@article{WalzBaumannKrachetal.2006,
  author    = {Walz, Bernd and Baumann, Otto and Krach, Christian and Baumann, Arnd and Blenau, Wolfgang},
  title     = {The aminergic control of cockroach salivary glands},
  year      = {2006},
  abstract  = {The acinar salivary glands of cockroaches receive a dual innervation from the subesophageal ganglion and the stomatogastric nervous system. Acinar cells are surrounded by a plexus of dopaminergic and serotonergic varicose fibers. In addition, seroton-ergic terminals lie deep in the extracellulor spaces between acinar cells. Excitation-secretion coupling in cockroach salivary glands is stimulated by both dopamine and serotonin. These monoamines cause increases in the intracellular concentrations of cAMP and Ca2+. Stimulation of the glands by serotonin results in the production of a protein-rich saliva, whereas stimulation by dopamine results in saliva that is protein-free. Thus, two elementary secretary processes, namely electrolyte/water secretion and protein secretion, are triggered by different aminergic transmitters. Because of its simplicity and experimental accessibility, cockroach salivary glands have been used extensively as a model system to study the cellular actions of biogenic amines and to examine the pharmacological properties of biogenic amine receptors. In this review, we summarize current knowledge concerning the aminergic control of cockroach salivary glands and discuss our efforts to characterize Periplaneta biogenic amine receptors molecularly},
  language  = {en}
}
@article{KammKammSchmidtetal.2006,
  author    = {Kamm, Birgit and Kamm, Michael and Schmidt, Matthias and Starke, Ines and Kleinpeter, Erich},
  title     = {Chemical and biochemical generation of carbohydrates from lignocellulose-feedstock (Lupinus nootkatensis) : quantification of glucose},
  issn      = {0045-6535},
  doi       = {10.1016/j.chemosphere.2005.03.073},
  year      = {2006},
  abstract  = {Different chemical and enzymatic methods were applied for the hydrolysis of main stems from Lupinus nootkatensis (harvest November 2002). The whole process (all steps) is based on the lignocellulose-feedstock biorefinery regime. The acid hydrolysis of L. was performed with concentrated hydrochloric acid; advantages in this process are exothermic hydrolysis and the possibility of acid recovery. Enzymatic hydrolysis achieved high yields of fermentable carbohydrates (regarding to input cellulose) with high selectivity. However, this way requires the generation of cellulose from L. by chemical pulping. Monosaccharide derivatives thus obtained were identified by their GC retention times and the corresponding MS fragmentation. Hexamethyldisilazane was used as derivatization reagent to prepare the trimethylsilyl derivatives of the carbohydrates and of the degradations products of cellulose from the different fractions. The glucose content was quantified by GC peak integration with respect to an internal standard.},
  language  = {en}
}
@article{RasovicSteelKleinpeteretal.2007,
  author    = {Rasovic, Aleksandar and Steel, Peter J. and Kleinpeter, Erich and Markovic, Rade},
  title     = {Regioselective synthesis of 1,3-thiazines by sequential 4-oxothiazolidine to 1,2-dithiole to 1,3-thiazine transformations : role of intramolecular non-bonded S...O interactions},
  doi       = {10.1016/j.tet.2006.12.075},
  year      = {2007},
  abstract  = {A new synthetic approach to 2,3-dihydro-4H-1,3-thiazine derivatives based upon reductive rearrangement of 1,2- dithiole-3-ylidene thiones has been developed. In turn, the 1,2-dithiole derivatives were prepared by an efficient ring- opening-closing process of 2-alkylidene-4-oxothiazolidines, induced in the presence of Lawesson's reagent by intramolecular non-bonded 1,5-type S...O interactions in the 4-oxothiazolidine precursors.},
  language  = {en}
}
@article{DelormeDuboisGarnieretal.2006,
  author    = {Delorme, Nicolas and Dubois, Monique and Garnier, Sebastien and Laschewsky, Andr{\´e} and Weinkamer, Richard and Zemb, Thomas and Fery, Andreas},
  title     = {Surface immobilization and mechanical properties of catanionic hollow faceted polyhedrons},
  issn      = {1520-1758},
  doi       = {10.1021/Jp054473+},
  year      = {2006},
  abstract  = {We report here for the first time on surface immobilization of hollow faceted polyhedrons formed from catanionic surfactant mixtures. We find that electrostatic interaction with the substrate dominates their adhesion behavior. Using polyelectrolyte coated surfaces with tailored charge densities, polyhedrons can thus be immobilized without complete spreading, which allows for further study of their mechanical properties using AFM force measurements. The elastic response of individual polyhedrons can be locally resolved, showing pronounced differences in stiffness between faces and vertexes of the structure, which makes these systems interesting as models for structurally similar colloidal scale objects such as viruses, where such effects are predicted but cannot be directly observed due to the smaller dimensions. Elastic constants of the wall material are estimated using shell and plate deformation models and are found to be a factor of 5 larger than those for neutral lipidic bilayers in the gel state. We discuss the molecular origins of this high stiffness},
  language  = {en}
}
@article{XieJelicicWangetal.2010,
  author    = {Xie, Zai-Lai and Jelicic, Aleksandra and Wang, Feipeng and Rabu, Pierre and Friedrich, Alwin and Beuermann, Sabine and Taubert, Andreas},
  title     = {Transparent, flexible, and paramagnetic ionogels based on PMMA and the iron-based ionic liquid 1-butyl-3- methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4]},
  issn      = {0959-9428},
  doi       = {10.1039/C0jm01733g},
  year      = {2010},
  abstract  = {The iron-containing ionic liquid (IL) 1-butyl-3-methylimidazolium tetrachloroferrate(III) [Bmim][FeCl4] has been used as a building block in the synthesis of transparent, ion-conducting, and paramagnetic ionogels. UV/Vis spectroscopy shows that the coordination around the Fe(III) ion does slightly change upon incorporation of the IL into PMMA. The thermal stability of the PMMA increases significantly with IL incorporation. In particular, the onset weight loss observed at ca. 265 degrees C for pure PMMA is completely suppressed. The ionic conductivity shows a strong temperature dependence and increases with increasing IL weight fractions. The magnetic properties are similar to those reported for the pure IL and are not affected by the incorporation into the PMMA matrix. The resulting ionogel is thus an interesting prototype for soft, flexible, and transparent materials combining the mechanical properties of the matrix with the functionality of the metal-containing IL, such as magnetism.},
  language  = {en}
}
@article{BeitzLaudienLoehmannsroebenetal.2006,
  author    = {Beitz, Toralf and Laudien, Robert and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Kallies, Bernd},
  title     = {Ion mobility spectrometric investigation of aromatic cations in the gas phase},
  issn      = {1089-5639},
  doi       = {10.1021/Jp055335n},
  year      = {2006},
  abstract  = {In this work, ion mobility (IM) spectra of more than 50 aromatic compounds were recorded with a laser-based IM spectrometer at atmospheric pressure. IM spectra of PAH in the laser desorption experiment show a high complexity resulting from the occurrence of monomeric, dimeric, and oligomeric cluster ions. The mobilities of all compounds were determined in helium as drift gas. This allows the calculation of the diffusion cross sections (Omega(calc)) on the basis of the exact hard sphere scattering model and their comparison with the experimentally determined diffusion cross sections (Omega(exp)). Extended Omega(exp)/Omega(calc) and Omega(exp/)mass correlations were performed in order to gain insight into conformational properties of cationic alkyl benzenes and internal rotation of phenyl rings in aromatic ions. This is demonstrated with some examples, such as the evaluation of the dihedral angle of the ions of 9,10- diphenylanthracene, o- and m-terphenyl, and 1,2,3- and 1,3,5-triphenylbenzene. Furthermore, sandwich and T-structures of dimeric PAH cations are discussed. The analysis was extended to oligomeric ions with up to nine monomer units. Experimental evidence is presented suggesting the formation of pi-stacks with a transition toward modified pi-stacks with increasing cluster size. The distance between monomeric units in dimeric and oligomeric ions was obtained},
  language  = {en}
}
@article{KleinpeterRollaKochetal.2006,
  author    = {Kleinpeter, Erich and Rolla, Nadja and Koch, Andreas and Taddei, Fernando},
  title     = {Hyperconjugation and the increasing bulk of OCOCX3 substituents in trans-1,4-disubstituted cyclohexanes destabilize the diequatorial conformer},
  issn      = {4393-4399},
  doi       = {10.1021/Jo0600858},
  year      = {2006},
  abstract  = {The trans diesters of 1,4-cyclohexanediol with a number of acetic acid analogues, CX3COOH, of varying steric hindrance and polarity (CX3 = Me, Et, iso-Pr, tert-Bu, CF3, CH2Cl, CHCl2, CCl3, CH2Br, CHBr2, CBr3) were synthesized, and the axial, axial/equatorial, equatorial conformational equilibria were studied by low-temperature H-1 NMR spectroscopy in CD2Cl2. The structures and relative energies of the axial, axial and equatorial, equatorial conformers were calculated at both the MP2/6-311G* and the MP2/6-311+G* levels of theory, and it was only by including diffuse functions that a good correlation of Delta G degrees(calcd) vs Delta G(exptl) could be obtained. Both the structures and the energy differences of the axial, axial and equatorial, equatorial conformers are discussed with respect to the established models of conformational analysis, viz., steric 1,3-diaxial and hyperconjugative interactions. Interestingly, the hyperconjugative interactions sigma(C-C)/sigma(C-H)->sigma*(C-O), together with a steric effect which also destabilizes the equatorial, equatorial conformers on increasing bulk of the substituents, proved to dominate the position of the conformational equilibria. In addition, the preference of the axial, axial conformers with respect to their equatorial, equatorial analogues was greater than expected from the conformational energies of the corresponding substituents in the monosubstituted cyclohexyl esters. The reason for this very interesting and unexpected result is also discussed},
  language  = {en}
}
@article{YonedaLealSeidletal.2007,
  author    = {Yoneda, Julliane Diniz and Leal, Katia Zaccur and Seidl, Peter Rudolf and Azeredo, Rodrigo Bagueira de V. and Kleinpeter, Erich},
  title     = {Camphor : a good model for illustrating NMR techniques},
  year      = {2007},
  abstract  = {CAMPHOR: A GOOD MODEL FOR ILLUSTRATING NMR TECHNIQUES. The use of Nuclear Magnetic Resonance spectroscopy to establish the three-dimensional structures of molecules is an important component of modern Chemistry courses. The combination of techniques that can be used for this purpose is conveniently illustrated by their application to the camphor molecule. This paper presents applications of several techniques used in NMR spectral interpretation in an increasing order of complexity. The result of individual experiments is illustrated in order to familiarize the user with the way connectivity through bonds and through space is established from 1D/2D-NMR spectra and molecular stereochemistry is determined from different NMR experiments},
  language  = {en}
}
@article{ModarresiAlamKhamooshiRostamizadehetal.2007,
  author    = {Modarresi-Alam, Ali Reza and Khamooshi, Ferydoon and Rostamizadeh, Mohsen and Keykha, Hossein and Nasrollahzahdeh, Mahmoud and Bijanzadeh, Hamid-Reza and Kleinpeter, Erich},
  title     = {Dynamic 1H NMR spectroscopic study of the restricted S-N rotation in aryl-N-(arylsulfonyl)-N- (triphenylphosphoranylidene)imidocarbamates},
  year      = {2007},
  abstract  = {Dynamic 1H NMR (500 MHz) investigation of aryl-N-(arylsulfonyl)-N-(triphenylphosphoranylidene)imidocarbamates in CDCl3, CD3COCD3, and CD3OD at the temperature range of 183-298 K is reported. The observed free energy barriers (almost 12 kcal mol;1) are attributed to conformational isomerization about the N{\`u}S bond and these barriers show very little solvent dependence.},
  language  = {en}
}
@article{ModarresiNajafiRostamizadehetal.2007,
  author    = {Modarresi, Ali Reza and Najafi, Parisa and Rostamizadeh, Mohsen and Keykha, Hossein and Bijanzadeh, Hamid-Reza and Kleinpeter, Erich},
  title     = {Dynamic 1H NMR study of the barrier to rotation about the C-N bond in primary carbamates and its solvent dependence},
  year      = {2007},
  abstract  = {The dynamic 1H NMR study of some primary carbamates in the solvents CDCl3 and CD3COCD3 between 183 and 298 K is reported. The free energies of activation, thus obtained (12.4 to 14.3 kcal mol-1), were attributed to the conformational isomerization about the N-C bond. These barriers to rotation show solvent dependence in contrast to the tertiary analogues and are lower in free energy by ca. 2-3 kcal mol-1.},
  language  = {en}
}
@article{SchwarzeDoscheFlehretal.2010,
  author    = {Schwarze, Thomas and Dosche, Carsten and Flehr, Roman and Klamroth, Tillmann and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Saalfrank, Peter and Cleve, Ernst and Buschmann, Hans-J{\"u}rgen and Holdt, Hans-J{\"u}rgen},
  title     = {Combination of a CT modulated PET and an intramolecular excimer formation to quantify PdCl2 by large fluorescence enhancement},
  issn      = {1359-7345},
  doi       = {10.1039/B919973j},
  year      = {2010},
  abstract  = {The [6.6](9,10)anthracenophane 1 (Scheme 1) is a selective fluoroionophore for the detection of PdCl2 with a large fluorescence enhancement factor (I/I-0 > 250).},
  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{KlikaKramerKleinpeter2009,
  author    = {Klika, Karel D. and Kramer, Markus and Kleinpeter, Erich},
  title     = {DFT computational studies of hydrogen bonding-based diastereomeric complexes : limitations and applications to enantiodifferentiation},
  issn      = {0166-1280},
  doi       = {10.1016/j.theochem.2009.08.003},
  year      = {2009},
  abstract  = {Molecular modeling calculations using DFT at the B3LYP/6-31G(d,p) level of theory have been performed on diastereomeric complexes formed between chiral carboxylate anions and chiral urea receptors, a combination previously demonstrated to enable enantiodifferentiation by electrochemical sensing. The calculations correctly predicted the stability order of the enantiomers in acetonitrile solution when the distinction between the enantiomers was above the declared threshold reliability value of 1 kcal mol;1 for computations at this level of theory. Thus, the calculations can not only be applied to predict the likely success of undertakings using the analytical method, it can also, provided ;E is sufficient, potentially be used to determine the absolute configuration of chiral analytes with at least the racemate in hand. The previously successful enantiodifferentiations of various amino acids and alcohols using chiral ion mobility spectroscopy (CIMS) with (S)-2-butanol as the chiral selector were also evaluated by DFT calculations. The calculations again correctly predicted the stability order of the enantiomers when the calculated ;E was above the threshold value though cases not providing a value for ;E above the threshold value was problematic for this system. Attempts to address this shortcoming included an expanded conformational evaluation, a broader analytical approach, and an extended basis set.},
  language  = {en}
}
@article{LippoldEidnerLippmannPipke2009,
  author    = {Lippold, Holger and Eidner, Sascha and Lippmann-Pipke, Johanna},
  title     = {Kinetic effects in the complexation of radionuclides with humic substances in the presence of Fe(III) and Al(III)},
  issn      = {0016-7037},
  doi       = {10.1016/j.gca.2009.05.010},
  year      = {2009},
  language  = {en}
}
@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{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{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{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{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{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{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{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}
}
@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{LaschewskyGarnierKirstenetal.2006,
  author    = {Laschewsky, Andr{\´e} and Garnier, Sebastien and Kirsten, Juliane and Mertoglu, Murat and Skrabania, Katja and Lutz, Jean-Francois},
  title     = {Comb-like polymeric surfactants by combining block and graft copolymer architectures},
  issn      = {0065-7727},
  year      = {2006},
  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{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{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{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{SchildeKellingUmbreenetal.2016,
  author    = {Schilde, Uwe and Kelling, Alexandra and Umbreen, Sumaira and Linker, Torsten},
  title     = {Crystal structures of three bicyclic carbohydrate derivatives},
  series = {Acta crystallographica Section E ; Crystallographic communications},
  volume    = {72},
  journal   = {Acta crystallographica Section E ; Crystallographic communications},
  number    = {12},
  publisher = {IUCR},
  address   = {Chester},
  issn      = {2056-9890},
  doi       = {10.1107/S2056989016018727},
  pages     = {1839 -- 1844},
  year      = {2016},
  abstract  = {The title compounds, [(1R,3R,4R,5R,6S)-4,5-bis(acetyloxy)-7-oxo-2-oxabicyclo- [4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acetyloxy-7- hydroxyimino-2-oxobicyclo[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and [(3aR,5R,6R,7R,7aS)-6,7-bis(acetyloxy)-2-oxooctahydropyrano[3,2-b]pyrrol-5- yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives. They can easily be synthesized in a few steps from commercially available glycals. As a result of the ring strain from the four-membered rings in (I) and (II), the conformations of the carbohydrates deviate strongly from the ideal chair form. Compound (II) occurs in the boat form. In the five-membered lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair conformation. As a result of the distortion of the sugar rings, the configurations of the three bicyclic carbohydrate derivatives could not be determined from their NMR coupling constants. From our three crystal structure determinations, we were able to establish for the first time the absolute configurations of all new stereocenters of the carbohydrate rings.},
  language  = {en}
}
@article{MeilingCywińskiBald2016,
  author    = {Meiling, Till Thomas and Cywiński, Piotr J. and Bald, Ilko},
  title     = {White carbon: Fluorescent carbon nanoparticles with tunable quantum yield in a reproducible green synthesis},
  series = {Scientific reports},
  volume    = {6},
  journal   = {Scientific reports},
  publisher = {Nature Publishing Group},
  address   = {London},
  doi       = {10.1038/srep28557},
  pages     = {9},
  year      = {2016},
  abstract  = {In this study, a new reliable, economic, and environmentally-friendly one-step synthesis is established to obtain carbon nanodots (CNDs) with well-defined and reproducible photoluminescence (PL) properties via the microwave-assisted hydrothermal treatment of starch and Tris-acetate-EDTA (TAE) buffer as carbon sources. Three kinds of CNDs are prepared using different sets of above mentioned starting materials. The as-synthesized CNDs: C-CND (starch only), N-CND 1 (starch in TAE) and N-CND 2 (TAE only) exhibit highly homogenous PL and are ready to use without need for further purification. The CNDs are stable over a long period of time (>1 year) either in solution or as freeze-dried powder. Depending on starting material, CNDs with PL quantum yield (PLQY) ranging from less than 1\% up to 28\% are obtained. The influence of the precursor concentration, reaction time and type of additives on the optical properties (UV-Vis absorption, PL emission spectrum and PLQY) is carefully investigated, providing insight into the chemical processes that occur during CND formation. Remarkably, upon freeze-drying the initially brown CND-solution turns into a non-fluorescent white/slightly brown powder which recovers PL in aqueous solution and can potentially be applied as fluorescent marker in bio-imaging, as a reduction agent or as a photocatalyst.},
  language  = {en}
}
@article{DoritiBrosnanWeidneretal.2016,
  author    = {Doriti, Afroditi and Brosnan, Sarah M. and Weidner, Steffen M. and Schlaad, Helmut},
  title     = {Synthesis of polysarcosine from air and moisture stable N-phenoxycarbonyl-N-methylglycine assisted by tertiary amine base},
  series = {Polymer Chemistry},
  volume    = {7},
  journal   = {Polymer Chemistry},
  publisher = {RSC Publ.},
  address   = {Cambridge},
  issn      = {1759-9954},
  doi       = {10.1039/C6PY00221H},
  pages     = {3067 -- 3070},
  year      = {2016},
  abstract  = {Polysarcosine (Mn = 3650-20 000 g mol-1, Đ ∼ 1.1) was synthesized from the air and moisture stable N-phenoxycarbonyl-N-methylglycine. Polymerization was achieved by in situ transformation of the urethane precursor into the corresponding N-methylglycine-N-carboxyanhydride, when in the presence of a non-nucleophilic tertiary amine base and a primary amine initiator.},
  language  = {en}
}
@article{OlejkoCywińskiBald2016,
  author    = {Olejko, Lydia and Cywiński, Piotr J. and Bald, Ilko},
  title     = {An ion-controlled four-color fluorescent telomeric switch on DNA origami structures},
  series = {Nanoscale},
  volume    = {8},
  journal   = {Nanoscale},
  publisher = {RSC Publ.},
  address   = {Cambridge},
  issn      = {2040-3372},
  doi       = {10.1039/C6NR00119J},
  pages     = {10339 -- 10347},
  year      = {2016},
  abstract  = {The folding of single-stranded telomeric DNA into guanine (G) quadruplexes is a conformational change that plays a major role in sensing and drug targeting. The telomeric DNA can be placed on DNA origami nanostructures to make the folding process extremely selective for K+ ions even in the presence of high Na+ concentrations. Here, we demonstrate that the K+-selective G-quadruplex formation is reversible when using a cryptand to remove K+ from the G-quadruplex. We present a full characterization of the reversible switching between single-stranded telomeric DNA and G-quadruplex structures using F{\"o}rster resonance energy transfer (FRET) between the dyes fluorescein (FAM) and cyanine3 (Cy3). When attached to the DNA origami platform, the G-quadruplex switch can be incorporated into more complex photonic networks, which is demonstrated for a three-color and a four-color FRET cascade from FAM over Cy3 and Cy5 to IRDye700 with G-quadruplex-Cy3 acting as a switchable transmitter.},
  language  = {en}
}
@article{NiedlBerensteinBeta2016,
  author    = {Niedl, Robert Raimund and Berenstein, Igal and Beta, Carsten},
  title     = {How imperfect mixing and differential diffusion accelerate the rate of nonlinear reactions in microfluidic channels},
  series = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  volume    = {18},
  journal   = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1463-9076},
  doi       = {10.1039/c6cp00224b},
  pages     = {6451 -- 6457},
  year      = {2016},
  abstract  = {In this paper, we show experimentally that inside a microfluidic device, where the reactants are segregated, the reaction rate of an autocatalytic clock reaction is accelerated in comparison to the case where all the reactants are well mixed. We also find that, when mixing is enhanced inside the microfluidic device by introducing obstacles into the flow, the clock reaction becomes slower in comparison to the device where mixing is less efficient. Based on numerical simulations, we show that this effect can be explained by the interplay of nonlinear reaction kinetics (cubic autocatalysis) and differential diffusion, where the autocatalytic species diffuses slower than the substrate.},
  language  = {en}
}
@article{ZabelWinterKellingetal.2016,
  author    = {Zabel, Andr{\´e} and Winter, Alette and Kelling, Alexandra and Schilde, Uwe and Strauch, Peter},
  title     = {Tetrabromidocuprates(II)-Synthesis, Structure and EPR},
  series = {International journal of molecular sciences},
  volume    = {17},
  journal   = {International journal of molecular sciences},
  number    = {4},
  publisher = {MDPI},
  address   = {Basel},
  doi       = {10.3390/ijms17040596},
  pages     = {14},
  year      = {2016},
  abstract  = {Metal-containing ionic liquids (ILs) are of interest for a variety of technical applications, e.g., particle synthesis and materials with magnetic or thermochromic properties. In this paper we report the synthesis of, and two structures for, some new tetrabromidocuprates(II) with several "onium" cations in comparison to the results of electron paramagnetic resonance (EPR) spectroscopic analyses. The sterically demanding cations were used to separate the paramagnetic Cu(II) ions for EPR measurements. The EPR hyperfine structure in the spectra of these new compounds is not resolved, due to the line broadening resulting from magnetic exchange between the still-incomplete separated paramagnetic Cu(II) centres. For the majority of compounds, the principal g values (g|| and gK) of the tensors could be determined and information on the structural changes in the [CuBr4]2- anions can be obtained. The complexes have high potential, e.g., as ionic liquids, as precursors for the synthesis of copper bromide particles, as catalytically active or paramagnetic ionic liquids.},
  language  = {en}
}
@article{PrinzHeckElleriketal.2016,
  author    = {Prinz, Julia and Heck, Christian and Ellerik, Lisa and Merk, Virginia and Bald, Ilko},
  title     = {DNA origami based Au-Ag-core-shell nanoparticle dimers with single-molecule SERS sensitivity},
  series = {Nanoscale},
  journal   = {Nanoscale},
  number    = {8},
  publisher = {RSC Publishing},
  address   = {Cambridge},
  doi       = {10.1039/C5NR08674D},
  pages     = {5612 -- 5620},
  year      = {2016},
  abstract  = {DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 1010, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled.},
  language  = {en}
}
@article{MondalMarquardtJaniaketal.2016,
  author    = {Mondal, Suvendu Sekhar and Marquardt, Dorothea and Janiak, Christoph and Holdt, Hans-J{\"u}rgen},
  title     = {Use of a 4,5-dicyanoimidazolate anion based ionic liquid for the synthesis of iron and silver nanoparticles},
  series = {Dalton transactions : an international journal of inorganic chemistry},
  journal   = {Dalton transactions : an international journal of inorganic chemistry},
  number    = {45},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1477-9226},
  doi       = {10.1039/C6DT00225K},
  pages     = {5476 -- 5483},
  year      = {2016},
  abstract  = {Sixteen new ionic liquids (ILs) with tetraethylammonium, 1-butyl-3-methylimidazolium, 3-methyl-1-octylimidazolium and tetrabutylphosphonium cations paired with 2-substituted 4,5-dicyanoimidazolate anions (substituent at C2 = methyl, trifluoromethyl, pentafluoroethyl, N,N′-dimethyl amino and nitro) have been synthesized and characterized by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA). The effects of cation and anion type and structure of the resulting ILs, including several room temperature ionic liquids (RTILs), are reflected in the crystallization, melting points and thermal decomposition of the ILs. ILs exhibited large liquid and crystallization ranges and formed glasses on cooling with glass transition temperatures in the range of -22 to -71 °C. We selected one of the newly designed ILs due to its bigger size, compared to the common conventional IL anion and high electron-withdrawing nitrile group leads to an overall stabilization anion that may stabilize the metal nanoparticles. Stable and better separated iron and silver nanoparticles are obtained by the decomposition of corresponding Fe2(CO)9 and AgPF6, respectively, under N2-atmosphere in newly designed nitrile functionalized 4,5-dicyanoimidazolate anion based IL. Very small and uniform size for Fe-nanoparticles of about 1.8 ± 0.6 nm were achieved without any additional stabilizers or capping molecules. Comparatively bigger size of Ag-nanoparticles was obtained through the reduction of AgPF6 by hydrogen gas. Additionally, the AgPF6 precursor was decomposed under microwave irradiation (MWI), fabricating nut-in-shell-like, that is, core-separated-from-shell Ag-nano-structures.},
  language  = {en}
}
@article{KlaperWessigLinker2015,
  author    = {Klaper, M. and Wessig, Pablo and Linker, Torsten},
  title     = {Base catalysed decomposition of anthracene endoperoxide},
  series = {Chemical communications : ChemComm},
  journal   = {Chemical communications : ChemComm},
  number    = {52},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1364-548X},
  doi       = {10.1039/C5CC08606J},
  pages     = {1210 -- 1213},
  year      = {2015},
  abstract  = {Catalytic amounts of a weak base are sufficient to induce the decomposition of anthracene endoperoxides to anthraquinone. The mechanism has been elucidated by isolation of intermediates in combination with DFT calculations. The whole process is suitable for the convenient generation of hydrogen peroxide under very mild conditions.},
  language  = {en}
}
@article{MatisSchoenbornSaalfrank2015,
  author    = {Matis, Jochen Ren{\´e} and Sch{\"o}nborn, Jan Boyke and Saalfrank, Peter},
  title     = {A multi-reference study of the byproduct formation for a ring-closed dithienylethene photoswitch},
  series = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  journal   = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  number    = {17},
  publisher = {The Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1463-9076},
  doi       = {10.1039/C5CP00987A},
  pages     = {14088 -- 14095},
  year      = {2015},
  abstract  = {Photodriven molecular switches are sometimes hindered in their performance by forming byproducts which act as dead ends in sequences of switching cycles, leading to rapid fatigue effects. Understanding the reaction pathways to unwanted byproducts is a prerequisite for preventing them. This article presents a study of the photochemical reaction pathways for byproduct formation in the photochromic switch 1,2-bis-(3-thienyl)-ethene. Specifically, using single- and multi-reference methods the post-deexcitation reaction towards the byproduct in the electronic ground state S0 when starting from the S1-S0 conical intersection (CoIn), is considered in detail. We find an unusual low-energy pathway, which offers the possibility for the formation of a dyotropic byproduct. Several high-energy pathways can be excluded with high probability.},
  language  = {en}
}
@article{PrestelMoeller2015,
  author    = {Prestel, Andreas and M{\"o}ller, Heiko Michael},
  title     = {Spatio-temporal control of cellular uptake achieved by photoswitchable cell-penetrating peptides},
  series = {Chemical communications : ChemComm},
  journal   = {Chemical communications : ChemComm},
  number    = {52},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1364-548X},
  doi       = {10.1039/C5CC06848G},
  pages     = {701 -- 704},
  year      = {2015},
  abstract  = {The selective uptake of compounds into specific cells of interest is a major objective in cell biology and drug delivery. By incorporation of a novel, thermostable azobenzene moiety we generated peptides that can be switched optically between an inactive state and an active, cell-penetrating state with excellent spatio-temporal control.},
  language  = {en}
}
@article{KlierKumke2015,
  author    = {Klier, Dennis Tobias and Kumke, Michael Uwe},
  title     = {Analysing the effect of the crystal structure on upconversion luminescence in Yb3+,Er3+-co-doped NaYF4 nanomaterials},
  series = {Journal of materials chemistry C ; Materials for optical and electronic devices},
  journal   = {Journal of materials chemistry C ; Materials for optical and electronic devices},
  number    = {3},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {2050-7526},
  doi       = {10.1039/C5TC02218E},
  pages     = {11228 -- 11238},
  year      = {2015},
  abstract  = {NaYF4:Yb:Er nanoparticles (UCNP) were synthesized under mild experimental conditions to obtain a pure cubic lattice. Upon annealing at different temperatures up to Tan = 700 °C phase transitions to the hexagonal phase and back to the cubic phase were induced. The UCNP materials obtained for different Tan were characterized with respect to the lattice phase using standard XRD and Raman spectroscopy as well as steady state and time resolved upconversion luminescence. The standard techniques showed that for the annealing temperature range 300 °C < Tan < 600 °C the hexagonal lattice phase was dominant. For Tan < 300 °C hardly any change in the lattice phase could be deduced, whereas for Tan > 600 °C a back transfer to the α-phase was observed. Complementarily, the luminescence upconversion properties of the annealed UCNP materials were characterized in steady state and time resolved luminescence measurements. Distinct differences in the upconversion luminescence intensity, the spectral intensity distribution and the luminescence decay kinetics were found for the cubic and hexagonal lattice phases, respectively, corroborating the results of the standard analytical techniques used. In laser power dependent measurements of the upconversion luminescence intensity it was found that the green (G1, G2) and red (R) emission of Er3+ showed different effects of Tan on the number of required photons reflecting the differences in the population routes of different energy levels involved. Furthermore, the intensity ratio of Gfull/R is highly effected by the laser power only when the β-phase is present, whereas the G1/G2 intensity ratio is only slightly effected regardless of the crystal phase. Moreover, based on different upconversion luminescence kinetics characteristics of the cubic and hexagonal phase time-resolved area normalized emission spectra (TRANES) proved to be a very sensitive tool to monitor the phase transition between cubic and hexagonal phases. Based on the TRANES analysis it was possible to resolve the lattice phase transition in more detail for 200 °C < Tan < 300 °C, which was not possible with the standard techniques.},
  language  = {en}
}
@article{KlierKumke2015,
  author    = {Klier, Dennis Tobias and Kumke, Michael Uwe},
  title     = {Upconversion NaYF4:Yb:Er nanoparticles co-doped with Gd3+ and Nd3+ for thermometry on the nanoscale},
  series = {RSC Advances : an international journal to further the chemical sciences},
  journal   = {RSC Advances : an international journal to further the chemical sciences},
  number    = {5},
  publisher = {RSC Publishing},
  address   = {London},
  issn      = {2046-2069},
  doi       = {10.1039/C5RA11502G},
  pages     = {67149 -- 67156},
  year      = {2015},
  abstract  = {In the present work, the upconversion luminescence properties of oleic acid capped NaYF4:Gd3+:Yb3+:Er3+ upconversion nanoparticles (UCNP) with pure β crystal phase and Nd3+ ions as an additional sensitizer were studied in the temperature range of 288 K < T < 328 K. The results of this study showed that the complex interplay of different mechanisms and effects, causing the special temperature behavior of the UCNP can be developed into thermometry on the nanoscale, e.g. to be applied in biological systems on a cellular level. The performance was improved by the use of Nd3+ as an additional dopant utilizing the cascade sensitization mechanism in tri-doped UCNP.},
  language  = {en}
}
@article{deCarvalhoMetzlerCherstvy2015,
  author    = {de Carvalho, Sidney J. and Metzler, Ralf and Cherstvy, Andrey G.},
  title     = {Inverted critical adsorption of polyelectrolytes in confinement},
  series = {Soft matter},
  journal   = {Soft matter},
  number    = {11},
  publisher = {Royal Society of Chemistry},
  address   = {London},
  issn      = {1744-6848},
  doi       = {10.1039/C5SM00635J},
  pages     = {4430 -- 4443},
  year      = {2015},
  abstract  = {What are the fundamental laws for the adsorption of charged polymers onto oppositely charged surfaces, for convex, planar, and concave geometries? This question is at the heart of surface coating applications, various complex formation phenomena, as well as in the context of cellular and viral biophysics. It has been a long-standing challenge in theoretical polymer physics; for realistic systems the quantitative understanding is however often achievable only by computer simulations. In this study, we present the findings of such extensive Monte-Carlo in silico experiments for polymer-surface adsorption in confined domains. We study the inverted critical adsorption of finite-length polyelectrolytes in three fundamental geometries: planar slit, cylindrical pore, and spherical cavity. The scaling relations extracted from simulations for the critical surface charge density sc—defining the adsorption-desorption transition—are in excellent agreement with our analytical calculations based on the ground-state analysis of the Edwards equation. In particular, we confirm the magnitude and scaling of sc for the concave interfaces versus the Debye screening length 1/k and the extent of confinement a for these three interfaces for small ka values. For large ka the critical adsorption condition approaches the known planar limit. The transition between the two regimes takes place when the radius of surface curvature or half of the slit thickness a is of the order of 1/k. We also rationalize how sc(k) dependence gets modified for semi-flexible versus flexible chains under external confinement. We examine the implications of the chain length for critical adsorption—the effect often hard to tackle theoretically—putting an emphasis on polymers inside attractive spherical cavities. The applications of our findings to some biological systems are discussed, for instance the adsorption of nucleic acids onto the inner surfaces of cylindrical and spherical viral capsids.},
  language  = {en}
}
@article{HentrichJungingerBrunsetal.2015,
  author    = {Hentrich, Doreen and Junginger, Mathias and Bruns, Michael and B{\"o}rner, Hans Gerhard and Brandt, Jessica and Brezesinski, Gerald and Taubert, Andreas},
  title     = {Interface-controlled calcium phosphate mineralization},
  series = {CrystEngComm},
  journal   = {CrystEngComm},
  number    = {17},
  publisher = {Royal Society of Chemistry},
  address   = {London},
  issn      = {1466-8033},
  doi       = {10.1039/C4CE02274B},
  pages     = {6901 -- 6913},
  year      = {2015},
  abstract  = {The phase behavior of an amphiphilic block copolymer based on a poly(aspartic acid) hydrophilic block and a poly(n-butyl acrylate) hydrophobic block was investigated at the air-water and air-buffer interface. The polymer forms stable monomolecular films on both subphases. At low pH, the isotherms exhibit a plateau. Compression-expansion experiments and infrared reflection absorption spectroscopy suggest that the plateau is likely due to the formation of polymer bi- or multilayers. At high pH the films remain intact upon compression and no multilayer formation is observed. Furthermore, the mineralization of calcium phosphate beneath the monolayer was studied at different pH. The pH of the subphase and thus the polymer charge strongly affects the phase behavior of the film and the mineral formation. After 4 h of mineralization at low pH, atomic force microscopy shows smooth mineral films with a low roughness. With increasing pH the mineral films become inhomogeneous and the roughness increases. Transmission electron microscopy confirms this: at low pH a few small but uniform particles form whereas particles grown at higher pH are larger and highly agglomerated. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirm the formation of calcium phosphate. The levels of mineralization are higher in samples grown at high pH.},
  language  = {en}
}
@article{BanerjeeStuekerSaalfrank2015,
  author    = {Banerjee, Shiladitya and St{\"u}ker, Tony and Saalfrank, Peter},
  title     = {Vibrationally resolved optical spectra of modified diamondoids obtained from time-dependent correlation function methods},
  series = {Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies},
  volume    = {17},
  journal   = {Physical chemistry, chemical physics : PCCP ; a journal of European chemical societies},
  number    = {29},
  publisher = {Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1463-9084},
  doi       = {10.1039/C5CP02615F},
  pages     = {19656 -- 19669},
  year      = {2015},
  abstract  = {Optical properties of modified diamondoids have been studied theoretically using vibrationally resolved electronic absorption, emission and resonance Raman spectra. A time-dependent correlation function approach has been used for electronic two-state models, comprising a ground state (g) and a bright, excited state (e), the latter determined from linear-response, time-dependent density functional theory (TD-DFT). The harmonic and Condon approximations were adopted. In most cases origin shifts, frequency alteration and Duschinsky rotation in excited states were considered. For other cases where no excited state geometry optimization and normal mode analysis were possible or desired, a short-time approximation was used. The optical properties and spectra have been computed for (i) a set of recently synthesized sp2/sp3 hybrid species with C[double bond, length as m-dash]C double-bond connected saturated diamondoid subunits, (ii) functionalized (mostly by thiol or thione groups) diamondoids and (iii) urotropine and other C-substituted diamondoids. The ultimate goal is to tailor optical and electronic features of diamondoids by electronic blending, functionalization and substitution, based on a molecular-level understanding of the ongoing photophysics.},
  language  = {en}
}
@article{RoderHille2015,
  author    = {Roder, Phillip and Hille, Carsten},
  title     = {A Multifunctional Frontloading Approach for Repeated Recycling of a Pressure-Controlled AFM Micropipette},
  series = {PLoS ONE},
  volume    = {10},
  journal   = {PLoS ONE},
  number    = {12},
  publisher = {Public Library of Science},
  address   = {Lawrence, Kan.},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0144157},
  year      = {2015},
  abstract  = {Fluid force microscopy combines the positional accuracy and force sensitivity of an atomic force microscope (AFM) with nanofluidics via a microchanneled cantilever. However, adequate loading and cleaning procedures for such AFM micropipettes are required for various application situations. Here, a new frontloading procedure is described for an AFM micropipette functioning as a force- and pressure-controlled microscale liquid dispenser. This frontloading procedure seems especially attractive when using target substances featuring high costs or low available amounts. Here, the AFM micropipette could be filled from the tip side with liquid from a previously applied droplet with a volume of only a few μL using a short low-pressure pulse. The liquid-loaded AFM micropipettes could be then applied for experiments in air or liquid environments. AFM micropipette frontloading was evaluated with the well-known organic fluorescent dye rhodamine 6G and the AlexaFluor647-labeled antibody goat anti-rat IgG as an example of a larger biological compound. After micropipette usage, specific cleaning procedures were tested. Furthermore, a storage method is described, at which the AFM micropipettes could be stored for a few hours up to several days without drying out or clogging of the microchannel. In summary, the rapid, versatile and cost-efficient frontloading and cleaning procedure for the repeated usage of a single AFM micropipette is beneficial for various application situations from specific surface modifications through to local manipulation of living cells, and provides a simplified and faster handling for already known experiments with fluid force microscopy.},
  language  = {en}
}
@article{BodrovaChechkinCherstvyetal.2015,
  author    = {Bodrova, Anna and Chechkin, Aleksei V. and Cherstvy, Andrey G. and Metzler, Ralf},
  title     = {Quantifying non-ergodic dynamics of force-free granular gases},
  series = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  journal   = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  number    = {17},
  issn      = {1463-9084},
  doi       = {10.1039/C5CP02824H},
  pages     = {21791 -- 21798},
  year      = {2015},
  abstract  = {Brownianmotion is ergodic in the Boltzmann-Khinchin sense that long time averages of physical observables such as the mean squared displacement provide the same information as the corresponding ensemble average, even at out-of-equilibrium conditions. This property is the fundamental prerequisite for single particle tracking and its analysis in simple liquids. We study analytically and by event-driven molecular dynamics simulations the dynamics of force-free cooling granular gases and reveal a violation of ergodicity in this Boltzmann- Khinchin sense as well as distinct ageing of the system. Such granular gases comprise materials such as dilute gases of stones, sand, various types of powders, or large molecules, and their mixtures are ubiquitous in Nature and technology, in particular in Space. We treat—depending on the physical-chemical properties of the inter-particle interaction upon their pair collisions—both a constant and a velocity-dependent (viscoelastic) restitution coefficient e. Moreover we compare the granular gas dynamics with an effective single particle stochastic model based on an underdamped Langevin equation with time dependent diffusivity. We find that both models share the same behaviour of the ensemble mean squared displacement (MSD) and the velocity correlations in the limit of weak dissipation. Qualitatively, the reported non-ergodic behaviour is generic for granular gases with any realistic dependence of e on the impact velocity of particles.},
  language  = {en}
}
@article{MaiBoyeYuanetal.2015,
  author    = {Mai, Tobias and Boye, Susanne and Yuan, Jiayin and V{\"o}lkel, Antje and Gr{\"a}wert, Marlies and G{\"u}nter, Christina and Lederer, Albena and Taubert, Andreas},
  title     = {Poly(ethylene oxide)-based block copolymers with very high molecular weights for biomimetic calcium phosphate mineralization},
  series = {RSC Advances : an international journal to further the chemical sciences},
  journal   = {RSC Advances : an international journal to further the chemical sciences},
  number    = {5},
  publisher = {RSC Publishing},
  address   = {London},
  issn      = {2046-2069},
  doi       = {10.1039/c5ra20035k},
  pages     = {103494 -- 103505},
  year      = {2015},
  abstract  = {The present article is among the first reports on the effects of poly(ampholyte)s and poly(betaine)s on the biomimetic formation of calcium phosphate. We have synthesized a series of di- and triblock copolymers based on a non-ionic poly(ethylene oxide) block and several charged methacrylate monomers, 2-(trimethylammonium)ethyl methacrylate chloride, 2-((3-cyanopropyl)-dimethylammonium)ethyl methacrylate chloride, 3-sulfopropyl methacrylate potassium salt, and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide. The resulting copolymers are either positively charged, ampholytic, or betaine block copolymers. All the polymers have very high molecular weights of over 106 g mol-1. All polymers are water-soluble and show a strong effect on the precipitation and dissolution of calcium phosphate. The strongest effects are observed with triblock copolymers based on a large poly(ethylene oxide) middle block (nominal Mn = 100 000 g mol-1). Surprisingly, the data show that there is a need for positive charges in the polymers to exert tight control over mineralization and dissolution, but that the exact position of the charge in the polymer is of minor importance for both calcium phosphate precipitation and dissolution.},
  language  = {en}
}
@article{MardoukhiJeonMetzler2015,
  author    = {Mardoukhi, Yousof and Jeon, Jae-Hyung and Metzler, Ralf},
  title     = {Geometry controlled anomalous diffusion in random fractal geometries},
  series = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  journal   = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  number    = {17},
  publisher = {Wiley-VCH Verl.},
  address   = {Weinheim},
  issn      = {1439-7641},
  doi       = {10.1039/c5cp03548a},
  pages     = {30134 -- 30147},
  year      = {2015},
  abstract  = {We investigate the ergodic properties of a random walker performing (anomalous) diffusion on a random fractal geometry. Extensive Monte Carlo simulations of the motion of tracer particles on an ensemble of realisations of percolation clusters are performed for a wide range of percolation densities. Single trajectories of the tracer motion are analysed to quantify the time averaged mean squared displacement (MSD) and to compare this with the ensemble averaged MSD of the particle motion. Other complementary physical observables associated with ergodicity are studied, as well. It turns out that the time averaged MSD of individual realisations exhibits non-vanishing fluctuations even in the limit of very long observation times as the percolation density approaches the critical value. This apparent non-ergodic behaviour concurs with the ergodic behaviour on the ensemble averaged level. We demonstrate how the non-vanishing fluctuations in single particle trajectories are analytically expressed in terms of the fractal dimension and the cluster size distribution of the random geometry, thus being of purely geometrical origin. Moreover, we reveal that the convergence scaling law to ergodicity, which is known to be inversely proportional to the observation time T for ergodic diffusion processes, follows a power-law BT� h with h o 1 due to the fractal structure of the accessible space. These results provide useful measures for differentiating the subdiffusion on random fractals from an otherwise closely related process, namely, fractional Brownian motion. Implications of our results on the analysis of single particle tracking experiments are provided.},
  language  = {en}
}
@article{JahnBuschmannHille2015,
  author    = {Jahn, Karolina and Buschmann, Volker and Hille, Carsten},
  title     = {Simultaneous Fluorescence and Phosphorescence Lifetime Imaging Microscopy in Living Cells},
  series = {Scientific Reports},
  journal   = {Scientific Reports},
  number    = {5},
  publisher = {Nature Publishing Group},
  address   = {London},
  issn      = {2045-2322},
  doi       = {10.1038/srep14334},
  pages     = {13},
  year      = {2015},
  abstract  = {In living cells, there are always a plethora of processes taking place at the same time. Their precise regulation is the basis of cellular functions, since small failures can lead to severe dysfunctions. For a comprehensive understanding of intracellular homeostasis, simultaneous multiparameter detection is a versatile tool for revealing the spatial and temporal interactions of intracellular parameters. Here, a recently developed time-correlated single-photon counting (TCSPC) board was evaluated for simultaneous fluorescence and phosphorescence lifetime imaging microscopy (FLIM/PLIM). Therefore, the metabolic activity in insect salivary glands was investigated by recording ns-decaying intrinsic cellular fluorescence, mainly related to oxidized flavin adenine dinucleotide (FAD) and the μs-decaying phosphorescence of the oxygen-sensitive ruthenium-complex Kr341. Due to dopamine stimulation, the metabolic activity of salivary glands increased, causing a higher pericellular oxygen consumption and a resulting increase in Kr341 phosphorescence decay time. Furthermore, FAD fluorescence decay time decreased, presumably due to protein binding, thus inducing a quenching of FAD fluorescence decay time. Through application of the metabolic drugs antimycin and FCCP, the recorded signals could be assigned to a mitochondrial origin. The dopamine-induced changes could be observed in sequential FLIM and PLIM recordings, as well as in simultaneous FLIM/PLIM recordings using an intermediate TCSPC timing resolution.},
  language  = {en}
}
@article{Kroener2015,
  author    = {Kr{\"o}ner, Dominik},
  title     = {Laser-driven electron dynamics for circular dichroism in mass spectrometry},
  series = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  volume    = {29},
  journal   = {Physical chemistry, chemical physics : PCCP ; a journal of European Chemical Societies},
  number    = {17},
  publisher = {The Royal Society of Chemistry},
  address   = {Cambridge},
  issn      = {1463-9076},
  doi       = {10.1039/C5CP02193F},
  pages     = {19643 -- 19655},
  year      = {2015},
  abstract  = {The distinction of enantiomers is a key aspect of chemical analysis. In mass spectrometry the distinction of enantiomers has been achieved by ionizing the sample with circularly polarized laser pulses and comparing the ion yields for light of opposite handedness. While resonant excitation conditions are expected to be most efficient, they are not required for the detection of a circular dichroism (CD) in the ion yield. However, the prediction of the size and sign of the circular dichroism becomes challenging if non-resonant multiphoton excitations are used to ionize the sample. Employing femtosecond laser pulses to drive electron wavepacket dynamics based on ab initio calculations, we attempt to reveal underlying mechanisms that determine the CD under non-resonant excitation conditions. Simulations were done for (R)-1,2-propylene oxide, using time-dependent configuration interaction singles with perturbative doubles (TD-CIS(D)) and the aug-cc-pVTZ basis set. Interactions between the electric field and the electric dipole and quadrupole as well as between the magnetic field and the magnetic dipole were explicitly accounted for. The ion yield was determined by treating states above the ionization potential as either stationary or non-stationary with energy-dependent lifetimes based on an approved heuristic approach. The observed population dynamics do not allow for a simple interpretation, because of highly non-linear interactions. Still, the various transition pathways are governed by resonant enantiospecific n-photon excitation, with preferably high transition dipole moments, which eventually dominate the CD in the ionized population.},
  language  = {en}
}