@article{WackerDahmsSengeetal.2007,
  author    = {Wacker, Philipp and Dahms, Katja and Senge, Mathias O. and Kleinpeter, Erich},
  title     = {Conformational Landscape of meso-(1,3-Dithian-2-yl)porphyrins},
  doi       = {10.1021/Jo0708700},
  year      = {2007},
  abstract  = {An investigation of the conformational landscape of 1,3-dithian-2-yl bearing porphyrins and the rotational behavior of the dithianyl substituents in meso position was carried out by variable-temperature (VT) NMR spectroscopy. Additionally, theoretical results for alternative conformations and energy barriers were obtained by molecular modeling. The study revealed different NH trans tautomers with regard to the orientation of the dithianyl ligands for the free base porphyrins 1-3. Relatively ruffled porphyrin core conformations were established for the transition states of the dithianyl rotation, resulting in a lower rotational energy barrier for the nickel(II) complex 4 compared to that of the free base systems. The data obtained and the first depiction of a rotational transition state for the rotation of bulky meso-alkyl substituents illustrate the close structural interplay between meso-alkyl substituents and the macrocycle conformation in porphyrins.},
  language  = {en}
}
@article{RudershausenDrexlerBansseetal.2007,
  author    = {Rudershausen, S. and Drexler, Hans-Joachim and Banße, Wolfgang and Kelling, Alexandra and Schilde, Uwe and Holdt, Hans-Joachim},
  title     = {Three polymorphs of bis(5-methylthio-1,2-dithiole-3-thione)-disulfide},
  doi       = {10.1002/crat.200610776},
  year      = {2007},
  abstract  = {The title compound, bis(5-methylthio-1,2-dithiole-3-thione)-disulfide, was yielded for the first time as by- product of the reaction of nickel(II) and cobalt(II) ions with 5-methylthio-1,2-dithiole-3-thione-4-thiolate. The compound can be obtained directly by oxidation of the ammonium salt of the ligand. C8H6S10 forms three polymorphs: (I), which crystallizes in the orthorhombic space group P212121, (II) and (III), which crystallize in the monoclinic space groups P21/c and P21/n, respectively. The crystal and molecular structures are presented here. The determination of the absolute configuration of (I) indicated the P-helical enantiomer. In contrast to this, the crystals of (II) und (III) are racemic, containing P- and M-helical enantiomers. The polymorphs differ in the kind of skewing around the disulfide bond and of the positions of the both dithiole rings to the S-S-moiety},
  language  = {en}
}
@article{ParkinsonAharonChangetal.2007,
  author    = {Parkinson, P. and Aharon, E. and Chang, M. H. and Dosche, Carsten and Frey, G. L. and K{\"o}hler, Anna and Herz, L. M.},
  title     = {Dimensionality-dependent energy transfer in polymer-intercalated SnS2 nanocomposites},
  doi       = {10.1103/Physrevb.75.165206},
  year      = {2007},
  abstract  = {We have investigated the influence of dimensionality on the excitation-transfer dynamics in a conjugated polymer blend. Using time-resolved photoluminescence spectroscopy, we have measured the transfer transients for both a three-dimensional blend film and for quasi-two-dimensional monolayers formed through intercalation of the polymer blend between the crystal planes of an inorganic SnS2 matrix. We compare the experimental data with a simple, dimensionality- dependent model based on electronic coupling between electronic transition moments taken to be point dipoles. Within this approximation, the energy-transfer dynamics is found to adopt a three-dimensional character in the solid film and a two-dimensional nature in the monolayers present in the SnS2-polymer nanocomposite.},
  language  = {en}
}
@article{Kleinpeter2007,
  author    = {Kleinpeter, Erich},
  title     = {Syntheses and conformational analyses of mono- and trans-1,4-dialkoxy substituted cyclohexanes : the steric substituent/skeleton interactions},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2007.06.094},
  year      = {2007},
  abstract  = {Mono- and trans-1,4-dialkoxy substituted cyclohexanes (alkyl=Me, Et, i-Pr, t-Bu) were prepared using the solvomercuration-demercuration (SM-DM) procedure. The axialaxial and axial,axialequatorial, equatorial conformational equilibria of the products were studied by low temperature 1H and 13C NMR spectroscopy in CD2Cl2. The structures and relative energies of the participating conformers were calculated at both the B3LYP (6-311G*//6-311+G*) and MP2 (6-311+G*//6-311G*) levels of theory. In the case of DFT, good correlations of ;Gocalcd versus ;Goexptl were obtained. Both the structures and the energy differences of the conformers have been discussed with respect to established models of conformational analysis, viz. steric and hyperconjugative interactions. In addition, 1JH,C coupling constants were considered with respect to the hyperconjugation present.},
  language  = {en}
}
@article{KleinpeterKlodKoch2007,
  author    = {Kleinpeter, Erich and Klod, Sabrina and Koch, Andreas},
  title     = {Visualization of through space NMR shieldings of aromatic and anti-aromatic molecules and a simple means to compare and estimate aromaticity},
  issn      = {0166-1280},
  doi       = {10.1016/j.theochem.2007.02.049},
  year      = {2007},
  abstract  = {Through space NMR shieldings of aromatic (benzene, mono-substituted and annelated benzenes, ferrocene, [14]- and [18]-annulenes, phenylenes and tetra- to heptahelicene) and anti-aromatic molecules (cyclobutadiene and pentalene) were assessed by ab initio molecular-orbital calculations. Employing the nucleus-independent chemical shifts (NICS) concept, these through space NMR shieldings were visualized as iso-chemical-shielding surfaces (ICSSs) and can be applied quantitatively to determine the stereochemistry of proximal nuclei. In addition, the distances in {\AA} at ICSS values of ±0.1 ppm in-plane and perpendicular-to-center of the aromatic ring system were employed as a simple means to compare and estimate qualitatively the aromaticity of the systems at hand.},
  language  = {en}
}
@article{HaebelBahrkePeter2007,
  author    = {Haebel, Sophie and Bahrke, Sven and Peter, Martin G.},
  title     = {Quantitative sequencing of complex mixtures of heterochitooligosaccharides by vMALDI-linear ion trap mass spectrometry},
  issn      = {0003-2700},
  doi       = {10.1021/Ac062254u},
  year      = {2007},
  abstract  = {Heterochitooligosaccharides possess interesting biol. properties. Isobaric mixts. of such linear heterochitooligosaccharides can be obtained by chem. or enzymic degrdn. of chitosan. However, the sepn. of such mixts. is a challenging anal. problem which is so far unresolved. It is shown that these isobaric mixts. can be sequenced and quantified simultaneously using std. derivatization and multistage tandem mass spectrometric techniques. A linear ion trap mass spectrometer equipped with a vacuum matrix-assisted laser desorption ionization (vMALDI) source is used to perform MS2 as well as MS3 expts. [on SciFinder (R)].},
  language  = {en}
}
@article{DoscheMicklerLoehmannsroebenetal.2007,
  author    = {Dosche, Carsten and Mickler, Wulfhard and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Agenet, Nicolas and Vollhardt, K. Peter C.},
  title     = {Photoinduced electron transfer in [N]phenylenes},
  issn      = {1010-6030},
  doi       = {10.1016/j.jphotochem.2006.12.038},
  year      = {2007},
  abstract  = {First studies of electron transfer in [N]phenylenes were performed in bimolecular quenching reactions of angular [3]- and triangular [4]phenylene with various electron acceptors. The relation between the quenching rate constants k(q) and the free energy change of the electron transfer (Delta G(CS)(0)) could be described by the Rehm- Weller equation. From the experimental results, a reorganization energy lambda of 0.7 eV was derived. Intramolecular electron transfer reactions were studied in an [N]phenylene bichomophore and a corresponding reference compound. Fluorescence lifetime and quantum yield of the bichromophor display a characteristic dependence on the solvent polarity, whereas the corresponding values of the reference compound remain constant. From the results, a nearly isoenergonic charge separation process can be determined. As the triplet quantum yield is nearly independent of the polarity, charge recombination leads to the population of the triplet state.},
  language  = {en}
}
@article{SchwarzeMuellerDoscheetal.2007,
  author    = {Schwarze, Thomas and Mueller, Holger and Dosche, Carsten and Klamroth, Tillmann and Mickler, Wulfhard and Kelling, Alexandra},
  title     = {Luminescence detection of open-shell transition-metal ions by photoinduced electron transfer controlled by internal charge transfer of a receptor},
  doi       = {10.1002/anie.200603992},
  year      = {2007},
  language  = {en}
}
@article{WackerKleinpeter2007,
  author    = {Wacker, Philipp and Kleinpeter, Erich},
  title     = {Stoichiometry, complex stability, molecular size and conformational variations of metal ion crown ether complexes subject to diffusion coefficients in nonaqueous solutions},
  doi       = {10.1007/s10847-007-9332-1},
  year      = {2007},
  abstract  = {Both the stoichiometry and complex stability constants of crown ether complexes with metal ions have been determined by examining gradual changes in their diffusional behavior in nonaqueous solution. Diffusion coefficients, D, were evaluated by pulsed field gradient (PFG) NMR titration experiments whilst complex stability constants were determined by nonlinear curve-fitting procedures, D versus csol., which also allow the treatment of multiple complexation equilibria (1:1 to 1:2 stoichiometries). Differences in the diffusion coefficients of the various free crown ethers with respect to their metal ion complexes indicate great sensitivity to both conformational changes and changes in molecular size upon complexation.},
  language  = {en}
}
@article{LaschewskyPoundSkrabaniaetal.2007,
  author    = {Laschewsky, Andr{\´e} and Pound, Gwenaelle and Skrabania, Katja and Holdt, Hans-Joachim and Teller, Joachim},
  title     = {Unsymmetrical bifunctional trithiocarbonate as unexpected by-product in the synthesis of a dithioester RAFT agent},
  issn      = {0303-402X},
  doi       = {10.1007/s.00396-007-1653-5},
  year      = {2007},
  abstract  = {The trithiocarbonate 2-(benzylsulfanylthiocarbonylsulfanyl) propanoic acid is formed as minor by-product in the synthesis of the dithioester 2-((2-phenylthioacetyl)sulfanyl) propanoic acid via the Grignard route. The mechanism for this side reaction is not clear. The isolated trithiocarbonate may act as unsymmetrical but bifunctional RAFT agent in the aqueous polymerization of N,N-dimethyl acrylamide. Therefore, it is important to separate it completely from the dithioester before engaging the latter in controlled free radical polymerization to guarantee a maximum control.},
  language  = {en}
}