The synthesis, structural characterization, and the study of the photophysical properties of complexes [Au 2 Ag 2 (C 6 F 5 ) 4 (NtCCH 3 ) 2 ] n (1) and [Au 2 Cu 2 (C 6 F 5 ) 4 (NtCCH 3 ) 2 ] n (2) have been carried out. The crystal structure of both complexes consists of polymeric chains formed by repetition of Au 2 Ag 2 or Au 2 Cu 2 units built up by metallophilic Au(I)‚‚‚M(I) interactions that are linked through Au(I)‚‚‚Au(I) interactions. Complexes 1 and 2 are brightly luminescent in the solid state at room temperature and at 77 K with lifetimes in the nanosecond range. Both compounds 1 and 2 undergo oligomerization in solution, as observed through UV-vis and excitation spectra in acetonitrile solutions at high concentrations. Thus, a correlation between the excitation spectra in solution at different concentrations and the absorption spectra in the solid state for complex 1 can be established. Time-dependent DFT calculations agree well with the experimental results and support the idea of that the origin of the luminescence of these complexes arises from orbitals located in the tetranuclear Au 2 M 2 units.

The reaction of gold nanoparticles with benzimididazol-2-ylidene ligands leads to the formation of well-defined bis-carbene gold(i) complexes, as shown by characterization techniques such as powder XRD and solid state NMR.

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The reactivity of benzimidazol-2-ylidenes with respect to gold nanoparticles (AuNPs) has been investigated using a combined experimental and computational approach. First, the grafting of benzimidazol-2-ylidenes bearing benzyl groups on the nitrogen atoms is described, and comparisons are made with structurally similar N-heterocyclic carbenes (NHCs) bearing other N-groups. Similar reactivity was observed for all NHCs, with 1) the erosion of the AuNPs under the effect of the NHC and 2) the formation of bis(NHC) gold complexes. DFT calculations were performed to investigate the modes of grafting of such ligands, to determine adsorption energies, and to rationalize the spectroscopic data. Two types of computational models were developed to describe the grafting onto large or small AuNPs, with either periodic or cluster-type DFT calculations. Calculations of NMR parameters were performed on some of these models, and discussed in light of the experimental data.

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.

Two water-soluble [Au( N-adeninate)(PR)] complexes (PR = PMe (1); PTA (3)) were synthesized by the coordination of the respective cationic [Au(PR)] fragment to the N position of the adeninate anion. Both complexes crystallize as dimers by aurophilic contacts of 3.2081(6) Å in 1 and 3.0942(7) and 3.0969(7) Å in 3, but different packings are observed due to the crystallizing solvent choice and the nature of the ancillary phosphine ligand. At this regard, different supramolecular behavior is observed in water, ranges from the formation of ultrathin nanowires of 5.3 ± 1.9 nm of diameter and up to 1.5 μm in length and leads to a blue-luminescent hydrogel for 1, to the single-crystallization of 3. Parallel computational studies carried out show that aurophilicity and N-H···N or O-H···N hydrogen bonding are comparable in strength, suggesting a competition between all types of weak forces in the final observed macroscopic properties.

We report the synthesis of novel perhalophenyl three-coordinated gold(I) complexes using 1,2-bis-(diphenylphosphino)benzene (dppBz) as the chelating ligand and [AuR(tht)] (R = C 6 F 5 , C 6 Cl 2 F 3 , C 6 Cl 5 ) as the perhalophenyl− gold(I) source, leading to [AuR(dppBz)] (R = C 6 F 5 (1), C 6 Cl 2 F 3 (2), C 6 Cl 5 (3)) complexes. The solid-state structures of compounds 2 and 3 consist of discrete three-coordinated Au(I) complexes, which show a distorted trigonal planar geometry for the gold center with dissimilar Au−P distances. The distorted structural arrangement is closely related to its photophysical properties. The studied complexes display very intense emissions at room temperature (RT) and at 77 K in the solid state. Studies of the emissive properties of the complexes at different temperatures suggest that the emissions are phosphorescent at 77 K and exhibit thermally activated delayed fluorescence (TADF) at RT. Firstprinciple calculations of the photophysical processes yielded rate constants for intersystem crossing and reverse intersystem crossing that are in excellent agreement with experimental data.

Brightly phosphorescent gold-based metallopolymers have been synthesized by reaction of nonluminescent reactants comprised of the commercially available polymer PVP = poly(4-vinylpyridine) and the Au(I) precursors [Au(C(6)X(5))THT] (X = F or Cl; THT = tetrahydrothiophene). The metallopolymer products exhibit remarkable photoluminescence properties including high solid-state quantum yield (up to 0.63 at RT) and coarse- and fine-tuning to multiple phosphorescence bands across the visible spectrum via luminescence thermochromism and site-selective excitation. The emissions are caused by intrachain and interchain aurophilic interactions between the linear Au(I) complexes in the metallopolymers. This investigation provides further manifestations of interesting chemistry and photophysics in N-heterocyclic coordination compounds of Au(I) by expansion from the small-molecule to the metallopolymer regime. The spectroscopic and material properties of the new class of metallopolymers are desirable for future studies that will utilize them as emitters for photonic applications such as polymer light-emitting diodes and sensors.