The template synthesis of the new macrocyclic and acyclic metal ion complexes derived from putrescine

The template reaction of 2,6-diacetylpyridine with biogenic diamine-putrescine in the presence of cadmium(II), mercury(II) or lead(II) ions produces the complexes of 22-membered macrocyclic ligand L-1 with an N-6 set of donor atoms as a result of [2+2] Schiff base cyclocondensation. The lead(II) complex containing Schiff base acyclic ligand L-2 terminated by one carbonyl and one amine group as product of the partial [2+2] condensation has been also isolated and might be regarded as possible intermediate in the formation of the macrocyclic L-1 complex. Analogous reaction involving the uranyl nitrate generates the complex containing the same Schiff base acyclic ligand L-2 as a final product of template reaction. The complexes were characterized by spectral data (IR, H-1 NMR, FAB-MS), thermogravimetric and elemental analyses. A notable feature of the FAB mass spectrum of the uranyl complex is the appearance of the clusters of the form [(UO2) nO](+) (n=1-7) along with the peak corresponding to molecular ion.