scholarly journals Cis-Dioxomolybdenum (VI) Complexes with N-donor Macrocyclic Ligands

2021 ◽  
Vol 12 (1) ◽  
pp. 1352-1364

The preparation of one monomeric [MoO2(L)](acac)2 having a Schiff base came by condensation of di-2-furanylethanedione with 2,3-diaminotoluene and 4 different complexes having formulation [MoO2(ML)](acac)2, from the result of [MoO2(L)](acac)2 with 1,3-diketones will be described with this paper. The preparation of each of these five MoO2 (VI) complexes was symbolized by thermal studies, UV-Vis, IR, elemental analyses, NMR, and molar conductance. The coordination number of molybdenum metal will be six. All 5 complexes of MoO2(VI) have a geometry of distorted octahedral arrangement. The octahedral arrangement of Mo-metal in prepared complexes is finished by 2 oxo O-atoms and 4 N-atoms from the synthesized ligand. All of the synthesized complexes demonstrated moderate action against S. aureus and S. typhi. The progression inside the antibacterial task being defined on the thought of chelation speculation.

2019 ◽  
Vol 31 (11) ◽  
pp. 2607-2612
Author(s):  
Ramesh Kumar Gautam ◽  
Chandra Prakash Singh ◽  
Shiv Govind Prasad ◽  
Rajul Saxena ◽  
Devendra Pratap Rao

A new MoO2(VI) complex of formulation [MoO2(L)](acac)2 prepared by a Schiff base, synthesized via reaction of di-2-furanylethanedione with 5-chloropyridine-2,3-diamine and four new MoO2(VI) complexes having formule [MoO2(ML)](acac)2, derived from cyclization of [MoO2(L)](acac)2 with β-diketones are reported in this work. The synthesized MoO2(VI) complexes were characterized on the basis of various analyses like thermal studies, UV-Vis, elemental analyses, NMR, IR and molar conductance. The coordination number of molybdenum metal is six. All the MoO2(VI) complexes have distorted octahedral structure in which Mo atom is coordinated with two O-atoms and four N-atoms. All the complexes show moderate activity against S. typhi and S. aureus. Advancement in the antibacterial task is thought to be of chelation speculation.


2018 ◽  
Vol 7 (4.37) ◽  
pp. 198
Author(s):  
Ahmed Razzaq Ibrahim Al-Faris ◽  
Wafaa Mahdi Sachit Alkoofee ◽  
. .

Metal complexes of the Schiff base ligand, synthesized via condensation p-dimethylamino benzaldehyde with Bis (4-aminoantipyrine) benzene 1, 4-diamine which has synthesized from condensation 1, 4-phenylene diamine and 4-aminoantipyrine, are synthesized from chloride salts of Co (II) and Ni(II) with ligand in ethanol. The metal complexes and ligand are characterized on the basis of elemental analyses, melting point, molar conductance, UV –Visible, FTIR and thermogravimetric analysis. The molar conductance data reveal that the metal chelates of the ligand with Co (II) and Ni (II) are electrolytes. The present results suggested that the Schiff base ligand as tetradentate is coordinated with metal ions through the four nitrogen atoms. 


2012 ◽  
Vol 9 (3) ◽  
pp. 532-540 ◽  
Author(s):  
Baghdad Science Journal

Two Schiff base ligands L1 and L2 have been obtained by condensation of salicylaldehyde respectively with leucylalanine and glycylglycine then their complexes with Zn(II)were prepared and characterized by elemental analyses , conductivity measurement , IR and UV-Vis .The molar conductance measurement indicated that the Zn(II) complexes are 1:1 non-electrolytes. The IR data demonstrated that the tetradentate binding of the ligands L1 and L2 . The in vitro biological screening effect of the investigated compounds have been tested against the bacterial species Staphlococcus aureus, Escherichia coil , Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa by the disc diffusion method . A comparative study of inhibition values of the Schiff base ligands and their complexes indicated that the complexes exhibit higher antimicrobial activity than the free ligands . Zinc ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium .


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Har Lal Singh ◽  
Jangbhadur Singh

New series of organotin(IV) complexes and Schiff bases derived from amino acids have been designed and synthesized from condensation of1H-indole-2,3-dione, 5-chloro-1H-indole-2,3-dione, andα-amino acids (phenylalanine, isoleucine, and glycine). All compounds are characterized by elemental analyses, molar conductance measurements, and molecular weight determinations. Bonding of these complexes is discussed in terms of their UV-visible, infrared, and nuclear magnetic resonance (1H,13C, and119Sn NMR) spectral studies. The results suggest that Schiff bases behave as monobasic bidentate ligands and coordinate with dibutyltin(IV) in octahedral geometry according to the general formula [Bu2Sn(L)2]. Elemental analyses and NMR spectral data of the ligands with their dibutyltin(IV) complexes agree with their proposed distorted octahedral structures. Few representative compounds are tested for their in vitro antibacterial activity against Gram-positive (B. cereus,Staphylococcusspp.) and Gram-negative (E. coli,Klebsiellaspp.) bacteria. The results show that the dibutyltin complexes are more reactive with respect to their corresponding Schiff base ligands.


2019 ◽  
Vol 41 (6) ◽  
pp. 1055-1055
Author(s):  
Ahmed Hassan Abdel Salam Ahmed Hassan Abdel Salam

Various six coordinated copper(II) complexes of novel (E)-4-hydroxy-6-methyl-3-(1-(p-tolylimino) ethyl-2H-pyran-2-one (HL1) and (E)-3-(1-(4-chlorophenylimino) ethyl-4-hydroxy-6-methyl-2H-pyran-2-one (HL2) derived from 3-Acetyl-2-hydroxy-6-methyl-4H-pyran-4-one (dehydroacetic acid, DHA) and aniline derivatives (p-chloroaniline and p-toluidine) were fabricated. The coordination mode of Schiff base donor atoms with copper ions was well investigated by thermal and elemental analyses, FTIR, UV-vis, 1H, 13C-NMR spectral tools and measurements of magnetic susceptibility as well as molar conductance at ambient temperature. The novel neutral bidentate Schiff base ligands (HL1 and HL2) linked to Cu(II) cation via the azomethine-N and hydroxyl-O atoms and to acetate and nitrate anions in bidentate bridging mode to form polymeric octahedral complexes. The thermal study showed the stepwise removal of water of hydration and anions and decomposition of these chelates. The decomposition products were examined and the relative thermal stabilities of these chelates were evaluated. Different parameters of activation were derived from the thermal curves by Coats–Redfern methodology. The degradation steps of the metal complexes had positive free energy values indicating their non-spontaneous nature. The antifungal and antibacterial activities of all investigated compounds were also studied. The magnetic susceptibility measurements and conductance data were investigated and provided evidence for the non-electrolytic character of the complexes.


2013 ◽  
Vol 16 (2) ◽  
pp. 109-114
Author(s):  
S. Asha Jebamary ◽  
R. Antony ◽  
S. Theodore David ◽  
K. Karuppasamy ◽  
S. Thanikaikarasan ◽  
...  

Four new Schiff bases have been derived from the condensation of acenapthoquinone and naphthylamines in 1:2 molar ratios. These Schiff base ligands were used to synthesise novel mononuclear Ni(II) complexes with square planar geometry. The ligands and the complexes have been investigated by elemental analyses, spectroscopic methods (FT-IR and UV-Vis.,), molar conductance and magnetic susceptibility studies. The electrochemical properties of Ni(II) complexes have been studied by cyclic voltammetry technique. The catalytic efficacy of the complexes has been analysed in the oxidation of toluene to benzyl alcohol, using H2O2. Biological activities of these ligands and complexes were checked against selected bacterial strains (E. coli and S. Aureus).


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
R. B. Sumathi ◽  
M. B. Halli

A new Schiff base and a new series of Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) complexes were synthesized by the condensation of naphthofuran-2-carbohydrazide and diacetylmonoxime. Metal complexes of the Schiff base were prepared from their chloride salts of Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) in ethanol. The ligand along with its metal complexes have been characterized on the basis of analytical data, IR, electronic, mass,1HNMR, ESR spectral data, thermal studies, magnetic susceptibility, and molar conductance measurements. The nonelectrolytic behaviour of the complexes was assessed from the measured low conductance data. The elemental analysis of the complexes confirm the stoichiometry of the type CuL2Cl2and MLCl2where M = Ni(II), Co(II), Cd(II), and Hg(II) and L = Schiff base. The redox property of the Cu(II) complex was investigated by electrochemical method using cyclic voltammetry. In the light of these results, Co(II), Ni(II), and Cu(II) complexes are assigned octahedral geometry, Cd(II), and Hg(II) complexes tetrahedral geometry. In order to evaluate the effect of metal ions upon chelation, both the ligand and its metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleaving capacity of all the complexes was analysed by agarose gel electrophoresis method.


2020 ◽  
Vol 10 (1) ◽  
pp. 1816-1824

Parent dioxomolybdenum(VI) complex formation by the reaction of MoO2(acac)2 with Schiff base tetradentate ligand, described in this paper. Schiff base tetradentate ligand [H2NCH2CH2 N=CC4H3S-CC4H3S=NCH2CH2NH2] obtained from the condensation of di-2-thienylethanedione with 1,2-diaminoethane. Macrocyclic molybdenum complexes were obtained from the cyclization of a synthesized complex with different 1,3 – diketones. The general formula of parent molybdenum complex is given as [MoO2( H2NCH2CH2 N=CC4H3S – CC4H3S=N CH2CH2NH2)](acac)2 and for macrocyclic molybdenum complex is [MoO2{(CH2CH2 N=CC4H3S – CC4H3S=N CH2CH2) N=C(R)CH2C(R’)=N}](acac)2. Ligand and all molybdenum complexes were characterized by elemental analyses(EA), molar conductivity(ΛM), ultraviolet(UV-Vis), and infrared (IR) spectral studies. The distorted octahedral geometry of element Mo in the parent as well as in macrocyclic molybdenum complexes is completed by two oxo O-atoms, four N-atoms from derived Schiff ligand.


2017 ◽  
Vol 72 (6) ◽  
pp. 415-420 ◽  
Author(s):  
Xiu-Yan Dong ◽  
Quan-Peng Kang ◽  
Bo-Xian Jin ◽  
Wen-Kui Dong

AbstractA new dinuclear Ni(II) complex, [{Ni(L)(C5H5N)}2], has been synthesized with 4-chloro-4′,6′-dibromo-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol (H2L), and characterized by elemental analyses, FT-IR, UV/Vis, molar conductance and X-ray crystallographic analysis. Each Ni(II) atom is located at a N2O2 coordination site of a completely deprotonated (L)2− unit. Two μ-phenoxo oxygen atoms from two [Ni(L)] units and two pyridine nitrogen atoms coordinate with two Ni(II) atoms. The two hexa-coordinated Ni(II) atoms have slightly distorted octahedral geometries. The μ-phenoxo bridges play important roles in assembling Ni2+ and (L)2− units. This 2:2 (Ni2+:(L)2−) structure is different from that of other Salamo-type Ni(II) complexes reported earlier.


2020 ◽  
Vol 41 (1) ◽  
pp. 16-25
Author(s):  
Prem Kumar Shrestha ◽  
Pawan Raj Shakya

Complexes of La(III), Pr(III), Nd(III), Sm(III), Gd(III) and Dy(III) with the Schiff-base, N,N′-di-4-(4’-heptadecyloxybenzoate)salicylidene-1,3-diaminopropane, (abbreviated as H2L) have been synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic, electronic, infrared, 1H and 13C NMR spectral techniques. The nephelauxetic ratio (β), the bonding parameter (b1/2), Sinha’s parameter (%δ) and angular overlap parameter (η) have been calculated from the electronic spectra of Pr(III), Nd(III), Sm(III) and Dy(III) complexes. Infrared and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as LH2) to the Ln(III) ions through two phenolate oxygens, rendering the overall geometry around Ln(III) to distorted square antiprism. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) shows the liquid crystalline property of the ligand with a nematic (N) mesophase. Among the metal complexes, only that of the Gd(III) exhibits smectic B (SmB) and nematic (N) phases. 


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