scholarly journals The First Metal Complexes of 4,6-diamino-1-hydro-5-hydroxy-pyrimidine-2-thione: Preparation, Physical and Spectroscopic Studies, and Preliminary Antimicrobial Properties

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Sahar I. Mostafa ◽  
Constantina Papatriantafyllopoulou ◽  
Spyros P. Perlepes ◽  
Nick Hadjiliadis
Keyword(s):  
Metal Ion ◽  
Room Temperature ◽  
Free Ligand ◽  
Antimicrobial Properties ◽  
Spectroscopic Studies ◽  
Ligand Field ◽  
Square Planar ◽  
Elemental Analyses ◽  
Bidentate Chelate

The new complexes[M2O5L2(H2O)2]⋅H2O (M=Mo,1;M=W,2),[RuL2(H2O)2]⋅H2O (3),[ML3]⋅xH2O (M=Rh,x=2,4;M=Ir,x=1,5),[RhL2(PPh3)2](ClO4)⋅2H2O (6),[PdL2]⋅2H2O (7),[PdL(phen)]Cl⋅H2O (8),[Re⁡OL2(PPh3)]Cl (9)and[UO2L2] (10)are reported, where LH is 4,6-diamino-1-hydro-5-hydroxy-pyrimidine-2-thione. The complexes were characterized by elemental analyses, physical techniques (molar conductivity, room-temperature magnetic susceptibility), and spectroscopic (IR, Raman, UV/VIS/ligand field, NMR, mass) methods. The ligandL−is in its thione form and behaves as a bidentate chelate with the deprotonated (hydroxyl) oxygen and the nitrogen of one amino group as donor atoms. Oxobridged dinuclear(1, 2)and various mononuclear(3–10)structures are assigned for the complexes in the solid state. The metal ion coordination geometries are octahedral(1–6, 9, 10)or square planar(7, 8). The free ligand LH and complexes1,4,7, and8were assayed in vitro for antimicrobial activity against two bacterial and two fungal cultures.

scholarly journals Synthesis, Spectroscopic, and Antimicrobial Studies on Bivalent Nickel and Copper Complexes of Bis(thiosemicrbazone)

2007 ◽  
Vol 2007 ◽  
pp. 1-7 ◽  
Author(s):  
Sulekh Chandra ◽  
Smriti Raizada ◽  
Monika Tyagi ◽  
Archana Gautam
Keyword(s):  
Metal Complexes ◽  
Metal Ion ◽  
Copper Complexes ◽  
Free Ligand ◽  
Antimicrobial Properties ◽  
Molar Conductance ◽  
Spectral Studies ◽  
Central Metal ◽  
Antimicrobial Studies

A series of metal complexes of Cu(II) and Ni(II) having the general composition[M(L)X2]with benzil bis(thiosemicarbazone) has been prepared and characterized by element chemical analysis, molar conductance, magnetic susceptibility measurements, and spectral (electronic, IR, EPR, mass) studies. The IR spectral data suggest the involvement of sulphur and azomethane nitrogen in coordination to the central metal ion. On the basis of spectral studies, an octahedral geometry has been assigned for Ni(II) complexes but a tetragonal geometry for Cu(II) complexes. The free ligand and its metal complexes have been tested in vitro against a number of microorganisms in order to assess their antimicrobial properties.

scholarly journals Synthesis, Spectroscopic, and Antimicrobial Studies on Bivalent Zinc and Mercury Complexes of 2-Formylpyridine Thiosemicarbazone

2009 ◽  
Vol 2009 ◽  
pp. 1-6 ◽  
Author(s):  
Sulekh Chandra ◽  
Shikha Parmar ◽  
Yatendra Kumar
Keyword(s):  
Metal Complexes ◽  
Metal Ion ◽  
Free Ligand ◽  
Antimicrobial Properties ◽  
Molar Conductance ◽  
Spectral Studies ◽  
Central Metal ◽  
Tetrahedral Geometry ◽  
Antimicrobial Studies

A series of metal complexes of Zn(II) and Hg(II) having the general composition [where L = 2-formylpyridine thiosemicarbazone; M = Zn(II) and Hg(II); X = , and ] have been prepared and characterized by elemental chemical analysis, molar conductance, and spectral (IR and mass) studies. The IR spectral data suggests the involvement of sulphur and azomethane nitrogen in coordination to the central metal ion. On the basis of spectral studies, a tetrahedral geometry has been assigned for Zn(II) and Hg(II) complexes. The free ligand and its metal complexes have been tested in vitro against a number of microorganisms in order to assess their antimicrobial properties.

Synthesis, Characterization and Biological Studies of Some Transition Metal Complexes with Pyrazine Schiff Base Hydra zone Ligand

2020 ◽  
Vol 15 (2) ◽  
pp. 61-72
Keyword(s):  
Metal Complexes ◽  
Metal Ion ◽  
Metal Salt ◽  
Free Ligand ◽  
Spectroscopic Studies ◽  
Fungal Species ◽  
Molar Conductance ◽  
Central Metal ◽  
Biological Studies

New pyrazine carbohydra zone ligand N'-(1-(5-chloro-2-hydroxyphenyl) ethylidene) pyrazine-2-carbohydrazide (H2L), prepared by the condensation of equimolar amounts of pyrazine-2-carbohydrazide with 2-hydroxy-5-chloroacetophenone in methanol, reacts with suitable metal salt precursors to give complexes of two general formulae: [M(HL)(Cl)(H2O)2] {M = Mn(II), Co(II), Ni(II) and Cu(II)} and [M(L)(H2O)] {M = Zn(II) and Cd(II)}. Structure of ligand was confirmed by elemental analysis, IR, 1H and 13C NMR and mass spectroscopy, while synthesized complexes were additionally characterized by magnetic susceptibility measurements, molar conductivity measurements, XRD, ESR (for Cu(II)), SEM and thermogravimetric analysis. Spectroscopic studies confirmed a tridentate ONO donor behavior of the ligand towards the central metal ion. The molar conductance (12–17 W–1 cm2 mol–1) measurements in DMSO indicated non-electrolytic nature. Thermal behavior of the complexes suggests their extended stability and the thermal decomposition generally proceeds via partial loss of the organic moiety and ends with the formation of respective metal oxide as a final product. Various kinetic and thermodynamic parameters were evaluated using the Coats-Redfern method. The solid-state electrical conductivity of the complexes measured in the temperature range 303-463 K suggested their semiconducting behavior. The ligand and its metal complexes were screened in vitro for their antibacterial activity against the Gram-positive bacteria S. aureus and B. subtilis, the Gram-negative bacteria E. coli and S. typhi and the fungi C. albicans and A. niger. The obtained results indicated improved activity of the complexes compared to the free ligand against all studied bacterial and fungal species.

New Dinuclear Transition Metal Complexes with the [M2(μ-dhbq)]n+ Core and 2-(2′-Pyridyl)quinoxaline (L) as a Terminal Ligand: Preparation and Characterization (dhbq2-= the Dianion of 2,5-Dihydroxy -1,4- benzoquinone; M = AgI, MnII, CoII, NiII, CuII, RuII, PdII, FeIII, RhIII; n = 0, 2, 4)

2001 ◽  
Vol 56 (4-5) ◽  
pp. 394-402 ◽  
Author(s):  
Sahar I. Mostafa ◽  
Spyros P. Perlepes ◽  
Nick Hadjiliadis
Keyword(s):  
Solid State ◽  
Nitrogen Atom ◽  
Transition Metal Complexes ◽  
Metal Ion ◽  
Spectroscopic Techniques ◽  
Pyridyl Nitrogen ◽  
Terminal Ligand ◽  
Square Planar ◽  
Elemental Analyses ◽  
Bidentate Chelate

Abstract Synthetic procedures are described that allow access to the new complexes [Mn2(dhbq)L2(H2O)4 (1), [Fe2(dhbq)L2(H2O)4](NO3)4 · 6H2O (2), [Co2(dhbq)Cl2L2(H2O)2] (3), [Ni2(dhbq)Cl2L2(H2O)2] (4), [Cu2(dhbq)Cl2L2(H2O)2] (5), [Ru2(dhbq)L2(H2O)4](ClO4)2 (6), [Rh2(dhbq)Cl2L2(H2O)2]Cl2·2H2O (7), [Pd2(dhbq)L2]Cl2·5H2O (8) and [Ag2(dhbq)L2] (9), where dhbq2- is the dianion of 2,5-dihydroxy-1,4-benzoquinone and L is the biheteroaromatic ligand 2-(2′-pyridyl)quinoxaline. The new complexes were characterized by elemental analyses and by a variety of physical and spectroscopic techniques. Dinuclear structures are assigned for the complexes in the solid state. The two metal ions are bridged by the bischelating dhbq2- ion, while L behaves as a bidentate chelate with the 2′-pyridyl nitrogen and the nearest quinoxaline nitrogen atom as the ligand atoms. The metal ion coordination geometries are octahedral, tetrahedral or square planar.

scholarly journals Synthesis, characterization and biological activity of a Schiff base derived from o-amino benzoic acid and its Co(II), Cd(II) and Ni(II) complexes

2020 ◽  
Vol 11 (1) ◽  
pp. 15-20
Author(s):  
Tasneem Ibrahim Hussein ◽  
Musa Abduelrahman Ahmed ◽  
Ismail Adam Arbab ◽  
Awad Salim Ibrahim ◽  
Mohamed Al-Bratty ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Schiff Base ◽  
Mass Spectra ◽  
Free Ligand ◽  
Antimicrobial Properties ◽  
Proton Nuclear Magnetic Resonance ◽  
Complexing Agent ◽  
Diffusion Technique ◽  
Nuclear Magnetic Resonance Spectra

Equimolar amounts of imidazoleacetophenone and 2-aminobenzoic acid were combined together and the Schiff base 4(1H-imidazole-yl)acetophenoneanthranilic acid was prepared as a new bidentate complexing agent. The synthesized ligand was reacted with cobalt(II), cadmium(II), and nickel(II) ions yielding air stable complexes. For quantification and characterization purposes, elemental analysis, infrared spectra, electronic spectra, proton nuclear magnetic resonance spectra and mass spectra studies were carried out on the obtained complexes and ligand. Thermogravimetric analysis and magnetic susceptibility measurements were also used for characterization. The ligand IR spectrum showed that the ligand acts as a bidentate coordinates to the metal ions through the nitrogen and oxygen atoms.Measurements of magnetic susceptibility for Ni(II) and Co(II) complexes were found to be 3.4 and 3.8 B.M., respectively, in the range normal for the octahedral geometry. The conductivity measurements revealed that the chelates are non-electrolytes. An in vitro antimicrobial investigation was also carried out for the free ligand and its metal complexes against a number of bacterial and fungal strains, to assess their antimicrobial properties by diffusion technique. Antimicrobial activity of the prepared complexes showed higher activity than the free ligand.

scholarly journals Synthesis and Antibacterial Studies of Novel Phosphorus Ligand 5-(2-diphenylphosphino) phenyl-1,2-dihydro-1,2,4-triazole-3-thione and its Metal Complexes with some Transition Metals

2010 ◽  
Vol 4 (2) ◽  
pp. 37-45
Author(s):  
Matheel D. Al-Sabti ◽  
Ahmed A. H. Al-Amiery ◽  
Thorria R. Marzoog ◽  
Yasmien K. Al-Majedy
Keyword(s):  
Metal Complexes ◽  
Free Ligand ◽  
Antimicrobial Properties ◽  
Cadmium Complex ◽  
Gram Positive Bacteria ◽  
Visible Spectra ◽  
Number Of Microorganisms ◽  
Ft Ir ◽  
The Stability

This study involves the chemical synthesis of the novel ligand 5-(2-diphenylphosphino) phenyl-1,2-dihydro-1,2,4-triazole-3-thione (DPDTT) by the reaction of 2-diphenylphosphino benzoic acid with absolute ethanol that yield ethyl 2-diphenylphosphino benzoate and by cyclization of this compound with thiosemicarbazide, DPDTT will be produced. The chelating complexes of this ligand with Cr(III), Co(II), Ni(II), Cu(II) and Cd(II) were also prepared and studied. The new complexes were characterized by FT-IR, UV/visible spectra, and room temperature magnetic susceptibility. The stability for the prepared complexes was also measured using the density function theory and it was found that the cadmium complex is the most stable and the chromium complex is the least stable. Free ligand and its metal complexes have been tested in vitro against a number of microorganisms, like gram positive bacteria Staphylococcus aureus and gram negative bacteria E. coli, Proteus vulgaris, Pseudomonas and Klebsiella in order to assess their antimicrobial properties. All complexes showed considerable activity against all the studied bacteria.

Antimicrobial Properties of Mono- and Di-fac-rhenium Tricarbonyl 2-Pyridyl-1,2,3-triazole Complexes

2016 ◽  
Vol 69 (5) ◽  
pp. 489 ◽  
Author(s):  
Sreedhar V. Kumar ◽  
Warrick K. C. Lo ◽  
Heather J. L. Brooks ◽  
Lyall R. Hanton ◽  
James D. Crowley
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Properties ◽  
13C Nmr Spectroscopy ◽  
1H And 13C Nmr ◽  
X Ray Crystallography ◽  
The Family ◽  
Elemental Analyses ◽  
Solid State Structures ◽  
Rhenium Tricarbonyl

A family of mono- and di-fac-rhenium tricarbonyl 2-pyridyl-1,2,3-triazole complexes with different aliphatic and aromatic substituents was synthesized in good-to-excellent yields (46–99 %). The complexes were characterized by 1H and 13C NMR spectroscopy, infrared spectroscopy, electronic (UV-visible) spectroscopy, high-resolution electrospray mass spectrometry, and elemental analyses. In four examples, the solid-state structures of the rhenium(i) complexes were confirmed by X-ray crystallography. The family of the mono- and di-rhenium(i) complexes and the corresponding 2-pyridyl-1,2,3-triazole was tested for antimicrobial activity in vitro against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) microorganisms. Agar-based disk diffusion assays indicated that most of the rhenium(i) complexes were active against Staphylococcus aureus and that the cationic rhenium(i) complexes were more active than the related neutral systems. However, in all cases, the minimum inhibitory concentrations for all the complexes were modest (i.e. 16–1024 µg mL–1).

Cobalt(II), nickel(II) and copper(II) complexes of some 2'-hydroxychalcones

1980 ◽  
Vol 33 (4) ◽  
pp. 737 ◽  
Author(s):  
M Palaniandavar ◽  
C Natarajan
Keyword(s):  
Infrared Spectra ◽  
Metal Ion ◽  
Magnetic Moments ◽  
Phenyl Group ◽  
Ligand Field ◽  
Square Planar ◽  
Spin Pairing ◽  
Square Configuration ◽  
Electron Sink ◽  
Octahedral Configuration

Metal(II) bis-chelates of the type ML2 [M = CoII, NiII, CuII; L = 2'- hydroxy-5'-X-chalcone where X = H, CH3, Cl] have been prepared and studied. Structures have been assessed by the measurement of magnetic moments, ligand field and infrared spectra and thermal properties. These chelates possess low-spin trans-square-planar configuration and show resistance to adduct formation in contrast to metal(II) chelates of β-diketones, salicylaldehyde, o-hydroxyaryl ketones and esters and o-hydroxy-crotonophenones, which have high-spin octahedral configuration. Extensive conjugation lowers the energy of the π3* orbital which enters into a very strong dπ-π3* interaction leading to spin-pairing. ��� Infrared spectra indicate that the carbonyl group is perturbed only slightly by coordination to metal. A change in metal ion affects v(C=O), v(M-O) and other vibrations and the order of stability, namely, Co ≈ Ni < Cu, inferred from these vibrations is as expected for the low-spin square configuration of the chelates. Introduction of substituents (5'-X) alters only v(M-O) significantly and the order of stability, namely, Cl > CH3 > H, derived from v(M-O) is consistent with Taft's resonance polar parameters of the substituents. All these observations are explained by the electron sink property of the phenyl group.

scholarly journals Bioinorganic Relevance of Some Cobalt(II) Complexes with Thiophene-2-glyoxal Derived Schiff Bases

2009 ◽  
Vol 6 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Prashant Singh ◽  
Shanu Das ◽  
Rajesh Dhakarey
Keyword(s):  
Spectral Data ◽  
Schiff Bases ◽  
Metal Ion ◽  
Free Ligand ◽  
Antimicrobial Activities ◽  
Carbonyl Oxygen ◽  
Azomethine Nitrogen ◽  
Ligand Field ◽  
Filter Paper Disc ◽  
Electronic Spectral Data

Complexes of Co(II) with two new Schiff bases TEAB [2-hydroxy-4-{[2-oxo-2-(thiophen-2-yl)ethylidene]amino}benzoic acid] and TEPC [N-[2-oxo-2-(thiophen-2-yl)ethylidene]pyridine-3-carboxamide] have been synthesized and characterized with the help of elemental analysis, magnetic, mass,1H-NMR,13C-NMR, IR and electronic spectral data. IR spectra manifest the coordination of the ligand to the metal ion through the carbonyl oxygen, azomethine nitrogen and thienyl sulphur atoms. With the help of electronic spectral data various ligand field parameters were also calculated. All these studies reveal the distorted octahedral Co(II) complexes. Synthesized compounds have also been screened against some micro organismsviz, Escherichia coli, Proteus vulgaris, Aspergillus nigerandAspergillus flavuswith the help of ‘filter paper disc’ technique. It has been observed that the antimicrobial activities of metal complexes are higher than that of the free ligand.

Fluorinated Alkoxides. Part VIII. Mixed Ligand Complexes of Perfluoropinacol with Ni2+, Pd2+, Pt2+ and Cu2+. Solvation Equilibria between 4- and 5-coordinate Ni2+

1975 ◽  
Vol 53 (6) ◽  
pp. 809-816 ◽  
Author(s):  
W. Stafford Cripps ◽  
Christopher J. Willis
Keyword(s):  
Metal Ion ◽  
Nickel Complexes ◽  
Mixed Ligand ◽  
Ligand Field ◽  
Electronic Effects ◽  
Unusual Behavior ◽  
Planar Structures ◽  
Square Planar ◽  
Phosphorus Containing ◽  
Fluorinated Alkoxides

Perfluoropinacol, (CF3)2C(OH)C(OH)(CF3)2, ionizes by loss of two protons, and the resulting dinegative ion (PFP2−) chelates to Ni2+, Pd2+, Pt2+, and Cu2+. A variety of stable neutral complexes may be isolated if the tetracoordination of the metal ion is completed with two monodentate or one bidentate nitrogen- or phosphorus-containing ligands; square-planar structures are invariably found. The structures of these complexes are contrasted with those of analogous halides, and it is concluded that electronic effects are predominant in determining them, although steric influences may sometimes be important. The ligand field strength of the perfluoropinacolato ion is approximately equal to that of the thiocyanate ion.The nickel complexes Ni(PFP)22− and (PFP)Ni(RNHCH2CH2NHR) react with donor solvents (water, methanol, pyridine, etc.) to give equilibria between four- and five-coordinate solvated species; six-coordinate species are not observed. This unusual behavior is attributed to the steric hindrance imposed by the bulk of the PFP2− ligand.

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