The syntheses of enantiopure tetraazamacrocycles analogous to cyclam,(S, S)-3,(R, R)-3 and (S, S, S, S)-4, have been carried out. NMR and semiempirical studies of 3 have revealed that this compound presents a rigid conformation with C2 symmetry, which is stabilized by intramolecular bifurcated hydrogen bonds. Structural studies for macrocycle 4 have shown that the presence of two cyclohexane rings of (S, S) configuration leads to the ...