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.

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.

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.

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.

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.

Synthesis and Structural Characterization of Phosphanide Gold(III)/Gold(I) Complexes and Their Thallium(III) and Gold(III) Precursors.

In this paper, we describe a series of diphenylphosphane and diphenylphosphanide gold(III) and gold(III)/gold(I) complexes containing 3,5-CClF as aryl ligands at gold that have been synthesized due to the arylating and oxidant properties of the new polymeric thallium(III) complex [TlCl(3,5-CClF)] (). Its reaction with [Au(3,5-CClF)(tht)] (tht = tetrahydrothiophene) produces the gold(III) complex [Au(3,5-CClF)(tht)] (), which allows the synthesis of the diphenylohosphane derivative [Au(3,5-CClF)(PPhH)] (). Its treatment with acetylacetonate gold(I) derivatives leads to two novel Au/Au phosphanido-bridged complexes, [PPN][Au(3,5-CClF)(µ-PPh)AuCl] () and [PPN][{(3,5-CClF)Au(µ-PPh)}Au] ().

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).

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.

Time-Dependent Molecular Rearrangement of [Au(-adeninate)(PTA)] in Aqueous Solution and Aggregation-Induced Emission in a Hydrogel Matrix.

An in-depth study of the molecular rearrangement of the complex [Au(-adeninate)(PTA)] (), promoted in aqueous solution, is presented. This complex, which has been previously described as forming dimers in its crystalline form, is also demonstrated as being able to assemble into an infinite Au···Au chain polymer. The structural motifs are tentatively related to the dramatic modification of the photoemissive properties of in water solution at long times, with the aid of UV-vis and photoluminescence measurements, PGSE-NMR, and theoretical calculations.

Rational Assembly of Metallophilic Gold(I)-Lead(II) and Gold(I)-Gold(I) Puzzle Pieces.

The assembly of two different building blocks, [{Au(C F ) }{PbCl(terpy)}] (terpy=2,2':6':2''-terpyridine) and [{Au(C F ) } {Pb(terpy)}] , acting as terminal or central pieces, respectively, gives rise to a decanuclear complex built via metallophilic and π-stacking interactions in which the number of Au ⋅⋅⋅Au and Au ⋅⋅⋅Pb contacts is finely controlled.

Perhalophenyl Three-Coordinate Gold(I) Complexes as TADF Emitters: A Photophysical Study from Experimental and Computational Viewpoints.

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 = CF, CClF, CCl) as the perhalophenyl-gold(I) source, leading to [AuR(dppBz)] (R = CF (), CClF (), CCl ()) complexes. The solid-state structures of compounds and 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.

Metallophilic Au(i)M(i) interactions (M = Tl, Ag) in heteronuclear complexes with 1,4,7-triazacyclononane: structural features and optical properties.

1,4,7-Triazacyclononane (TACN) has been used for the first time to support Au(i)M [M = Tl(i), Ag(i)] metallophilic interactions in the formation of heteronuclear gold(i) complexes having luminescence properties. The compounds {[{Au(C6Cl5)2}Tl(TACN)]2}n (1), [{Au(C6F5)2}Tl(TACN)] (2), [{Au(C6Cl5)2}Ag(TACN)] (3), and [{Au(C6F5)2}{Ag(TACN)}2Au(C6F5)2] (4) have been synthesized by reacting TACN and the polymeric starting organometallic gold(i) compounds [{Au(C6X5)2}M]n (M = Ag(i), Tl(i); X = Cl, F) in a 1 : 1 molar ratio, in THF. 1, 3 and 4 have also been structurally characterized and their optical properties explained on the basis of their structural features with the support of TD-DFT calculations.

Zigzag vs Helicoidal Gold-Silver 1D Chains: Influence of Subtle Interactions in the Spatial Arrangement of Supramolecular Systems.

The reaction of 4'-(2-thienyl)-2,2':6',2,2''-terpyridine (S-terpy) with the heterometallic complexes [AuAgR(OEt)] (R = CF, CCl) leads to the compounds [{Au(CX)}Ag(S-terpy)] (X = F (), Cl ()). The X-ray diffraction analysis of the complexes shows an alternating disposition of the metals -Au-Ag-Au-Ag- in 1D infinite polymeric chains. Despite the fact of having the same metallic sequence, the spatial arrangement observed for both complexes is very different, since for [{Au(CF)}Ag(S-terpy)] () the metals adopt a zigzag disposition, whereas an helicoidal distribution of the interacting metals is observed for the complex [{Au(CCl)}Ag(S-terpy)] ().

Application of Supervised Machine Learning for Behavioral Biomarkers of Autism Spectrum Disorder Based on Electrodermal Activity and Virtual Reality.

Objective: Sensory processing is the ability to capture, elaborate, and integrate information through the five senses and is impaired in over 90% of children with autism spectrum disorder (ASD). The ASD population shows hyper-hypo sensitiveness to sensory stimuli that can generate alteration in information processing, affecting cognitive and social responses to daily life situations. Structured and semi-structured interviews are generally used for ASD assessment, and the evaluation relies on the examiner's subjectivity and expertise, which can lead to misleading outcomes.

Structural and Luminescence Properties of Heteronuclear Gold(I)/Thallium(I) Complexes Featuring Metallophilic Interactions Tuned by Quinoline Pendant Arm Derivatives of Mixed Donor Macrocycles.

Reaction of the heterometallic complex [{Au(CF)}Tl] with the quinoline pendant arm derivatives and of the mixed donor macrocycles [12]aneNSO and PhenNS affords the new Au(I)/Tl(I) complexes [{Au(CF)}Tl()] (), [{Au(CF)}Tl()] (), [{Au(CF)Tl}{Au(CF)Tl()}] (), and [{Au(CF)Tl}{Au(CF)Tl()}] () depending on the reaction molar ratios used. These complexes present different optical properties strictly related to their structural features and to the presence of Au(I)···Tl(I) metallophilic interactions, which are finely tuned by the coordinating quinoline moiety and have been studied experimentally and theoretically via TD-DFT calculations.

Balancing ionic and H-bonding interactions for the formation of Au(i) hydrometallogels.

The ionic complex [Au(N-adenine)(PMe)](CFCO) (1) displays a supramolecular structure built up through ionic, π-stacking, C-HO, C-HN and C-HAu interactions. Ab initio calculations permit the characterization of the nature of these interactions. Complex 1 is luminescent in the solid state at 77 K.

Temperature-assisted formation of reversible metallophilic Au-Ag interaction arrays.

A temperature-controlled self-assembly process in a solution of [Ag(terpy)]nn+ and [Au(C6F5)2]- units has been performed. For this, the crystallisation of the complex [{Au(C6F5)2}Ag(terpy)]n under the same experimental conditions, changing only the temperature, allows the synthesis of polymorphs [{Au(C6F5)2}2Ag2(terpy)2]n (2a) at 298 K and [{Au(C6F5)2}Ag(terpy)]n (2b) at 280 K. The X-ray diffraction studies previously reported for 2a revealed a polymeric structure with an unusual + + - - + + - - charge sequence, whereas for polymorph 2b, a more classical + - + - disposition has been obtained.

Stimuli-Responsive Solvatochromic Au(I)-Ag(I) Clusters: Reactivity and Photophysical Properties Induced by the Nature of the Solvent.

Reaction of the heterometallic polymer [AuAg(CCl)(OEt)] with 4 equiv of pyridazine leads to the new discrete complex [AuAg(CCl)(μ-CHN)(CHN)] (1). Complex 1 is solvoluminescent, leading to drastic structural changes, depending on the coordination ability of the chosen solvent. Thus, the reaction of complex 1 with acetonitrile leads to a new Au(I)-Ag(I) complex of stoichiometry [AuAg(CCl)(μ-CHN)(NCMe)] ·2CHCN(2), while if the reaction is carried out with a noncoordinating solvent such as dichloromethane, complex [AuAg(CCl)(CHN)] ·CHCl (3) is obtained.

Influence of the Number of Metallophilic Interactions and Structures on the Optical Properties of Heterometallic Au/Ag Complexes with Mixed-Donor Macrocyclic Ligands.

The reactivity of the polymeric gold(I)/silver(I) compound [AuAg(CF)(OEt)] toward the 12-membered mixed-donor macrocyclic ligands 1,7-diaza-4,10-dithiacyclododecane (L), 1-aza-4,7,10-trithiacyclododecane (L), N-quinolinylmethyl-1-aza-4,7,10-trithiacyclododecane (L), and N, N'-bis(quinolinylmethyl)-1,7-diaza-4,10-dithiacyclododecane (L) was studied. The reactions were carried out using different molar ratios depending on the coordination properties of the ligands, which were modified by changing the donor atoms present in the macrocyclic framework (sulfur or nitrogen) or by linking one or two methylquinoline pendant-arms at the secondary nitrogen atom(s). X-ray diffraction analysis of the new complexes obtained show a nuclearity that increases on increasing the number of donor atoms in the ligands.

Dispersive Forces and Dipole Moment Increase as Driving Forces for the Formation of an Unprecedented Metallophilic Heterotrimetallic System.

The crystal structure of the polymeric complex [Au Ag Tl (C F ) (L ) ] (L =1-aza-4,10-dithia-7-oxacyclododecane) displays heterotrimetallic Ag⋅⋅⋅Au⋅⋅⋅Tl moieties and is held by unsupported metallophilic interactions. This complex emits at 500 nm in the solid state. Ab initio calculations show that the large thermodynamic stability that helps the formation of this heterotrimetallic system arises from the combination of dispersive forces and a very large dipole moment in the supramolecular arrangement.

Cooperative Au(I)···Au(I) Interactions and Hydrogen Bonding as Origin of a Luminescent Adeninate Hydrogel Formed by Ultrathin Molecular Nanowires.

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.

Unequal coordination environment in complexes of the type [AuAg(R)(L)]. An immiscible solvent mixture as a key point in the control of ligand replacement.

Following an acid-base strategy, based on the reaction between gold(i) basic fragments and acid silver salts, it is possible to obtain heterometallic polymers of the general formula [AuAg(R)(L)] (R = CClF; L = pyrimidine). Using this new heterometallic complex [AuAg(CClF)(pym)] (1) as a starting material, and a good coordinating solvent such as acetonitrile, it is possible to modify the arrangement of the ligands connected to the silver centres and to obtain three different tetranuclear AuAg building blocks leading to the new polymer [AuAg(CClF)(μ-pym)(NCMe)] (2). Both complexes display very intense luminescence emission.

Lead encapsulation by a golden clamp through multiple electrostatic, metallophilic, hydrogen bonding and weak interactions.

The structure of the complex [{Pb(HBpz)}{Au(o-CBrF)(HBpz)}] consists of a host-guest heterometallic system built up through a plethora of interactions including electrostatic, metallophilic, H-bonding, AuBr or weak CC or PbBr contacts. Computational studies show that the dispersive interactions are responsible for the attraction of the Pb(ii) cationic moiety within the basket-like trinuclear Au(i) fragment, whereas the ionic component of the interaction placed at the rings produces a molecular clamp.