Template synthesis, spectroscopic studies and biological screening of macrocyclic complexes derived from thiocarbohydrazide and benzil

A novel series of complexes of the type [M(TML)X₂]; where TML is a tetradentate macrocyclic ligand; M = Co(II), Ni(II), Cu(II) or Zn(II); X = Cl⁻, CH₃COO⁻ or NO ₃ ⁻ have been synthesized by template condensation of benzil and thiocarbohydrazide in the presence of divalent metal salts in methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, molecular weight determination, magnetic measurements, electronic, NMR, infrared and far infrared spectral studies. Electronic spectra along with magnetic moments suggest the six coordinate octahedral geometry for these complexes. The low value of molar conductance indicates them to be non-electrolytes. The biological activities of metal complexes have been tested in vitro against a number of pathogenic bacteria to assess their inhibiting potential.     

Template synthesis and characterization of N<Subscript>6</Subscript> 12-membered macrocyclic complexes derived from isatin and ethylenediamine

Novel series of complexes of the type [M(TML)X₂], where TML is a tetradentate macrocyclic ligand; M = Co(II), Ni(II), Cu(II), Zn(II); X = Cl⁻, NO₃⁻, CH₃COO⁻, have been synthesized by template condensation of isatin and ethylenediamine in the presence of divalent metal salts in a methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, molecular weight determination, magnetic measurements, NMR, infrared and far infrared spectral studies. The low value of molar conductance indicates them to be nonelectrolytes. All the complexes are supposed to have distorted octahedral geometry. The text was submitted by the authors in English.     

Synthesis and spectral and antibacterial studies of bivalent transition metal ion macrocyclic complexes

A new series of the macrocyclic complexes of type [M(C₁₈H₁₆N₄O₂)X₂], where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and X = Cl⁻, NO₃⁻, CH₃COO₋, has been synthesized by the condensation of succinyldihydrazide with benzil in the presence of bivalent metal ions. The complexes have been characterized with the aid of elemental analyses, conductance measurements, and electronic, NMR, and infrared spectral studies. On the basis of these studies, a six-coordinate distorted octahedral geometry in which two nitrogen and two carbonyl oxygen atoms are suitably placed for coordination toward metal ion has been proposed for all the complexes. The complexes were tested for their in vitro antibacterial activity. Some of the complexes showed remarkable antibacterial activity against some selected bacterial strains.     

Synthesis,spectroscopic studies,and antibacterial activities of 14-membered tetraazamacrocyclic complexes of divalent transition metal ions

A new series of macrocyclic complexes, [M(C₄₈H₃₂N₄)X₂], where M?=?Co(II),?Ni(II),?Cu(II), and Zn(II); X?=?Cl^?,?NO₃ ^?,?CH₃COO^?, have been synthesized by condensation of 1,8-diaminonaphthalene and benzil, in the presence of divalent metal salts in methanolic medium. The complexes have been characterized by elemental analyses, conductance measurements, magnetic measurements, and electronic, NMR, IR, and MS spectral studies. The low value of molar conductance indicates the presence of non-electrolytes. A distorted octahedral geometry is proposed for the complexes. The metal complexes were also tested for their in vitro antibacterial activities against some bacterial strains and compared with the standard antibiotic Ciprofloxacin. Some tested complexes show good antibacterial activities against some bacterial strains.     

Synthesis and spectral study of biologically active macrocyclic complexes of divalent transition metal ions

The condensation reaction of succinyldihydrazide with glyoxal in the presence of divalent metal ions (1: 1: 1) results in the formation of the complexes of type [M(C₆H₈N₄O₂)X₂], where M = Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and X = Cl⁻, NO₃⁻, CH₃COO⁻. The complexes have been characterized with the aid of elemental analyses, conductance measurements and electronic, NMR, infrared spectral studies. On the basis of these studies, a six-coordinated distorted octahedral geometry in which two nitrogen and two carbonyl oxygen atoms are suitably placed for coordination toward metal ion, has been proposed for all the complexes. The complexes were tested for their in vitro antibacterial activity. Some of the complexes showed remarkable antibacterial activities against some selected bacterial strains.     

Synthesis,structural characterization,and antibacterial studies of a tetradentate macrocyclic ligand and Its Co(II), Ni(II), and Cu(II) complexes

A novel macrocyclic tetradentate ligand 1,5,8,12-tetraaza-2,4,9,11-tetraphenyl-6,7:13,14-dibenzocyclohexadeca- 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 NO₃⁻). 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 Staphylococcus aureus. The metal complexes have higher activity than the free ligand and metal salts. The text was submitted by the authors in English.     

Spectroscopic and antimicrobial studies of macrocyclic metal complexes derived from 1,8-diaminonaphthalene and dimedone

A new series of macrocyclic metal complexes have been synthesized and characterized by the template condensation reaction of 1,8-diaminonaphthalene and dimedone in presence of divalent transition metals, resulting into the formation of the macrocyclic complexes of the type: [M(C₃₆H₃₆N₄)X₂]; where M = Co(II), Ni(II), Cu(II), Zn(II) and X = Cl^?, NO₃ ^?, CH₃COO^?. The synthesized macrocyclic complexes have been characterized with the aid of elemental analysis, conductance measurements, magnetic susceptibility measurements, electronic, infrared, NMR, Mass and ESR spectral studies. The complexes were also investigated for their fluorescence activity. Electronic spectra along with magnetic moments suggest the six coordinated octahedral geometry for all these complexes. The low value of molar conductance indicates them to be non-electrolyte. The in vitro antimicrobial activities of these macrocyclic complexes have also been investigated against some bacterial strains and yeast. Further minimum inhibitory concentration shown by these complexes against these pathogens was compared with MIC shown by standard antibiotic and standard antifungal drug.     

Spectroscopic studies and antibacterial activities of some new 16-membered octaazamacrocyclic complexes derived from thiocarbohydrazide and pentane-2,4-dione

A series of macrocyclic complexes of the type [M(C12H20N8S2)X2]; where M=Co(II), Ni(II), Cu(II), Zn(II); X=Cl-, NO3-, CH3COO- has been synthesized by template condensation of thiocarbohydrazide and pentane-2,4-dione in the presence of divalent metal salts in methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic measurements, electronic, NMR, IR, EPR and MS spectral studies. The low value of molar conductance indicates them to be non-electrolytes. On the basis of various studies a distorted octahedral geometry may be proposed for all of these complexes. These metal complexes were also tested for their in vitro antibacterial activities against some Gram-positive bacterial strains, i.e., Bacillus subtilis, Bacillus stearothermophilus and two Gram-negative bacterial strains, i.e., Escherichia coli, Pseudomonas putida. The results obtained were compared with standard antibiotics, Chloramphenicol and Streptomycin and found that some of the synthesized complexes show good antibacterial activities as compared to the standard antibiotics.     

Synthesis and characterization of complexes of Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) with macrocycle 3,4,11,12-tetraoxo-1,2,5,6,9,10,13,14-octaaza-cyclohexadeca-6,8,14,16-tetraene and their biological screening

A new series of complexes is synthesized by template condensation of glyoxal and oxalyldihydrazide in methanolic medium in the presence of divalent cobalt, nickel, copper, zinc and cadmium salts forming complexes of the type: [M(C₈H₈N₈O₄)X₂] where M = Co^(II), Ni^(II), Cu^(II), Zn^(II), Cd^(II) and X = Cl⁻¹, Br⁻¹, NO ₃ ⁻¹ , OAc⁻¹. The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic susceptibility measurements, electronic, n.m.r., infrared and far infrared spectral studies. On the basis of these studies, a six coordinate octahedral geometry for these complexes has been proposed. The biological activities of the metal complexes have been tested in vitro against a number of pathogenic bacteria to assess their inhibiting potential. Most of the compounds have been found to exhibit remarkable antibacterial activities.     

Physicochemical and Biological Characterization of Transition Metal Complexes with a Nitrogen Donor Tetra-dentate Novel Macrocyclic Ligand

A novel tetradentate nitrogen donor [N₄] macrocyclic ligand, i.e. 3,5,13,15,21,22-hexaaza-2,6,12,16-tetramethyl-4,14-dithia-tricyclo[15.3.1.1(7–11)]docosane-1(21),2,5,7,9,11(22),12,15,17,19-decaene, has been synthesized. Mn(II), Co(II), Ni(II) and Cu(II) complexes with this ligand have been prepared and subjected to elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H-n.m.r. (Ligand), i.r., electronic, and e.p.r. spectral studies. On the basis of molar conductance the complexes may be formulated as [M(L)X₂] and [Ni(L)]X₂ [where M = Mn(II), Co(II) and Cu(II), and X = Cl⁻ and NO₃⁻] due to their nonelectrolytic nature in dimethylsulphoxide (DMSO). All the complexes are of the high spin type and are six coordinated. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry has been assigned to Mn(II) and Co(II), square planar for Ni(II) complexes, and tetragonal for Cu(II) complexes. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against several species of bacteria and plant pathogenic fungi.     

Synthesis spectroscopic and biological approach in the characterization of novel [N<Subscript>4</Subscript>] macrocyclic ligand and its transition metal complexes

A novel tetradentate nitrogen donor [N₄] macrocyclic ligand, i.e. 1,3,4,8,9,11-hexaaza-2,10-dithia-5,12-dioxo-7,14-diphenyl-cyclotetradecane (L), has been synthesized. Manganese(II),cobalt(II), nickel(II) and copper(II) complexes with this ligand have been prepared and subjected to elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H-n.m.r. (Ligand), i.r., electronic, and e.p.r. spectral studies. On the basis of molar conductance the complexes may be formulated as [M(L)X₂] [where M = Mn^II, Co^II, Ni^II, and Co^II,and X = Cl⁻ & NO ₃ ⁻ ] due to their nonelectrolytic nature in dimethylformamide (DMF). All the complexes are of the high spin type and are six coordinated. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry has been assigned to Mn^II, and ^II, ^II, complexes, and tetragonal for copper(II) complexes. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against several species of bacteria and plant pathogenic fungi.     

Modern spectroscopic and biological approach in the characterization of a novel 14-membered [N<Subscript>4</Subscript>] macrocyclic ligand and its transition metal complexes

A novel tetradentate nitrogen donor [N₄] macrocyclic ligand, i.e. 1,3,4,8,9,11-hexaaza-2,5,10,12-tetraoxo-7,14-diphenyl-cyclotetradecane (L), has been synthesized. Mn(II), Co(II), Ni(II) and Cu(II) complexes of this ligand have been prepared and subjected to elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, ¹H-n.m.r. (Ligand), i.r., electronic, and e.p.r. spectral studies. On the basis of molar conductance the Mn(II), Co(II) and Cu(II) complexes may be formulated as [M(L)X₂] [where X = Cl⁻ & NO ₃ ⁻ ] due to their non-electrolytic nature in dimethylformamide (DMF). Whereas the Ni(II) complexes are 1:2 electrolytes and formulated as [Ni(L)]X₂. All the complexes are of the high spin type and are six/four coordinate. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry has been assigned to Mn(II) and Co(II), square planar for Ni(II) complexes, and tetragonal for Cu(II) complexes. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against several species of bacteria and plant pathogenic fungi.     

Synthesis and spectroscopic characterization of transition metal complexes of a 12-membered tetraaza [N<Subscript>4</Subscript>] macrocyclic ligand and their biological activity

Cobalt(II), nickel(II) and copper(II) complexes are synthesized with 1,3,7,9-tetraaza- 4,6,10,12-tetraphenyl-2,8-dithiacyclododecane, a tetradentate ligand (L) and characterized by elemental analysis, molar conductance measurements, magnetic susceptibitity measurements, mass, i.r., electronic and e.p.r. spectral studies. All the complexes are non-electrolytes so they may be formulated as [M(L)X₂] [where, M = Co(II), Ni(II) and Cu(II) and X = Cl⁻ and NO ₃ ⁻ ]. All the complexes are of high spin type. On the basis of i.r., electronic and e.p.r. spectral studies an octahedral geometry has been assigned for Co(II) and Ni(II) complexes and tetragonal geometry for Cu(II) complexes. The antimicrobial activities of the ligand and its complexes, as growth inhibiting agents, have been screened in vitro against two different species of bacteria and plant pathogenic fungi.     

Synthesis,spectral, and antifungal studies of transition metal complexes with sixteen-membered hexadentate macrocylic ligand

A novel hexadentate nitrogen donor [N₆] macrocyclic ligand viz, 1,5,11,15,21,22-hexaaza-2,14-dimethyl-l4,12-diphenyltricyclo[15.3.1.I(7–11)]docosane[1,4,6,8,10(22)-11,14,16,18,20(21)]decaene (L), has been synthesised. The Co (II), Ni (II), and Cu (II) complexes with this ligand have been prepared and subjected to elemental analysis, molar conductance, magnetic susceptibility measurements, mass, ¹H NMR (ligand), IR, electronic, and ESR spectral studies and electrochemical investigation. On the basis of molar conductance the complexes can be formulated as [M(L)]X₂ (where M = Co (II), Ni (II), Cu (II) and X = Cl⁻ and NO₃⁻) due to their 1: 2 electrolytic nature in DMSO. All the complexes are of the high-spin type and are six-coordinated. On the basis of IR, electronic, and ESR spectral studies, an octahedral geometry has been assigned for the Co(II) and Ni(II) complexes, whereas a tetragonal geometry for the Cu(II) complexes was found. Antimicrobial activity of L and its complexes as growth inhibiting agents have been screened in vitro against two species (F. moniliformae and R. solani) of plant pathogenic fungi. The text was submitted by the authors in English.     

Synthesis,structural, and biological studies of some bivalent metal ion complexes with the tridentate Schiff base ligand

New complexes of a Schiff base derived from 2-hydroxy-5-chloroacetophenone and glycine with Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and UO₂(VI) have been synthesized. The ligand and the complexes have been characterized on the basis of analytical data, electrical conductance, IR, ESR, and electronic spectra, magnetic susceptibility measurements and thermogravimetric analysis. The ligand acts as a dibasic tridentate (ONO) donor molecule in all the complexes except the Zn(II) complex, where it acts as a monobasic bidentate (OO) donor. Antibacterial activities of the ligand and its metal complexes have been determined by screening the compounds against various Gram(+) and Gram(−) bacterial strains. The solid state d.c. electrical conductivity of the ligand and its complexes has been measured over 313–398 K and the complexes were found to be of semiconducting nature. The article is published in the original.     

Synthesis,characterization and antimicrobial activity of a new macrocycle and its transition metal complexes

The semicarbazone (L¹) has been prepared by reaction of semicarbazide and glutaraldehyde (2 : 1) in distilled water and methanol (1 : 1). The reaction of semicarbazide, glutaraldehyde and diethyl oxalate in distilled water and methanol gave Schiff-base L², 1,2,4,7,9,10-hexaazacyclo-pentadeca-10,15-dien-3,5,6,8-tetraone. Complexes of first row transition metal ions Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) have also been synthesized. The ligand and its complexes were characterized by elemental analysis, molar conductance, magnetic moment measurements, IR, ¹H NMR, UV–Visible spectra and thermogravimetric analysis (TGA). Molar conductance values show that the complexes of Ni(II), Cu(II), Zn(II), Mn(II) and Co(II) are 1 : 2 electrolytes. On the basis of electronic spectral studies and molar conductance measurements an octahedral structure has been proposed for Mn(II) and Co(II) complexes, tetrahedral for Zn(II) complex and square planar for Ni(II) and Cu(II). The thermal behavior of the compounds, studied by TGA in a nitrogen atmosphere up to 800°C, reveal that the complexes have higher thermal stability than the macrocycle. All the synthesized compounds and standard drugs kanamycin (antibacterial) and miconazole (antifungal) have been screened against bacterial strains Staphylococcus areus, Escherichia coli and fungal strains Candida albicans, Aspergillus niger. The metal complexes inhibit growth of bacteria to a greater extent than the ligand.     

Synthesis,spectral and antimicrobial studies of transition metal complexes with novel macrocyclic ligand containing C=N and CO–NH group

This article reports synthesis of Co(II), Ni(II), Mn(II), Cu(II), and Zn(II) complexes with a new macrocyclic ligand 1,4,11,14-tetraazacyclonanodeca-5,10-dioxo-1,14-diene (H₂L). The ligand (L₁) was prepared by reaction of adipic acid and ethylenediamine in 1 : 2 ratio while the macrocycle was derived from 1,4-bis-(2′-amino-ethanamide)butane and glutaraldehyde. The synthesized complexes were characterized by elemental analysis, molar conductance, spectral analyses (¹H NMR spectra, FT-IR spectra, electronic spectra, and mass spectra), magnetic susceptibility measurements, and thermogravimetric studies. On the basis of electronic spectral studies and molar conductance measurements, octahedral geometry was confirmed for Ni(II), Mn(II), and Co(II) while tetrahedral for Zn(II) and square planar for Cu(II) complexes. The TGA results revealed that the complexes exhibited higher thermal stability than the macrocycle. All the complexes were screened against bacterial and fungal strains and preliminary antimicrobial results showed that these complexes inhibited bacterial/fungal growth to a greater extent than the ligand.     

New 14-membered octaazamacrocyclic complexes of divalent transition metal ions with their antimicrobial and spectral studies

A novel series of macrocyclic complexes of the type [M(C₁₈H₁₄N₁₀S₂)X₂]; where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); X = Cl^?, NO₃^?, CH₃COO^? has been synthesized by [2+2] condensation of thiocarbohydrazide and isatin in the presence of divalent metal salts in methanolic medium. The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic measurements, electronic, NMR and infrared spectral studies. The low value of molar conductance indicates them to be non-electrolytes. On the basis of various studies a distorted octahedral geometry may be proposed for all of these complexes. These metal complexes were also tested for their in vitro antimicrobial activities against some Gram-positive bacteria viz.Staphylococcus aureus, Bacillus subtilis, and some Gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa and some fungal strains Aspergillus niger, Aspergillus flavus (molds), Candida albicans, Saccharomyces cerevisiae (yeasts). The results obtained were compared with standard antibiotic: Ciprofloxacin and the standard antifungal drug: Amphotericin-B.