Modern spectroscopic techniques in the characterization of Schiff base macrocyclic ligand and its complexes with transition metals

Mn(II), Co(II), Ni(II), and Cu(II) complexes with a new azamacrocyclic tetradentate [N-4] ligand i.e. 2,3,9,10-tetraphenyl;1,4,8,11-tetraazacyclotetradeca;1,3,8,10-tetraene (L) have been synthesized and characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, (HNMR)-H-1, IR, electronic and EPR spectral studies. On the basis of their non-electrolytic nature, the probable formula of the complexes is proposed to be [M(L)X-2], where M=Mn(II), Co(II), Ni(II), and Cu(II), X=Cl- and NO3, in dimethylformamide (DMF). All the complexes are of high-spin type and found to have six coordinated, octahedral geometry for Mn(II), Co(II), and Ni(II) complexes, and tetragonal for Cu(II) complexes. Macrocyclic ligand and its complexes have also been screened against pathogenic bacteria and fungi in vitro as growth inhibiting agent. (c) 2005 Elsevier B.V. All rights reserved.