Synthesis, Structural Characterization, and Antibacterial Studies of a Tetradentate Macrocyclic Ligand and Its Co(II), Ni(II), and Cu(II) Complexes

摘要

A novel macrocyclic tetradentate ligand 1,5,8,12-tetraaza-2,4,9,11-tetraphenyl-6,7:13,14-dibenzo-cyclohexadeca-1,4,8,11-tetraene (L) has been synthesized. Cobalt(II), nickel(II), and copper(II) complexes of this ligand have been prepared and characterized by elemental analysis, molar conductance measurements, magnetic susceptibitity measurements, and mass, IR, electronic, and ESR spectral studies. The molar conductance measurements correspond to a nonelectrolytic nature for all the complexes, which can be formulated as [M(L)X2] (where M = Co(II), Ni(II), and Cu(II); X=Cl~- and NO5). On the basis of IR, electronic, and ESR spectral studies, an octahedral geometry has been assigned to the Co(II) and Ni(II) complexes, whereas a tetragonal geometry was found for the Cu(II) complexes. The investigated compounds and uncomplexed metal salts and the ligands were tested against bacterial species like Sarcina lutea, Escherchia coli, and Staphylococ-cus aureus. The metal complexes have higher activity than the free ligand and metal salts.