Template synthesis of macrocyclic complexes and their spectroscopic and antibacterial studies

A new series of macrocyclic complexes of type [M(TML)X]X₂, where M = Cr(III), Fe(III), TML is tetradentate macrocyclic ligand, and X = Cl^?, NO₃^?, CH₃COO^?, have been synthesized by condensation of isatin and ethylenediamine in the presence of metal salt. The complexes were synthesized by both conventional and microwave methods. The complexes have been characterized with the help of elemental analysis, conductance measurement, magnetic measurement, and infrared, far infrared, and electronic spectral studies. Molar conductance values indicate them to be 1:2 electrolytes. Electronic spectra along with magnetic moments suggest five-coordinate square pyramidal geometry for these complexes. The complexes were also tested for their in vitro antibacterial activity. Some of the complexes showed satisfactory antibacterial activitiy.     

Biologically active macrocyclic complexes derived from diaminonaphthalene and glyoxal: Template synthesis and spectroscopic approach

A novel series of complexes of the type [M(C(24)H(16)N(4))X(2)]; where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); X = Cl(-1), NO(-1)(3), CH(3)COO(-1) has been synthesized by template condensation of 1,8-diaminonaphthalene and glyoxal 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. 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 and antifungal activities to assess their inhibiting potential.     

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]X₂, where M = Cr(III), Mn(III), or Fe(III), TML is tetradentate macrocyclic ligand, and X = Cl^?, NO₃^?, CH₃COO^? for Cr(III), Fe(III) and X = CH₃COO^? 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.     

Antibacterial activity and spectral studies of trivalent chromium, manganese, iron macrocyclic complexes derived from oxalyldihydrazide and glyoxal

A new series of complexes is synthesized by template condensation of oxalyldihydrazide and glyoxal in methanolic medium in the presence of trivalent chromium, manganese and iron salts forming complexes of the type: [M(C(8)H(8)N(8)O(4))X]X(2) where M = Cr(III), Mn(III), Fe(III) and X = Cl(-1), NO(-1)(3), CH(3)COO(-1). The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic susceptibility measurements, electronic, NMR, infrared and far infrared spectral studies. On the basis of these studies, a five coordinate square pyramidal geometry for these complexes has been proposed. The biological activities of the metal complexes were tested in vitro against a number of pathogenic bacteria and some of the complexes exhibited remarkable antibacterial activities.     

Biologically active macrocyclic complexes derived from diaminonaphthalene and glyoxal: Template synthesis and spectroscopic approach

A novel series of complexes of the type [M(C₂₄H₁₆N₄)X₂]; where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); X = Cl^{? 1}, , CH₃COO^{? 1} has been synthesized by template condensation of 1,8-diaminonaphthalene and glyoxal 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. 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 and antifungal activities to assess their inhibiting potential.     

Synthesis, characterization and antitumor properties of some metal complexes of 3- and 5-substituted salicylaldehyde 2-pyridinylhydrazones

Complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Pt(II) with 3- and 5-substituted salicylaldehyde 2-pyridinylhydrazones (XSPH, X = H, 3-NO2, 3-CH3O, 5-Br, 5-Cl, 5-CH3, or 5-NO2) have been prepared and characterized by elemental analysis, conductance measurements, magnetic moments (300-78 K), and spectral studies. On the basis of these studies a monomeric, high-spin, distorted octahedral structure for Mn(XSPH)2 and Fe(XSPH)2, a dimeric, high-spin, five-coordinate structure for Co(XSBH)Cl, a dimeric, low-spin, five-coordinate structure for Ni(XSPH)Cl and Zn(XSPH)(OAc), and a square-planar structure for M(XSPH)Cl.H2O (M = Cu(II) or Pt(II] complexes are suggested. The polycrystalline ESR spectra of Cu(II) complexes are isotropic and suggest dx2-y2 ground state in square-planar stereochemistry. M?ssbauer spectral results indicate distorted octahedral structure for iron(II) complexes. All the metal(II) complexes have been screened for their antitumor activity against P388 lymphocytic leukemia test system in mice and have been found to possess no significant activity at the dosages used.     

Synthesis,physico-chemical characterization and antimicrobial activity of cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes with some acyldihydrazones

Complexes of the type [M(bssdh)]Cl and [M(dspdh)]Cl, where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); Hbssdh = benzil salicylaldehyde succinic acid dihydrazone, Hdspdh = diacetyl salicylaldehyde phthalic acid dihydrazone have been synthesized and characterized with the help of elemental analyses, electrical conductance, magnetic susceptibility measurements, electronic, ESR and IR spectra and X–ray diffraction studies. Magnetic moment values and electronic spectral transitions indicate a spin free octahedral structure for Co(II), Ni(II) and Cu(II) complexes. IR spectral studies suggest that both the ligands behave as monobasic hexadentate ligands coordinating through three > C = O, two > C = N– and a phenolate group to the metal. ESR spectra of Cu(II) complexes are axial type and suggest as the ground state. X–ray powder diffraction parameters for [Co(bssdh)]Cl and [Co(dspdh)]Cl complexes correspond to an orthorhombic crystal lattice. The ligands as well as their metal complexes show a significant antifungal and antibacterial activity against various fungi and bacteria. The metal complexes are more active than the parent ligands.     

Antibacterial activity and spectral studies of trivalent chromium,manganese, iron macrocyclic complexes derived from oxalyldihydrazide and glyoxal

A new series of complexes is synthesized by template condensation of oxalyldihydrazide and glyoxal in methanolic medium in the presence of trivalent chromium, manganese and iron salts forming complexes of the type: [M(C₈H₈N₈O₄)X]X₂ where M = Cr(III), Mn(III), Fe(III) and X = Cl^{? 1}, , CH₃COO^{? 1}. The complexes have been characterized with the help of elemental analyses, conductance measurements, magnetic susceptibility measurements, electronic, NMR, infrared and far infrared spectral studies. On the basis of these studies, a five coordinate square pyramidal geometry for these complexes has been proposed. The biological activities of the metal complexes were tested in vitro against a number of pathogenic bacteria and some of the complexes exhibited remarkable antibacterial activities.     

Synthesis, characterization and antibacterial properties of some trivalent metal complexes with [(2-hydroxy-1-naphthaldehyde)-3-isatin]-bishydrazone

Complexes of manganese(III), iron(III) and cobalt(III) with a bishydrazone, formed by condensation of isatin monohydrazone with 2-hydroxy-1-naphthaldehyde, have been synthesized. The spectral data reveal that the ligand acts as monobasic tridentate, coordinating through the deprotonated naphtholate oxygen, azomethine nitrogen, and carbonyl oxygen. Molar conductance values adequately support the electrolytic nature of the complexes. On the basis of the above observations the complexes have been formulated as [M(NIB)2]X where M = Mn(III), Fe(III) or Co(III); X = Cl-, NO3(-); or OAc-; HNIB = [(2-hydroxy-1-naphthaldehyde)-3-isatin]-bishydrazone. Based on electronic spectral data and magnetic moment values, an octahedral geometry has been proposed. The iron(III) complex has been subjected to thermal decomposition studies. The ligand and the metal complexes have been screened for their antibacterial activity and it has been observed that the complexes are more potent bactericides than the ligand.     

Synthesis, physico-chemical characterization and antimicrobial activity of cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes with some acyldihydrazones

Complexes of the type [M(bssdh)]Cl and [M(dspdh)]Cl, where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II); Hbssdh = benzil salicylaldehyde succinic acid dihydrazone, Hdspdh = diacetyl salicylaldehyde phthalic acid dihydrazone have been synthesized and characterized with the help of elemental analyses, electrical conductance, magnetic susceptibility measurements, electronic, ESR and IR spectra and X-ray diffraction studies. Magnetic moment values and electronic spectral transitions indicate a spin free octahedral structure for Co(II), Ni(II) and Cu(II) complexes. IR spectral studies suggest that both the ligands behave as monobasic hexadentate ligands coordinating through three > C = O, two > C = N- and a phenolate group to the metal. ESR spectra of Cu(II) complexes are axial type and suggest d(x(2)-y(2)) as the ground state. X-ray powder diffraction parameters for [Co(bssdh)]Cl and [Co(dspdh)]Cl complexes correspond to an orthorhombic crystal lattice. The ligands as well as their metal complexes show a significant antifungal and antibacterial activity against various fungi and bacteria. The metal complexes are more active than the parent ligands.     

Structural and microbial studies of some transition metal complexes

N-pyridinobenzamide-2-carboxylic acid has been synthesized. Its binary and ternary (using 8-hydroxy-quinoline as the other ligand) Cu(II), Ni(II), Co(II), and Zn(II) complexes have been synthesized and characterized by their elemental analysis, molecular weight determination, molar conductance, infrared and electronic spectral data, and magnetic measurements. Antibacterial activity of these ligands and their metal complexes has been determined on gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria at 37 degrees C, and antifungal activity has been determined on common fungi viz. Aspergillus niger, Aspergillus nidulense, and Candida albicans at 28 degrees C. A considerable increase in the biocidal activity of these ligands on being coordinated with metal ions has been reported.     

Syntheses and anti-inflammatory activity of diphenylamine-2,2'-dicarboxylic acid and its metal complexes

Diphenylamine-2,2'-dicarboxylic acid and its Cu(II), Ni(II), Co(II) and Zn(II) complexes have been synthesized and characterized by their elemental analyses, molecular weight determination, molar conductance, infrared and electronic spectra and magnetic measurements. The Zinc complex was tested by different methods for its anti-inflammatory activity and found to be equipotent to naproxen and ibuprofen, though at higher doses.     

Mononuclear and dinuclear complexes derived from new potentially heptadentate acyclic Schiff bases

New potentially heptadentate compartmental ligands have been prepared by reaction of o-acetoacetylphenol or 3-formylsalycilic acid with diethylenetriamine or bis-3-aminopropyl-phenylphosphine.These Schiff bases contain an inner O₂N₂X (X = N, P) and an outer O₂O₂ coordination site which can bond, in close proximity, two similar or dissimilar metal ions.With some metal salts (nickel(II), copper(II) and uranyl(VI) acetates) mononuclear, homo- and heterodinuclear complexes have been synthesized. The spectroscopic, magnetic and electrochemical properties of these complexes have been studied. The catalytic activity of a binuclear copper(II) complex towards the oxidation of 3,5-di-t-butylcatechol to the corresponding quinone was also investigated.     

Complexes of a macrocyclic ligand having both mono- and binucleating capability: binuclear Mn(II), Fe(II), Co(II), Ni(II), Zn(II) complexes

Bi-nuclear complexes of 28- atom membered macrocycles derived from 2,6-diacetyl pyridine and the amines 3,3′-diamino dipropylamine or 3,3′-diamino-N-methyl dipropylamine have been prepared by template synthesis on Ag⁺ or Pb²⁺. Template synthesis can also be accomplished, in the case of 3,3′-diamino dipropylamine, but not its N-methyl derivative, on Gp(II) metal ions, with accompanying rearrangement of the macrocycle. All the complexes produced by template synthesis can be transmetallated with the first transition series metal ions M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) to give binuclear and in some cases, mononuclear, derivatives. The binuclear complexes show no evidence of magnetic exchange interaction from magnetic susceptibility measurements in the range 93-300 K. The cyclovoltammetric behaviour of mono- and bi-nuclear Fe(II) complexes is compared.     

Synthesis, physico-chemical studies of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes with some p-substituted acetophenone benzoylhydrazones and their antimicrobial activity

Complexes of the type [M(pabh)(H2O)Cl], [M(pcbh)(H2O)Cl] and [M(Hpabh)(H2O)2 (SO4)] where, M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); Hpabh = p-amino acetophenone benzoyl hydrazone and Hpcbh = p-chloro acetophenone benzoyl hydrazone have been synthesized and characterized with the help of elemental analyses, electrical conductance, magnetic susceptibility measurements, electronic, ESR and IR spectra, thermal (TGA & DTA) and X-ray diffraction studies. Co(II), Ni(II) and Cu(II) chloride complexes are square planar, whereas their sulfate complexes have spin-free octahedral geometry. ESR spectra of Cu(II) complexes with Hpabh are axial and suggest d(x(2)-y(2) as the ground state. The ligand is bidentate bonding through > C = N--and deprotonated enolate group in all the chloro complexes, whereas, >C = N and >C = O groups in all the sulfato complexes. Thermal studies (TGA & DTA) on [Cu(Hpabh)(H2O)2(SO4)] indicate a multistep decomposition pattern, which are both exothermic and endothermic in nature. X-ray powder diffraction parameters for [Co(pabh)(H2O)Cl] and [Ni(Hpabh)(H2O)2(SO4)] correspond to tetragonal and orthorhombic crystal lattices, respectively. The ligands as well as their complexes show a significant antifungal and antibacterial activity. The metal complexes are more active than the ligand.     

Inhibitory activity of palladium(II) and platinum(II) complexes with isoxazole and its derivatives

The investigation of the inhibitory activity on the membrane bonded ATP-ase of the M(L)₂X₂ complexes [where M = Pd(II), Pt(II); L = isoxazole(isox), 3,5-dimethylisoxazole(3,5-diMeisox), 3-methyl,5-phenylisoxazole(3-Me,5-Phisox), 3,5-diphenylisoxazole-(3,5-diPhisox), and 4-amino-3,5-dimethylisoxazole(4-ADI); X = Cl, Br] is reported. These results show that the complexes with isox and its methyl and phenyl derivatives have a much stronger inhibitory effect than the corresponding free ligands; in the 4-ADI compounds this activity drops. The Pd(II) complexes have a greater effect than the Pt(II) derivatives. The interaction occurs with SH groups and probably also with other active centers of the enzyme. These conclusions have been correlated with the E.S.C.A. spectra. These measurements show that the electron density of the complexes on the central metal ion and N_ring atom or N_ring and N-hexocyclic atoms on passing from chloride to bromide derivatives changes slightly.     

Transition metal complexes with N, S donor ligands as synthetic antioxidants: synthesis, characterization and antioxidant activity

Transition metal complexes containing bidentate N, S donor ligands i.e., carvone thiosemicarbazone [(RS)-5-isopropenyl-2-methylcyclohex-2-en-1-one thiosemicarbazone (IPMCHTSC)] and carvone N(1)-phenylthiosemicarbazone [(RS)-5-isopropenyl-2-methylcyclohex-2-en-1-one phenylthiosemicarbazone (IPMCHPhTSC)] have been synthesized. All the metal complexes (1-8) have been characterized by elemental analysis, molar conductance measurement and various spectral studies [infrared (IR), electronic, fast-atom bombardment (FAB) mass and NMR (for ligands)] and thermogravimetric analysis. FAB mass spectroscopic studies of (1), (3), (4), (5), (6) (7), and (8) suggest their monomeric nature. Metal complexes are [M(LH)Cl(2)] and [M(LH)(2)Cl(2)] type, where M?=?Fe(III), Co(II), and Cu(II) and LH?=?IPMCHTSC and IPMCHPhTSC. The proposed geometries of the complexes were octahedral for 1:2 complexes, square planar for 1:1 complexes and distorted octahedral for Cu(II) complexes (1:2). The free radical scavenging activity of ligands (IPMCHTSC and IPMCHPhTSC) and their metal complexes have been determined at the concentration range of 10-400 μg/mL by means of their interaction with the stable free radical 2,2'-diphenyl-1-picrylhydrazyl and 5-200 μg/mL by 2,2'-Azinobis-3-ethylbenzothiazoline-6-sulphonic acid. All the compounds have shown encouraging antioxidant activities.     

In vitro antileukemia, antibacterial and antifungal activities of some 3d metal complexes: chemical synthesis and structure - activity relationships

The present paper describes the synthesis, characterization and in vitro biological evaluation screening of different classes (ammoniacates, dioximates, carboxylates, semi- and thiosemicarbazidates) of Co(II), Co(III), Cu(II), Ni(II), Mn(II), Zn(II) and Fe(III) complexes. Schiff bases were obtained from the reaction of some salicyl aldehydes with, respectively, furoylhydrazine, benzoylhydrazine, semicarbazide, thiosemicarbazide and S-methylthiosemicarbazide to give tridentate ligands containing ONO, ONS or ONN as donor atoms. The synthetic metal complexes are of various geometrical and electronic structures, thermodynamic and thermal stabilities, and magnetic and conductance properties. All complexes, except those of Cu, are octahedral. Some Cu, Co and Mn compounds have a dimeric or a polymeric structure. The composition and structure of complexes were analysed by elemental analysis, IR and (1)H NMR and (13)C NMR spectroscopies, and magnetochemical, thermoanalytical and molar conductance measurements. All ligands and metal complexes were tested as inhibitors of human leukemia (HL-60) cells growth, and the most potent, the Cu(II) complexes, have been also tested for their in vitro antibacterial and antifungal activities. Structure-activity relationships were carried out.     

N-(2-Pyridyl)acetamide complexes of palladium(II), cobalt(II), nickel(II), and copper(II)

N-(2-Pyridyl)acetamide (aapH) complexes of palladium(II), cobalt(II), nickel(II), and copper(II) have been studied by means of magnetic susceptibilities, and infrared, electronic, and PMR spectra. In the octahedral complexes M(aapH)₂X₂(M = Co, Ni, Cu; X = Cl, Br, NCS, NO₃), bidentate aapH is chelated through the pyridine-N and amid-O atomes, whereas in the square-planar Pd(aapH)₂X₂ (X = Cl, Br) unidentate aapH is coordinated through the pyridine-N atom alone. Under alkaline conditions aapH is deprotonated in the presence of palladium(II) to form Pd(aap)₂·4H₂O, aap being an anionic bidentate ligand and chelating through the pyridine-N and amide-O atoms.