Paramagnetic Pd+ centers in the polymeric matrices of palladium(I) sorbates and 4-pentenate

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Substituted 1-(isoxazol-3-yl)methyl-1H-1,2,3-triazoles: Synthesis,palladium(II) complexes,and high-turnover catalysis in aqueous media

New substituted 3-((1H-1,2,3-triazol-1-yl)methyl)-5-arylisoxazoles (aryl?=?Ph, p-Tol) and 2-(5-phenylisoxazol-3-yl)-5-(2-(1-((5-(p-tolyl)isoxazol-3-yl)methyl)-1H-1,2,3-triazol-4-yl)ethyl)-1,3,4-oxadiazole were synthesized by means of click-chemistry procedures. The obtained compounds were used as ligands in preparation of palladium(II) complexes, and the latter proved to be high-turnover-number catalysts for CC cross-coupling reactions under Green Chemistry conditions. One of the ligands was structurally characterized by single crystal X-ray diffraction, and the structure of complexes was determined by ¹H, ¹³C, ¹⁵N NMR spectroscopy and quantum-chemical modeling.     

Europium Coordination Complexes as Potential Anticancer Drugs: Their Partitioning and Permeation Into Lipid Bilayers as Revealed by Pyrene Fluorescence Quenching

The present study was undertaken to evaluate the membrane-associating properties of a series of novel antitumor agents, Eu(III) coordination complexes (EC), using the pyrene fluorescence quenching as an analytical instrument. Analysis of EC-induced decrease in pyrene fluorescence intensity in terms of partition and solubility-diffusion models allowed us to evaluate the partition and permeation coefficients of the examined compounds into the lipid vesicles prepared from zwitterionic lipid phosphatidylcholine (PC) and its mixtures with cholesterol (Chol) and anionic lipid cardiolipin (CL). The drug-lipid interactions were found to have the complex nature determined by both EC structure and lipid bilayer composition. High values of the obtained partition and permeation coefficients create the background for the development of EC liposomal formulations.     

Dependence of the Average Size of Particles Formed during Steady Mixing on their Concentration in Immiscible Polymer Blends

A linear increase in the size of ethylene-propylene rubber particles with its content in polypropylene matrix at steady mixing in a batch mixer was observed. This type of the dependence is predicted by the theory of dynamic equilibrium between the droplet breakup and coalescence. However, theoretical calculation of droplet radius extrapolated to zero concentration of EPR and slope of the dependence of droplet radius versus concentration, based on the effective shear rate (related to mixing conditions), are in strong disagreement with the experimental results. Reasons for these discrepancies between theories and experimental results are thoroughly elucidated.     

Unusual coordination of a chloride ion to six copper ions: Synthesis and crystal structure of copper(II) complexes with 4-(4-hydroxyphenyl)-1,2,4-triazole

Novel copper(II) complexes, molecular [Cu₆(μ₆-Cl)(μ₃-OH)₂(μ-L)₆Cl₉(H₂O)₃] · 3H₂O (1) and polymeric [Cu(μ-L)(μ-OH)(H₂O)₂]Cl (2) (L = 4-(4-hydroxyphenyl)-1,2,4-triazole), have been prepared and characterized by X-ray structural analysis. Compound 1 appears to be an unusual example of a chloride ion with six equal Cu–Cl distances of 2.8397(3) Å. It has also been characterized by X-ray powder diffraction and magnetic measurements. Both complexes have distorted octahedral configurations of copper ions; the coordination cores are CuN₂Cl₂O₂ or CuN₂Cl₃O (1) and CuN₂O₄ (2).     

Synthesis and crystal structure of Ln2MGe4O12, Ln=rare-earth element or Y; M=Ca, Mn, Zn

The crystal structure of the promising optical materials Ln₂M²⁺Ge₄O₁₂, where Ln=rare-earth element or Y; M=Ca, Mn, Zn and their solid solutions has been studied in detail. The tendency of rare-earth elements to occupy six- or eight-coordinated sites upon iso- and heterovalent substitution has been studied for the Y_2−xEr_xCaGe₄O₁₂ (x=0-2), Y_2−2xCe_xCa_1+xGe₄O₁₂ (x=0-1), Y₂Ca_1−xMn_xGe₄O₁₂ (x=0-1) and Y_2−xPr_xMnGe₄O₁₂ (x=0-0.5) solid solutions. A complex heterovalent state of Eu and Mn in Eu₂MnGe₄O₁₂ has been found.     

Synthesis and ring transformation of substituted S‐(1‐phenylpyrrolidine‐2‐ones‐3‐yl)isothiuronium salts to substituted 2‐imino‐5‐[2‐(phenylamino)ethyl]thiazolidin‐4‐ones

Dedicated to Professor Jaromír Kaválek on the occasion of his 65^th birthday Substituted S‐(1‐phenylpyrrolidin‐2‐on‐3‐yl)isothiuronium salts in weakly basic media undergo intramolecular recyclisation reaction in which the γ‐lactam cycle is split and a thiazolidine cycle is formed. A series of six substituted 2‐imino‐5‐[2‐(phenylamino)ethyl]‐thiazolidin‐4‐ones have been prepared by this reaction.     

Synthesis and structural characterization of novel zinc(II) and cadmium(II) complexes with pyridine-phosphine chalcogenide ligands

New pyridine-phosphine chalcogenide ligands, tris[2-(2-pyridyl)ethyl]phosphine sulfide 1a and tris[2-(2-pyridyl)ethyl]phosphine selenide 1b, react with zinc(II) and cadmium(II) chlorides in EtOH at room temperature to afford complexes of compositions 2ZnCl₂·2L (2, L = 1a) and 3CdCl₂·2L (3a,b, L = 1a,b) in high yields. The solid-state structure of complexes 2, 3 has been proved by X-ray analysis data. Complex 2 is a centrosymmetric dimer, where two atoms of zinc are bonded by two bridging pyridine-phosphine sulfide ligands through N atoms. Complexes 3a,b exist as polymeric chains with each bridging ligand acting as a chelate N,S- or N,Se-donor to one cadmium(II) center and as a pyridine N-donor to the next cadmium(II) center.     

Oxidative addition reaction of o-quinones to triphenylantimony: novel triphenylantimony catecholate complexes

New catecholate Sb(V) complexes triphenyl(3,6-di-tert-butylcatecholato)antimony(V) Ph₃Sb(3,6-DBCat) (1) and triphenyl(perchloroxanthrenecatecholato)antimony(V) Ph₃Sb(^OXCat_Cl) (2) were synthesized by the oxidative addition reaction of corresponding o-quinones (3,6-di-tert-butyl-o-benzoquinone and perchloroxanthrenequinone-2,3) with triphenylantimony. Catecholates 1 and 2 can alternatively be synthesized by reacting the appropriate thallium catecholate with triphenylantimony dichloride. The oxidative addition reaction of an equimolar ratio of 4,4′-di-(3-methyl-6-tert-butyl-o-benzoquinone) and triphenylantimony yielded 4-(2-methyl-5-tert-butyl-cyclohexadien-1,5-dion-3,4-yl)-(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V) Ph₃Sb(Cat-Q) (3); in the case of a 1:2 molar ratio, complex 4,4′-di-[(3-methyl-6-tert-butyl-catecholato)triphenylantimony(V)] Ph₃Sb(Cat-Cat)SbPh₃ (4) resulted. Complexes 1-4 were characterized by IR- and ¹H NMR spectroscopy. Molecular structures of 1, 2 and 4 were determined by X-ray crystallography to be a distorted tetragonal-pyramidal.     

Fluorinated aminoalkoxide and ketoiminate indium complexes as MOCVD precursors for In2O3 thin film deposition

The syntheses of two distinctive types of indium complex derived from trimethylindium (InMe(3)) are reported. The first kind has a generalized structural formula [InMe(2)(amak)](2), where (amak)H is an abbreviation for a series of chelating amino alcohol ligands HOC(CF(3))(2)CH(2)NHR, R = (CH(2))(2)OMe (1), Me (2), and Bu(t) (3), as well as HOC(CF(3))(2)CH(2)NMe(2) (4); while the second type of complex is illustrated by [InMe(2)(keim)] (5), for which (keim)H is a tridentate ketoimine ligand of structural formula O=C(CF(3))CH(2)C(CF(3))=NCH(2)CH(2)NMe(2). The solid-state structures of 2 and 5 were determined using single crystal X-ray diffraction studies. For the aminoalkoxide complexes 2-4, the existence of dimeric In(2)O(2) core structures in the solid state has been established with the amino fragment located trans to the alkoxide ligands, in a molecular arrangement which is in contrast to the distorted, trigonal bipyramidal geometry observed for the ketoiminate complex 5. Moreover, VT NMR studies of 2 revealed a rapid dimer-to-monomer equilibration and simultaneous rupture of the N-->In dative interaction, affording two interconvertible isomers related by having the N-Me substituents in either trans or cis dispositions. For complexes 2 and 5, deposition of In(2)O(3) thin films was successfully conducted at temperatures 400-500 degrees C, using O(2) as the carrier gas to induce indium oxide deposition and to suppress carbon impurity present in the thin film. Scanning electron micrographs (SEMs) revealed the surface morphologies. The atomic composition of these films was examined by both X-ray photoelectron spectroscopy (XPS) and Rutherford backscattering (RBS) methods, while X-ray diffraction studies (XRD) confirmed the formation of a preferred orientation along the (222) planes.