Jesús Orduna

Tetrathiafulvalene Crowns: Redox‐Switchable Ligands

A series of redox-responsive ligands that associate the electroactive tetrathiafulvalene core with polyether subunits of various lengths has been synthesized. X-ray structures are provided for each of the free ligands. The requisite structural criteria for reaching switchable ligands are satisfied for the largest macrocycles, that is, planarity of the 1,1,3,3-tetrathiafulvalene (TTF) pi system and correctly oriented coordinating atoms. The ability of these ligands to recognize various metal cations as a function of the cavity size has been investigated by various techniques (LSIMS, 1H NMR, and UV/Vis spectroscopy, cyclic voltammetry). These systems exhibit an unprecedented high coordination ability among TTF crown ethers. Their switchable ligating properties have been confirmed by cyclic voltammetry, and metal-cation complexation has been illustrated by X-ray structures of three of the corresponding metal complexes (Pb2+, Sr2+, and Ba2+). Solid-state structures of these complexes display original packing modes with channel-like arrangements.

Non-targeted metabolomic approach reveals urinary metabolites linked to steroid biosynthesis pathway after ingestion of citrus juice

Citrus juice intake has been highlighted because of its health-promoting effects. LC-MS based metabolomics approaches are applied to obtain a better knowledge on changes in the concentration of metabolites due to its dietary intake and allow a better understanding of involved metabolic pathways. Eight volunteers daily consumed 400 mL of juice for four consecutive days and urine samples were collected before intake and 24h after each citrus juice intake. Urine samples were analysed by nanoHPLC-q-TOF, followed by principal component analysis (PCA) and Students t-test (p<0.05). PCA showed a separation between two groups (before and after citrus juice consumption). This approach allowed the identification of four endocrine compounds (tetrahydroaldosterone-3-glucuronide, cortolone-3-glucuronide, testosterone-glucuronide and 17-hydroxyprogesterone), which belonged to the steroid biosynthesis pathway as significant metabolites upregulated by citrus juice intake. Additionally, these results confirmed the importance of using the non-targeted metabolomics technique to identify new endogenous metabolites, up- or down-regulated as a consequence of food intake.

Synthesis, characterization, and optical properties of novel 1,3-dithiole donor-based chromophores

In this paper we describe the synthesis and the optical properties of new push–pull systems with a 1,3-dithiole moiety as a donor, a thiophene ring in the spacer group and two strong acceptors. The role of the thiophene ring as an auxiliary donor was also investigated. All chromophores in this study exhibit high decomposition temperatures, above 230 °C. The macroscopic nonlinear response has been evaluated by incorporating some of the chromophores as a guest in a polycarbonate (PC) host matrix.

On the reaction of anthranilic acid with thionyl chloride : the actual structure of Kametani's sulfinamide anhydride

Abstract Despite previous reports, no sulfinamide anhydride is formed from the reaction of anthranilic acid with thionyl chloride, the actual product being 2-sulfinylaminobenzoyl chloride. this excludes iminoketene formation in the reactions of this activated form of anthranilic acid.

Inertness of the [Re6Se5Cl3]5+ cluster core to substitution by OH− in organic solutions: synthesis, structural and liquid secondary ion mass spectroscopy characterization of K(H2O)2[Re6Se5Cl9] and (n-Bu4N)[Re6Se5Cl9] and the crystal structure of (n-Bu4N)2[Re6Se6Cl8]

When ethanol solutions of K[Re6Se5Cl9] are allowed to crystallize, the compound formulated K(H2O)2[Re6Se5Cl9] (1) is obtained. Extensive characterization, which includes chemical analysis, X-ray structure determination and liquid secondary ion mass spectrometry (LSIMS), supports this formulation, which differs from that proposed earlier, K[Re6Se5(OH)2Cl7]·H2O. This conclusively demonstrates that no substitution of an inner μ-core halogen by OH− occurs within the cluster core. This is discussed and shown to be fully consistent with the present well-documented chemistry, n which requires that substitutions of halogen by divalent elements only are allowed. The paper is complemented n by the crystal structures of (n-Bu4N)[Re6Se5Cl9] and (n-Bu4N)2[Re6Se6Cl8], which had not yet been properly reported.

Anionic Derivatives of Perfluorinated Trimethylgold

The homoleptic compound [PPh4 ][CF3 AuCF3 ] cleanly undergoes photoinduced oxidative addition of CF3 I to afford the organogold(III) derivative [PPh4 ][(CF3 )3 AuI] in good yield and under mild conditions. This compound provides a convenient entry to the chemistry of the perfluorinated (CF3 )3 Au fragment, the properties of which were analyzed with the aid of DFT methods and compared with those of the homologous non-fluorinated (CH3 )3 Au moiety. It was found that reductive elimination of CX3 -CX3 in the former (X=F) requires a much higher energy barrier than in the latter (X=H) and is therefore considerably less favored. This can be considered as one of the main features underlying the significantly higher stability associated to the (CF3 )3 Au fragment and its derivatives. This unsaturated, 14-electron species can be stabilized by coordination of any of the halide ligands, including fluoride. In fact, the whole series of anionic [PPh4 ][(CF3 )3 AuX] complexes (X=F, Cl, Br, I, CN) has now been isolated and conveniently characterized. Evidence for intermolecular decomposition pathways upon thermolysis in the condensed phase is presented.

Gold(I) fluorohalides: theory and experiment

The anionic trifluoromethylgold(I) derivatives [CF3 AuX]- , which have been prepared and isolated as their [PPh4 ]+ salts in good yield, undergo thermally induced difluorocarbene extrusion in the gas phase, giving rise to the mixed gold(I) fluorohalide complexes [F-Au-X]- (X=Cl, Br, I). These triatomic species have been detected by tandem mass spectrometry (MS2) experiments and their properties have been analyzed by DFT methods. The CF2 extrusion mechanism from the Au-CF3 moiety serves as a model for the CF2 insertion into the Au-F bond, since both reactivity channels are connected by the microreversibility principle.

Tetrhmethvl Bis[N-(2-benzothiazolyl)dithiocarbonimidates]: Novel Reagents for Heterocyclic Polymer Synthesis

Abstract The title compounds, prepared in a one-pot procedure, can be reacted with a variety of dinucteophiles to obtain molecules with four benzoazole rings, thus allowing a new, promising approach to the synthesis of heterocyclic polymers.

Synthesis and study of aminomethyltetrathiafulvalene derivatives and their charge-transfer complexes

Abstract The synthesis of tertiary aminomethyltetrathiafulvalenes is reported. These new donors have been prepared in one step using tetrathiafulvalene as starting material,, and they have been characterized spectroscopically and electrochemically. Some of their charge-transfer complexes have been synthesized and studied. Conductivity, degree of charge-transfer and spectroscopic data are reported. The variation of their EPR parameters with temperature is also discussed.

An Organogold(III) Difluoride with a trans Arrangement

The trans isomer of the organogold(III) difluoride complex [PPh4 ][(CF3 )2 AuF2 ] has been obtained in a stereoselective way and in excellent yield by reaction of [PPh4 ][CF3 AuCF3 ] with XeF2 under mild conditions. The compound is both thermally stable and reactive. Thus, the fluoride ligands are stereospecifically replaced by any heavier halide or by cyanide, the cyanide affording [PPh4 ][trans-(CF3 )2 Au(CN)2 ]. The organogold fluoride complexes [CF3 AuFx ]- (x=1, 2, 3) have been experimentally detected to arise upon collision-induced dissociation of the [trans-(CF3 )2 AuF2 ]- anion in the gas phase. Their structures have been calculated by DFT methods. In the isomeric forms identified for the open-shell species [CF3 AuF2 ]- , the spin density residing on the metal center is found to strongly depend on the precise stereochemistry. Based on crystallographic evidence, it is concluded that Auiii and Agiii have similar covalent radii, at least in their most common square-planar geometry.