@article{GrotjahnLehmannAurichetal.2001,
  author    = {Grotjahn, Manuela and Lehmann, S. and Aurich, Ines and Holdt, Hans-Joachim and Kleinpeter, Erich},
  title     = {NMR spectroscopic and molecular modelling studies of the solution structure and complexational behaviour of some bis(benzocrown ether)s},
  year      = {2001},
  abstract  = {Structural information about the bis(benzo crown ether)s I-VI and their complexes with alkali metal cations was deduced from the 13C NMR chemical shifts, the salt-induced 1H and 13C chemical shifts and the vicinal 1H,1H coupling constants. Especially the isomerism with respect to the amide O=C - NH bonds and imine fragments were assigned by various useful NMR parameters ( C=O, 1JN,H, 1JC,H) and proved to be E,E-anti,anti. Furthermore, stereochemical information about preferred conformations about flexible bonds was obtained from 2D ROESY NMR experiments. The complex formation (2:1 complexes and sandwich-like 1:1 complexes, respectively) were determined also by 23Na NMR spectroscopy. The conformational study of the crown ethers was accompanied and corroborated by molecular dynamics and quantum chemical calculations.},
  language  = {en}
}
@article{KleinpeterGrotjahnKlinkaetal.2001,
  author    = {Kleinpeter, Erich and Grotjahn, Manuela and Klinka, Karel D. and Drexler, Hans-Joachim and Holdt, Hans-J{\"u}rgen},
  title     = {Conformational and complexational study of some maleonitrile mixed oxadithia crown ethers by NMR spectroscopy and molecular modelling},
  year      = {2001},
  abstract  = {The macrocyclic ring interconversion of four maleonitrile mixed oxadithia crown ethers of variable ring size, mn-12-S2O2, mn-15-S2O3, mn-18-S2O4 and fn-12-S2O2, were studied by 1H and 13C NMR spectroscopy and by molecular modelling. The barriers to ring interconversion were estimated using variable temperature NMR spectroscopy and from the calculated activation energies, together with the spin-lattice relaxation times of the CH2 carbon atoms, conclusions were drawn regarding the intramolecular flexibility of the crown ethers in both the free state as well as the complexed state incorporating either AgI, BiIII, SbIII, PdII or PtII metal cations. Furthermore, both the stoichiometry of the complexes and the coordination sites of the crown ethers to the various cations were also clearly implicated. Molecular modelling was also utilised to ascertain the preferred conformers of the four compounds and their corresponding complexes, the results of which corroborated the experimental NMR results to a high degree.},
  language  = {en}
}
@article{HoldtDrexlerStarkeetal.2001,
  author    = {Holdt, Hans-J{\"u}rgen and Drexler, Hans-Joachim and Starke, Ines and Grotjahn, Manuela and Kleinpeter, Erich},
  title     = {Homologous series of the PdCl2 and PtCl2 complexes of maleonitrile-dithiacrown ethers : synthesis, crystal structures, NMR spectroscopy and mass spectrometry},
  year      = {2001},
  language  = {en}
}