Preparation and characterisation of some new asymmetric tetraaza macrocyclic complexes of nickel(II)

The synthesis of a new neutral, asymmetrically substituted nickel(II) tetraaza macrocyclic complex has been performed via the template condensation of an asymmetric, acyclic precursor with 1,3-propanediamine. The peripheral aromatic nitro group of this asymmetric macrocycle undergoes catalytic reduction with hydrogen to produce the corresponding aromatic primary amine complex. The asymmetric nature of these materials is clearly demonstrated with the aid of ¹H and ¹³C NMR spectroscopy. The synthesis of a new 15-membered macrocycle is also described. Deacylation of this macrocycle gives either the neutral macrocycle or the related asymmetric, monoprotonated macrocyclic salt, depending upon the reaction conditions. © 1992.