Synthesis, spectroscopic characterization, and in vitro antimicrobial activity of complexes
01 Jan 2015-
TL;DR: In this paper, a tetradentate ligand was synthesized and characterized using elemental analyses, spectra (IR, 1 H NMR and ESR), molar conductance, magnetic moment, and thermal studies.
Abstract: New metal(II)/(III) complexes with novel Schiff base, resulted from the condensation of propane-1,3- diamine with bisaldehyde, as tetradentate ligand have been synthesized and characterized using elemental analyses, spectra (IR, 1 H NMR and ESR), molar conductance, magnetic moment, and thermal studies. The IR data sug- gest the coordination mode for the Schiff base ligand which behaves as a tetradentate with the metal ions. Based on the elemental analysis, magnetic studies, electronic, and ESR data, octahedral geometry was proposed for the complexes. The ESR spectra of the Cu(II) complex in powdered form showed an axial symmetry with 2 B1g as ground state and hyperfine structure. The thermal stability and degradation of the Schiff base ligand and its metal complexes were studied by TG. The molar conductance in DMF solution indicates that all complexes are electrolytes. The free Schiff base ligand and its metal complexes were tested for their in vitro antimicrobial activity against gram-positive and gram-negative organisms. The results showed that the synthesized complexes exhibited higher antimicrobial activity than their free Schiff base ligand. Of all the studied complexes, the Cu(II) and Co(II) complexes exhibited high antimicrobial activity at low micromolar inhibitory con- centrations compared to the other complexes, amikacin standard, and the free Schiff base ligand.
Citations
More filters
TL;DR: In this article, a new Schiff base ligand (HL) with the IUPAC name 2-(((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)imino)(phenyl)methyl)benzoic acid.
Abstract: The condensation of o-benzoyl benzoic acid and 4-aminoantipyrine resulted in the formation of novel Schiff base ligand (HL) with the IUPAC name 2-(((1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)imino)(phenyl)methyl)benzoic acid. The synthesized Schiff base ligand and its complexes with M(II)/(III) transition elements (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)) were characterized by elemental, magnetic susceptibility, molar conductivity, spectroscopic (1H NMR, mass, UV–visible, FTIR, ESR), thermal and X-ray powder diffraction. The data showed that the complexes had composition of the MHL type. The diffused reflectance spectra, magnetic susceptibility and ESR spectral data of the complexes confirm an octahedral geometry around metal ions. The thermal analysis data revealed the decomposition of the complexes in three to five successive decomposition steps within the temperature range of 30–1000°C, and the activation thermodynamic parameters were reported. The molecular structures of the Schiff base ligand and its Mn(II) and Zn(II) metal complexes are optimized theoretically, and the quantum chemical parameters are calculated. In order to predict the binding between o-benzoyl benzoic acid, 4-aminoantipyrine and HL ligand with the Escherichia coli bacterial RNA (4p20) receptor, molecular docking was carried out. The in vitro antimicrobial screening of the newly synthesized compounds was tested against different bacterial and fungal organisms. The results showed that the metal complexes have biologically activity more than the new Schiff base ligand against the tested organisms. The Schiff base ligand and its complexes were also screened for their anticancer activity against breast cancer cell line (MCF7). The Mn(II), Cr(III) and Cd(II) complexes were found to have low IC50 values which support the possibility of using them as cytotoxic agents and hence might become good anticancer agent in clinical trials.
55 citations
Cites background from "Synthesis, spectroscopic characteri..."
...These data suggested an octahedral geometry around Cu(II) ion in the complex [38, 48, 49]....
[...]
...The metal chelates showed new bands in the region of 526–599, 497–548 cm and 417–477 cm, which can be attributed to the formation of M–O, M–O of coordinated water and M– N bonds, respectively [38]....
[...]
..., which shows an octahedral geometry [38, 48]....
[...]
...An intense new band which appeared at 1592 cm in the condensed product, HL, can be assigned to m(C=N) of the azomethine moiety [38] confirming the formation of the Schiff base ligand (Supplementary Figure 2)....
[...]
...This phenomenon appears because of the coordination of azomethine nitrogen to the metal ions [38, 39]....
[...]
01 Jan 2012
TL;DR: In this article, four novel azo compounds were synthesized: o-phenylazo-(C14H13N3O2) (I), p-bromo-O-PNO-PN 3O2 (II) and p-methoxy-OPNO 2 (III) were compared with electron ionization (EI) mass spectral fragmentation pathways and thermal decomposition mechanisms.
Abstract: Four novel azo compounds were synthesized: o-phenylazo-(C14H13N3O2) (I), p-bromo-o-phenylazo-(C14H13BrN3O2) (II), p-methoxy-o-phenylazo-(C15H16N3O3) (III), and p-nitro-o-phenylazo-p-acetamidophenol (C14H13N4O4) (IV). These compounds were carefully investigated using elemental analyses, IR, and thermal analyses (TA) in comparison with electron ionization (EI) mass spectral (MS) fragmentation at 70 eV. Semi-empirical MO calculation, PM3 procedure, has been carried out on the four azo dyes (I–IV), both as neutral molecules and the corresponding positively charged molecular ions. These included molecular geometries (bond length, bond order, and charge distribution, heats of formation, and ionization energies). The mass spectral fragmentation pathways and thermal decomposition mechanisms were reported and interpreted on the basis of molecular orbital (MO) calculations. They are found to be highly correlated to each other. Also, the Hammett’s effects of p-methoxy, p-bromo, and p-nitro-substituents of phenyl azo groups on the thermal stability of these dyes (I–IV) are studied by experimental (TA and MS) in comparison with MO calculations, and the data obtained are discussed. This research aimed chiefly to throw more light on the structures of the four prepared azo derivatives of acetoamidophenol (p-cetamol). The data refering to the thermal stability of these dyes can be used in industry for effective dyeing purposes under different thermal conditions.
12 citations
TL;DR: Jayalakshmi Rajendran, Anbarasu Govindharaji, Chozhanathmisra Manickam and * Rajavel Rangappan.
1 citations
Cites background from "Synthesis, spectroscopic characteri..."
...The spectrum of homo-binuclear Ni(II) complex exhibited two d–d bands at 612 and 442 nm corresponds to 3 A2g (F) → 3 T1g (F) and 3 A2g (F) → 3 T1g (P) transitions, respectively, which describe the octahedral geometry of the Ni(II) complex [20]....
[...]
References
More filters
01 Jan 1979
TL;DR: In this article, the authors propose a method for the synthesis of Macrocyclic Compound and Synthesis of MacroCycle Complexes (SCC) using a 2,6-Pyridyl Group (P2S2).
Abstract: 1. General Introduction.- 1. Introductory Comments.- 2. General Comments.- 2.1. Definition of a Macrocyclic Compound.- 2.2. Historical Background.- 2.3. Abbreviations of Macrocyclic Compounds.- 2.4. Units.- 2.5. Chapter Layout.- References.- 2. Synthesis of Macrocyclic Complexes.- 1. Introduction.- 2. Tridentate Ligands.- 3. Tetradentate Ligands.- 3.1. N4 Donor Atoms.- 3.2. N2O2 Donor Atoms.- 3.3. N2S2 Donor Atoms.- 3.4. S4 Donor Atoms.- 3.5. P4 and P2S2 Donor Atoms.- 4. Pentadentate Ligands.- 5. Sexadentate Ligands.- 6. Binucleating Ligands.- 7. Clathrochelates.- 8. Conclusions.- References.- 3. Thermodynamics and Kinetics of Cation-Macrocycle Interaction.- 1. Introduction.- 2. Parameters Determining Cation Selectivity and Complex Stability.- 2.1. Relative Sizes of Cation and Ligand Cavity.- 2.2. Arrangement of Ligand Binding Sites.- 2.3. Type and Charge of Cation.- 2.4. Type of Donor Atom.- 2.5. Number of Donor Atoms.- 2.6. Substitution on the Macrocyclic Ring.- 2.7. Solvent.- 3. Macrocyclic Effect.- 3.1. Tetramines.- 3.2. Cyclic Polyethers.- 3.3. Solvation Effects.- 3.4. Mixed Donor Groups.- 3.5. Multiple Juxtapositional Fixedness.- 3.6. Cryptate Effect.- 3.7. Summary.- 4. Table of Thermodynamic Data.- 5. Kinetics.- 5.1. Antibiotic Macrocycles.- 5.2. Cyclic Polyethers.- 5.3. Macrobicyclic Ligands.- References.- 4. Structural Aspects.- 1. Introduction.- 1.1. Scope and Organization.- 1.2. Order of Tabulation.- 2. Class 1: Cyclic Amines-Saturated Polyaza Macrocycles.- 2.1. Introduction.- 2.2. Configurations and Conformations of Coordination Cyclic Tetramines.- 2.3. Metal-Ion-Nitrogen Distances.- 2.4. Substituents on the Macrocycle.- 2.5. Chelate Angles.- 2.6. Listing of Structures of Compounds of Cyclic Amines.- 3. Class 2: Cyclic Imines and Cyclic Amine-Imines (Unsaturated Polyaza Macrocycles with all Nitrogen Atoms Coordinated).- 3.1. Discussion of Structures.- 3.2. Conformation of Macrocycles.- 3.3. Substituents on the Macrocycle.- 3.4. Metal Ion-Nitrogen Distances.- 3.5. Listing of Reported Structures of Cyclic Imine and Cyclic Amine-Imine Compounds.- 4. Class 3: Macrocycles Including a 2,6-Pyridyl Group.- 4.1. Discussion of Structures.- 4.2. Listing of Reported Structures of Compounds of Macrocycles Including a 2,6-Pyridyl Group.- 5. Class 4: Tetraazamacrocycles with 2-Imino(or 2-amido)-benzaldimine Chelate Rings.- 5.1. Discussion of Structures.- 5.2. Listing of Structures of Tetraazamacrocycles with l-Imino(or l-amido)-2-aldiminobenzene Chelate Rings (o-Iminobenzaldimine and o-Amidobenzaldimine Derivatives).- 6. Class 5: Dibenzo[b,i]-l,4,8,11-tetraazacyclotetradec-2,4,6,9,11-hexaenato(2-) Compounds.- 6.1. Discussion of Structures.- 6.2. Listing of Structures of Bzo2[14]hexaenato(2-)N4 Compounds.- 7. Class 6: Cyclic Hydrazines and Hydrazones.- 7.1. Discussion of Structures.- 7.2. Listing of Structures of Cyclic Hydrazine and Hydrazone Compounds.- 8. Class 7: Cyclic Tetraethers and Tetrathiaethers (Tetraoxo- and Tetrathiamacrocycles).- 8.1. Discussion of Structures.- 8.2. Listing of Structures of Tetraoxa- and Tetrathiamacrocycles.- 9. Class 8: Macrocycles with More Than One Type of Heteroatom.- 9.1. Discussion of Structures.- 9.2. Listing of Structures of Compounds.- 10. Class 9: Binucleating Macrocycles.- 10.1. Discussion of Structures.- 10.2. Listing of Structures of Binucleating Macrocycles.- 11. Class 10: Cyclic Phosphazenes.- 11.1. Discussion of Structures.- 11.2. Listing of Structures of Cyclic Phosphazene Compounds.- 12. Class 11: Clathrochelates.- 12.1. Discussion of Structures.- 12.2. Listing of Structures of Clathrochelate Compounds.- 13. Conclusion.- References.- 5. Ligand Field Spectra and Magnetic Properties of Synthetic Macrocyclic Complexes.- 1. Introduction.- 2. Nickel Complexes.- 2.1. Nickel(II) Macrocyclic Complexes.- 2.2. Macrocyclic Complexes of Nickel(I) and Nickel(III).- 3. Copper Complexes.- 3.1. Macrocyclic Copper(II) Complexes.- 3.2. Magnetic Interactions in Binuclear Macrocyclic Copper Complexes.- 3.3. Macrocyclic Complexes of Copper(I) and Copper(III).- 4. Cobalt Complexes.- 4.1. Cobalt(II) Macrocyclic Complexes.- 4.2. Macrocyclic Cobalt(III) Complexes.- 4.3. Cobalt(I) Macrocyclic Complexes.- 5. Iron Complexes.- 5.1. Low-Spin (S = 0) Iron(II) Macrocycles.- 5.2. High-Spin (S = 2) Iron(II) Macrocycles.- 5.3. Intermediate Spin (S = 1) Iron(II) Macrocycles.- 5.4. Low-Spin (S = 1/2) Iron(III) Macrocycles.- 5.5. High-Spin (5 = 5/2) and Intermediate-Spin (S = 3/2) Iron(III) Macrocycles.- 5.6. Other Iron-Containing Macrocycles.- 6. Manganese Complexes.- 6.1. Macrocyclic Complexes of Manganese(II).- 6.2. Macrocyclic Complexes of Manganese(III).- References.- 6. Chemical Reactivity in Constrained Systems.- 1. Introduction.- 2. Predominantly Metal-Centered Reactions.- 2.1. Coordinative Lability.- 2.2. Oxidation-Reduction Reactions of Simple Stoichiometry.- 3. Reactions of the Macrocyclic Ligands.- 3.1. Oxidative Dehydrogenations..- 3.2. Hydrogenation.- 3.3. Substitutions into the Macrocyclic Ligand.- 3.4. N-Alkylations.- 3.5. Additions.- 4. Reactions Involving Free Radicals, Unusual Oxidation States, and Excited States.- 4.1. Free Radical Reactions.- 4.2. Complexes Containing Metals in Unusual Oxidation States.- 4.3. Photochemical Reactions.- 4.4. Photochemistry of Cobalt-Alkyl Complexes.- References.- 7. Metal Complexes of Phthalocyanines.- 1. Introduction.- 2. Molecular Structure.- 3. Electronic Structure.- 4. Spectral Properties.- 5. Synthesis of New Derivatives.- 6. Redox Reactions.- 7. Aggregation of Complexes.- 8. Chromium Complexes.- 9. Manganese Complexes.- 10. Iron Complexes.- 11. Cobalt Complexes.- 12. Group IV Metal Complexes.- 13. Catalytic Activity.- 14. Comparison of Chemistry of Chromium, Manganese, Iron, and Cobalt Complexes.- References.- 8. Coordination Chemistry of Porphyrins.- 1. Introduction.- 2. Synthesis.- 3. Structure.- 4. Reactions.- 5. Chlorins and Corrins.- References.- 9. Physicochemical Studies of Crown and Cryptate Complexes.- 1. Introduction.- 2. Synthetic Methods.- 2.1. Crown Polyethers.- 2.2. [2]-Cryptands.- 2.3. [3]- and [4]-Cryptands.- 3. Metal-Cation Complexes: Preparation and Structure.- 3.1. Monocyclic Ligands (Crowns).- 3.2. Macropolycyclic Ligands (Cryptands).- 4. Complexes in Solutions: Experimental Techniques.- 4.1. General Considerations.- 4.2. Electrochemical Techniques.- 4.3. Spectroscopic Techniques.- 4.4. Extraction Studies.- 4.5. Calorimetric Techniques.- 4.6. Relaxation Techniques.- 5. Conclusion.- References.- 10. Natural-Product Model Systems.- 1. Introduction.- 1.1. Model Systems-Criticisms, Objectives, and Definitions.- 1.2. Importance of X-Ray Structural Analyses.- 1.3. Evolution of Models.- 2. Macrocyclic Complexes as Models.- 2.1. Macrocyclic Ethers and Thiaethers in Model Systems.- 2.2. Synthetic Tetraazamacrocyclic Systems.- 2.3. Fundamental Studies of Synthetic Macrocyclic Ligand Complexes.- 3. Modeling of Heme Proteins.- 3.1. Studies Involving Metals Other than Iron.- 3.2. Iron(II) Carbon Monoxide Complexes.- 3.3. Dioxygen Complexes.- 3.4. Cytochromes.- 4. Binuclear Systems.- 4.1. Cofacial Diporphyrins.- 4.2. Unsymmetrical Binuclear Systems.- 5. Comments on Vitamin B12 and Related Inorganic Systems.- References.
660 citations
TL;DR: In this paper, the reaction of ruthenium(II) complexes with bidentate Schiff base ligands derived by condensing salicylaldehyde with aniline, o-, m- or p-toluidine has been carried out.
Abstract: The reactions of ruthenium(II) complexes, [RuHCl(CO)(PPh3)2(B)] [B = PPh3, pyridine (py) or piperidine (pip)], with bidentate Schiff base ligands derived by condensing salicylaldehyde with aniline, o-, m- or p-toluidine have been carried out. The products were characterised by analytical, i.r., electronic, 1H-n.m.r. and 31P-n.m.r. spectral studies and are formulated as [RuCl(CO)(L)(PPh3)(B)] (L = Schiff base anion; B = PPh3, py or pip). An octahedral structure has been tentatively proposed for the new complexes. The Schiff bases and the new complexes were tested in vitro to evaluate their activity against the fungus Aspergillus flavus.
573 citations
TL;DR: A series of 2,4-dichloro-5-fluorophenyl bearing Mannich base was prepared from triazole Schiff bases by aminomethylation with formaldehyde and secondary/substituted primary amines to show promising antibacterial and antifungal activity.
460 citations
TL;DR: Heterocyclic bidentate Schiff bases were associated with substantially higher antibacterial activities than some commercial antibiotics.
348 citations
TL;DR: 4-(4-Hydroxy-benzylidene-imino)phenyl)-morpholine (7) was found to be the most potent antimicrobial activity with MIC of 25, 19, 21, 16, 29, 20 and 40 microg/ml against S. aureus, S. epidermidis, B. cereus, M. luteus, E. albicans and A. niger, respectively.
287 citations