Synthesis,characterization and DFT aspects of some oxovanadium(IV) and manganese(II) complexes involving dehydroacetic acid and β-diketones

Six new mixed-ligand oxovanadium(IV) and manganese(II) complexes of the general composition [VO(dhaH)(L¹H)(L²)] and [Mn(dhaH)(L¹H)(L²)], where dhaH=dehydroacetic acid, L¹H=β-ketoenolates viz., acetoacetanilide (aaaH), o-acetoacetotoluidide (o-aatdH), o-acetoacetanisidide (o-aansH) and L²=benzimidazole (bzl), 3-methyl-1phenyl-2pyrazoline-5one (mphp), 2-aminobenzimidazole (abzl) or 2-aminobenzathiozole (abtz) have been synthesized. The resultant complexes were characterized on the basis of elemental analysis, molar conductance, magnetic measurements, mass spectrometry, thermogravimetric analysis, infrared and electron spin resonance studies. The thermal decomposition processes of one representative of the complexes are discussed and the order of reaction (n), the activation energies (E_a), the pre-exponential factor (A), have been calculated from thermogravimetric (TG) and differential thermogravimetric (DTG) curves. Gaussian 09 software package was used to carry out theoretical computation using density functional theory (DFT) methods with Becke3-Lee-Yang-Parr (B3LYP) hybrid exchange-correlation functional and the standard LANL2 MB basis set. Based on combined experimental-theoretical characterization, a suitable octahedral structure has been proposed for this class of complexes.     

Preparation of Schiff’s base complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) and their spectroscopic, magnetic, thermal, and antifungal studies

The potassium salt of salicylidene-DL-alanine (KHL), bis(benzylidene)ethylenediamine (A¹), thiophene-o-carboxaldene-p-toluidine (A²), and its metal complexes of the formula [(M^II(L)(A)(H₂O)] (M = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II); A = A¹ or A²) are prepared. They are characterized by elemental analysis, magnetic susceptibility measurements, thermogravimetric analysis, and infrared and electronic spectral studies. The electronic spectral and magnetic moment data suggest an octahedral geometry for the complexes. All of these complexes, metal nitrates, fungicides (bavistin and emcarb), and ligands are screened for their antifungal activity against Aspergillus niger, Fusarium oxysporum, and Aspergillus flavus using a plate poison technique. The complexes show higher activity than those of the free ligands, metal nitrate, and the control (DMSO) and moderate activity against bavistin and emcarb. The text was submitted by the authors in English.     

新型三齿多吡啶钴(II)、钌(II)配合物的合成、表征及其与DNA的作用研究

合成了两种新型三齿多吡啶钴(II)和钌(II)的混配配合物[Co(TolylTPy)(H₂Bzimpy)]Cl₂ [TolylTPy＝4'-对甲基苯 基-2,2':6',2'-三联吡啶, H₂Bzimpy＝2,6-二(苯并咪唑-2)吡啶] (A)和Ru(TolylTPy)(Bzimpy) (B). 用元素分析, IR, ¹H NMR等对它们进行了表征, 测定了配合物B的晶体结构, 用电子吸收光谱、荧光光谱等研究了配合物与小牛胸腺DNA(CTDNA)的相互作用及其对pBR322 DNA的断裂作用. 结果表明, 配合物A和B与CTDNA的作用属静电结合, 凝胶电泳实验说明配合物A在310 nm光辐射15 min, 可使超螺旋pBR322 DNA断裂为开环缺口型和线型DNA.     

Synthesis,Structural, and Antibacterial Studies of Some Mixed Ligand Complexes of Zn(II), Cd(II), and Hg(II) Derived From Citral Thiosemicarbazone and N-Phthaloyl Amino Acids

A series of new mixed ligand complexes of Zn(II), Cd(II), and Hg(II) with cis-3,7-dimethyl-2,6-octadienthiosemicarbazone (CDOTSC; LH) and N-phthaloyl amino acids (AH) have been synthesized by the reaction of metal dichloride with ligands CDOTSC and N-phthaloyl derivative of DL-glycine (A₁H), L-alanine (A₂H), or L-valine (A₃H) in a 1:1:1 molar ratio in dry refluxing ethanol. All the isolated complexes have the general composition [M(L)(A)]. The plausible structure of these newly synthesized complexes has been proposed on the basis of elemental analyses, molar conductances, molecular weight measurement, and various spectral (IR, ¹H NMR, and ¹³C NMR) studies, and four coordinated geometries have been assigned to these complexes. All the complexes and ligands have been screened for their antibacterial activity.     

Ni(II) and Cu(II) complexes of new unsymmetrical N2O2 Schiff bases derived from 3-(2-aminobenzylimino)-1-phenylbutan-1-ol: synthesis,structure, antibacterial properties,and electrochemistry

Two new N₂O₂ unsymmetrical Schiff bases, H₂L¹ = 3-[({o-[(E)-(o-hydroxyphenyl)methylideneamino]phenyl}methyl)imino]-1-phenyl-1-buten-1-ol and H₂L² = 3-[({o-[(E)-(2-hydroxy-1-naphthyl)methylideneamino]phenyl}methyl)imino]-1-phenyl-1-buten-1-ol, and their copper(II) and nickel(II) complexes, [CuL¹] (1), [CuL²] (2), [NiL¹] (3), and [NiL²] (4), have been synthesized and characterized by elemental analyses and spectroscopic methods. The crystal structures of these complexes have been determined by X-ray diffraction. The coordination geometry around Cu(II) and Ni(II) centers is described as distorted square planar in all complexes with the CuN₂O₂ coordination more distorted than the Ni ones. The electrochemical studies of these complexes indicate a good correlation between the structural distortion and the redox potentials of the metal centers. The ligand and metal complexes were also screened for their in vitro antibacterial activity.     

Polydentate Schiff-base ligands and their Cd(II) and Cu(II) metal complexes: synthesis,characterization, biological activity and electrochemical properties

Synthesis, characterization, microbiological activity and electrochemical properties of the Schiff-base ligands A¹–A⁵ and their Cd(II) and Cu(II) metal complexes are reported. The ligands and their complexes have been characterized by elemental analysis, FT–IR, UV–Vis, ¹H- and ¹³C-NMR, mass spectra, magnetic susceptibility and conductance measurements. In the complexes, all the ligands are bidentate, the oxygen in the ortho position and azomethine nitrogen atoms of the ligands coordinate to the metal ions. The keto-enol tautomeric forms of the Schiff-base ligands A¹–A⁵ have been investigated in polar and non-polar organic solvents. Antimicrobial activity of the ligands and metal complexes were tested using the disc diffusion method and the chosen strains include Bacillus megaterium and Candida tropicalis. The electrochemical properties of the ligands A¹–A⁵ and their Cu(II) metal complexes have been investigated at different scan rates (100–500?mV?s^?1) in DMSO.     

Synthesis,Spectroscopic Characterization,and Antifungal Activity of Some Mixed Ligand Complexes of Zn(II), Cd(II), and Hg(II)

A series of new mixed ligand complexes of Zn(II), Cd(II), and Hg(II) with citronellal thiosemicarbazone [3,7-dimethyl-6-octene-1-a1 thiosemicarbazone (LH)] and N-phthaloyl amino acids (AH) have been synthesized by the reaction of metal(II) chloride with ligands citronellal thiosemicarbazone (DOTSC) and N-phthaloyl glycine [1,3-dihydro-1,3-dioxo-2H-isoindole-2-acetic acid (A₁H)] or N-phthaloyl alanine [1,3-dihydro-1,3-dioxo-α(methyl)-2H-isoindole-2-acetic acid (A₂H)] in 1:1:1 molar ratio in dry refluxing ethanol. All the complexes have been characterized by elemental analyses, molar conductance measurement, molecular weight measurement, IR, and multinuclear NMR (¹H and ¹³C{¹H}) spectral studies. IR, ¹H, and ¹³C{¹H} NMR spectral studies suggest the involvement of azomethine-N, thiol-S atoms of the thiosemicarbazone moiety and both carboxylate-O of N-phthaloyl amino acid moiety in coordination with central metal(II) ion, and four coordinated geometries have been assigned to these complexes. The free ligands and metal complexes have been screened for their antifungal activity against two fungal strains, Fusarium moniliformae and Macrophomina phaseolina, using the the radial growth method. The results of antifungal activity show that metal complexes show enhanced higher activity than the free ligands.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and spectral studies of copper(II), nickel(II), cobalt(II) and vanadyl(II) complexes of tridentate Schiff bases of 1,2,3,5,6,7,8,8a-octahydro-3-oxo-N,1-diphenyl-5-(phenylmethylene)-2-naphthalenecarboxamide

Summary Metal(II) chelates of Schiff bases derived from the condensation of 1,2,3,5,6,7,8,8a-octahydro-3-oxo-N,1-diphenyl-5-(phenylmethylene)-2-naphthalenecarboxamide with o-aminophenol (KAAP), o-aminothiophenol (KAAT) or o-aminobenzoic acid (KAAB) have been prepared and characterized. The complexes are of the type [M(N₂X)]₂ for M = Cu^II and M(NX)₂·nH₂O for M = Ni^II, Co^II and VO^II (X = phenolic oxygen, thiophenolic sulphur or carboxylic oxygen; n = 0 or 2). Conductivity data indicate that the complexes are non-ionic. The Schiff bases behave as dibasic tridentate ligands in their copper(II) complexes and as monobasic bidentate ligands in their nickel(II), cobalt(II) and vanadyl(II) complexes. The subnormal magnetic moments of the copper(II) complexes are ascribed to an antiferromagnetic exchange interaction arising from dimerization. Nickel(II) and cobalt(II) complexes are trans octahedral whereas vanadyl(II) complexes are square pyramidal     

Biomimetic complexes of Mn(II), Fe(III), Co(II), and Ni(II) with 1,10-phenanthroline and a salen type ligand: tailored synthesis,characterization, DFT,enzyme kinetics,and antibacterial screening

Abstract

A symmetrical tetradentate Schiff base, o-HACPHENEN, was prepared by condensation of 1,2-bis(ethylenediamine) with o-hydroxyacetophenone in 1:2 molar ratio. The Schiff base ligand and 1,10-phenanthroline were used for the tailored synthesis of four mixed-ligand complexes, [Mn(o-HACPHENEN)(1,10-phen)] (1), [Fe(o-HACPHENEN)(1,10-phen)]Cl (2), [Co(o-HACPHENEN)(1,10-phen)] (3), and [Ni(o-HACPHENEN)(1,10-phen)] (4). The ligand and complexes were characterized on the basis of elemental analyses, ESI-MS, molar conductance, electronic, FT-IR, ¹H-NMR, and ¹³C-NMR spectra. DFT study was used to optimize the geometry of the investigated compounds. Using Gaussian09 molecular modeling, HOMO-LUMO study, bond lengths, bond angles, molecular electrostatic potential map (MEP), and Mulliken charge were also evaluated. Complexes displayed remarkable catalase-like activity in the disproportion reactions of hydrogen peroxide. The kinetics of the activity were investigated and data are fitted in Lineweaver Burk plot, revealing Michaelis Menten behavior. The catalase activity of ligand and complexes were found in the order 1 > 2 > 4 > 3 > o-HACPHENEN. Compounds were screened for their antibacterial activity against gram-negative bacteria Escherichia coli in comparison to standard drugs. Complexes were more potent than Schiff base. The MIC of complexes was also studied.     

Synthesis,spectral, and antifungal studies of transition metal complexes with sixteen-membered hexadentate macrocylic ligand

A novel hexadentate nitrogen donor [N₆] macrocyclic ligand viz, 1,5,11,15,21,22-hexaaza-2,14-dimethyl-l4,12-diphenyltricyclo[15.3.1.I(7–11)]docosane[1,4,6,8,10(22)-11,14,16,18,20(21)]decaene (L), has been synthesised. The Co (II), Ni (II), and Cu (II) complexes with this ligand have been prepared and subjected to elemental analysis, molar conductance, magnetic susceptibility measurements, mass, ¹H NMR (ligand), IR, electronic, and ESR spectral studies and electrochemical investigation. On the basis of molar conductance the complexes can be formulated as [M(L)]X₂ (where M = Co (II), Ni (II), Cu (II) and X = Cl⁻ and NO₃⁻) due to their 1: 2 electrolytic nature in DMSO. All the complexes are of the high-spin type and are six-coordinated. On the basis of IR, electronic, and ESR spectral studies, an octahedral geometry has been assigned for the Co(II) and Ni(II) complexes, whereas a tetragonal geometry for the Cu(II) complexes was found. Antimicrobial activity of L and its complexes as growth inhibiting agents have been screened in vitro against two species (F. moniliformae and R. solani) of plant pathogenic fungi. The text was submitted by the authors in English.     

Synthesis,characterization, thermal and redox behavior,and biological activity of Ni(II), Cu(II), and Zn(II) complexes containing pyridoxine and imidazole moieties

Several mixed ligand complexes [M(II)(PN)(B)] [M(II) = Ni(II), Cu(II), and Zn(II)] derived from pyridoxine (PN) and imidazoles (B), namely imidazole (him), benzimidazole (bim), histamine (hist), and L-histidine (his), were synthesized. The complexes are characterized by elemental analysis, IR, UV-Vis ¹H NMR, and ESR spectroscopy. In [M(II)(PN)B], the monovalent anion of PN is bidentate to M(II) (–O, –OH), him, bim monodentate (–N), hist bidentate (–N, –N), and his tridentate (–O, –N, –N). Magnetic moment studies showed that the Ni(II) complexes and Cu(II)–PN–his have octahedral configuration while the other Cu(II) complexes have distorted tetrahedral geometry. The g _∥/A _∥ values calculated from the X-band ESR spectra of Cu(II) complexes in DMSO at 300 and 77 K supports the geometry. The thermal behavior (TG/DTA) of the synthesized complexes indicates the presence of lattice as well as coordinated water in the complexes. The in vitro biological activity of the mixed ligand complexes was tested against common bacteria, yeast, and fungi. The results in comparison with the control indicate that most of the complexes exhibit higher biological activities. The oxidative DNA cleavage studies of the mixed ligand complexes were performed using gel electrophoresis.     

Synthesis,characterization, electrochemical and in-vitro antimicrobial studies of Co(II), Ni(II), and Cu(II) complexes with Schiff bases of formyl coumarin derivatives

A series of Co(II), Ni(II), and Cu(II) complexes have been synthesized with Schiff bases (H₂L^I and H₂L^II) derived from 8-formyl-7-hydroxy-4-methylcoumarin or 5-formyl-6-hydroxycoumarin and o-aminophenol. Structures have been proposed from elemental analyses, spectral (IR, UV-Vis, FAB-mass, and Fluorescence), magnetic, and thermal studies. The measured low molar conductance values in DMF indicate that the complexes are non-electrolytes. Elemental analyses indicate ML · 3H₂O [M = Co(II), Ni(II), and Cu(II)] stoichiometry. Spectroscopic studies suggest coordination through azomethine nitrogen, phenolic oxygen of o-aminophenol, and the coumarin via deprotonation. The Schiff bases and their complexes have been screened for antibacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella typhi) and antifungal (Aspergillus niger, Aspergillus flavus, and Cladosporium) activities by minimum inhibitory concentration (MIC) method. The redox behavior of the complexes was investigated using cyclic voltammetry (CV).     

Synthesis,characterization, and biological investigation of new mixed-ligand complexes

A novel series of mixed-ligand complexes of 5,5′-{(1E,1E′)-1,4-phenelynebis(diazene-2,1-diyl)}bis(quinolin-8-ol) (H₂L₁) as a primary ligand and 4-aminoantipyrine(L₂) as a secondary ligand with Mn(II) ion were prepared using two general formulae: [Mn₂(H₂L₁)₂(L₂)₂X₄].4Cl (X = OH₂( 1 ), ONO₂⁻( 2 ), Cl=nil; OAc( 3 ), Cl = nil) and [Mn₂(H₂L₁)(L₂)₂(O₂SO₂)₂]( 4 ). Free ligands and their complexes were characterized. Electronic absorption spectra of the mixed-ligand complexes indicate a distorted octahedral geometry around the central metal ion, and the anions X⁻ are in the axial positions for all compounds. The ligands behave in a neutral bidentate manner, through nitrogen atoms and oxygen atoms of the carbonyl group (L₂), whereas H₂L₁ coordinated through nitrogen and OH groups as a neutral bidentate ligand. All complexes do not contain coordinated water molecules, but complex ( 1 ) contains four water molecules. The water molecules are removed in a single step. The complexes exhibited magnetic susceptibility corresponding to five unpaired electrons. The antimicrobial activity of the Mn(II) mixed-ligand complexes ( 1–4 ) against two gram-positive bacteria, three local gram-negative bacteria, and three fungi species was tested. Mn(II) mixed-ligand complex ( 2 ) exhibited significant antibacterial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas sp. Mixed-ligand complex ( 2 ) exhibited a high potential cytotoxicity against the growth of human lung cancer cells.     

Cobalt(III), nickel(II) and ruthenium(II) complexes of 1,10-phenanthroline family of ligands: DNA binding and photocleavage studies

DNA binding and photocleavage characteristics of a series of mixed-ligand complexes of the type [M(phen)₂LL]ⁿ⁺ (where M = Co(III), Ni(II) or Ru(II), LL = 1,10-phenanthroline (phen), phenanthroline-dione (phen-dione) or dipyridophenazine (dppz) andn = 3 or 2) have been investigated in detail. Various physico-chemical and biochemical techniques including UV/Visible, fluorescence and viscometric titration, thermal denaturation, and differential pulse voltammetry have been employed to probe the details of DNA binding by these complexes; intrinsic binding constants (K _b) have been estimated under a similar set of experimental conditions. Analysis of the results suggests that intercalative ability of the coordinated ligands varies as dppz>phen>phen-dione in this series of complexes. While the Co(II) and Ru(II) complexes investigated in this study effect photocleavage of the supercoiled pBR 322 DNA, the corresponding Ni(II) complexes are found to be inactive under similar experimental conditions. Results of detailed investigations carried out inquiring into the mechanistic aspects of DNA photocleavage by [Co(phen)₂(dppz)]³⁺ have also been reported.     

Synthesis,structural characterization,antimicrobial, DNA-binding,and photo-induced DNA cleavage activity of some bio-sensitive Schiff base copper(II) complexes

Schiff base mixed-ligand copper complexes [CuL¹(phen)Cl₂], [CuL¹(bipy)Cl₂], [Cu(L¹)₂Cl₂], [Cu(L²)₂Cl₂], [CuL²(bipy)Cl₂], and [CuL²(phen)Cl₂] (where L^1?=?4-[3,4-dimethoxy-benzylidene]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazole-3-one; L^2?=?4-[3-hydroxy-4-nitro-benzylidene]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazole-3-one; phen?=?1,10-phenanthroline; and bipy?=?2,2′-bipyridine) have been synthesized and characterized. Their DNA-binding properties have been studied by electronic absorption spectra, viscosity, and electrochemical measurements. The absorption spectral and viscosity results suggest that the copper(II) complexes bind to DNA via partial intercalation. The addition of DNA resulting in the decrease of the peak current of the copper(II) complexes indicates their interaction. Interaction between the complexes and DNA has also been investigated by submarine gel electrophoresis. The copper complexes cleave supercoiled pUC19 DNA to nicked and linear forms through hydroxyl radical and singlet oxygen in the presence of 3-mercaptopropionic acid as the reducing agent. These copper complexes promote the photocleavage of pUC19 DNA under irradiation at 360?nm. Mechanistic study reveals that singlet oxygen is likely to be the reactive species responsible for the cleavage of plasmid DNA by the synthesized complexes. The in vitro antimicrobial study indicates that the metal chelates have higher activity against the bacterial and fungal strains than the free ligands.     

Copper(II), nickel(II) and cobalt(II) complexes of oxaldihydrazide and succindihydrazide Schiff bases with salicylaldehyde ando-hydroxyacetophenone

Summary Polymeric copper(II), nickel(II) and cobalt(II) complexes of the type M₂L where M = Cu^II, Ni^II or Co^II and H₄L = disalicylaldimine oxamide (H₄A), di(o-hydroxyacetophenoneimine)oxamide (H₄B), disalicylaldimine succinamide (H₄C) or di(o-hydroxyacetophenoneimine)succinamide (H₄D), have been synthesized and characterized by analysis, i.r. and electronic spectra and magnetic moment data. Copper(II) complexes and some of the nickel(II) and cobalt(II) complexes are planar while other nickel(II) complexes are distorted octahedral and other cobalt(H) complexes are square pyramidal. Anomalously low magnetic moments of some complexes have been related to M-M interactionsvia oxo-bridge structures.     

Mixed Ligand Complex Formation of Cetirizine Drug with Bivalent Transition Metal(II) Ions in the Presence of 2-Aminomethylbenzimidazole: Synthesis,Structural, Biological,pH-Metric and Thermodynamic Studies

Mononuclear copper(II), cobalt(II) and nickel(II) complexes of cetirizine (CTZ = 2-[2-[4-[(4-chlorophenyl)phenyl methyl]-piperazine-1-yl]-ethoxy]acetic acid) in the presence of 2-aminomethyl-benzimidazole·2HCl (AMBI), as a representative example of heterocyclic bases, were synthesized and studied by different physical techniques. All mixed-ligand complexes have been fully characterized with the help of elemental analyses, molecular weight determinations, molar conductance, magnetic moments and spectroscopic data. The formulae of the isolated complexes are [M(AMBI)(CTZ)(NO₃)(H₂O)₂]·nH₂O where AMBI is the neutral bidentate 2-aminomethylbenzimidazole, CTZ the deprotonated cetirizine and n = 1 for Co(II) or 0 for Cu(II) and Ni(II) complexes. The measured molar conductance values in DMSO indicate that the complexes are non-electrolytes. The formation equilibria of the ternary complexes have been investigated. Ternary complexes are formed by a simultaneous mechanism. Stoichiometry and stability constants for the complexes formed are reported. The concentration distribution of the complexes in solution was evaluated as a function of pH. The thermodynamic parameters were calculated from the temperature dependence of the equilibrium constants and are discussed. The synthesized metal chelates have been screened for their antimicrobial activities against the selected types of Gram-positive (G⁺) and Gram-negative (G^?) bacteria. They were found to be more active against Gram positive than Gram negative bacteria. The antimicrobial activity in terms of metal ions obeys this order: Cu(II) > Ni(II) > Co(II).     

Green Synthesis of new Trizole Based Heterocyclic Amino Acids Ligands and their Transition Metal Complexes. Characterization,Kinetics, Antimicrobial and Docking Studies

Two novel amino acids imine ligands (H₂L₁ and H₂L₂) have been synthesized using green condensation reaction from 2‐[3‐Amino‐5‐(2‐hydroxy‐phenyl)‐5‐methyl‐1,5‐dihydro‐[1, 2, 4]triazol‐4‐yl]‐3‐(1H‐indol‐3‐yl)‐propionic acid with benzaldehyde/p‐flouro benzaldehyde (1:1 molar ratio) in the presence of lemon juice as a natural acidic catalyst in aqueous medium. Their transition metal complexes have been prepared in a molar ratio (1:1). Characterization of the ligands and complexes using elemental analysis, spectroscopic studies, ¹HNMR, ¹³CNMR, and thermal analysis has been reported. E*, ΔH*, ΔS* and ΔG* thermodynamic parameters, were calculated to throw more light on the nature of changes accompanying the thermal decomposition process of these complexes. The molar conductance measurement of metal complexes showed nonelectrolyte behavior. The metal complexes of the two ligands have tetrahedral geometry with a general molecular structure [M(H₂L)X_n], where [(M = Mn (II), Co (II), Cu (II) and Zn (II), X = Cl, n = 2]; M = VO (II), X = SO₄, n = 1] for H₂L₁. [M = Co (II), Cu (II), Zn (II)] for H₂L₂. Antibacterial activity of the complexes against (Bacillis subtilis, Micrococcus luteus, Escherichia coli), also antifungal activity against (Aspergillus niger, Candida Glabarta, Saccharomyces cerevisiae) have been screened. The results showed that all complexes have antimicrobial activity higher than free ligands. Molecular docking studies results showed that, all the synthesized compounds having minimum binding energy and have good affinity toward the active pocket, thus, they may be considered as good inhibitor of targeting PDB code: 1SC7 (Human DNA Topo‐isomerase I).     

Synthesis, spectral characterization, catalytic and antibacterial studies of new Ru(III) Schiff base complexes containing chloride/bromide and triphenylphosphine/arsine as co-ligands

A new Ru(III) Schiff base complexes of the type [RuX(EPh₃)L] (X = Cl/Br; E = P/As; L = dianion of the Schiff bases were derived by the condensation of 1,4-diformylbenzene with o-aminobenzoic acid/o-aminophenol/o-aminothiophenol in the 1:2 stoichiometric ratio) have been synthesized from the reactions of [RuX₃(EPh₃)₃] with appropriate Schiff base ligands in benzene in the 2:1 stoichiometric ratio. The new complexes have been characterized by analytical, spectral (IR, electronic, ¹H, ¹³C NMR and ESR), magnetic moment and electrochemical studies. An octahedral structure has been tentatively proposed for all these new complexes. All the new complexes have been found to be better catalyst for the oxidation of alcohols using molecular oxygen as co-oxidant at ambient temperature and aryl–aryl coupling reactions. These complexes were also subjected to antibacterial activity studies against Escherichia coli, Aeromonas hydrophilla and Salmonella typhi.     

Synthesis,characterization, and catalytic oxidation of ethylbenzene over host (zeolite-Y)/guest (copper(II) complexes of tetraaza macrocyclic ligands) nanocomposite materials

Cu(II) complexes of 14- and 16-membered tetraaza macrocyclic ligands have been encapsulated in nanopores of zeolite-Y by a two-step process in the liquid phase: (1) adsorption of [bis(diamine)copper(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, and 1,3-diaminobenzene); [Cu(N–N)₂]²⁺–NaY; in the nanopores of the zeolite-Y and (2) in situ condensation of the copper(II) precursor complex with ethylcinnamate. The new host–guest nanocomposite materials were characterized by chemical analysis and spectroscopic methods. The “neat” and encapsulated complexes exhibit good catalytic activity in the oxidation of ethylbenzene at 333 K, using tert-butyl hydroperoxide as the oxidant. Acetophenone was the major product though small amounts of o- and p-hydroxyacetophenones were also formed revealing that C–H bond activation takes place both at benzylic and aromatic ring carbon atoms.