TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Grotjahn, Manuela
A1  - Klinka, Karel D.
A1  - Drexler, Hans-Joachim
A1  - Holdt, Hans-Jürgen
T1  - Conformational and complexational study of some maleonitrile mixed oxadithia crown ethers by NMR spectroscopy and molecular modelling
N2  - 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.
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Holdt, Hans-Jürgen
A1  - Drexler, Hans-Joachim
A1  - Starke, Ines
A1  - Grotjahn, Manuela
A1  - Kleinpeter, Erich
T1  - Homologous series of the PdCl2 and PtCl2 complexes of maleonitrile-dithiacrown ethers : synthesis, crystal structures, NMR spectroscopy and mass spectrometry
Y1  - 2001
ER  -