Νέας παρείχοντο. Modelli ed esperienze storiche alle origini della visione greca sulla struttura delle flotte achemenidi

Questo contributo indaga la rappresentazione greca dei meccanismi di allestimento e di funzionamento delle flotte achemenidi. In Erodoto e in larga parte della tradizione successiva, e così per conseguenza nella comune vulgata, sono infatti le genti della costa mediterranea soggetta ai Persiani a fornire al Gran Re non soltanto gli equipaggi e la loro esperienza nella pratica del mare, bensì anche le imbarcazioni da guerra stesse (gli scafi). Quello che sembra emergere da queste fonti è, allora, un quadro per cui il controllo del Gran Re sulle unità navali delle flotte persiane (perlomeno a partire dai grandi exploits di inizio V secolo a.C.) si sarebbe essenzialmente limitato al loro utilizzo in periodo di conflitto. Secondo questa posizione, vale a dire, i sovrani achemenidi non avrebbero gestito direttamente la produzione delle navi da guerra, né ne avrebbero detenuto la ‘proprietà’ in maniera continuativa, a vantaggio dei sudditi della costa mediterranea. Riassunta nella ricorrente espressione παρέχειν τὰς νέας («fornire le navi»), questa visione viene nel presente saggio sottoposta ad un (ri)esame, con l’obiettivo di rintracciare i presupposti che, in termini di esperienze storiche vissute o recepite dai Greci durante il V secolo a.C., condussero questi ultimi ad elaborarla, e che furono alla base della sua diffusione nei periodi successivi

Synthesis, structures and photoluminescence properties of silver complexes of cyclic (alkyl)(amino)carbenes

Silver complexes of cyclic (alkyl)(amino)carbenes (CAACs), (RL)nAgX (n = 1, X = Cl, Br, I; n = 2, X = OTf; R = Me2, Et2, or adamantyl) are accessible in high yields by reacting free carbenes with silver salts. The smaller carbene ligand Me2L leads to the formation of a mixture of neutral (Me2L)AgCl and cationic [(Me2L)2Ag]+ products. The transmetallation of (AdL)AgCl with copper and gold halides gives the corresponding copper and gold compounds (AdL)MCl (M = Cu and Au) in a clean and quantitative reaction. Whereas (Me2L)AgCl is monomeric in the solid state, (Et2L)AgCl crystallizes as a Cl-bridged dimer. None of the compounds show metal-metal interactions. The complexes show blue photoluminescence, which consists of a fluorescence component with a lifetime of several nanoseconds, as well as a long-lived emission in the microsecond regime

Copper and gold cyclic (alkyl)(amino)carbene complexes with sub-microsecond photoemissions: Structure and substituent effects on redox and luminescent properties

Copper and gold halide and pseudo-halide complexes stabilized by methyl-, ethyl- and adamantyl-substituted cyclic (alkyl)(amino)¬carbene (CAAC) ligands are mostly linear monomers in the solid state, without aurophilic Au···Au interactions. (Et2L)CuCl shows the highest photoluminescence quantum yield (PLQY) in the series, 70%. The photoemissions of Me2L and Et2L copper halide complexes show S1 → S0 fluorescence on the ns time scale, in agreement with theory, as well as a minor long-lived emission. Monomeric (Me2L)CuNCS is a white emitter, while dimeric [(Et2L)Cu(µ-NCS)]2 shows intense yellow emission with a PLQY of 49%. The reaction of (AdL)MCl (M = Cu or Au) with phenols ArOH (Ar = Ph, 2,6-F2C6H3, 2,6-Me2C6H3, 3,5-But2C6H3, 2-But-5-MeC6H3, 2-pyridyl), thiophenol, or aromatic amines H2NAr' (Ar' = Ph, 3,5-(CF3)2C6H3, C6F5, 2-py) afforded the corresponding phenolato, thiophenolato and amido complexes. Whereas the emission wavelengths are only marginally affected by the ring substitution pattern, the PL intensities respond sensitively to the presence of substituents in ortho or meta position. In gold aryloxides PL is controlled by steric factors, with strong luminescence in compounds with Au-O-C-C torsion angles <50. Calculations confirm the dependence of oscillator strength on the torsion angle, as well as the inter-ligand charge transfer nature of the emission. The HOMO/LUMO energy levels were estimated based on first reduction and oxidation potentials

Glycoligands et Glycocomplexes – exploration de la chimie de coordination d'une nouvelle famille de ligands chiraux

Glycoligands are metal chelators centred on carbohydrate scaffolds. They were obtained by functionalisation of monosaccharides with Lewis bases. Systematic variations of the central platform were performed (pyranoses and furanoses with various configurations and conformations) in the case of the ligands bearing three 2-picolyl ether functions (triether ligands). We have also considered the functionalisation of aminodeoxy-furanoses to yield aminodeoxy and diamino ligands. The complexing properties of this family of ligands were studied for divalent late transition 3d metal cations. The complexes were characterised structu- rally and spectroscopically. Some of the complexes were studied by circular dichroism (CD) spectroscopy. The diastereoselective nature of the complex synthesis was outlined as well as an empirical correlation between the pattern of the CD signal and the conformation of the pyranose or furanose scaffold. In a selected case, the thermochemical characterization of the glycoligand complexation reaction was performed by isothermal titration calorimetry. This study evidenced the effect of the inclusion of the chelating site in a cyclic pyranoside. The superoxide dismutase-like activity of an air-oxidised Mn(III)-diaminoglycocomplex was assayed by the means of the McCord-Fridovich testLes « glycoligands » sont des complexants obtenus par fonctionnalisation avec des bases de Lewis de structures centrales de type sucre. Nous avons fait varier de manière sys tématique la nature d'une plateforme centrale monosaccharidique (pyrannoses et furannoses de configurations et conformations variées) dans le cadre de l'étude des complexes dérivés de ligands contenant trois fonctions éther de 2-picolyle (ligands « triéther »). Nous avons considéré également des ligands « aminoéther » et « diamino » obtenus respectivement par fonctionnalisation de dérivés de type aminodésoxy-furannose et diaminodidésoxy-furannose. Les propriétés de complexation de cette famille de ligands pour les cations divalents 3d (Mn . . . Cu) ont été appréciées à travers des études structurales (diffraction des rayons X) et spectroscopiques. Divers complexes ont été étudiés par dichroïsme circulaire prouvant le caractère diastéréosélectif de la réaction de complexation et mettant en évidence une corré- lation empirique entre la conformation des cycles pyrannosique ou furannosique et la forme du signal. Dans un exemple choisi, la complexation a été caractérisée thermodynamiquement (par titration calorimétrique isotherme) afin de mettre en évidence l'effet de l'inclusion du site de chélation dans une structure cyclique. L'activité de type superoxyde dismutase d'un glycocomplexe diamino de manganèse s'oxydant à l'état Mn(III) en solution aqueuse aérobie a été mesurée à l'aide du test de McCord-Fridovich

"Recensione al volume: Beatrice Pestarino, "Kypriōn Politeia""

Recensione al volume: Beatrice Pestarino, "Kypriōn Politeia. The Political and Administrative Systems of the Classical Cypriot City-Kingdoms", Leiden – Boston: Brill, 2022, 301 pp

"Sulla 'talassocrazia' dei Ciprioti in età arcaica. Una propensione marittima di lungo corso e le sue cristallizzazioni storiografiche".

The concept of ‘thalassocracy’ loomed large across Greek historiographical production, but its roots may be traced back to distinct historical situations experienced in the Aegean and the Eastern Mediterranean during the Archaic age. The so-called ‘List of the Thalassocracies’ preserved by the chronographer Eusebius from Caesarea contains a specific entry about the Cypriots, whose examination might be useful with a view to understand that document overall. The key for this task consists in an assessment of the longue durée of Cyprus’ role as a major maritime outpost and a source of naval expertise in the service of the continental empires of the Near East (first, the Neo-Assyrian, then the Persian Achaemenid one) between the mid-8th and the beginning of the 5th century B.C

Glycoligands et Glycocomplexes – exploration de la chimie de coordination d'une nouvelle famille de ligands chiraux

Glycoligands are metal chelators centred on carbohydrate scaffolds. They were obtained by functionalisation of monosaccharides with Lewis bases. Systematic variations of the central platform were performed (pyranoses and furanoses with various configurations and conformations) in the case of the ligands bearing three 2-picolyl ether functions (triether ligands). We have also considered the functionalisation of aminodeoxy-furanoses to yield aminodeoxy and diamino ligands. The complexing properties of this family of ligands were studied for divalent late transition 3d metal cations. The complexes were characterised structu- rally and spectroscopically. Some of the complexes were studied by circular dichroism (CD) spectroscopy. The diastereoselective nature of the complex synthesis was outlined as well as an empirical correlation between the pattern of the CD signal and the conformation of the pyranose or furanose scaffold. In a selected case, the thermochemical characterization of the glycoligand complexation reaction was performed by isothermal titration calorimetry. This study evidenced the effect of the inclusion of the chelating site in a cyclic pyranoside. The superoxide dismutase-like activity of an air-oxidised Mn(III)-diaminoglycocomplex was assayed by the means of the McCord-Fridovich testLes « glycoligands » sont des complexants obtenus par fonctionnalisation avec des bases de Lewis de structures centrales de type sucre. Nous avons fait varier de manière sys tématique la nature d'une plateforme centrale monosaccharidique (pyrannoses et furannoses de configurations et conformations variées) dans le cadre de l'étude des complexes dérivés de ligands contenant trois fonctions éther de 2-picolyle (ligands « triéther »). Nous avons considéré également des ligands « aminoéther » et « diamino » obtenus respectivement par fonctionnalisation de dérivés de type aminodésoxy-furannose et diaminodidésoxy-furannose. Les propriétés de complexation de cette famille de ligands pour les cations divalents 3d (Mn . . . Cu) ont été appréciées à travers des études structurales (diffraction des rayons X) et spectroscopiques. Divers complexes ont été étudiés par dichroïsme circulaire prouvant le caractère diastéréosélectif de la réaction de complexation et mettant en évidence une corré- lation empirique entre la conformation des cycles pyrannosique ou furannosique et la forme du signal. Dans un exemple choisi, la complexation a été caractérisée thermodynamiquement (par titration calorimétrique isotherme) afin de mettre en évidence l'effet de l'inclusion du site de chélation dans une structure cyclique. L'activité de type superoxyde dismutase d'un glycocomplexe diamino de manganèse s'oxydant à l'état Mn(III) en solution aqueuse aérobie a été mesurée à l'aide du test de McCord-Fridovich