1 H and 13 C NMR study of paramagnetic chiral macrocyclic lanthanide complexes

The chiral macrocyclic complexes obtained in a template condensation of (R,R )-1,2-diaminocyclohexane and 2,6-diformylpyridine, [LnL](NO3 )3 , Ln=La(III), Ce(III), Eu(III) and Yb(III), were studied by 1Hand 13C NMR spectroscopy. The signal assignment was based on COSY, NOESY and HMQC measurements and the isotropic shifts of the paramagnetic complexes were analysed. The spectra of the investigated compounds in methanol–chloroform solution indicate a D2-symmetrical, helical conformation of the ligand. The chiral [LnL](NO3 )3 complexes are able to form diastereoisomeric adducts with D- and L-aminoacids that can be distinguished by 1H NMR spectroscopy.