomalous diffusion. Such heterogeneous diffusion processes are analysed for the cases of exponential, power-law, and logarithmic dependencies of the diffusion coefficient on the particle position. Combining analytical approaches with stochastic simulations, we show that the functional form of the space-dependent diffusion coefficient and the initial conditions of the diffusing particles are vital for their statistical and ergodic properties. In all three cases a weak ergodicity breaking between the time and ensemble averaged mean squared displacements is observed. We also demonstrate a population splitting of the time averaged traces into fast and slow diffusers for the case of exponential variation of the diffusivity as well as a particle trapping in the case of the logarithmic diffusivity. Our analysis is complemented by the quantitative study of the space coverage, the diffusive spreading of the probability density, as well as the survival probability.}, language = {en} } @article{ShainyanFettkeKleinpeter2008, author = {Shainyan, Bagrat A. and Fettke, Anja and Kleinpeter, Erich}, title = {Push-pull vs captodative aromaticity}, issn = {1089-5639}, doi = {10.1021/jp804999m}, year = {2008}, abstract = {Vinylogs of fulvalenes with cyclopropenyl and cyclopentadienyl moieties attached either to different carbon atoms (c-C3H2-CH-CH=C5H4-c, 7) or to the same carbon atom [X=C(c-C3H2)(c-C5H4), 10] [X = CH2; C(CN)2; C(NH2)2; C(OCH2)2; O; c-C3H2; c-C5H4; SiH2; CCl2] of the double bond inserted between the two rings are examined theoretically at the B3LYP/ 6;311G(d,p) level. Both types of compounds are shown to possess aromaticity, which was called "push;pull" and "captodative" aromaticity, respectively. For the captodative mesoionic structures X=C(c-C3H2)(c-C5H4), the presence of both the two aromatic moieties and the C=C double bond is the necessary and sufficient condition for their existence as energetic minima on the potential energy surface. Aromatic stabilization energy (ASE) was assessed by the use of homodesmotic reactions and heats of hydrogenation. Spatial magnetic criteria (through space NMR shieldings, TSNMRS) of the two types of vinylogous fulvalenes 7 and 10 have been calculated by the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept of Paul von Ragu{\´e}; Schleyer, and visualized as iso-chemical-shielding surfaces (ICSS) of various sizes and directions. TSNMRS values can be successfully employed to visualize and quantify the partial push;pull and captodative aromaticity of both the three- and five-membered ring moieties. In addition, the push;pull effect in compounds 7 and 10 could be quantified by the occupation quotient ;*C=C/;C=C of the double bond inserted between the two rings.}, language = {en} } @article{Kleinpeter2008, author = {Kleinpeter, Erich}, title = {Quantification of the (Anti)Aromaticity of Fulvalenes Subjected to -Electron Cross-Delocalization}, doi = {10.1021/Jo701520j}, year = {2008}, abstract = {Fulvalenes 3-12 were theoretically studied at the ab initio level of theory. For the global minima structures, the occupation of the bonding (pi)C=C orbital of the interring C=C double bond obtained by NBO analysis quantitatively proves pi-electron cross-delocalization resulting in, at least partially, 2- or 6pi-electron aromaticity and 8pi- electron antiaromaticity for appropriate moieties. The cross-conjugation was quantified by the corresponding occupation numbers and lengths of the interring C=C double bonds, while the aromaticity or antiaromaticity due to cross- delocalization of the pi-electrons was visualized and quantified by through-space NMR shielding surfaces.}, language = {en} } @article{KleinpeterFettke2008, author = {Kleinpeter, Erich and Fettke, Anja}, title = {Quantification of the (anti)aromaticity of fulvenes subject to ring size}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2008.02.137}, year = {2008}, abstract = {Tria-, penta-, hepta- and nonafulvenes (1-4) have been studied theoretically at the MP2 ab initio level of theory. For the global minimum structures, the occupation of the bonding ;C=C orbital of the exocyclic C=C double bond, obtained by NBO analysis, quantitatively proves ;-electron delocalization which can reveal partial 2-, 6- and 10-;-electron aromaticity, and 4-, 8- and 12-;-electron antiaromaticity of the ring moieties. Beside the corresponding occupation number, this conjugation was quantified by the length of the exocyclic C=C double bond whilst the (anti)aromaticity of the ring moieties of 1-4 was visualized and quantified by through space NMR shielding surfaces (TSNMRS).}, language = {en} } @article{KleinpeterStamboliyska2008, author = {Kleinpeter, Erich and Stamboliyska, Bistra A.}, title = {Quantification of the Push-Pull Character of Donor-Acceptor Triazenes}, doi = {10.1021/Jo8013758}, year = {2008}, abstract = {The Push-pull character of two series of donor-acceptor triazenes has been quantified by C-13 and N-15 chemical shift differences of the partial N(1)=N(2) and N(3)=C(4) double bonds in the central linking C=N-N=N-C unit and by the quotient of the occupations of both the bonding pi and antibonding orbitals pi* of these partial double bonds. Excellent correlations of the two estimates, to quantify the push-pull effect, with the bond lengths strongly recommend the occupation quotients pi*/pi, the N-15 chemical shift differences Delta delta[N(l),N(2)], and the corresponding bond lengths as reasonable sensors for quantifying charge alternation along the C=N-N=N-C linking unit, for the donor- acceptor quality of the triazenes 1 and 2 and for the molecular hyperpolarizability beta(0) of these compounds. Within this context, certain Substances can be strongly recommended for NLO application.}, language = {en} } @article{KleinpeterKochMikhovaetal.2008, author = {Kleinpeter, Erich and Koch, Andreas and Mikhova, Bozhana and Stamboliyska, Bistra A. and Kolev, Tsonko M.}, title = {Quantification of the push-pull character of the isophorone chromophore as a measure of molecular hyperpolarizability for NLO applications}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2007.12.107}, year = {2008}, abstract = {The push-pull character of a series of para-phenyl substituted isophorone chromophores has been quantified by the 13C chemical shift difference of the three conjugated partial C=C double bonds and the quotient of the occupations of both the bonding and anti-bonding orbitals of these C=C double bonds as well. The correlations of the two push-pull quantifying parameters, and to the corresponding bond lengths, strongly recommend ;*c=c/ ;c=c as the general parameter to estimate charge alternation and as a very useful indication of the molecular hyperpolarizabilities for NLO application of the compounds studied.}, language = {en} } @article{Kleinpeter2008, author = {Kleinpeter, Erich}, title = {Quantitative study and visualization of spherical 2(N + 1)2 homoaromaticity by through space NMR shieldings (TSNMRS)}, doi = {10.1016/j.theochem.2007.11.029}, year = {2008}, abstract = {The through space NMR shielding (TSNMRS) values of adamantane, the 2(N + 1)2 spherical (4c, 2e) homoaromatic compounds 1,3-dehydro-5,7-adamantandiyl dication (C10H122+) and 1,3-dehydro-5,7-cubandiyl dication (C8H42+), and the (6c, 8e) homoaromatic compound 2,2;,4,4;,6,6;,8,8;,10,10;-dehydroadamantane tetracation (C10H44+) have been ab initio calculated, employing the NICS concept, and visualized as iso-chemical shielding surfaces (ICSSs). TSNMRS values can be successfully employed to study both the endohedral and exohedral aromaticity/ antiaromaticity of the compounds studied.}, language = {en} } @article{KramerKainmuellerFlehretal.2008, author = {Kramer, Rolf A. and Kainm{\"u}ller, Eva K. and Flehr, Roman and Kumke, Michael Uwe and Bannwarth, Willi}, title = {Quenching of the long-lived Ru(II)bathophenanthroline luminescence for the detection of supramolecular interactions}, year = {2008}, language = {en} } @article{MarmodeeKlerkdeKumkeetal.2008, author = {Marmod{\´e}e, Bettina and Klerk de, Joost and Kumke, Michael Uwe and Ariese, Freek and Gooijer, Cees}, title = {Spectroscopic investigations of complexes between Eu(III) and aromatic carboxylic ligands}, doi = {10.1016/j.jallcom.2007.04.150}, year = {2008}, abstract = {In order to obtain information on the number and symmetry of the different Eu3+ complexes formed with several hydroxybenzoic acids, ultra-low temperature luminescence measurements at 4.7 K were carried out. Hydroxybenzoic acids were used as simple model compounds for metal binding structures in humic substances (HS). Information on the complexes was extracted from high-resolution total luminescence spectra (TLS), which were obtained by scanning through the D-5(0) <-- F-7(0) transition of Eu(III) with a pulsed dye laser and measuring the emission in the wavelength range of the D- 5(0) --> F-7(0) and D-5(0) --> F-7(0) transitions simultaneously. By extracting the crystal field strength parameter N- v(B-2q) from the TLS, it was found that N-v(B-2q) was not directly correlated with the excitation energy. Further, the symmetry of the individual complexes formed was extracted from the experimental data. (C) 2007 Elsevier B.V. All rights reserved.}, language = {en} } @article{LopezFrancoCalderondelaBarcaValdezetal.2008, author = {L{\´o}pez-Franco, Yolanda L. and Calder{\´o}n de la Barca, Ana M. and Valdez, Miguel A. and Peter, Martin G. and Rinaudo, Marguerite and Chambat, G{\´e}rard and Goycoolea, Francisco M.}, title = {Structural characterization of mesquite (Prosopis velutina) gum and its fractions}, issn = {1616-5187}, doi = {10.1002/mabi.200700285}, year = {2008}, abstract = {Structural and physicochem. characteristics of mesquite gum (from Prosopis velutina) were investigated using FT- IR spectroscopic, mass spectrometric and chromatog. methods. Four fractions (F-I, F-IIa, F-IIb and F-III) were isolated by hydrophobic interaction chromatog. The samples were characterized and analyzed for their monosaccharide and oligomers compn. by high performance anion-exchange chromatog. with pulsed amperometric detection (HPAEC-PAD). L-Arabinose (L-Ara) and D-galactose (D-Gal) were found as the main carbohydrate constituent residues in the polysaccharides from mesquite gum and their ratio (L-Ara/D-Gal) varied within the range 2.54 to 3.06 among the various fractions. Small amts. of D- glucose (D-Glc), D-mannose (D-Man) and D-xylose (D-Xyl) were also detected, particularly in Fractions IIa, IIb and III. IR spectroscopy identified polysaccharides and protein in all the samples. Data from mass spectrometry (MALDI-TOF MS) was consistent with the idea that the structure corresponding to the periphereal chains of Fraction I is predominantly a chain of pentoses attached to uronic acid. [on SciFinder (R)].}, language = {en} } @phdthesis{Kotsmar2008, author = {Kotsm{\´a}r, Csaba}, title = {Structure and dynamics of mixed milk protein/surfactant interfacial layers}, address = {Potsdam}, pages = {X, 123 S. : Ill., graph. Darst.}, year = {2008}, language = {en} } @article{ShainyanMeshcheryakovSterkhovaetal.2008, author = {Shainyan, Bagrat A. and Meshcheryakov, Vladimir I. and Sterkhova, I. V. and Kelling, Alexandra and Schilde, Uwe}, title = {Structure of the molecule of 1,2-bis(1-ethyl-1 H -1,2,3-triazol-4-yl)diazene 1-oxide in the crystal and in solutions}, issn = {1070-4280}, year = {2008}, abstract = {Reduction of 4-nitro-1-ethyl-1H-1,2,3-triazole with aluminum in alkaline medium resulted in a syn-isomer of 1,2- bis(1-ethyl-1H-1,2,3-triazol-4-yl)diazene 1-oxide. The latter according to the data of X-ray diffraction analysis existed in the crystal as the most stable s-cis,s-trans-conformer, and in solution, as showed NMR data, as a mixture of s-cis,s-trans- and s-trans,s-trans-conformers. The data of quantum-chemical calculations are in agreement with the results of the structural studies.}, language = {en} } @phdthesis{Biernat2008, author = {Biernat, Anne}, title = {Synthese seltener Kohlenhydrate unter Verwendung der ringschließenden Olefinmetathese}, address = {Potsdam}, pages = {174 S.: graph. Darst.}, year = {2008}, language = {de} } @article{MondalDeyBaburinetal.2008, author = {Mondal, Suvendu Sekhar and Dey, Subarna and Baburin, Igor A. and Kelling, Alexandra and Schilde, Uwe and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {Syntheses of two imidazolate-4-amide-5-imidate linker based hexagonal metal-organic frameworks with flexible ethoxy substituent}, doi = {10.1039/C3CE41632A}, year = {2008}, abstract = {A rare example of in situ linker generation with the formation of soft porous Zn- and Co-MOFs (IFP-9 and -10, respectively) is reported. The flexible ethoxy groups of IFP-9 and -10 protrude into the 1D hexagonal channels. The gas- sorption behavior of both materials for H2, CO2 and CH4 showed wide hysteretic isotherms, typical for MOFs having a flexible substituent which can give rise to a gate effect.}, language = {en} } @article{HeydenreichKochSzatmarietal.2008, author = {Heydenreich, Matthias and Koch, Andreas and Szatm{\´a}ri, Istv{\´a}n and Fulop, Ferenc and Kleinpeter, Erich}, title = {Synthesis and conformational analysis of naphth[1,2-e][1,3]oxazino[4,3-a][1,3]isoquinoline and naphth[2,1- e][1,3]oxazino[4,3-a]isoquinoline derivatives}, doi = {10.1016/j.tet.2008.05.025}, year = {2008}, abstract = {Through the cyclization of 1-(;-hydroxynaphthyl)-1,2,3,4-tetrahydroisoquinoline and 1-(;- hydroxynaphthyl)-1,2,3,4-tetrahydroisoquinoline with formaldehyde, phosgene, p-nitrobenzaldehyde or p-chlorophenyl isothiocyanate, 8-substituted 10,11-dihydro-8H,15bH-naphth[1,2-e][1,3]oxazino[4,3-a]isoquinolines (3 and 4) and 10,11- dihydro-8H,15bH-naphth[2,1-e][1,3]oxazino[4,3-a]isoquinolines (15 and 16) were prepared. Conformational analysis of both the piperidine and the 1,3-oxazine moieties of these heterocycles by NMR spectroscopy and an accompanying theoretical study revealed that these two conformationally flexible six-membered ring moieties prefer twisted chair conformers.}, language = {en} } @article{OPUS4-10769, title = {Synthesis and conformational analysis of phenyl-substituted 1,3,2-oxazaphosphino[4,3-a]- and 1,2,3- oxathiazino[4,3-a]isoquinolines}, year = {2008}, abstract = {Through the ring closures of tetrahydroisoquinoline 1,3-amino alcohols bearing a phenyl group in the side- chain, diastereomers of novel 1- or 2-phenyl-substituted 1,3,2-oxazaphosphino[4,3-a]isoquinoline 4-oxides, and 1,2,3- oxathiazino[4,3-a]isoquinoline 4-oxides and 4,4-dioxides were prepared. NMR analysis and DFT calculations on the prepared tetrahydroisoquinoline-condensed 1,2,3-heterocycles revealed that their conformational equilibria of cis1-trans-cis2 type are influenced by the relative configuration of P-4 in the 1,3,2-oxazaphosphinanes, and by the position of the phenyl group in the 1,2,3-oxathiazines.}, language = {en} } @article{SchusterKochHeydenreichetal.2008, author = {Schuster, Ildik{\´o} and Koch, Andreas and Heydenreich, Matthias and Kleinpeter, Erich and Forr{\´o}, Enik{\"o} and L{\´a}z{\´a}r, L{\´a}szl{\´o} and Sillanp{\"a}{\"a}, Reijo and Fulop, Ferenc}, title = {Synthesis and Conformational Analysis of Tetrahydroisoquinoline-Fused 1,3,2-Oxazaphospholidines and 1,2,3- Oxathiazolidines}, year = {2008}, abstract = {The cyclizations of tetrahydroisoquinoline 1,2-amino alcohols with phenylphosphonic dichloride, bis(2- chloroethyl)phosphoramidic dichloride, thionyl chloride and sulfuryl chloride were utilized to synthesize 1,5,6,10b- tetrahydro-1,3,2-oxazaphospholo[4,3-a]isoquinolines (2, 3), 1,5,10,10a-tetrahydro-1,3,2-oxazaphospholo[3,4- b]isoquinolines (8, 9), 1,5,6,10b-tetrahydro-1,2,3-oxathiazolo[4,3-a]isoquinolines (4-6) anda 1,5,10,10a-tetrahydro- 1,2,3-oxathiazolo[3,4-b]isoquinoline (11), which are the first representatives of these ring systems. NMR spectroscopic analysis revealed the existence of conformational equilibria that are fast on the NMR timescale. Theoretical DFT calculations pointed to the participation of generally two preferred conformers in the conformational equilibria; the positions of the equilibria were indicated by the experimental NMR spectroscopic parameters, and they are in good agreement with the theoretically calculated energy differences of the participating conformers. For two compounds, which could be not isolated (10, 12), both the preferred conformers and the stereochemistry could be concluded from the DFT calculation results.}, language = {en} } @phdthesis{HordyjewiczBaran2008, author = {Hordyjewicz-Baran, Zofia}, title = {Synthesis and study of the aggregation behavior of hydrophilically modified polybutadienes}, address = {Potsdam}, pages = {101 S.: Ill., graph. Darst.}, year = {2008}, language = {en} } @phdthesis{HordyjewiczBaran2008, author = {Hordyjewicz-Baran, Zofia}, title = {Synthesis and Study of the Aggregation Behavior of Hydrophilically Modified Polybutadienes}, address = {Potsdam}, pages = {101 S., : graph. Darst.}, year = {2008}, language = {en} } @article{MondalBhuniaDemeshoketal.2008, author = {Mondal, Suvendu Sekhar and Bhunia, Asamanjoy and Demeshok, Serhiy and Kelling, Alexandra and Schilde, Uwe and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {Synthesis of a Co(II)-imidazolate framework from an anionic linker precursor: gas-sorption ans magnetic proberties}, year = {2008}, abstract = {A Co(II)-imidazolate-4-amide-5-imidate based MOF, IFP-5, is synthesized by using an imidazolate anion-based novel ionic liquid as a linker precursor under solvothermal conditions. IFP-5 shows significant amounts of gas (N2, CO2, CH4 and H2) uptake capacities. IFP-5 exhibits an independent high spin Co(II) centre and antiferromagnetic coupling.}, language = {en} } @phdthesis{Yagci2008, author = {Yagci, Yavuz Emre}, title = {Synthesis of poly(tartar amide)s and poly-(gluco amide)s as antifreeze additives}, address = {Potsdam}, pages = {vi, 86 S.: Ill., graph. Darst.}, year = {2008}, language = {en} } @phdthesis{Yagci2008, author = {Yagci, Yavuz Emre}, title = {Synthesis of poly(tartar amide)s and poly-(gluco amide)s as antifreeze additives}, address = {Potsdam}, pages = {86 S., ii-vi, : graph. Darst.}, year = {2008}, language = {en} } @article{SchaeferBung2008, author = {Sch{\"a}fer-Bung, Boris}, title = {The interplay of wave packet dephasing, optimization efficiency, and target state population in optimally controlled isotope selective photoionization}, issn = {0301-0104}, year = {2008}, abstract = {The mutual dependencies of characteristic quantities for an isotope selective photoionization, namely optimization efficiency, target state population, and wave packet dephasing are presented for the NaK dimer. A pre- optimized pulse shape obtained from the maximization of the isotopomer ratio 23Na39K/23Na41K for the first excited electronic state serves as an initial guess for the subsequent optimization. For the ionization it provides almost vanishing population of the heavier ionic isotopomer and an ionic isotopomer ratio which is significant higher than the findings obtained from former investigations. The wave packet motions on the first excited state of the neutral molecule are in phase for both isotopomers. The optimization procedure, i.e. the simultaneous maximization of the 23Na39K+ photoionization yield and the minimization of the 23Na41K+ photoionization yield for the electronic ground state is based on optimal control theory and leads to a rise of ionic ground state population for both isotopomers related to a significant wave packet dephasing. Upon optimization the isotopomer ratio of the yields falls due to incidental resonances of vibronic transitions. The interplay of the observables are discussed and compared with the values obtained from an optimization which was started from a pure Gaussian pulse shape.}, language = {en} } @article{HilleBergBresseletal.2008, author = {Hille, Carsten and Berg, Maik and Bressel, Lena and Munzke, Dorit and Primus, Philipp and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Dosche, Carsten}, title = {Time-domain fluorescence lifetime imaging for intracellular pH sensing in living tissues}, doi = {10.1007/s00216-008-2147-0}, year = {2008}, abstract = {pH sensing in living cells represents one of the most prominent topics in biochemistry and physiology. In this study we performed one-photon and two-photon time-domain fluorescence lifetime imaging with a laser-scanning microscope using the time-correlated single-photon counting technique for imaging intracellular pH levels. The suitability of different commercial fluorescence dyes for lifetime-based pH sensing is discussed on the basis of in vitro as well of in situ measurements. Although the tested dyes are suitable for intensity-based ratiometric measurements, for lifetime- based techniques in the time-domain so far only BCECF seems to meet the requirements of reliable intracellular pH recordings in living cells.}, language = {en} } @article{DeviAlSutiDoscheetal.2008, author = {Devi, Lekshmi Sudha and Al-Suti, Mohammed K. and Dosche, Carsten and Khan, Muhammad S. and Friend, Richard H. and K{\"o}hler, Anna}, title = {Triplet energy transfer in conjugated polymers : I. Experimental investigation of a weakly disordered compound}, year = {2008}, abstract = {Efficient triplet exciton emission has allowed improved operation of organic light-emitting diodes (LEDs). To enhance the device performance, it is necessary to understand what governs the motion of triplet excitons through the organic semiconductor. Here, we have investigated triplet diffusion using a model compound that has weak energetic disorder. The Dexter-type triplet energy transfer is found to be thermally activated down to a transition temperature T- T, below which the transfer rate is only weakly temperature dependent. We show that above the transition temperature, Dexter energy transfer can be described within the framework of Marcus theory. We suggest that below T-T, the nature of the transfer changes from phonon-assisted hopping to quantum-mechanical tunneling. The lower electron-phonon coupling and higher electronic coupling in the polymer compared to the monomer results in an enhanced triplet diffusion rate.}, language = {en} } @article{KleinpeterKoch2008, author = {Kleinpeter, Erich and Koch, Andreas}, title = {Trisannelated benzenes - Aromatic molecules or 1,3,5-cyclohexatriene derivatives subjected to magnetic properties}, doi = {10.1016/j.theochem.2008.02.013}, year = {2008}, abstract = {The through space NMR shielding (TSNMRS) values of two tricyclobutabenzene (TCBB) derivatives 2, of the corresponding hexamethylene and hexaoxo TCBB derivatives 3, of [4n]annuleno[4n + 2]annulene 5 and of its tricyclobutadiene parent compound 4 have been ab initio calculated by the GIAO perturbation method employing the nucleus- independent chemical shift (NICS) concept of Paul von Ragu{\´e} Schleyer, and visualized as iso-chemical shielding surfaces (ICSS). TSNMRS values can be successfully employed to quantify and visualize the aromaticity of the central, and in 5 also of the terminal benzene ring moieties.}, language = {en} } @article{YinSchubertStilleretal.2008, author = {Yin, Chunhong and Schubert, Marcel and Stiller, Burkhard and Castellani, Mauro and Neher, Dieter and Kumke, Michael Uwe and H{\"o}rhold, Hans-Heinrich}, title = {Tuning of the excited-state properties and photovoltaic performance in PPV-based polymer blends}, doi = {10.1021/Jp803977k}, year = {2008}, language = {en} } @phdthesis{Olak2008, author = {Olak, Claudia}, title = {Untersuchung zur Rolle von Adapterprotein-Komplexen im Targeting der Glucosetransporter GLUT8 und GLUT4}, address = {Potsdam}, pages = {131,xii S. : graph. Darst.}, year = {2008}, language = {de} } @article{ShainyanUshakovMeshcheryakovetal.2008, author = {Shainyan, Bagrat A. and Ushakov, Igor A. and Meshcheryakov, Vladimir I. and Koch, Andreas and Kleinpeter, Erich}, title = {Variable temperature NMR and theoretical study of the stereodynamics of 5-trifluoromethylsulfonyl-1,3,5- dioxaazinane : Perlin effect subject to heteroatom substitution}, year = {2008}, abstract = {Multinuclear dynamic NMR spectroscopy of 5-trifluoromethylsulfonyl-1,3,5-dioxaazinane (4) revealed the existence of two close in energy chair conformers with differently oriented CF3 groups with respect to the ring. Of the two alternative routes for their interconversion, the ring inversion path with intermediate formation of the corresponding 2,5-twist-conformer is preferred, with the energy barrier of 11.2 kcal/mol in excellent agreement with the experimental value (11.7 kcal/mol). The Perlin effect is studied experimentally and calculated theoretically for all CH2 groups and found to be subject to the nature of the adjacent heteroatoms O and N, respectively.}, language = {en} } @article{KleinpeterKochSeidl2008, author = {Kleinpeter, Erich and Koch, Andreas and Seidl, Peter R.}, title = {Visualization and quantification of the anisotropic effect of C=C double bonds on 1H NMR spectra of highly congested hydrocarbons-indirect estimates of steric strain}, doi = {10.1021/Jp801063t}, year = {2008}, abstract = {The anisotropic effect of the olefinic C=C double bond has been calculated by employing the NICS (nucleus independent chemical shift) concept and visualized as an anisotropic cone by a through space NMR shielding grid. Sign and size of this spatial effect on 1H chemical shifts of protons in norbornene, exo- and endo-2-methylnorbornenes, and in three highly congested tetracyclic norbornene analogs have been compared with the experimental 1H NMR spectra as far as published. 1H NMR spectra have also been calculated at the HF/6-31G* level of theory to get a full, comparable set of proton chemical shifts. Differences between ;(1H)/ppm and the calculated anisotropic effect of the C=C double bond are discussed in terms of the steric compression that occurs in the compounds studied.}, language = {en} }