Browsing by Subject "Gold"

Now showing 1 - 7 of 7
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    Assembly of Heterometallic Rigid-Rod Complexes and Coordination Oligomers from Gold(I) Metalloligands
    (American Chemical Society, 2015-06-18) Cámara, Verónica; Barquero, Natalia; Bautista, Delia; Gil-Rubio, Juan; Vicente, José; Química Inorgánica
    The reactions of TpylC6H4C≡CAuL (Tpyl = 2,2':6',2''-terpyridin-4'-yl; L = PPh3, CNXy; Xy = 2,6-dimethylphenyl) with MX2·nH2O (M = Fe, X = ClO4; M = Co, X = BF4; M = Zn, X = TfO, ClO4) in a 2:1 molar ratio give complexes [M(TpylC6H4C≡CAuL)2]X2. Similarly, the reactions of PPN[(TpylC6H4C≡C)2Au] (PPN = (Ph3P)2N) with an equimolar amount of MX2·nH2O give coordination oligomers [M{(TpylC6H4C≡C)2Au}]nXn (M = Fe, Zn, X = ClO4; M = Co, X = BF4). The complexes and oligomers have been isolated and characterized. The crystal structures of [Fe(TpylC6H4C≡CAuCNXy)2](ClO4)2 and [Co(TpylC6H4C≡CAuPPh3)2](BF4)2 have been determined by X-ray diffraction. The hydrodynamic sizes of complexes [M(TpylC6H4C≡CAuPPh3)2]X2 and coordination oligomers [M{(TpylC6H4C≡C)2 Au}]nXn have been studied by NMR diffusion spectroscopy and Dynamic Light Scattering (DLS) measurements.
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    Avita. Nuevo anillo visigodo de oro
    (Universidad de Murcia, Servicio de Publicaciones, 2020) Martínez Chico, David
    Un nuevo anillo visigodo de oro, seguramente procedente de Soria y datado en el siglo VI d. C., es editado. Sobre su chatón circular, hay un epígrafe inciso que corresponde con un nombre personal femenino: Auita. Además, el anillo constituye un buen testimonio de la onomástica latina en época visigoda
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    Dinuclear Au(I), Au(II) and Au(III) Complexes with (CF2)n Chains: Insights into The Role of Aurophilic Interactions in the Au(I) Oxidation
    (Wiley- VCH GmbH, 2021-09-07) Portugués, Alejandro; Bautista, Delia; Gil-Rubio, Juan; Química Inorgánica
    New dinuclear Au(I), Au(II) and Au(III) complexes containing (CF2)n bridging chains were obtained. Metallomacrocycles [Au2{μ-(CF2)4}{μ-diphosphine}] show an uncommon figure-eight structure, the helicity inversion barrier of which is influenced by aurophilic interactions and steric constraints imposed by the diphosphine. Halogenation of LAu(CF2)4AuL (L=PPh3, PMe3, (dppf)1/2, (binap)1/2) gave [Au(II)]2 species, some of which display unprecedented folded structures with Au –Au bonds. Aurophilic interactions facilitate this oxidation process by preorganizing the starting [Au(I)]2 complexes and lowering its redox potential. The obtained [Au(II)]2 complexes undergo thermal or photochemical elimination of R3PAuX to give Au(III) perfluorinated auracycles. Evidence of a radical mechanism for these decomposition reactions was obtained.
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    Haloperfluorocarbons with Gold(I) Organometallic Complexes. Perfluoroalkyl Gold(I) and Gold(III) Complexes
    (Wiley, 2019-09-04) Portugués, Alejandro; López-García, Inmaculada; Jiménez-Bernad, Javier; Bautista, Delia; Gil-Rubio, Juan; Química Inorgánica
    The study of perfluoroalkyl metal complexes is key to understanding and improving metal-promoted perfluoroalkylation reactions. Herein we report the synthesis of the first gold complexes with primary or secondary perfluoroalkyl ligands by photoinitiated reactions between Au(I) organometallic complexes and iodoperfluoroalkanes. Complexes of the types LAuRF (L = PPh3 or N,N-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; RF = n-C4F9, n-C6F13, i-C3F7, c-C6F11) and [Au(RF)(Ar)I(PPh3)] (Ar = 2,4,6-trimethylphenyl) have been isolated and characterized. Alkynes RFC≡CR were formed by reaction of Ph3PAuC≡CR (R = Ph, nHex) with IRF (RF = n-C4F9, i-C3F7). Evidences of a photoinitiated radical mechanism for these reactions have been obtained. Au(III) complexes [Au(n-C4F9)(X)(Y)L] (X = Y = Cl, Br, I, Me; X = Me, Y = I) have been prepared or in situ generated, and their thermal or photochemical decomposition reactions have been studied
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    Mecanismos de garantía de los certificados de plata cubanos.
    (Revista Numismática Hécate., 2024) Menchaca García, Roberto; Sin departamento asociado
    Los certificados plata fueron los primeros billetes impresos por la República de Cuba. Este signo monetario se emitió entre 1934 y 1949 para circular en sustitución de la plata amonedada. Si bien estaban originalmente garantizados por esta última, la garantía de los billetes fue cambiando a lo largo del tiempo. El presente trabajo estudia los distintos mecanismos de garantía que tuvieron estos billetes hasta su desmonetización oficial en 1953.
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    Reductive Elimination Reactions in Gold(III) Complexes Leading to C(sp3)–X (X = C, N, P, O, Halogen) Bond Formation: Inner-Sphere vs SN2 Pathways
    (American Chemical Society, 2023-01-19) Portugués Rodríguez, Alejandro; Martínez-Nortes, Miguel Ángel; Bautista, Delia; González Herrero, Pablo; Gil Rubio, Juan; Química Inorgánica
    The reactions leading to the formation of C–heteroatom bonds in the coordination sphere of Au(III) complexes are uncommon, and their mechanisms are not well known. This work reports on the synthesis and reductive elimination reactions of a series of Au(III) methyl complexes containing different Au–heteroatom bonds. Complexes [Au(CF3)(Me)(X)(PR3)] (R = Ph, X = OTf, OClO3, ONO2, OC(O)CF3, F, Cl, Br; R = Cy, X = Me, OTf, Br) were obtained by the reaction of trans-[Au(CF3)(Me)2(PR3)] (R = Ph, Cy) with HX. The cationic complex cis-[Au(CF3)(Me)(PPh3)2]OTf was obtained by the reaction of [Au(CF3)(Me)(OTf)(PPh3)] with PPh3. Heating these complexes led to the reductive elimination of MeX (X = Me, Ph3P+, OTf, OClO3, ONO2, OC(O)CF3, F, Cl, Br). Mechanistic studies indicate that these reductive elimination reactions occur either through (a) the formation of tricoordinate intermediates by phosphine dissociation, followed by reductive elimination of MeX, or (b) the attack of weakly coordinating anionic (TfO– or ClO4–) or neutral nucleophiles (PPh3 or NEt3) to the Au-bound methyl carbon. The obtained results show for the first time that the nucleophilic substitution should be considered as a likely reductive elimination pathway in Au(III) alkyl complexes.
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    The Coordination and Supramolecular Chemistry of Gold Metalloligands
    (Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2017-10-13) Gil-Rubio, Juan; Vicente, José; Química Inorgánica
    This review article deals with the use of gold metalloligands as building blocks for the assembly of heterometallic complexes. Several families of gold complexes decorated with crown-ether, amide, pyridine, bipyridine, terpyridine, carboxylato, aminoacid or π-alkyne binding sites have been reported. Adducts of these metalloligands with alkaline or transition metal cations, or with transition metal or lanthanide complexes, have been isolated and structurally characterized. The reported heterometallic species range from simple dinuclear complexes to self-assembled supramolecules, coordination polymers or solids. New structural motifs have been found in these complexes. Most of these metalloligands and complexes are photoluminescent and some of them show switchable emissions based on the formation and rupture of metallophilic contacts. Potential applications as sensors, sensitizers, in vivo imaging agents and anticancer drugs are envisaged.