Manuel Montiel

Unsupported Au(I)⋯Cu(I) interactions: influence of nitrile ligands and aurophilicity on the structure and luminescence

The synthesis, structural characterization and the study of the photophysical properties of complexes [AuCu(C6F5)2(N[triple bond]C-CH3)2] 1, [AuCu(C6F5)2(N[triple bond]C-Ph)2]2 2, and [AuCu(C6F5)2(N[triple bond]C-CH=CH-Ph)2] 3 have been carried out. The crystal structures of complexes 1-3 consist of dinuclear Au-Cu units built from mediated metallophilic Au(I)...Cu(I) interactions. In the case of complex 2 two dinuclear units interact via an aurophilic interaction leading to a tetranuclear Cu-Au-Au-Cu arrangement. Complex 2 is brightly luminescent in solid state at room temperature and at 77 K with a lifetime in the nanoseconds range, while complexes 1 and 3 do not display luminescence under the same conditions. The presence of the aurophilic interaction in complex 2 seems to be responsible for the blue luminescence observed. DFT and time-dependent DFT calculations agree with the experimental results and support the idea that the origin of the luminescence of these complexes arise from orbitals located in the interacting metals.

Multiple Evidence for Gold(I)⋅⋅⋅Silver(I) Interactions in Solution

[AuAg3(C6F5)(CF3CO2)3(CH2PPh3)]n (2) was prepared by reaction of [Au(C6F5)(CH2PPh3)] (1) and [Ag(CF3CO2)] (1:3). The crystal structures of complexes 1 and 2 were determined by X-ray diffraction, and the latter shows a polymeric 2D arrangement built by Au...Ag, Ag...Ag, and Ag...O contacts. The metallophilic interactions observed in 2 in the solid state seem to be preserved in concentrated THF solutions, as suggested by EXAFS, pulsed-gradient spin-echo NMR, and photophysical studies, which showed that the structural motif [AuAg3(C6F5)(CF3CO2)3(CH2PPh3)] is maintained under such conditions. Time-dependent DFT calculations agree with the experimental photophysical energies and suggest a metal-to-ligand charge-transfer phosphorescence process. Ab initio calculations give an estimated interaction energy of around 60 kJ mol(-1) for each Au...Ag interaction.

Pyridine gold complexes. an emerging class of luminescent materials

Pyridine-type ligands are considered one of the most versatile ligands in photochemistry since they can act as emitters themselves or as donor or acceptors of electronic density depending on the electronic character of the substituents of the rings and the metal centers bonded to them. Gold is a well known metal with an impressive tendency to form metal aggregates through metal-metal interactions and, therefore, gold complexes bearing these ligands are tailored derivatives with potential as emitting materials. The new possibilities of experimental and theoretical studies that appear with the easy synthesis of a new class of luminescent materials formed by the combination of pyridine ligands and gold are shown here.

A step forward in gold–silver metallophilicity. An AuAg4 moiety with a square pyramidal arrangement

By reaction of the Lewis base NBu4[Au(3,5-C6F3Cl2)2] and AgCF3COO in the presence of NBu4CF3COO the heterometallic compound (NBu4)2[Au(3,5-C6F3Cl22Ag4(CF3COO)5] (2) is obtained. The structure displays an unprecendented square pyramidal AuAg4 arrangement built up through four AuAg closed-shell interactions and two Au-C-Ag 3c-2e- bridges.

Solvent Induced Luminescence in Supramolecular Heterobimetallic Gold(I)- Copper(I) Complexes with a Bidentate Nitrile Ligand

Heterobimetallic complexes (Cu(NC-Cy-CN)2)(Au(C6F5)2)·0.5 Toluene (1) and (Cu(NC-Cy- CN)2)(Au(C6F5)2)·CH2Cl2 (2) and (AuCu(C6F5)2(NC-Cy-CN)2)·CH2Cl2 (3) (with the same stoichiometry but different structure) have been synthesized and the crystal structure of complex 2·CH2Cl2 has been characterized through X-ray dif- fraction studies. The structure shows a cationic (Cu(NC-Cy-CN)2) + polymer that runs parallel to the crystallographic y axis, which is formed by the copper centers and the nitrile bridging ligands, and (Au(C6F5)2) - anions that link the polym- eric chain via non-classical C-H···Au hydrogen bonds. Complexes 1, 2 and 3 only differ in the solvents and the time used for their synthesis but this greatly affects their photophysical properties. Complexes 1, 2 and 3 are brightly luminescent in solid state at room temperature with lifetimes in the microseconds range. Complexes 1 and 2 display emissions arising from IL transitions while for complex 3 an emission arising from a MLCT is proposed.

Luminescent Gold(I)-Thallium(I) Arrays through N-Bidentate Building Blocks

Heteropolynuclear gold(I)-thallium(I) complexes of the type [TlLn][Au(C6F5)2] (L = py (2), 2,2’- bipy (3), 1,10-phen (4) or 4,4’-bipy and THF (5); n = 1, 2) have been obtained from reactions of the corresponding N-donor ligands with the precursor {Tl[Au(C6F5)2]}n (1). The crystal structures of complexes 3 - 5 have been determined by X-ray diffraction showing one- (3, 4) or three-dimensional (5) arrays. All complexes are photoluminescent in the solid state at RT and at 77 K. The strong visible emissions of complexes 2 - 5 are displayed over a wide range of wavelengths (460 - 620 nm) depending on the environment of the thallium(I) centres and on the nature of the N-donor ligand.