Computational Characterization of Unsupported Au(I)···Ir(I) Metallophilic Interactions: Evidence for Strong Dispersive Stabilization.

Unsupported metallophilic interactions remain experimentally unexplored in gold-iridium heterobimetallic complexes. To address this gap, we conducted a computational study on a series of model systems of the form [Ir(CO)X(PH)][AuR], where X = Cl, Br, and I and R = H, CH, NH, and PH, to evaluate their strength and feasibility. Optimizations were performed at the MP2/def2-TZVPP level of theory, and interaction energies at equilibrium distances were assessed through potential energy curves (PECs).

Unraveling Unsupported Gold···Platinum Metallophilic Interactions: An In-Depth Computational and Topological Study.

We have computationally studied the attraction between gold and platinum atoms in a series of unsupported model systems with formulas /-[Pt(CH)(NH)][Au(CH)(NH)] (), /-[Pt(CH)(NH)][Au(CH)(NH)] (), [Pt(CH)(NH)][Au(CH)] (), and {[Pt(NH)][Au(CH)]} (). These systems stem from the simplification of the well-known orthometalated complexes of these metals, allowing for a clearer-as-possible description of the metallophilic interaction while reducing computation cost and keeping chemical representativeness. To achieve this goal, we fully optimized the model systems at the MP2 level of theory with the def2-TZVP basis sets.

An organometallic approach to sub-2 nm thiolate-protected Au nanoclusters with enhanced catalytic and therapeutic properties.

Thiolate-protected gold nanoclusters (AuNCs) of sub-2 nm size have been synthesized through a novel bottom-up approach using the organometallic precursor [Au(CF)(tht)] (tht = tetrahydrothiophene) in a one-pot reaction under mild conditions. This protocol is simple, rapid (1 h), versatile (applicable to thiolate ligands of varying molecular sizes), and reproducible, yielding AuNCs with low size dispersion. Furthermore, the resulting nanomaterials exhibited remarkable catalytic activity, effectively reducing the pollutant 4-nitrophenol to 4-aminophenol, as well as promising photothermal and photodynamic properties upon exposure to an 808 nm laser, converting light into thermal energy and generating reactive oxygen species (ROS).

Red Emissive 1D Copper(I) Thiolates and Green Emissive 2D Copper(I) Halide Thiolates Displaying Second Harmonic Generation and Two-Photon Absorption Processes.

Copper(I), as a d metal, is a promising affordable noncritical raw material finding great interest for the development of photoluminescent materials. Halide and thiolate-based copper(I) compounds are known for their efficient emission and good stability. In order to rationalize the effect of these two anions in the structure and photoemission of Cu(I) compounds, two new families of coordination polymers have been synthesized: the copper(I)-thiolates: [Cu(p-SPhX)] (X = F, Cl, Br), and the copper halide thiolates: [CuCl(p-SPhX)] (X = F, Cl, Br).

Enhancing the Stability and Catalytic Performance of Gold Subnanoclusters Mediated by Au···H-C Hydrogen Bonding and Au···π Interactions.

Gold subnanoclusters (AuSNCs) exhibit remarkable catalytic activity; however, their short-lived transient existence and strong tendency for self-aggregation remain disadvantageous for practical application. Considering that weak secondary interactions, such as Au···H-C or Au···π, could enhance the stability of the subnanocluster system, we have assessed their influence on the stabilization through a combination of experimental and computational analyses. We have evaluated the stabilization ability of different functional groups toward the AuSNCs system.

Effect of the 1D/2D dimensionality in copper and silver thiolate coordination polymers on their photophysical properties.

A series of four new copper and silver-thiolate, [M(-SPhCOR)] (M = Cu, Ag and R = H, Me), coordination polymers is reported. The study shows that the hydrogen bonding between the carboxylic acids directs the formation of a 2D structure associated with poor photoemission, while the steric hindrance of the ester groups allows the assembly of a 1D network coupled with bright luminescence.

Na and Cl adsorption derived enhancement in 4-nitrophenol reduction using Au/Ag nanoparticle: An experimental and theoretical study.

4-Nitrophenol (4-NP) is an organic contaminant attached to textiles, pharmaceuticals, and pesticides. Its presence has been increasingly detected in various water bodies such as lakes, rivers, and occasionally in drinking water. The present work shows the reduction of 4-NP using a hybrid catalytic system composed of gold and silver nanoparticles supported onto the biogenic porous silica (AgAu-SiO).

Visible light enhanced catalytic activity of Au subnanoclusters: the importance of d-sp interband transitions.

Polymers can serve as an effective matrix to stabilize gold nanoparticles. These materials offer a continuous light-activated supply of subnanoclusters, which are composed of a few atoms. We report an efficient approach to enhance the catalytic activity of gold subnanoclusters by feeding of these species through the generation of hot carriers 5d-6s6p interband transitions on PEG-stabilized Au nanoparticles.

Recent Trends in Group 11 Hydrogen Bonding.

Conventional hydrogen bonding (H-bonding) has been extensively studied in organic and biological systems. However, its role in transition metal chemistry, particularly with Group 11 metals (i. e.

Terpyridine isomerism as a tool for tuning red-to-NIR emissive properties in heteronuclear gold(I)-thallium(I) complexes.

The polymeric linear chain [AuTl(CCl)] reacts with three terpyridine-type ligands substituted with thiophene groups containing N-donor centres in different relative positions (L1, L2 and L3), leading to the Au(I)/Tl(I) complexes [AuTl(CCl)(L1)] (1), [{AuTl(CCl)}(L2)] (2) and [AuTl(CCl)(L3)] (3). X-Ray diffraction studies reveal that L1 acts as a chelate, while L2 and L3 act as bridging ligands, resulting in different coordination indexes for the thallium(I) centre. These structural differences strongly influence their optical properties, and while compounds 2 and 3 emit near the limit of the visible range, complex 1 emits in the infrared region.

Experimental and computational studies of the optical properties of 2,5,8-tris(phenylthiolato)heptazine with an inverted singlet-triplet gap.

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 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.

Heteronuclear Gold(I)-Copper(I) Complexes with Thia- and Mixed Thia-Aza Macrocyclic Ligands: Synthesis, Structures and Optical Properties.

The reactivity of the heterometallic polynuclear complexes [{Au(R) } Cu (MeCN) ] (R=C F , C Cl ) with the thioether crowns 1,4,7-trithiacyclononane (L1, [12]aneS ), 1,4,8,11-tetrathiacyclododecane (L2, [14]aneS ), 1,4,7,10,13,16,19,22-octathiacyclotetracosane (L3, [24]aneS ), and the quinoline functionalized pendant arm derivatives of the 12-membered mixed-donor macrocycles 1-aza-,4,7,10-trithiacyclododecane ([12]aneNS ) and 1,7-diaza-4,10-dithiacyclododecane ([12]aneN S ), L4 and L5, respectively, was investigated in THF solution. While with L4 and L5 only ionic compounds of general formulation [Cu(L)][Au(R) ] 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) }{Cu(L)}] and featuring Au⋅⋅⋅Cu interactions were also obtained. All of them display rather unusual non-classical C-H⋅⋅⋅Au hydrogen interactions.

Vapochromic behaviour of a gold(I)-lead(II) complex as a VOC sensor.

The reaction among [AuAg(CF)(OEt)], PbCl and terpyridine leads to the polymeric complex [{Au(CF)}{Pb(terpy)}] (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.

Mechanochemical preparation of strongly emissive monosubstituted triarylphosphane gold(i) compounds activated by hydrogen bonding driven aggregations.

Gold(i) triarylphosphane compounds are a well-known class of coordination compounds displaying from mild to strong emissive properties. Mechanochemical approaches to the preparation, spectroscopic characterization, X-ray diffraction structural determination, and photophysical studies of green emissive neutral linear monophosphane or neutral pseudo-T-shaped or cationic bis-phosphane gold(i) compounds, are herein discussed. The mechanochemical approach to the preparation of gold(i) derivatives was particularly successful for ligands bearing the carboxylic group, while the preparation with esterified ligands yields better results with solvent-mediated methods.

Deciphering the Primary Role of Au⋅⋅⋅H-X Hydrogen Bonding in Gold Catalysis.

Au⋅⋅⋅H-X (X=N or C) hydrogen bonding is gaining increasing interest, both in the study of its intrinsic nature and in their operability in different fields. While the role of these interactions has been studied in the stabilization of gold(I) complexes, their role during the minimum free energy reaction pathway of a given catalytic process remains unexplored. We report herein that complex [Au(C≡CPh)(pip)] (pip=piperidine) catalyses the A -coupling reaction for the synthesis of propargylamines, thanks to the ability of Au(I) to promote weak hydrogen bonding interactions with the reactants along the free energy profile.

Spontaneous Water-Promoted Self-Aggregation of a Hydrophilic Gold(I) Complex Due to Ligand Sphere Rearrangement.

Aggregating gold(I) complexes in solution through short aurophilic contacts promotes new photoluminescent deactivation pathways (aggregation-induced emission, AIE). The time dependence of spontaneous AIE is seldom studied. We examine the behavior of complex [Au(-hypoxanthinate)(PTA)] () in an aqueous solution with the aid of variable-temperature NMR, time-resolved UV-Vis and photoluminescence spectroscopy, and PGSE NMR.

Switching On/Off of a Solvent Coordination in a Au(I)-Pb(II) Complex: High Pressure and Temperature as External Stimuli.

The benzonitrile solvate {[{Au(CF)}{Pb(terpy)}]·NCPh} () (terpy = 2,2':6',2″-terpyridine) displays reversible reorientation and coordination of the benzonitrile molecule to lead upon external stimuli. High-pressure X-ray diffraction studies between 0 and 2.1 GPa reveal a 100% of conversion without loss of symmetry, which is totally reversible upon decompression.

Boosting the Catalytic Performance of AuAg Alloyed Nanoparticles Grafted on MoS Nanoflowers through NIR-Induced Light-to-Thermal Energy Conversion.

MoS 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 MoS NFs provides a material with a broad absorption in the Vis-NIR region of the electromagnetic spectrum.

Silver-Based Terpyridine Complexes as Antitumor Agents.

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.

A "gold standard" computational proof for the existence of gold(III) aurophilicity.

The existence of aurophilic gold(III)⋯gold(III) interactions has for a long time been neglected due to structural arguments and comparison with the aurophilicity of gold(I) compounds. We show with calculations at the CCSD(T) level of theory that the [Au(CH)(NH)] dimer has a metallophilic dispersion interaction between the gold(III) atoms of 10.5 kJ mol.

AuAg Nanoparticles Grafted on TiO@N-Doped Porous Carbon: Improved Depletion of Ciprofloxacin under Visible Light through Plasmonic Photocatalysis.

TiO2 nanoparticles (NPs) were modified to obtain photocatalysts with different composition sophistication and displaying improved visible light activity. All of them were evaluated in the photodegradation of ciprofloxacin. The band gap of TiO2 NPs was successfully tailored by the formation of an N-doped porous carbon (NPC)-TiO2 nanohybrid through the pyrolysis of melamine at 600 °C, leading to a slight red-shift of the absorption band edge for nanohybrid NPC-TiO2 1.

Spontaneous generation of photoemissive aurophilic oligomers in water solution based on the 2-thiocytosine ligand.

Complexes [Au(-2-thiocytosinate)(PMe)] (2, 2-thiocytosine = 4-amino-2-mercaptopyrimidine) and [Au(-2-thiocytosine)(PMe)](CFCO) (3) have been prepared by the reaction of [Au(acac)(PMe)] (1, acac = acetylacetonate) or [Au(OCOCF)(PMe)] with 2-thiocytosine, respectively. The equimolecular mixture of complexes 1 and 3 also produces [{Au(PMe)}(μ-, -2-thiocytosinate)](CFCO) (4), which features two distinct [Au(PMe)] groups coordinated to the S and N atoms of the heterocycle. Complex 4 experiences a ligand redistribution process in water solution that liberates [Au(PMe)](CFCO) and a brightly coloured and luminescent species of [Au (μ-, -2-thiocytosinate) ] stoichiometry, presumably as a tetraauracycle ( = 4).

An organometallic approach for the preparation of Au-TiO and Au-g-CN nanohybrids: improving the depletion of paracetamol under visible light.

The photocatalytic degradation of paracetamol (a common analgesic also known as acetaminophen) in ultrapure water with different photocatalytic systems was performed under ultraviolet or visible irradiation. The photocatalysts employed were: commercial Degussa-P25 TiO and Au-TiO under UVA irradiation (365 nm) and g-CN and Au-g-CN under visible light irradiation (low-power (4 × 10 W) white light LEDs), improving the effectiveness of degradation rates when the gold nanoparticles (Au NPs) were combined with the semiconductors. The nanostructured photocatalysts were synthesised and characterised by transmission electron microscope (TEM), UV-vis diffuse reflectance spectroscopy and, in the case of g-CN photocatalysts by X-ray photoelectron spectroscopy (XPS).

Combination of Au-Ag Plasmonic Nanoparticles of Varied Compositions with Carbon Nitride for Enhanced Photocatalytic Degradation of Ibuprofen under Visible Light.

Au-Ag/g-CN nanohybrids - were synthesized by the one-pot self-reduction of the organometallic precursor [AuAg(CF)(OEt)] in the presence of graphitic carbon nitride (g-CN), leading to two populations of alloyed Au-Ag nanoparticles (NPs) of different size and composition on the surface of g-CN, i.e., Ag-enriched Au-Ag NPs of smaller size and Au-enriched Au-Ag NPs of larger size.

Computational prediction of Au(I)-Pb(II) bonding in coordination complexes and study of the factors affecting the formation of Au(I)-E(II) (E = Ge, Sn, Pb) covalent bonds.

We have studied computationally the Au-M (M = Ge, Sn, Pb) bonding trends in a series of model systems [(PH3)3Au-(MCl3)] (M = Ge (4), Sn (5), Pb (6)). For this, we have fully optimized the model systems at the MP2 level of theory, computing the Au-M bonding energy at the equilibrium distances applying the counterpoise (cp) correction to the basis-set superposition error (BSSE) and performing a natural energy decomposition analysis (NEDA). Furthermore, a topological analysis of the electron density using QTAIM, ELF and DORI tools was performed.