| Abstrakt: |
Isomeric cis-2,9-bis(aminomethyl)-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecanes (6a and 6b) and their octahedral (4) and square-planar nickel(II) complexes (5) have been prepared and characterized. X-ray crystallographic investigations of the octahedral complexes have confirmed a folded conformation of the macrocyclic ring. Protonation of the pendant amino groups results in a change in the Ni configuration, which is accompanied by a concomitant change of the macrocycle conformation from a folded to a planar one. The structures of the protonated, square-planar complexes and of the free ligands have been established mainly on the basis of their 1H- and 13C-NMR spectra. |
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