H-1 and C-13 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)(2), Ln = La( III), Ce(III), Eu(III) and Yb(III), were studied by H-1 and C-13 NMR spectr oscopy. The signal assignment was based on COSY, NOESY and HMQC measurement s and the isotropic shifts of the paramagnetic complexes were analysed. The spectra of the investigated compounds in methanol-chloroform solution indi cate a D-2-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 H-1 NMR spectroscopy. Copyright ( C) 1999 John Wiley & Sons, Ltd.