Search results for "2505"
showing 10 items of 10 documents
Hexakis(diethylacetamide)iron(II) hexahalorhenate(IV) ionic salts: X-ray structures and magnetic properties
2015
Two novel Fe<sup>II</sup>-Re<sup>IV</sup> compounds of general formula [Fe<sup>II</sup>(DEA)<inf>6</inf>][Re<sup>IV</sup>X<inf>6</inf>] where DEA = diethylacetamide and X = Cl (1) and Br (2) have been prepared and magnetostructurally characterised. Complexes 1 and 2 are isomorphic ionic salts that crystallise in the trigonal crystal system with space group R(-3). The rhenium(IV) ion in 1 and 2 is six-coordinate with six chloro (1) or bromo (2) ligands building a regular octahedral chromophore. The Fe<sup>II</sup> ion is also six-coordinate, and bonded to six oxygen atoms from six DEA molecules. [Fe<sup>…
Syntheses and properties of tetrathio- and tetraseleno metalates [(C5Me4R)2NbE2]2M (E=S, Se; M=Cr, Mo; R=Me, Et) with peripheric niobocene ligands
1998
Abstract Reactions of Cp*2Nb(η2-S2)H 1 (Cp*=C5Me5 (a), C5Me4Et (b)) and Cp*2Nb(η2-Se2H) 3 with 0.5 equivalents of M(CO)6 (M=Cr, Mo) in boiling toluene give the CO free complexes [Cp*2NbE2]2M 4–7. X-ray diffraction analyses have been carried out for the Mo complexes 5a (E=S) and 7a (E=Se) showing that the structures contain ME4 tetrahedral cores with two attached niobocene ligands thus forming a nearly linear trimetallic unit. Absorption spectra and electrochemical studies of complexes 4–7 are described. Characteristic of the novel CrSe4 chromophor are four reversible one electron redox steps. Chemical oxidation of 4a and 5a with [(C5H5)2Fe]PF6 gives the salts {[Cp*2NbS2]2M}PF6 (M=Cr, Mo) 10…
Crystal and solution structures of di-n-butyltin(IV) complexes of 5-[(E)-2-(4-methoxyphenyl)-1-diazenyl]quinolin-8-ol and benzoic acid derivatives: E…
2009
Abstract Reactions of nBu2SnCl(L1) (1), where L1 = acid residue of 5-[(E)-2-(4-methoxyphenyl)-1-diazenyl]quinolin-8-ol, with various substituted benzoic acids in refluxing toluene, in the presence of triethylamine, yielded dimeric mixed ligand di-n-butyltin(IV) complexes of composition [nBu2Sn(L1)(L2–6)]2 where L2 = benzene carboxylate (2), L3 = 2-[(E)-2-(2-hydroxy-5-methylphenyl)-1-diazenyl]benzoate (3), L4 = 5-[(E)-2-(4-methylphenyl)-1-diazenyl]-2-hydroxybenzoate (4), L5 = 2-{(E)-4-hydroxy-3-[(E)-4-chlorophenyliminomethyl]-phenyldiazenyl}benzoate (5) and L6 = 2-[(E)-(3-formyl-4-hydroxyphenyl)-diazenyl]benzoate (6). All complexes (1–6) have been characterized by elemental analyses, IR, 1H,…
Desulfurization and ring opening of thiirane induced by tantalocene trihydride complexes: Synthesis, reactivity and X-ray structure of Cp′2Ta(=S)(S-i…
1999
The reaction of the tantalocene trihydride complexes Cp′ 2 TaH 3 1 (Cp′= η 5 -C 5 H 4 t Bu) or Cp″CpTaH 3 1′ (Cp″= η 5 -C 5 H 2 -1,2-Me 2 -4- t Bu) with propylene sulfide was found to proceed via an unprecedented sulfur transfer and regioselective ring opening reaction at once to yield sulfido-thiolato tantalocene complexes Cp′ 2 Ta(S)(S- i Pr) 2a whose structure has been determined by X-ray crystallography or Cp″CpTa(S)(S- i Pr) 2′a . Complex 1 reacts with ethylene sulfide to give Cp′ 2 Ta(S)(S–Et) 2b . The reactivity of 2a towards a variety of electrophilic moities has been investigated: protonation (with HBF 4 ) and alkylation (with MeI) reactions occur at the terminal sulfur ligand, …
On the formation of inclusion complexes at the solid/liquid interface of anchored temperature-responsive PNIPAAM diblock copolymers with γ-cyclodextr…
2017
The thermal responsive behavior of adsorbed layers of diblock copolymers of poly(N-isopropylacrylamide) (PNIPAAM) and poly((3-acrylamidopropyl)trimethylammonium chloride) (PAMPTMA(+)) with γ-cyclodextrin (γ-CD) at the solid/liquid interface has been investigated using three in situ techniques: null ellipsometry, quartz–crystal microbalance with dissipation monitoring, and neutron reflectometry. The measurements provided information about the adsorbed amounts, the layer thickness, hydration and viscoelastic properties, and the interfacial structure and composition. The copolymers adsorb to silica with the cationic PAMPTMA(+) blocks sitting as anchors in a flat conformation and the PNIPAAM ch…
Heterometallic CoII-CoIII-MII alkoxido-bridged heptanuclear motifs (M = Cu, Zn). Syntheses, crystal structures and magnetic properties
2018
Two new alkoxido-bridged heterometallic complexes of formula [CoIICoIII 3CuII 3(dea)6(CH3COO)3](ClO4)0.75(CH3COO)1.25 (1) and [CoII 2CoIII 2ZnII 3(tea)2(piv)6(CH3O)2(OH)2(CH3OH)2]·H2O 2 (H2dea=diethanolamine, H3tea=triethanolamine and Hpiv=pivalic acid) have been assembled using aminoalcohol ligands. The cationic core in 1 possesses a threefold crystallographic axis, and it exhibits a set of three copper(II), one cobalt(II) and three cobalt(III) ions arranged as a hexagon of alternating copper(II) and cobalt(III) ions around the central cobalt(II) ion. Each edge of the hexagon is defined by a double alkoxido bridge, the outer one being bis-monodentate with copper(II)-cobalt(III) pair wherea…
Behavior of alloying elements during anodizing of Mg-Cu and Mg-W alloys in a fluoride/glycerol electrolyte
2015
Anodizing of sputtering-deposited magnesium and Mg-0.75at.%Cu and Mg-1.23at.%W alloys has been carried out in a fluoride/ glycerol electrolyte. The aims of the study were to investigate the enrichment of alloying elements in the alloy immediately beneath the anodic film and the migration of alloying element species in the film. The specimens were examined by electron microscopy and ion beam analysis. An enrichment of copper is revealed in the Mg-Cu alloy that increases with the anodizing time up to ∼6×1015 Cu atoms cm-2. Copper species are then incorporated into the anodic film and migrate outwards. In contrast, no enrichment of tungsten occurs in the Mg-W alloy, and tungsten species are im…
Touching the upper limit for ferromagnetic interactions in hetero-bridged dinuclear [Cu-2(II)] complexes using a novel N-5-dinucleating ligand bearin…
2012
A novel N-5-dinucleating ligand 4-amino-3,5-bis(bipyridine-2-yl)-1,2,4-triazole allows the preparation for the first time, and under mild conditions, of single and mixed amido(R-NH-)-bridged copper(II) complexes, the latter exhibiting very strong ferromagnetic coupling.
Hydrogen bonding patterns of 7,9-dimethylguanine and its transplatinum(II) complexes
2002
Methylation at the N7 position is one of the most frequently naturally occurring modifications of guanosine. This alteration drastically changes the hydrogen bonding and acid–base properties of the guanine nucleobase. Here we show on the example of the model nucleobase 7,9-dimethylguanine that due to blockage of N7 of the purine ring, new hydrogen bonding patterns occur on the minor groove binding face of this nucleobase involving the ring nitrogen N3 and the exocyclic amino group N2H2. The free 7,9-dimethylguaninium ion and several transplatinum(II) complexes of the this ligand are presented and discussed. Methylation at N7 drastically changes the acid–base and hydrogen bonding properties …
Synthesis and mesomorphism of related series of triphilic ionic liquid crystals based on 1,2,4-triazolium cations
2021
Abstract The synthesis, liquid crystal and conductivity properties of a series of 27 salts based on the 5-(4-(alkyloxy)phenyl)-1,2,4-triazol-4-ium cation bearing a perfluoroalkyl chain with triflate, tetrafluoroborate and bistriflimide anion are reported. The cations are regarded as triphilic on account of their three distinct regions – hydrocarbon, fluorocarbon and ionic. The mesophases were characterised by a combination of polarised optical microscopy, calorimetry and small-angle scattering experiments using both X-rays and neutrons, while thermal stability was probed using thermogravimetric analysis. The liquid crystal properties are found to be dependent on the anion and the length of …