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The reactivity of the heterometallic polynuclear complexes [{Au(R)2}2Cu2(MeCN)2]n (R=C6F5, C6Cl5) with the thioether crowns 1,4,7‐trithiacyclononane (L1, [12]aneS3), 1,4,8,11‐tetrathiacyclododecane (L2, [14]aneS4), 1,4,7,10,13,16,19,22‐octathiacyclotetracosane (L3, [24]aneS8), and the quinoline functionalized pendant arm derivatives of the 12‐membered mixed‐donor macrocycles 1‐aza‐,4,7,10‐trithiacyclododecane ([12]aneNS3) and 1,7‐diaza‐4,10‐dithiacyclododecane ([12]aneN2S2), L4 and L5, respectively, was investigated in THF solution. While with L4 and L5 only ionic compounds of general formulation [Cu(L)][Au(R)2] were isolated and structurally characterized (none of them featuring Au⋅⋅⋅Cu interactions), with L1‐L3, beside similar ionic compounds, some heteronuclear complexes of general formulation [{Au(R)2}{Cu(L)}] and featuring Au⋅⋅⋅Cu interactions were also obtained. All of them display rather unusual non‐classical C−H⋅⋅⋅Au hydrogen interactions. The complexes display in the solid state different optical properties related to their structures, which have been studied experimentally and theoretically via TD‐DFT calculations. In particular, all compounds of the type [{Au(R)2}{Cu(L)}] featuring Au⋅⋅⋅Cu metallophilic interactions display luminescence in the solid state both at room temperature (RT) and at 77 K. On the contrary, ionic compounds of general formulation [Cu(L)][Au(R)2], except [Cu(L4)][Au(C6F5)2], are not luminescent. [ABSTRACT FROM AUTHOR]

Photophysical properties of the three-fold symmetric 2,5,8-tris(phenylthiolato)heptazine molecule (1) are studied from combined experimental and computational viewpoints. The intense blue photoemission of 1 in the solid state and in toluene solution is proposed to have a fluorescent origin on the basis of a relatively short emission lifetime and no detectable triplet decay. Calculations at correlated ab initio levels of theory also show that 1 has a large inverted singlet–triplet (IST) gap, a non-vanishing spin–orbit coupling matrix element between the first excited singlet and triplet states, and a fast intersystem crossing rate constant that leads to singlet population from the higher-lying triplet state. The IST gap implies that the first excited singlet state is the lowest excited one, agreeing with the measured fluorescent behaviour of 1. IST gaps are also obtained for the oxygen-containing (2) and selenium-containing (3) analogues of 1 at the ADC(2) level of theory, but not for the tellurium one (4). Calculations of the magnetically induced current density demonstrate that the heptazine core of 1 is globally non-aromatic due to the alternation of carbon and nitrogen atoms along its external rim. [ABSTRACT FROM AUTHOR]

The reaction among [Au2Ag2(C6F5)4(OEt2)2]n, PbCl2 and terpyridine leads to the polymeric complex [{Au(C6F5)2}2{Pb(terpy)}]n (1). Its crystal structure reveals potential voids close to the lead centres large enough to hold different molecules. The availability of these free sites allows complex 1 to act as a VOC sensor. Thus, when 1 is exposed to different solvent vapours such as acetonitrile, toluene or THF, variations in its solid appearance and its photophysical properties are observed as a consequence of the formation of the new polymorphs [{Au(C6F5)2}2{Pb(terpy)(CH3CN)2}]n (2), [{Au(C6F5)2}2{Pb(terpy)}]n·Tol (3) and [{Au(C6F5)2}2{Pb(terpy)(THF)}]n·THF (4). Each polymorph displays a different emission energy depending on its structure and the presence of metallophilic interactions. In addition, the reversible solvent molecule exchange allows the tuning of the luminescence emissions in the greenish yellow–red range. DFT and TD-DFT calculations were performed to explain the origin of the luminescence of all these complexes. [ABSTRACT FROM AUTHOR]

Silver complexes bearing substituted terpyridine or tetra‐2‐pyridinylpyrazine ligands have been prepared and structurally characterised. The study of the anticancer properties of silver complexes with this type of ligands is scarce, despite the possibilities of combining the properties of the metal and the ability of the ligands for DNA binding. Here, the antiproliferative activity, stability, CT‐DNA binding, and mechanism of cell death of these types of derivatives are studied. High cytotoxicity against different tumour cells was observed, and, more important, a great selectivity index has been detected between tumour cells and healthy lymphocytes T for some of these compounds. The CT‐DNA interaction study has shown that these derivatives are able to interact with CT‐DNA by moderate intercalation. Furthermore, cell death studies indicate that these derivatives promote the apoptosis by a mitochondrial pathway. [ABSTRACT FROM AUTHOR]

MoS2 nanoflowers (NFs) obtained through a hydrothermal approach were used as the substrate for the deposition of tiny spherical bimetallic AuAg or monometallic Au nanoparticles (NPs), leading to novel photothermal-assisted catalysts with different hybrid nanostructures and showing improved catalytic performance under NIR laser irradiation. The catalytic reduction of pollutant 4-nitrophenol (4-NF) to the valuable product 4-aminophenol (4-AF) was evaluated. The hydrothermal synthesis of MoS2 NFs provides a material with a broad absorption in the Vis-NIR region of the electromagnetic spectrum. The in situ grafting of alloyed AuAg and Au NPs of very small size (2.0–2.5 nm) was possible through the decomposition of organometallic complexes [Au2Ag2(C6F5)4(OEt2)2]n and [Au(C6F5)(tht)] (tht = tetrahydrothiophene) using triisopropilsilane as reducing agent, leading to nanohybrids 1–4. The new nanohybrid materials display photothermal properties arising from NIR light absorption of the MoS2 NFs component. The AuAg-MoS2 nanohybrid 2 showed excellent photothermal-assisted catalytic activity for the reduction of 4-NF, which is better than that of the monometallic Au-MoS2 nanohybrid 4. The obtained nanohybrids were characterised by transmission electron microscopy (TEM), High Angle Annular Dark Field—Scanning Transmission Electron Microscopy—Energy Dispersive X-ray Spectroscopy (HAADF-STEM-EDS), X-ray photoelectron spectroscopy and UV-Vis-NIR spectroscopy. [ABSTRACT FROM AUTHOR]

New luminescent heterometallopolymers [(Au‐C6F5)m(AgOSO2CF3)n (PVP)] with different Au:Ag molar ratios were synthesized. The luminescent emissions of these polymers are strongly dependent on the temperature, excitation wavelengths, and the Au(I):Ag(I) molar ratio. The incorporation of a precise amount of Ag(I) atoms in the backbone of [(Au‐C6F5)m(PVP)] metallopolymer allows a controlled tuning of the emission energy in the green‐blue range. [ABSTRACT FROM AUTHOR]

Small size AuAg colloidal nanoparticles (AuAg NPs) are prepared through the mild decomposition of the organometallic precursor [Au2Ag2(C6F5)4(OEt2)2]n in THF, using polyvinylpyrrolidone (PVP) as the stabilizing polymer. These nanoparticles are directly deposited on the surface of TiO2 NPs through impregnation in solution at RT or under hydrothermal conditions. AuAg–TiO2–rGO (rGO = reduced graphene oxide) hybrid nanostructures are also prepared under hydrothermal reduction of graphene oxide. The obtained nanomaterials have been characterized through XRD, TEM, HRTEM, solid state UV/vis, Raman and XPS. The use of the nanomaterials as plasmonic photocatalysts under visible white LED light and sunlight is studied and the possible mechanisms of the catalytic degradation of methylene blue (MB) are proposed. The localized surface plasmon resonance (LSPR) displayed by the spherical AuAg nanoparticles enhances their ability of visible light absorption, whereas graphene nanosheets provide a very efficient charge carrier separation, allowing a good performance of the photocatalysts under low-power white LED sources or sunlight. [ABSTRACT FROM AUTHOR]