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The two new mononuclear complexes were prepared by reacting symmetric Schiff base, containing pyrimidine rings and the metal chlorides of Pd(II) and Pt(II) in methanol. The mononuclear structure of the complexes was confirmed on the basis of elemental analyses, magnetic susceptibility, IR, UV-Vis, NMR, DTA/TGA and API-ES mass spectral data. The interaction of these metal complexes with fish sperm double-stranded DNA (dsDNA) was studied electrochemically based on the oxidation signals of guanine and adenine. Differential pulse (DP) voltammetry by using renewable pencil graphite electrode was employed to monitor the DNA interaction at the surface or in solution. The results indicate that Pd(II) and (Pt) complexes with Schiff base ligand having pyrimidine rings strongly interacted with DNA., (2010 Elsevier Masson SAS. All rights reserved.)

A phenol based novel Schiff base polydentate symmetric ligand was prepared. The complexes were prepared by reacting ligand and the metal chlorides of Cu (II), Ni(II), Co(II) and Fe(II) in methanol to get a series of mononuclear complexes. The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility data, IR, UV-Vis, NMR and API-ES mass spectral data. The mononuclear structure of the complexes was confirmed on the basis of elemental analyses, magnetic susceptibility and API-ES mass spectral data. The ligand and all the metal complexes were evaluated for their antimicrobial activity against four Gram-positive bacteria (Staphylococcus aureus ATCC 6538, S. aureus ATCC 25923, Bacillus cereus ATCC 7064 and Micrococcus luteus ATCC 9345), one Gram-negative bacterium (Escherichia coli ATCC 4230), and three yeast (Candida albicans ATCC 14053, Candida krusei ATCC 6258 and Candida parapsilosis ATCC 22019) strains. Therefore, newly synthesized the ligand and two complexes [(Cu(II) and Co(II)] showed good biological activity against all tested bacteria and yeast strains., (Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.)

This study includes the synthesis, characterization, electrochemical analysis and photoluminescence properties of a Schiff base ligand bearing a pyrimidine ring and its Co(II), Ni(II), Cu(II) and Pd(II) metal complexes. The Schiff base ligand was derived from the condensation reaction of a pyrimidine amine with 2-hydroxy-1-naphthaldehyde. The structures were characterized using FT-IR, UV-Vis, elemental analysis, magnetic susceptibility and electrolytic conductivity. The ligand and its metal complexes displayed strong violet emissions upon UV exposure. The photoluminescence quantum yield and excited-state decay were measured for the ligand and its complexes. The excited-state lifetime for the ligand was 3.70 ns and its quantum yield of luminescence was found to be 0.40. A reduction in photoluminescence intensity and quantum yield was observed upon metal ion complexation. The compounds synthesized were studied by cyclic voltammetry to probe the existence of electrochemical reduction and oxidation processes. [ABSTRACT FROM AUTHOR]

The preparation, characterization, magnetic measurements, antimicrobial activity, and photoluminescence properties of a number of metal complexes with a Schiff base ligand derived from 2, 6-diformyl-4-methylphenol and 1-amino-5-benzoyl-4-phenyl-1 H-pyrimidine-2-thione are reported herein. UV/Vis spectra and magnetic measurements infer square planar stereochemistry for PdII and PtII complexes, and octahedral arrangement for the other metal complexes. The compounds results in intense emission (where λmax = 402 nm) upon irradiation by UV light. The photoluminescence quantum yields and long excited-state lifetimes of the ligand and its complexes were calculated as 42 % and 3.94 ns, respectively. The photoluminescence intensities and quantum yields of metal complexes changed upon complexation with various metal ions. The ligand and its complexes are of interest as organic emitting materials for electroluminescent devices. The complexes were additionally evaluated for in vitro the antimicrobial activity against bacterial and fungal strains. While CuII, CoII, and PtII complexes have good antifungal efficiency against yeast (MICs, 80 μg ·mL-1), only the complex [Cu(L)(AcO)] ·4H2O had effective and selective antimicrobial activity against all tested microorganisms with MIC values in the range of 40-80 μg ·mL-1, except for E. coli ATCC 4230. This study suggests that the complex [Cu(L)(AcO)] ·4H2O may be a new potential antimicrobial substance towards bacteria and fungi. [ABSTRACT FROM AUTHOR]

A new Schiff base, {1-[(5-bromo-2-hydroxy-benzylidene)-amino]-4-phenyl-2-thioxo-1,2-dihyro-pyrimidin- 5-yl}-phenyl-methanone, was synthesized from N-amino pyrimidine-2-thione and 5-bromsalicylaldehyde. Metal complexes of the Schiff base were prepared from acetate salts of Cu(II), Ni(II), Co(II), Pd(II), and PtCl2 in methanol. The chemical structures of the Schiff base ligand and its metal complexes were confirmed by spectroscopic analysis. All of the compounds were evaluated for their antimicrobial against 4 gram-positive bacteria, 1 gram-negative bacterium, and 3 yeast strains. The Schiff base and the Cu(II) and Co(II) complexes showed good biological activity against all tested bacteria and yeast strains. [ABSTRACT FROM AUTHOR]

A new Schiff base, {1-[(2-hydroxy-naphthalen-1-ylmethylene)-amino]-4-phenyl-2-thioxo-1, 2-dihydro-pyrimidin-5-yl}-phenyl-methanone, has been synthesized from N-amino pyrimidine-2-thione and 2-hydroxynaphthaldehyde. Metal complexes of the Schiff base were prepared from acetate/chloride salts of Cu(II), Co(II), Ni(II), Zn(II), and Cd(II) in methanol. The chemical structures of the Schiff-base ligand and its metal complexes were confirmed by elemental analyses, IR, 13C-NMR, 1H-NMR, API-ES, UV-Visible spectroscopy, magnetic susceptibility, and thermogravimetric analyses. The electronic spectral data and magnetic moment measurements suggest mononuclear octahedral and mononuclear or binuclear square planar structures for the metal complexes. In light of these results, it was suggested that this ligand coordinates to each metal atom by hydroxyl oxygen, azomethine nitrogen, and thione sulfur to form octahedral complexes with Cd(II) and Zn(II). [ABSTRACT FROM AUTHOR]

Anew series of two types of acyclic binuclear Schiff base complexes, prepared by the template condensation of N-aminopyrimidine and 2,3-butandion in the presence of Cu(II), Ni(II), Co(II) and Zn(II) in n-BuOH solution, were analyzed and characterized by elemental analyses, IR and electronic spectroscopy, conductivity and magnetic measurements. From the conductivity measurements, it is concluded that the complex of NiII is a 1:1 type of electrolyte. All the complexes have sub-normal magnetic moments in accordance with their binuclear nature. The thermal behaviour of the complexes was studied by thermogravimetry. [ABSTRACT FROM AUTHOR]

The template synthesis of diacetyl or benzil and 1-amino-5-benzoyl-4-phenyl-1H-pyrimidine-2-one in the presence of Fe(III) and Cr(III) results in the formation of acyclic complexes of the types [ML1X2]X, [ML2X2]X, and [Fe2(L1)2Cl4]Cl2 · H2O, where M = Fe(III), Cr(III), L1 (benzyl derivative), or L2 (diacetyl derivative) are N2O2/ONO acyclic ligands and X = Cl, NO3). The complexes have been characterized by elemental analyses, molar conductance, magnetic measurements, IR, and UV/VIS spectral studies. [ABSTRACT FROM AUTHOR]

Cu(II), Co(II), Ni(II), and Zn(II) metal complexes of a new SNO tridentate heterocyclic Schiff base derived from the reaction of 1-amino-5-benzoyl-4-phenyl-1H-pyrimidine-2-thione with salicylaldehyde have been synthesized and characterized on the basis of elemental analyses, electronic, IR, and 1H NMR spectra, and also by molar conductivity measurements, magnetic moment measurements and thermogravimetric analyses (TGA). It has been found that the Schiff base behaves as a neutral tridentate SNO ligand forming chelates with 1:2 or 1:1 (metal:ligand) stoichiometry. The complexes of Co(II), Ni(II), and Zn(II) are proposed to have an octahedral structure, while the Cu(II) complex is suggested to have a square–pyramidal geometry. All of the complexes show nonelectrolytic behavior. [ABSTRACT FROM AUTHOR]

In this study, Cu(II) complex, C 52 H 40 CuN 6 O 10 , was synthesized and the molecular structure was characterized by experimental Electron Paramagnetic Resonance (EPR), vibrational frequencies, absorption wavelengths and compared with theoretical methods. The molecular geometry was calculated and optimized by using Gaussian 09 software and DFT-B3LYP and B3PW91 methods with the LanL2DZ basis sets in ground state. The theoretical vibrational frequencies, was optimized geometric parameters such as bond lengths, bond angles and torsion angles and absorption wavelengths, NBO, FMO analysis, HOMO-LUMO energy and nonlinear optical properties, molecular electrostatic potential, spin density have been calculated via quantum chemical methods. Theoretically calculated data were compared with experimentally measured data. Also, the results obtained by using the two basis sets were compared with each other. [ABSTRACT FROM AUTHOR]

• The novel Cu(II), Co(II), and Fe(II) complexes of N 3 S 2 type pentadentate Schiff base were synthesized and characterized. • All compounds were tested against Gram-positive, Gram-negative, and yeast strains for antibacterial activity. • Synthesized compounds were compared to the stable free radical DPPH for antioxidant activity. • In docking study, all the metal complexes, especially Co(II) complex [CoL], have a higher binding affinity than free ligand. • Docking indicated that all compounds had a strong negative affinity for S. aureus amino acids. The compound H 2 L, which is a ligand with five coordinating atoms, consisting of three nitrogen atoms and two sulfur atoms (N 3 S 2), was reacted with Fe(OAc) 2 , Cu(OAc) 2.H 2 O, and Co(OAc) 2 ·4H 2 O to form the corresponding metal complexes ([FeL], [CuL], [CoL]). Many techniques, including NMR (for ligand), FT-IR, UV–Vis, elemental analysis, and molar conductivity, were used to characterize the synthesized compounds. According to the spectrum of data, complex molecule structures have a distorted triangular bipyramidal geometry with five coordination locations. The compounds that exhibit non-electrolyte behavior in solution do not possess any conductivity features. Evaluation was performed to determine the antioxidant activity of the synthesized compounds in comparison to the stable free radical DPPH. The ligand and its metal complexes were evaluated for antibacterial activity against several Gram-positive and Gram-negative bacteria, as well as a yeast strain. In comparison to the common antibiotic Amoxycillin/Clavulanic Acid (AMC-30), the Schiff base ligand (H 2 L) and its Cu(II) metal complex showed noticeably larger inhibitory zones against S. aureus. All the compounds showed a high negative binding affinity for S. aureus amino acid molecules when they were docked. The results indicated that the metal complexes, particularly the cobalt complex, exhibited a higher affinity for binding compared to the free ligand. [Display omitted] [ABSTRACT FROM AUTHOR]

This study covers the synthesis, structural characterization by experimental FT-IR, 1 H NMR and 13 C NMR, UV–Vis and single crystal XRD and comparison with theoretical calculations of a Schiff base compound bearing phenoxy group, C 34 H 28 N 2 O 4 by using the DFT method 6-311G(d,p) basis set. The molecular geometry, the dipole moments, electrostatic potential, vibrational frequencies, HOMO-LUMO energy were calculated. NBO, NLO, thermodynamic properties and Fukui function were studied. In this work, theoretical values show good agreement with experimental values. [ABSTRACT FROM AUTHOR]

The Schiff base compound 3,3′-(1,4-phenylimino)-bis-[1,3-bis-(4-methoxyphenyl) propan-1-one)], formulated as C 40 H 36 N 2 O 6, and its Cu(II) complex were synthesized and characterized by analytical analysis, various spectral techniques such as FT-IR, NMR, UV–vis, magnetic measurements and molar conductivity. Thermo gravimetric analysis (TGA and DTA) carried out to obtain information about its thermal stability. The molecular structure and spectroscopic properties of the ligand were obtained with FT-IR, 1 H and 13 C NMR, UV–vis investigations as experimentally and compared with theoretical results obtained from DFT/B3LYP/6-311++G(d,p) basis set. In addition to molecular calculations of the title compound, molecular electrostatic potential (MEP), dipole moments, atomic charges, HOMO–LUMO, NLO and NBO analysis were computed. The calculated results show that the optimized geometry can well reproduce the crystal structure parameters, and the theoretical vibrational frequencies, 1 H and 13 C NMR chemical shifts show good agreement with experimental values. Photoluminescence properties of the ligand and its Cu(II) complex were examined. [ABSTRACT FROM AUTHOR]

[Display omitted] • In this study, a novel SNS pincer type ligand and its metal complexes have been synthesised and identified. • All the compounds were characterized by physical measurements, as well as spectroscopic techniques. • These complexes were investigated as catalysts for the fixation of CO 2 to cyclic carbonates. • All the complexes showed good catalytic activity as catalyst for CO 2 insertion into cyclic carbonates. A new tridentate pincer type ligand 2,6-bis[[(4-methylphenyl)thio]carbonyl]pyridine (L),possessing nitrogen donor and two sulfur (SNS) donor set was metallized with Pd(OAc) 2 , Ni(OAc) 2 , Cu(OAc) 2 and Co(OAc) 2 , respectively, and the new bidentate (L-Pd) and tridentate SNS pincer type complexes (L-Ni, L-Cu, L-Co) were obtained.The synthesized compounds were characterized by various methods such as X-ray (for ligand), NMR, Mass, UV–Vis, FT-IR, elemental analysis, molar conductivity.The spectral data showed that the molecular structure of Pd(II) complex exhibitsa four-coordinated square planar structure around the metal center, while other complexes exhibit a distorted triangular bipyramidal geometry with five coordination. There are no conductivity characteristics in the complexes showing non-electrolyte nature in solution. Furthermore, the compounds were utilized as catalysts in the synthesis of cyclic carbonates from epoxide and CO 2. The tridentate SNS pincer type complex (L-Co) showed the highest catalytic activity (at 100 °C and 1.6 MPa of CO 2 pressure) for the carboxylation of epichlorohydrin with 90.3% conversion after just 1 h. [ABSTRACT FROM AUTHOR]