Synthesis, physico-chemical and antimicrobial screening studies on 14 and 16-membered hexaazamacrocyclic complexes bearing pendant amine groups

Abstract

The synthesis and characterization of a series of 14 and 16-membered hexaazamacrocyclic complexes, which were obtained via template condensation of 1,2- diaminoethane or 1,3-diaminopropane, formaldehyde and hydrazine hydrate in the presence of first row transition metal salts are reported. Complexes of the types, [ML¹(NO3)2]; [CuL¹](NO3)2 and [ML²Cl2]; [CuL²]Cl2 (where M = Co(II), Ni(II) and Zn(II)), were obtained. Elemental analyses, IR spectra, ¹H NMR, EPR, UV-Vis, magnetic susceptibility and conductivity measurements have ascertained the overall geometry and stereochemistry of the complexes. An octahedral geometry has been suggested for all the complexes, except for copper compounds, in which the metal centre coordinates to the four nitrogen atoms of macrocyclic ligand in a square planar fashion. These complexes were screened against different fungi and bacteria in vitro and were found to be potentially active in the concentration 5 mg mL-1.

Keywords

• formaldehyde
• hydrazine hydrate
• hexaazamacrocylic complexes
• spectral studies template condensation