Icosaniobate: a new member of the isoniobate family

Icosaniobate [Nb20O54]8- was synthesized by reacting [H4Nb6O19]4- with NO in tetrahydrofuran or MeNO2. A single-crystal X-ray diffraction study of its n-tetrabutylammonium salt [a = 17.7284(18) A, b = 33.542(3) A, c = 34.316(2) A, Z = 4, and space group P22(1)2(1)] revealed a dimeric structure where two decaniobate ions are condensed sharing two terminal O atoms. Unlike that in [(NbW5O18)2O]4-, the Nb-O-Nb bridges in icosaniobate are bent. The nonlinear bridging reduces the maximum possible symmetry of the dimeric anion to mm2, which it closely approximates.     

A new member of the oxygen-photosensitizers family: a water-soluble polymer binding a platinum complex

The grafting of a 2-picolylamine Pt(ii) complex into polymethacrylic acid has been successfully performed. The obtained polymer is water soluble, and it represents the first example of a platinum-containing polymer able to photogenerate singlet oxygen.     

Synthesis and properties of a new member of the calixnaphthalene family: a C(2)-symmetrical endo-calix[4]naphthalene

The synthesis of a new endo-calix[4]naphthalene is described. The reaction sequence involves the cyclocondensation of a key bisnaphthylmethane intermediate (8) with formaldehyde. This key intermediate (8) is formed using a modified Suzuki-Miyaura Pd-catalyzed cross-coupling reaction between bromomethylnaphthyl (6) and naphthylboronic acid (7), both of which can be derived from 2-hydroxynaphthoic acid.     

In1.08Gd0.92Ge2O7: a new member of the thortveitite family

Indium gadolinium digermanium heptaoxide, In_1.08Gd_0.92Ge₂­O₇, with a thortveitite‐type structure, has been prepared as a polycrystalline powder material by a high‐temperature solid‐state reaction. As in the mineral thortveitite, the crystal structure belongs to the monoclinic system, with space group C2/m (No. 12). The precise structural parameters were obtained by applying the Rietveld method of refinement to the X‐ray powder diffraction data. This layered structure presents, on one side, a honeycomb‐like arrangement of the unique octahedral site, which is occupied randomly by In and Gd atoms, and, on the other side, sheets of isolated Ge₂O₇ diortho‐groups made up of double tetrahedra sharing a common vertex and displaying C_2h point symmetry. This compound showed a remarkable photoluminescence effect when it was irradiated with the X‐ray beam during the X‐ray diffraction measurements, and with the α beam during the Rutherford back‐scattering spectrometry experiments employed to analyze the chemical stoichiometry.     

Generalized gradient exchange functionals based on the gradient-regulated connection: a new member of the TCA family

A new type of generalized gradient approximation exchange functional coupled with the TCA correlation model has been proposed. Based on gradient-regulated connection, this exchange functional is able to mix performances of a modified PBE for the bulk region, to those of the PW91 for the asymptotic one, leading to a significant improvement on the modelization of weak interacting systems, while keeping a good accuracy for the atomization energies.     

Isolation of a new member of the ecdysteroid glycoside family: 2-deoxy-20-hydroxyecdysone 22-O-beta-D-glucopyranoside

A new ecdysteroid glycoside, 2-deoxy-20-hydroxyecdysone 22-O-beta-D-glucopyranoside, is isolated from the herb Silene italica ssp. nemoralis (Waldst. and Kit.) Nyman. The compound is purified with multistep chromatography, such as classical column chromatography on alumina and droplet countercurrent distribution. Also, it is expanded using twice low-pressure reversed-phase liquid column chromatography. Chromatography in four steps results in the purified 2-deoxy-20-hydroxyecdysone 22-O-beta-D-glucopyranoside. Two other ecdysteroids have also been separated, including the formerly identified integristerone A and 24(28)-dehydromakisterone A.     

Dy2Ni7Sn3: a new member of the CaCu5 family of intermetallics

Single crystals of didysprosium heptanickel tritin were synthesized from the constituent elements by arc‐melting. Two of the five Ni atoms are at general sites and all other atoms are at sites with either twofold or m symmetry. The structure contains `DyNi<sub>5</sub>Sn' and `DyNi₂Sn₂' fragments and represents a new member of the CaCu₅ series of intermetallics.     

Synthesis and properties of a new family of cyclodextrin analogues

The chemical synthesis of a series of cyclic oligosaccharides built up from (14)-linked alternatingD– andl-pyranosidic units is described for the first time. Key intermediates employed were disaccharides representing minimal repeating units. These disaccharides (monomers) have been prepared in specifically modified forms so that they bear both glycosyl donor (cyanoethylidene group) and glycosyl acceptor (trityloxy group) functions. Polycondensation-cyclisation of these disaccharide monomers, catalysed by TrC1O₄ under normal conditions of dilution, has led to series of homologous cyclic oligosaccharides with an even number of sugar residues (6, 8, 10, 12,etc.) in each case. Cyclic hexa- and octa-saccharides, based onl-rhamnose andD-mannose as the alternating monosaccharides units, have been deprotected to produce analogues of - and -cyclodextrins (CDs) and the X-ray crystal structure of the cyclic octasaccharide has been determined.     

A dihydroxo-bridged Fe(II)-Fe(III) complex: a new member of the diiron diamond core family

The first structurally characterized Fe(II)-Fe(III) complex containing a M2(mu-OH)2 diamond core is a Robin and Day class II mixed-valence complex.     

Synthesis of aminimides derived from oleic acid: a new family of drag-reducing surfactants

Large-scale syntheses of aminimide surfactants that serve as low temperature drag-reducing agents in ethylene glycol-water mixtures are described. Preliminary drag reduction results are presented and the susceptibility of the surfactants to methanolysis is discussed.     

Iridium complex of porphycene: a new member of metalloporphycene

Iridium(Ⅲ) porphycene complex was synthesized and structurally characterized for the first time. The introduction of the posttransition iridium(Ⅲ) ion not only significantly enhances the absorption intensity at the end of visible region, but also displays efficient singlet oxygen quantum yield(76%), which is applicable for photodynamic therapy in living cells.     

Synthesis of a new family of hexakisferrocenyl hexagons and their electrochemical behavior

The design and synthesis of two new hexakisferrocenyl hexagons has been achieved via coordination-driven self-assembly wherein the size and relative distribution of six ferrocene moieties has been precisely controlled. Insight into the structure and electronic properties of these supramolecules was obtained through electrochemical studies.     

Synthesis and properties of a new family of phosphorus- and nitrogen-containing ionenes

Polyquaternization reactions of bis[2-(4-pyridyl)ethyl]phenylethylphosphine oxide and tris[2-(4-pyridyl)ethyl]phosphine oxide with 1,4-dibromobutane were implemented for the first time to give linear (water-soluble) and cross-linked (limitedly water swelling), respectively, representatives of new phosphorus- and nitrogen-containing ionenes. The synthesized linear ionenes react with heparin and polyacrylic acid yielding water-insoluble polyelectrolyte complexes.     

Synthesis and characterization of a new family of spin bearing TTF ligands

The syntheses and characterization of two new tetrathiafulvalene (TTF) derivatives bearing pyridine-based substituents and 1,5'-dimethyl-6-oxoverdazyl radicals are described. The TTF-pyridine and bipyridine aldehydes were prepared via a palladium-catalyzed cross-coupling reaction between mono(tributylstannyl)tetrathiafulvalene (3) and the appropriate formylpyridyl halides (4). The radical precursors, the corresponding 1,2,4,5-tetrazanes, were prepared by condensation of the bis(1-methylhydrazide) of carbonic acid with the TTF bearing pyridyl aldehyde. Oxidation of tetrazanes 8 and 9 with 1,4-benzoquinone afforded the donor radicals 1 and 2 as 1:1 complexes with hydroquinone. Both complexes are stable in the solid state and their electronic properties have been characterized by EPR, cyclic voltammetry, and UV/vis spectroscopy. The TTF core of both compounds was oxidized both chemically and electrochemically to afford the corresponding cation diradical species. The electronic properties of both donor radicals have been probed by cyclic voltammetry, UV-vis spectroscopy, and preliminary EPR measurements.     

A carbazole-containing porphyrinoid: synthesis and oxidation to the porphyrin-state

Carbazole-containing porphyrinoid was synthesised for the first time via Suzuki-Miyaura cross-coupling reaction. Oxidation with MnO(2) yielded its porphyrin-state featuring macrocyclic aromaticity in exchange for the loss of the resonance energies of the benzene rings.     

Synthesis and coating of cobalt ferrite nanoparticles: a first step toward the obtainment of new magnetic nanocarriers

Monodisperse and stable cobalt ferrite (CoFe2O4) nanoparticles (5.4 nm) have been produced, coated with mono- and difunctional phosphonic and hydroxamic acids, and fully characterized (using thermogravimetric analysis (TGA), dynamic light scattering (DLS), IR spectroscopy, transmission electron microscopy (TEM), and superconducting quantum interference device (SQUID) measurements). Cobalt leakage of the coated nanoparticles has been also studied. Magnetic measurements show the possible applications in hyperthermia at low frequencies, and for this reason, water-soluble coated CoFe2O4 can be seen as a first step toward the obtainment of novel systems for biomagnetic applications.