Search results for "coinage"
showing 8 items of 18 documents
Metallophilicity-assisted assembly of phosphine-based cage molecules.
2014
A family of supramolecular cage molecules has been obtained via self-assembly of the phosphine-gold coordination complexes following an aurophilicity-driven aggregation approach. Use of the di- (PP) or tridentate (PPP) phosphine ligands Pn (n = 2, 3) with rigid polyaromatic backbones leads to clean formation of the coordination Pn(Au(tht))n(n+) species, sequential treatment of which with H2O/NEt3 and excess of H2NBu(t) gives the finite 3D structures of two major types. The cylindrical-like hexametallic cages [(PPAu2)3(μ3-NBu(t))2](2+) are based on the diphosphines PP = 1,4-bis(diphenylphosphino)benzene (1), 4,4'-bis(diphenylphosphino)biphenyl (2), 4,4"-bis(diphenylphosphino)terphenyl (3), w…
Hallazgo de un denario merovingio inédito de Marsella en la ciudad de Tarragona (España)
2019
Documentamos el importante descubrimiento de un denario merovingio procedente de Masilia (Marsella) en la ciudad catalana de Tarragona (España). Debido a la escasez de esta tipología, no solamente en el suelo peninsular, creemos que su publicación es de una gran importancia. Y más aún considerando que el estudio de las relaciones comerciales tanto de corto como de largo recorrido entre el reino visigodo de Toledo y la Francia merovingia se mantiene poco desarrollado. We study the important fi nding of a Merovingian denarius from Masilia (Marseille) in the Catalan city of Tarragona (Spain). Due to the scarcity of this coinage, not only in the Iberian Peninsula, we believe that its publicatio…
Recent visigothic coin findings. Gold and bronze in the north of Cáceres
2017
El artículo pretende documentar una serie de monedas visigodas de oro y bronce encontradas fortuitamente dentro de la provincia de Cáceres, todas ellas de forma aislada y en solitario. La procedencia exacta de todas las piezas no se conoce del todo, aunque están circunscritas con seguridad a Cáceres. Además, dos de las monedas son inéditas: un triente pseudo-imperial a nombre de Justiniano I y un tremís de Égica y Witiza procedente de Acci. The paper aims to document a series of Visigoth gold and bronze coins fortuitously found in the province of Cáceres, all of them isolated and alone. The exact origin of all the coins is not fully known, but it is confined surely within Cáceres. Furthermo…
DELAYED ELECTRON EMISSION OF NEGATIVELY CHARGED TUNGSTEN CLUSTERS
1996
The delayed electron emission of negatively charged tungsten clusters has been investigated on a time scale from 1 to 500 ms. After being stored in a Penning trap clusters ions [Formula: see text] were heated via multiphoton absorption (hν=1.81 eV). In contrast to alkali and coinage metals no photofragmentation could be detected. Instead, for all cluster sizes studied so far only a decrease in the initial ion intensity as a function of time after excitation was observed. This decrease is not caused by ion loss from the trap, but has to be attributed to neutralization via delayed electron emission. The presented results strongly suggest that this process can be viewed as “thermionic emissio…
Bond Stretching and Redox Behavior in Coinage Metal Complexes of the Dichalcogenide Dianions [(SPh2P)2CEEC(PPh2S)2]2− (E=S, Se): Diradical Character …
2011
The metathetical reactions of a) [Li(tmeda)]2[(S)C(PPh2S)2] (Li2⋅3 c) with CuCl2 and b) [Li(tmeda)]2[(SPh2P)2CSSC(PPh2S)2] (Li2⋅4 c) with two equivalents of CuCl both afford the binuclear CuI complex {Cu2[(SPh2P)2CSSC(PPh2S)2]} (5 c). The elongated (C)S[BOND]S(C) bond (ca. 2.54 and 2.72 Å) of the dianionic ligand observed in the solid-state structure of 5 c indicate the presence of diradical character as supported by theoretical analyses. The treatment of [Li(tmeda)]2[(SPh2P)2CSeSeC(PPh2S)2] (Li2⋅4 b) and Li2⋅4 c with AgOSO2CF3 produce the analogous AgI derivatives, {Ag2[(SPh2P)2CEEC(PPh2S)2]} (6 b, E=Se; 6 c, E=S), respectively. The diselenide complex 6 b exhibits notably weaker Ag[BOND]Se…
Combinatorial Identification of Hydrides in a Ligated Ag40 Nanocluster with Non-compact Metal Core
2019
No formation of bulk silver hydride has been reported. Until very recently, only few silver nanoclusters containing hydrides have been successfully prepared. However, due to the lack of effective techniques and also poor stability of hydride-containing Ag nanoclusters, the identification of hydrides’ location within Ag nanoclusters is challenging and not yet achieved although some successes have been reported on clusters of several Ag atoms. In this work, we report a detailed structural and spectroscopic characterization of the [Ag40(DMBT)24(PPh3)8H12]2+ (Ag40H12) cluster (DMBT=2,4-dimethylbenzenethiol). The metal framework consists of three-concentric shells of Ag8@Ag24@Ag8 which can be de…
Phosphorus-Chalcogen Ring Expansion and Metal Coordination
2017
The reactivity of 4-membered (RPCh)2 rings (Ch = S, Se) that contain phosphorus in the +3 oxidation state is reported. These compounds undergo ring expansion to (RPCh)3 with the addition of a Lewis base. The 6-membered rings were found to be more stable than the 4-membered precursors, and the mechanism of their formation was investigated experimentally and by density functional theory calculations. The computational work identified two plausible mechanisms involving a phosphinidene chalcogenide intermediate, either as a free species or stabilized by a suitable base. Both the 4- and 6-membered rings were found to react with coinage metals, giving the same products: (RPCh)3 rings bound to the…
NEW RESTORED DENARIUS OF TRAJAN FROM CARCABOSO, CÁCERES (CONVENTUS EMERITENSIS, LUSITANIA)
2019
A recent and new Republican denarius restored by Trajan is studied and discussed. The issue is extremely rare as no image of it is known so far. It was found in Carcaboso, Cáceres (Conventus Emeritensis, Lusitania), very near of the road known as Vía de la Plata, very surely in a Roman mansio.