Synthesis, crystal structures and spectroscopic properties of three Zn–cyclen–aminoacid complexes with new macrocyclic configurations

Synthesis and characterization of a series of novel Zn–cyclen–aminoacid complexes are reported and non-covalent interactions were used for the conformation changes description. In addition to the TRANS-I ++++ (same position of NH hydrogen atoms in both isomers) configuration we observed two different isomers in the case of the [{Zn(Δ-cyclen)(HGly)}{Zn(Λ-cyclen)(HGly)}](ClO4)4 · 2H2O (1), [{Zn(Δ-cyclen)(S-HPhe)}{Zn(Λ-cyclen)(S-HPhe)}](ClO4)4 (2) and [Zn(Δ-cyclen)(S-HAla)](ClO4)2 (3) complexes with pentacoordinated zinc atom. Moreover, work also deals with the correlation between spectral and structural properties of the prepared complexes and their thermal stability.