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The novel four SNS pincer‐type thioether containing Pd (II) complexes were synthesized and characterized by using FT‐IR, UV‐Vis, mass, elemental analysis techniques. The complexes were used as catalysts in the synthesis of vitamin K3 (2‐methyl‐1,4‐naphthoquinone) from 2‐methyl naphthalene. Hydrogen peroxide was used as green oxidant in acetic acid and sulfuric acid medium. L2‐Pd (II) and L3‐Pd (II) complexes showed the best catalytic activity with 62.63% and 61.05% selectivities in the conversions of 82.61% and 87.84%, respectively. Moreover, in silico studies on Pd (II) complexes have shown that L2‐Pd (II) and L3‐Pd (II) complexes have low band gaps between LUMO and HOMO energy levels and their electrostatic energy values are higher than other complex structures. This reveals that they have better chemical activity than other complexes and also supports the experimental studies carried out in this research. The conversions and the selectivities of these complexes are one of the best compared to the literature. Peroxyacetic acid with sulfuric acid is a very important oxidant in the oxidation of 2‐methyl naphthalene to 2‐methyl‐1,4‐naphthoquinone. [ABSTRACT FROM AUTHOR]

Two new chiral thiosemicarbazide ligands and their Cu (II), Ni (II), Pd (II), and Zn (II) complexes were synthesized and characterized by nuclear magnetic resonance (NMR) (only for ligand), Fourier transform infrared (FT‐IR), ultraviolet visible (UV‐Vis), mass, and elemental analysis. The antioxidant activity of ligands and their metal complexes was examined. It was found that the antioxidant activity of metal complexes was better than their ligands. In addition, the antioxidant activity, as reflected by free radical scavenging, was evaluated. Besides, Pd (II) complexes exhibited better antioxidant activity than Ni (II), Cu (II), and Zn (II) complexes. Therefore, complexes (3a‐Pd and 3b‐Pd) can be used as an antioxidant agent or antioxidant test standard. [ABSTRACT FROM AUTHOR]

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]

A new heterocyclic compound N-(5-benzoyl-2-oxo-4-phenyl-2H-pyrimidin-1-yl)-oxalamic acid has been synthesized from N-amino pyrimidine-2-one and oxalylchloride. Bis-chelate complexes of the ligand were prepared from acetate/chloride salts of Cu(II), Co(II), Mn(II), Ni(II), Zn(II), Cd(II), and Pd(II) in methanol. The structures of the ligand and its metal complexes were characterized by microanalyses, IR, AAS, NMR, API-ES, UV-Vis spectroscopy, magnetic susceptibility, and thermogravimetric analyses. An octahedral geometry has been suggested for all the complexes, except for Pd(II) complex, in which the metal center is square planar. Each ligand binds using C(2)=O, HN, and carboxylate. The cyclic voltammograms of the ligand and the complexes are also discussed. The new synthesized compounds were evaluated for antimicrobial activities against Gram-positive, Gram-negative bacteria and fungi using the microdilution procedure. The Cu(II) complex displayed selective and effective antibacterial activity against one Gram-positive spore-forming bacterium (Bacillus cereus ATCC 7064), two Gram-positive bacteria (Staphylococcus aureus ATCC 6538 and S. aureus ATCC 25923) at 40-80 µg mL-1, but poor activity against Candida species. The Cu(II) complex might be a new antibacterial agent against Gram-positive bacteria. [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]

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 heterocylic Schiff base derived from 1-amino-5-benzoyl-4-phenyl-1H-pyrimidine-2-one with 3-hydroxy-salicylaldehyde have been synthesized and characterized on the basis of elemental analyses, electronic, IR and 1H NMR spectra, molar conductivity measurements, magnetic moment measurements and thermogravimetric analyses (TGA). It has been found that the Schiff base behaves as a neutral bidentate (NO) or tridentate (ONO) ligand forming chelates with 1:2 (metal:ligand) stoichiometry and octahedral geometry. The conductivity data for the Ni(II) complex is consistent with that expected for a weak electrolyte. [ABSTRACT FROM AUTHOR]

Two novel tridentate SNS pincer type ligands, 2,6-bis[[(2 ′ -methoxyphenyl)thio]methyl]pyridine (L1) and 2,6-bis[[(2 ′ -chlorophenyl)thio]methyl]pyridine (L2), each possessing two sulfur and one nitrogen donor functionalities (SNS), based on 2,6-bis(thioether)pyridine ligands were prepared and metallised with CuCl 2 · 2 H 2 O and FeCl 2 · 4 H 2 O metal salts. Two new unanticipated complexes were obtained from the L2 ligand, the dimeric bidentate Cu(I) complex [ Cu 2 ( κ 2 - L 2) 2 Cl 2 ] and tridentate Fe(II) complex [ Fe ( κ 3 - L 2) Cl 2 ] while two new tridentate pincer-type complexes M( κ 3 -L1) Cl 2 ] ( M = Cu , Fe ) were formed from the L1 ligand. It was observed that the structure of this Cu(I) complex has a tetrahedral geometry using single crystal X-ray diffraction analysis. In addition, catalytic properties of metal complexes towards the formation of cyclic carbonates from CO 2 and epoxides were investigated. The less sterically hindered Fe(II) complex with the L1 ligand [ Fe ( κ 3 - L 1) Cl 2 ] (2) showed the best catalytic activity. Several parameters including temperature, time, epoxide identity and CO 2 pressure were investigated to find the optimum catalytic reaction conditions. Moreover, DFT studies of these compounds are presented in the study. Two novel tridentate SNS pincer type ligands and their metal complexes were synthesized and characterized. In addition, the catalytic properties of the metal complexes towards the formation of cyclic carbonates from CO 2 and epoxides were investigated. The less sterically hindered [Fe( κ 3 -L1) Cl 2 ] (2) showed the best catalytic activity. Several parameters including temperature, time, epoxide identity and CO 2 pressure were investigated to find the optimum catalytic reaction conditions. Moreover, DFT studies of these compounds are presented in the study. [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]

The novel four SNS pincer‐type thioether containing Pd (II) complexes were synthesized and characterized by using FT‐IR, UV‐Vis, mass, elemental analysis techniques. The complexes were used as catalysts in the synthesis of vitamin K3 (2‐methyl‐1,4‐naphthoquinone) from 2‐methyl naphthalene. Hydrogen peroxide was used as green oxidant in acetic acid and sulfuric acid medium. L2‐Pd (II) and L3‐Pd (II) complexes showed the best catalytic activity with 62.63% and 61.05% selectivities in the conversions of 82.61% and 87.84%, respectively. Moreover, in silico studies on Pd (II) complexes have shown that L2‐Pd (II) and L3‐Pd (II) complexes have low band gaps between LUMO and HOMO energy levels and their electrostatic energy values are higher than other complex structures. This reveals that they have better chemical activity than other complexes and also supports the experimental studies carried out in this research. The conversions and the selectivities of these complexes are one of the best compared to the literature. Peroxyacetic acid with sulfuric acid is a very important oxidant in the oxidation of 2‐methyl naphthalene to 2‐methyl‐1,4‐naphthoquinone. [ABSTRACT FROM AUTHOR]

Two pincer ligands, 2,6-bis[[(2′-methylphenyl)thio]methyl]pyridine ( SNS-1 ) and 2,6-bis[[(2′,6′-dimethylphenyl)thio]methyl]pyridine ( SNS-2 ), each possessing a central pyridyl N -donor flanked by two thioether S-Ar functionalities were prepared and metallated with CoCl 2 , FeCl 2 ·4H 2 O, CuCl 2 ·2H 2 O metal salts. The products of reaction with SNS-1 were three new tridentate pincer complexes [M(κ 3 - SNS-1 )Cl 2 ] (M = Fe, Co, Cu). The reactions of ligand SNS-2 yielded analogous complexes, [M(κ 3 - SNS-2 )Cl 2 ], for FeCl 2 and CoCl 2 but in the case of the reaction with CuCl 2 the product was an unanticipated Cu(I) complex [Cu(κ 2 - SNS-2 )Cl]. Single crystal X-ray diffraction analysis revealed that this Cu(I) complex displayed a bidentate S,N ligand and a pseudo-trigonal planar geometry for the Cu center. The ability of these metal complexes to catalyze the formation of cyclic carbonates from CO 2 and epoxides was investigated and the less sterically hindered Co(II) complex, [Co(κ 3 - SNS-1 )Cl 2 ] showed superior activity. The effects of variation in time, temperature, CO 2 pressure, and epoxide identity were investigated. [ABSTRACT FROM AUTHOR]

Taking into account the broad spectrum of catalytic and bioactivity, it has been importance the compounds containing pyridine in the molecular structure. Here we report the synthesis, structural and spectroscopic analysis of a novel compound (the title compound) containing pyridine and m -xylene with thioether-bridge. The molecular structure of compound brought to light by X-ray single crystal structure determination. The spectroscopic properties of the compound were examined by FT-IR and NMR ( 1 H and 13 C) techniques. FT-IR spectra of the target compound in solid state was observed in the region 4000–400 cm −1 . The 1 H and 13 C NMR spectra were recorded in DMSO-d 6 solution. The molecular geometry were those obtained from the X-ray structure determination was optimized using density functional theory (DFT/B3LYP) method with the 6-31G+(d, p) basis set in ground state. From the optimized geometry of the molecule, geometric parameters (bond lengths, bond angles and torsion angles), vibrational assignments and chemical shifts of the title compound have been theoretically calculated and compared with the experimental data. [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]

• 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 SNS pincer type ligand, 2,6-bis[[(4-bromophenyl)thio]carbonyl]pyridine (L) and its metal complexes (L-Pd, L-Ni, L-Fe, L-Cu) were synthesized and characterized by using X-ray (for ligand), NMR (for ligand), UV-Vis, FT-IR, mass, elemental analysis techniques. The products of reaction with L were new bidentate pincer complex [Pd(κ2- L)(OAc) 2 ] and three tridentate pincer complexes [M(κ3- L)(OAc) 2 ] (M = Fe, Ni, Cu). The molecular structure of ligand (L) was characterized by X-ray single crystal structure determination. The molecular structures of Fe, Cu, and Ni complexes exhibit a five-coordinate distorted trigonal bipyramidal geometry around their metal centers, while the Pd complex exhibits a four-coordinated square plane structure. Moreover, the compounds were used to obtain cyclic carbonates from the reaction of epoxide and CO 2 as catalysts. The best performance was obtained in the presence of L-Pd catalyst and DMAP as co-catalyst, with a 93.9% yield and 98.9% selectivity. [Display omitted] [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]

Abstract: A ligand(N-APTH) and Co(II)complex compound of bidentate ligand which contains a ring of the pyrimidine have been produced. For the optical transmission measurements of the Co(II)complex compound thin films, a UV–Visible (UV–Vis) spectrophotometer was employed. As a result of optical measurements, it was revealed that Co(II)complex compound tends to show a semiconductor characteristic with the bandgap value of 3.46eV. An attempt has been made to explore the rectifying and ohmic properties of Al/Co(II)complex compound/Cu structures assuming that Co(II)complex compound may exhibit a rectifier or ohmic behavior, depending on the fabrication process, when brought into an appropriate contact with a metal. From current–voltage (I–V) measurements, it was found that the device could show good ohmic and rectifying properties intentionally depending on the experimental process followed during fabrication. [Copyright &y& Elsevier]

Abstract: We have produced a Ligand(N-APTH) and Cu(II)Complex of bidentate ligand containing a ring of the pyrimidine. Optical transmission measurements of the Ligand(N-APTH) and Cu(II)Complex thin films were performed by using a UV–Visible (UV–VIS) spectrophotometer. From the optical measurements, it was seen that the materials show semiconductor behaviors giving appropriate bandgaps with the values of 3.15eV and 2.36eV for Ligand(N-APTH) and Cu(II)Complex, respectively. With the pre-assumption that the material may exhibit a rectifier or ohmic behavior when it is brought into an appropriate contact with a metal, an attempt to explore the rectifying and ohmic properties of Al/Ligand(N-APTH)/Cu and Al/Cu(II)Complex/Cu contacts was made. As a result of current–voltage (I–V) measurements, it was discovered that the devices show excellent rectifier properties with a rectification ratio of about 10−3 for Al/Ligand(N-APTH)/Cu and 10−5 for Al/Cu(II)Complex/Cu rectifier contacts, respectively. [ABSTRACT FROM AUTHOR]