Macrocyclic metal complexes derived from 2,6-diaminopyridine and isatin with their antibacterial and spectroscopic studies.

Condensation reaction of 2,6-diaminopyridine with isatin in the presence of divalent metal ions results in the formation of the macrocyclic complexes of the type [M(C(26)H(16)N(8))X(2)], where M=Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and X=Cl(-), NO(3)(-), CH(3)COO(-). The complexes have been characterized with the aid of elemental analyses, conductance measurements, electronic, NMR, infrared and EPR spectral studies. The lower values of molar conductance indicate them to be non-electrolytes. On the basis of these studies, a six coordinate distorted octahedral geometry in which four nitrogen atoms are suitably placed for coordination towards metal ion, has been proposed for all the complexes. The complexes were tested for their in vitro antibacterial activity. Some of the complexes showed good antibacterial activities against some selected bacterial strains.

Synthesis, spectroscopic, and antibacterial activity of tetraazamacrocyclic complexes of trivalent chromium, manganese, and iron.

A new series of macrocyclic complexes of type [M(TML)X]X(2), where M = Cr(III), Mn(III), or Fe(III), TML is tetradentate macrocyclic ligand, and X = Cl(-), NO(3)(-), CH(3)COO(-) for Cr(III), Fe(III) and X = CH(3)COO(-) for Mn (III), has been synthesized by condensation of benzil and succinyldihydrazide in the presence of metal salt. The complexes have been so formulated due to the 1:2 electrolytic nature of these complexes as shown by conductivity measurements. The complexes have been characterized with the help of various physicochemical techniques such as elemental analysis, molar conductance, electronic and infrared spectral studies, and magnetic susceptibility. On the basis of these studies, a five-coordinate distorted square pyramidal geometry, in which two nitrogens and two carbonyl oxygen atoms are suitably placed for coordination toward the metal ion, has been proposed for all the complexes. The complexes have been tested for their in vitro antibacterial activity. Some of the complexes show remarkable antibacterial activities against some selected bacterial strains. The minimum inhibitory concentrations shown by these complexes have been compared with those shown by some standard antibiotics such as linezolid and cefaclor.

Template synthesis, spectroscopic studies and biological activities of macrocyclic complexes derived from thiocarbohydrazide and glyoxal.

A novel series of complexes of the type [M(TML)X2]; where TML is Tetradentate Macrocyclic Ligand; M = Co(II), Ni(II), Cu(II), Zn(II)or Cd(II); X = Cl-, CH3COO- or NO3- have been synthesized by template condensation of glyoxal and thiocarbohydrazide in the presence of divalent metal salts in methanolic medium. The complexes have been characterized by elemental analyses, conductance measurements, molecular weight determination, magnetic measurements, electronic, NMR, infrared and far infrared spectral studies. Electronic spectra along with magnetic moments suggest a six coordinate octahedral geometry for these complexes. The low molar conductance values indicates them to be non-electrolytes. The biological activities of the metal complexes have been tested in vitro against a number of pathogenic bacteria to assess their inhibitory potential.