The role of a redox-active non-innocent ligand in additive-free C-C Glaser-Hay and Suzuki coupling reactions by an -aminophenol palladium(ii) complex.

A novel mononuclear palladium complex with 2-(3,5-di--butyl-2-hydroxyphenyl amino) benzonitrile as a non-innocent ligand (abbreviated as PdL ) was synthesized, and characterized by IR, UV-Vis, H and C NMR spectroscopies and elemental analysis. The crystal structure clearly showed that the metal center was in a square planar environment. The bond lengths obtained from X-ray structure analysis revealed that both ligands are in the -iminobenzosemiquinone radical form.

Biradical -iminobenzosemiquinonato(1-) complexes of nickel(ii): catalytic activity in three-component coupling of aldehydes, amines and alkynes.

The six-coordinated bis--iminosemiquinone complex, NiL , in which L is the -iminosemiquinone 1-electron oxidized form of the tridentate -aminophenol benzoxazole-based ligand HL, was synthesized and characterized. The crystal structure of the complex reveals octahedral geometry with a NiNO coordination sphere in which Ni(ii) has been surrounded by two tridentate L ligands. This compound exhibits ( = 1) with both spin and orbital contribution to the magnetic moment and antiferromagnetic coupling between two electrons on two L ligands which results in a triplet spin ground state ( = 1).

Factors Affecting the Stability of Platinum(II) Complexes with 1,2,4-Triazolo[1,5-]pyrimidine Derivatives and Tetrahydrothiophene-1-Oxide or Diphenyl Sulfoxide.

The platinum(II) complexes of general formula [PtCl(dstp)(S-donor)] were dstp 5,7-dimethyl-1,2,4-triazolo[1,5-]-pyrimidine (dmtp), 5,7-ditertbutyl-1,2,4-triazolo[1,5-]pyrimidine (dbtp), 5-methyl-7-isobutyl-1,2,4-triazolo[1,5-]pyrimidine (ibmtp) or 5,7-diphenyl-1,2,4-triazolo[1,5-]pyrimidine (dptp), whereas S-tetrahydrothio-phene-1-oxide (TMSO) or diphenyl sulfoxide (DPSO) were synthesized in a one-pot reaction. Here, we present experimental data (H, C, N, Pt NMR, IR, X-ray) combined with density functional theory (DFT) computations to support and characterize structure-spectra relationships and determine the geometry of dichloride platinum(II) complexes with selected triazolopyrimidines and sulfoxides. Based on the experimental and theoretical data, factors affecting the stability of platinum(II) complexes have been determined.

Attachment of Chiral Functional Groups to Modify the Activity of New GPx Mimetics.

A series of new chiral benzisoselenazol-3(2)-ones and their corresponding diselenides bearing an -amido function substituted on the nitrogen atom with various aliphatic and aromatic moieties were synthesized. All derivatives representing pairs of enantiomers or diastereoisomers were obtained to thoroughly evaluate the three-dimensional structure-activity correlation. First, bensisoselenazol-3(2)-ones were synthesized by reacting 2-(chloroseleno)benzoyl chloride with an appropriate enantiomerically pure amine.

Adenylate kinases of thermophiles and : biochemical and kinetic studies.

Adenylate kinases (AK) play a pivotal role in the regulation of cellular energy. The aim of our work was to achieve the overproduction and purification of AKs from two groups of bacteria and to determine, for the first time, the comprehensive biochemical and kinetic properties of adenylate kinase from Gram-negative (AK) and Gram-positive (AK). Therefore we determined and values, and the effects of temperature, pH, metal ions, donors of the phosphate groups and inhibitor ApA for both thermophilic AKs.

Biological Inspirations: Iron Complexes Mimicking the Catechol Dioxygenases.

Within the broad group of Fe non-heme oxidases, our attention was focused on the catechol 1,2- and 2,3-dioxygenases, which catalyze the oxidative cleavage of aromatic rings. A large group of Fe complexes with N/O ligands, ranging from N to NOS, was developed to mimic the activity of these enzymes. The Fe complexes discussed in this work can mimic the intradiol/extradiol catechol dioxygenase reaction mechanism.

Assessing the Interactions of Statins with Human Adenylate Kinase Isoenzyme 1: Fluorescence and Enzyme Kinetic Studies.

Statins are the most effective cholesterol-lowering drugs. They also exert many pleiotropic effects, including anti-cancer and cardio- and neuro-protective. Numerous nano-sized drug delivery systems were developed to enhance the therapeutic potential of statins.

Platinum(II) Complexes with Bulky Disubstitute Triazolopyrimidines as Promising Materials for Anticancer Agents.

Herein, we present dicarboxylate platinum(II) complexes of the general formula [Pt(mal)(DMSO)(L)] and [Pt(CBDC)(DMSO)(L)], where L is dbtp 5,7-diutyl-1,2,4-triazolo[1,5-]pyrimidine) or ibmtp (7-isobutyl-5-methyl-1,2,4- triazolo[1,5-]pyrimidine), as prospective prodrugs. The platinum(II) complexes were synthesized in a one-pot reaction between -[PtCl(DMSO)], silver malonate or silver cyclobutane-1,1-dicarboxylate and triazolopyrimidines. All platinum(II) compounds were characterized by FT-IR, and H, C, N and Pt NMR; and their square planar geometries with one monodentate N(3)-bonded 5,7-disubstituted-1,2,4-triazolo[1,5-]pyrimidine, one S-bonded molecule of dimethyl sulfoxide and one O,O-chelating malonato (, ) or O,O-chelating cyclobutane-1,1-dicarboxylato (, ) was determined.

A biradical oxo-molybdenum complex containing semiquinone and -aminophenol benzoxazole-based ligands.

We report a new mononuclear molybdenum(iv) complex, MoOLL, in which L (2,4-di--butyl -semibenzoquinone ligand) has been prepared from the reaction of the -iminosemibenzoquinone form of a tridentate non-innocent benzoxazole ligand, L, and MoO(acac). The complex was characterized by X-ray crystallography, elemental analysis, IR and UV-vis spectroscopy and magnetic susceptibility measurements. The crystal structure of MoOLL revealed a distorted octahedral geometry around the metal centre, surrounded by one O and two N atoms of L and two O atoms of L.

Ancillary ligand electro-activity effects towards phenyl acetylene homocoupling reaction by a nickel(ii) complex of a non-innocent -amino phenol ligand: a mechanistic insight.

A new Ni(ii) complex, was synthesized from the reaction of a non-innocent -aminophenol ligand, and Ni(OAc). The crystal structure of NiL (in which, IS stands for iminosemiquinone radical ligand with cyanide (shown by N in NIS) substituent on phenolate rings) exhibits the square planar environment of Ni(ii). The complex has been crystalized in the monoclinic system and Ni(ii) was surrounded by two oxygen and two nitrogen atoms of two ligands.

A manganese(iii) Schiff base complex immobilized on silica-coated magnetic nanoparticles showing enhanced electrochemical catalytic performance toward sulfide and alkene oxidation.

In this study, a novel Mn(iii)-Schiff base complex was synthesized and characterized. The structure of this complex was determined to be a deformed octahedral coordination sphere by single-crystal X-ray diffraction analysis. The Mn(iii)-Schiff base complex was supported on silica-coated iron magnetic nanoparticles axial coordination by one-step complex anchoring to produce a heterogenized nanocatalyst.

Nanoencapsulation of a ruthenium(ii) complex with triazolopyrimidine in liposomes as a tool for improving its anticancer activity against melanoma cell lines.

Two types of ruthenium(ii) complexes containing 1,2,4-triazolo[1,5-a]pyrimidines of the general formulas [RuCl(dmso)(L)] ((1)-(3)) and [RuCl(dmso)(L)] ((4)-(6)), where L represents 1,2,4-triazolo[1,5-a]pyrimidine (tp for (1)), 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp for (2)), 7-isobutyl-5-methyl-1,2,4-trizolo[1,5-a]pyrimidine (ibmtp for (3)), 5,7-diethyl-1,2,4-triazolo[1,5-a]pyrimidine (detp for (4)), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp for (5)) and 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (dptp for (6)), have been synthesized and characterized by elemental analysis, infrared, multinuclear magnetic resonance spectroscopic techniques (H, C, and N), and X-ray (for (3), (4), and (5)). All these complexes have been thoroughly screened for their in vitro cytotoxicity against melanoma cell lines A375 and Hs294T, indicating cis,cis,cis-[RuCl(dbtp)(dmso)] (5) as the most active representative, in addition to being non-toxic to normal human fibroblasts (NHDF) and not inducing hemolysis of human erythrocytes. In order to develop an intravenous formulation for (5), liposomes composed of soybean phosphatidylcholine (SPC), cholesterol (Chol) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG) were prepared and subsequently characterized.

Towards A New Approach for the Description of Cyclo⁻2,4-Dihydroxybenzoate, A Substance Which Effectively Mimics Zearalenone in Imprinted Polymers Designed for Analyzing Selected Mycotoxins in Urine.

A method of purifying cyclododecyl 2,4-dihydroxybenzoate as a potential replacement template molecule for preparation of molecularly-imprinted polymers for isolation of zearalenone in urine was developed. Full physicochemical characteristics of cyclododecyl 2,4-dihydroxybenzoate for the first time included crystallographic analysis and molecular modelling, which made possible the determination of the similarity between the cyclododecyl 2,4-dihydroxybenzoate and zearalenone molecules. The obtained molecularly-imprinted polymers show very high in vitro selectivity towards zearalenone due to specific interactions (e.

Role of purinergic receptors in the Alzheimer's disease.

Etiology of the Alzheimer's disease (AD) is not fully understood. Different pathological processes are considered, such as amyloid deposition, tau protein phosphorylation, oxidative stress (OS), metal ion disregulation, or chronic neuroinflammation. Purinergic signaling is involved in all these processes, suggesting the importance of nucleotide receptors (P2X and P2Y) and adenosine receptors (A1, A2A, A2B, A3) present on the CNS cells.

Redox active ligand and metal cooperation for C(sp)-H oxidation: extension of the galactose oxidase mechanism in water-mediated amide formation.

Redox interplay between a ligand and a metal can provide a profound driving force for the promotion of unprecedented reactions. This work presents an intriguing water-assisted oxidative transformation of imine to amide with no formal change in the metal oxidation state in the copper and nickel complexes of an aminophenol ligand versus a zinc analogue.

Strategies for overcoming tropical disease by ruthenium complexes with purine analog: Application against Leishmania spp. and Trypanosoma cruzi.

Tropical diseases currently constitute a major health problem and thus a challenge in the field of drug discovery. The current treatments show serious disadvantages due to cost, toxicity, long therapy duration and resistance, and the use of metal complexes as chemotherapeutic agents against these ailments appears to be a very attractive alternative. Herein, we describe three newly synthesized ruthenium complexes with a bioactive molecule, the purine analogue 5,6,7-trimethyl-1,2,4-triazolo[1,5-a]pyrimidine (tmtp): cis,fac-[RuCl(dmso)(tmtp)] (1), mer-[RuCl(dmso)(HO)(tmtp)]·2HO (2) and fac,cis-[RuCl(HO)(tmtp)] (3).

Rational design of dicarboxylato platinum(II) complexes with purine-mimetic ligands as novel anticancer agents.

Six novel platinum(II) complexes containing purine-mimetic ligands (5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp), 7-isobutyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp), 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp)) and dicarboxylato ligands (glutarato (glut) or cyclobutane-1,1-dicarboxylato (CBDC)) have been prepared and characterized with multinuclear magnetic resonance (H, C, N, Pt) NMR, infrared (IR) and X-ray crystallography. Spectroscopic data in solid state and in solution unambiguously confirm the square-planar geometry of Pt(II) with two monodentate N3-bonded 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidine ligands and one O-chelating dicarboxylato ligand. Next, the effect of all the platinum(II) compounds on the viability of normal or cancer cells and their putative mechanisms of action have been investigated.

New Chiral Ebselen Analogues with Antioxidant and Cytotoxic Potential.

New chiral camphane-derived benzisoselenazol-3(2H)-ones and corresponding diselenides have been synthetized using a convenient one-pot procedure. Se-N bond was efficiently converted to an Se-Se bond, which could also be easily re-oxidized to the initial benzisoselenazolone moiety. The antioxidant activity of camphor derivatives was evaluated and compared to the reactivity of a series of N-amino acid benzisoselenazol-3(2H)-ones obtained by a modified procedure involving the improved synthesis and isolation of the diseleno bis(dibenzoic) acid.

Role of the purinergic signaling in epilepsy.

Adenine nucleotides and adenosine are signaling molecules that activate purinergic receptors P1 and P2. Activation of A1 adenosine receptors has an anticonvulsant action, whereas activation of A2A receptors might initiate seizures. Therefore, a significant limitation to the use of A1 receptor agonists as drugs in the CNS might be their peripheral side effects.

Role of pro-inflammatory cytokines of pancreatic islets and prospects of elaboration of new methods for the diabetes treatment.

Several relations between cytokines and pathogenesis of diabetes are reviewed. In type 1 and type 2 diabetes an increased synthesis is observed and as well as the release of pro-inflammatory cytokines, which cause the damage of pancreatic islet cells and, in type 2 diabetes, the development of the insulin resistance. That process results in the disturbed balance between pro-inflammatory and protective cytokines.

The structural conversion of multinuclear titanium(IV) μ-oxo-complexes.

For the first time we report the structural conversion processes of hexanuclear μ-oxo-Ti(IV) complexes into tetranuclear ones. Single-crystal X-ray diffraction studies reveal that metastable hexanuclear μ-oxo complexes ([Ti6O6(O(t)Bu)(O2CR')6]) are formed in the first stage of reactions between [Ti(O(t)Bu)4] and branched carboxylic acids R'COOH (R' = C(Me)2Et, CH2(t)Bu, (t)Bu). In the next stage they convert into tetranuclear μ-oxo-Ti(IV) complexes of the formula [Ti4O4(O(t)Bu)4(O2CR')4].

Cytotoxic malonate platinum(II) complexes with 1,2,4-triazolo[1,5-a]pyrimidine derivatives: structural characterization and mechanism of the suppression of tumor cell growth.

A series of malonate (mal) platinum(II) complexes of the general formula [Pt(mal)(L)2], where L=5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) (1), 7-isobutyl-5-methyl-1,2,4-triazolo[1,5-a]pyrimidine (ibmtp) (2) or 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) (3), has been prepared and characterized using multinuclear ((1)H, (13)C, (15)N, (195)Pt) NMR, IR and electrospray ionization mass spectrometry (ESIMS). Furthermore, the crystal structures of [Pt(mal)(dmtp)2]∙4H2O (1a) and [Pt(mal)(dbtp)2]∙CHCl3 (3a) have been determined using single-crystal X-ray diffraction. The spectroscopic characterization unambiguously confirmed the square-planar geometry of Pt(II) with two monodentate N3-bonded 5,7-disubstituted-1,2,4-triazolo[1,5-a]pyrimidines and one O-chelating malonate.

Structural studies of copper(II) complexes with 2-(2-aminoethyl)pyridine derived Schiff bases and application as precursors of thin organic-inorganic layers.

Cu(ii) complexes with Schiff bases derived from 2-pyridin-2-ylethanamine were obtained and characterized by UV-Vis, fluorescence, and IR spectra. The X-ray crystal structures determined for [Cu(ii)(epy(di-t-Buba))Cl] × 0.042H2O and [Cu(ii)(epy(di-t-Buba))O2CCH3] revealed tetrahedral distortion of the Cu(ii) coordination sphere in the solid phase.

Relationship between the induction of inflammatory processes and infectious diseases in patients with ischemic stroke.

Pro-inflammatory cytokines participate in the induction of ischemic stroke. So far, their participation in the cerebral ischemia was proven for the tumor necrosis factor TNF-α, interleukin-1 (IL-1), and interleukin-6 (IL-6). The release of the pro-inflammatory cytokines into the extracellular space causes the enlargement of the brain damage region, and consequently increases the neurological deficit and negatively affects the survival rate prognoses.