A Chiral Gold Nanocluster Au20 Protected by Tetradentate Phosphine Ligands

The chirality of a gold nanocluster can be generated from either an intrinsically chiral inorganic core or an achiral inorganic core in a chiral environment. The first structural determination of a gold nanocluster containing an intrinsic chiral inorganic core is reported. The chiral gold nanocluster [Au₂₀(PP₃)₄]Cl₄ (PP₃=tris(2‐(diphenylphosphino)ethyl)phosphine) has been prepared by the reduction of a gold(I)–tetraphosphine precursor in dichloromethane solution. Single‐crystal structural determination reveals that the cluster molecular structure has C₃ symmetry. It consists of a Au₂₀ core consolidated by four peripheral tetraphosphines. The Au₂₀ core can be viewed as the combination of an icosahedral Au₁₃ and a helical Y‐shaped Au₇ motif. The identity of this Au₂₀ cluster is confirmed by ESI‐MS. The chelation of multidentate phosphines enhances the stability of this Au₂₀ cluster.     

Pentanuclear Gold(I) Cluster with an Axially Chiral Biaryl Center: Synthesis and Chiral Transformation

We synthesized and structurally characterized a novel pentanuclear gold(I) cluster by a Ag(I)‐mediated organometallic transformation. The racemic mixture of this pentanuclear gold cluster has been successfully transformed into an enantio‐rich hexanuclear cluster compound by adding adscititious chiral species [Au₂(S‐BINAP)₂]²⁺ (S‐BINAP = (S)‐2,2’‐bis(diphenylphosphino)‐1,1’‐binaphthyl). In this process, a [AuPPh₃]⁺ species in the pentanuclear cluster is replaced by [Au₂(S‐BINAP)₂]²⁺. This strategy represents a new method for the designed construction of chiral metal clusters.     

Neue Gold‐Selen‐Komplexverbindungen: Synthesen und Strukturen von [Au10Se4(dpppe)4]Br2, [Au2Se(dppbe)]∞, [(Au3Se)2(dppbp)3]Cl2 und [Au34Se14(tpep)6(tpepSe)2]Cl6

Novel Gold Selenium Complexes: Syntheses and Structures of [Au₁₀Se₄(dpppe)₄]Br₂, [Au₂Se(dppbe)]_∞, [(Au₃Se)₂(dppbp)₃]Cl₂, and [Au₃₄Se₁₄(tpep)₆(tpep^Se)₂]Cl₆ The reaction of gold phosphine complexes [(AuX)(PR₃)] (X= halogen; R = org. group) with Se(SiMe₃)₂ yield to new chalcogeno bridged gold complexes. Especially within the use of polydentate phosphine ligands cluster complexes like [Au₁₀Se₄(dpppe)₄]Br₂ ( 1 ) (dpppe = 1, 5‐Bis(diphenylphosphino)pentane), [Au₂Se(dppbe)]_∞ ( 2 ) (1, 4‐Bis(diphenylphosphino)benzene), [(Au₃Se)₂(dppbp)₃]Cl₂ ( 3 ) (dppbp = 4, 4′‐Bis‐diphenylphosphino)biphenyl) und [Au₃₄Se₁₄(tpep)₆(tpep^Se)₂]Cl₆ ( 4 ) (tpep = 1, 1, 1‐Tris(diphenylphosphinoethyl)phosphine, tpep^Se = 1, 1‐Bis(diphenylphosphinoethyl)‐1‐(diphenylselenophosphinoethylphosphine) could be isolated and their structures could be determined by X‐ray diffraction. ( 1: Space group P1 (No. 2), Z = 2, a = 1642.1(11), b = 1713.0(9), c = 2554.0(16) pm, α = 80.41(3)°, β = 76.80(4)°, γ = 80.92(4)°; 2: Space group P2₁/n (No. 14), Z = 4, a = 947.3(2), b = 1494.9(3), c = 2179.6(7) pm, β = 99.99(3)°; 3: Space group P2₁/c (No. 14), Z = 8, a = 2939.9(6), b = 3068.4(6), c = 3114.5(6) pm, β = 109.64(3)°; 4: Space group P1 (No. 2), Z = 1, a = 2013.7(4), b = 2420.6(5), c = 2462.5(5) pm, α = 77.20(3), β = 74.92(3), γ = 87.80(3)°).     

The Unprecedented [S4N2O10]2− Anion in the Molecular Gold Complexes [Au2Br2(S4N2O10)2] and [Au2Cl2(S4N2O10)2](S2O5Cl2)

The reaction of hexachlorophosphazene, P₃N₃Cl₆, with SO₃ and the gold halides AuCl₃ and AuBr₃, respectively, leads to the new cyclic anionic tetramer, [S₄N₂O₁₀]²⁻, which is coordinated to Au³⁺ in the dimeric complexes [Au₂X₂(S₄N₂O₁₀)₂] (X=Cl, Br). The [S₄N₂O₁₀]²⁻ anion can be seen as the condensation product of two sulfate anions, [SO₄]²⁻_, and two amidosulfate anions, [NH₂SO₃]⁻.     

Aurophilic Interactions in the Self‐Assembly of Gold Nanoclusters into Nanoribbons with Enhanced Luminescence

Aurophilic interactions (Au^I???Au^I) are crucial in directing the supramolecular self‐assembly of many gold(I) compounds; however, this intriguing chemistry has been rarely explored for the self‐assembly of nanoscale building blocks. Herein, we report on studies on aurophilic interactions in the structure‐directed self‐assembly of ultrasmall gold nanoparticles or nanoclusters (NCs, <2 nm) using [Au₂₅(SR)₁₈]^? (SR=thiolate ligand) as a model cluster. The self‐assembly of NCs is initiated by surface‐motif reconstruction of [Au₂₅(SR)₁₈]^? from short SR‐[Au^I‐SR]₂ units to long SR‐[Au^I‐SR]_x (x>2) staples accompanied by structure modification of the intrinsic Au₁₃ kernel. Such motif reconstruction increases the content of Au^I species in the protecting shell of Au NCs, providing the structural basis for directed aurophilic interactions, which promote the self‐assembly of Au NCs into well‐defined nanoribbons in solution. More interestingly, the compact structure and effective aurophilic interactions in the nanoribbons significantly enhance the luminescence intensity of Au NCs with an absolute quantum yield of 6.2 % at room temperature.     

Formation of the ionic gold(III) complex [Au3{S2CN(CH2)4O}6][Au2Cl8][AuCl4] in chemisorption systems [M{S2CN(CH2)4O}2] n -[AuCl4]−/2 M HCl (M = Cd, Zn): Supramolecular structure and thermal behavior

The interaction of freshly precipitated cadmium and zinc morpholinedithiocarbamates with solutions of AuCl₃ in 2 M HCl is studied. In both cases, the heterogeneous reactions of gold(III) binding from solutions lead to the formation of the ionic gold(III) complex [Au₃{S₂CN(CH₂)₄O}₆][Au₂Cl₈][AuCl₄] (I), whose molecular and supramolecular structures are determined by X-ray diffraction analysis. Compound I includes centrosymmetric and noncentrosymmetric cations [Au{S₂CN(CH₂)₄O}₂]⁺ in a ratio of 1: 2. According to the manifested structural differences, the complex cations are related as conformers (cations A are Au(1) and cations B are Au(2)). At the supramolecular level, the isomeric cations form linear trinuclear structural fragments [Au₃{S₂CN(CH₂)₄O}₆]³⁺ [A...B...A] due to secondary bonds Au...S of 3.6364 Å. The anionic part of compound I is presented by [AuCl₄]^? and centrosymmetric binuclear [Au₂Cl₈]^2?, whose formation involved secondary bonds Au...Cl of 3.486 and 3.985 Å. The ultimate chemisorption capacity of cadmium and zinc morpholinedithiocarbamates calculated from the binding of gold(III) is 901.7 and 1010.4 mg of Au³⁺ per 1 g of the sorbent, respectively (i.e., each miononuclear fragment of the chemisorption complexes [M{S₂CN(CH₂)₄O}₂] participates in binding of two gold atoms). To establish the conditions for the isolation of bound gold, the thermal properties of compound I are studied by simultaneous thermal analysis. The thermal destruction process includes the thermolysis of the dithiocarbamate part of the complex and anions [AuCl₄]^? and [Au₂Cl₈]^2? with the reduction of gold to the metal, being the only final product of the thermal transformations of compound I.     

An Inherently Chiral Au24 Framework with Double‐Helical Hexagold Strands

2,3‐bis(diphenylphosphino)butane enantiomers (chiraphos, L) used as chiral auxiliaries results in the preferential formation of an unprecedented Au₂₄ framework with inherent chirality. The crystal structure of [Au₂₄L₆Cl₄]²⁺ ( 1 ) has a square antiprism‐like octagold core twinned by two helicene‐like hexagold motifs, where the inherent chirality is associated with the helical arrangement. The clusters carrying (R,R)‐ and (S,S)‐ diphosphines had right‐ and left‐handed strands, respectively. Circular dichroism spectra showed peaks in the visible to near‐IR region, some of which did not coincide with absorption bands, suggesting the enantiomeric Au₂₄ frameworks possess unique chiroptical properties. The Au₂₄ frameworks were thermally robust, which could be attributed to the superatomic concept (18 e^? system) and the steric constraint effects of the bridging ligand units.     

Atomically Tailored Gold Nanoclusters for Catalytic Application

Recent advances in the synthetic chemistry of atomically precise metal nanoclusters (NCs) have significantly broadened the accessible sizes and structures. Such particles are well defined and have intriguing properties, thus, they are attractive for catalysis. Especially, those NCs with identical size but different core (or surface) structure provide unique opportunities that allow the specific role of the core and the surface to be mapped out without complication by the size effect. Herein, we summarize recent work with isomeric Au_n NCs protected by ligands and isostructural NCs but with different surface ligands. The highlighted work includes catalysis by spherical and rod‐shaped Au₂₅ (with different ligands), quasi‐isomeric Au₂₈(SR)₂₀ with different R groups, structural isomers of Au₃₈(SR)₂₄ (with identical R) and Au₃₈S₂(SR)₂₀ with body‐centred cubic (bcc) structure, and isostructural [Au₃₈L₂₀(PPh₃)₄]²⁺ (different L). These isomeric and/or isostructural NCs have provided valuable insights into the respective roles of the kernel, surface staples, and the type of ligands on catalysis. Future studies will lead to fundamental advances and development of tailor‐made catalysts.     

Polycations Stabilised by Borosulfates: [Au3Cl4][B(S2O7)2] and the One-Dimensional Metal [Au2Cl4][B(S2O7)2](SO3)

(SO₄)-rich silicate analogue borosulfates are able to stabilise cationic cluster-like and chain-like aggregates. Single crystals of [Au₃Cl₄][B(S₂O₇)₂] and [Au₂Cl₄][B(S₂O₇)₂](SO₃) were obtained by solvothermal reaction with SO₃, and the electronic properties were investigated by means of density functional theory–based calculations. [Au₃Cl₄][B(S₂O₇)₂] exhibits a cluster-like cation, and the cationic gold-chloride strands in [Au₂Cl₄][B(S₂O₇)₂](SO₃) are found to resemble one-dimensional metallic wires. This is confirmed by polarisation microscopy.     

Gold(I)‐Catalyzed Enantioselective Intermolecular Hydroarylation of Allenes with Indoles and Reaction Mechanism by Density Functional Theory Calculations

Chiral binuclear gold(I) phosphine complexes catalyze enantioselective intermolecular hydroarylation of allenes with indoles in high product yields (up to 90 %) and with moderate enantioselectivities (up to 63 % ee). Among the gold(I) complexes examined, better ee values were obtained with binuclear gold(I) complexes, which displayed intramolecular Au^I Au^I interactions. The binuclear gold(I) complex 4c [(AuCl)₂( L3 )] with chiral biaryl phosphine ligand (S)‐(−)‐MeO‐biphep ( L3 ) is the most efficient catalyst and gives the best ee value of up to 63 %. Substituents on the allene reactants have a slight effect on the enantioselectivity of the reaction. Electron‐withdrawing groups on the indole substrates decrease the enantioselectivity of the reaction. The relative reaction rates of the hydroarylation of 4‐X‐substituted 1,3‐diarylallenes with N‐methylindole in the presence of catalyst 4c [(AuCl)₂( L3 )] / AgOTf [ L3 =(S)‐(−)‐MeO‐biphep], determined through competition experiments, correlate (r²=0.996) with the substituent constants σ. The slope value is −2.30, revealing both the build‐up of positive charge at the allene and electrophilic nature of the reactive Au^I species. Two plausible reaction pathways were investigated by density functional theory calculations, one pathway involving intermolecular nucleophilic addition of free indole to aurated allene intermediate and another pathway involving intramolecular nucleophilic addition of aurated indole to allene via diaurated intermediate E2 . Calculated results revealed that the reaction likely proceeds via the first pathway with a lower activation energy. The role of Au^I Au^I interactions in affecting the enantioselectivity is discussed.     

Asymmetric 1,4-addition of aryltrialkoxysilanes to α,β-unsaturated esters and amides catalyzed by a chiral rhodium complex

A highly enantioselective 1,4-addition of aryltrialkoxysilanes to α,β-unsaturated esters and amides was successfully catalyzed by a chiral rhodium complex generated from [Rh(cod)(MeCN)₂]BF₄ and (S)-BINAP.     

Monohydride-Dichloro Rhodium(III) Complexes with Chiral Diphosphine Ligands as Catalysts for Asymmetric Hydrogenation of Olefinic Substrates

We report full details of the synthesis and characterization of monohydride-dichloro rhodium(III) complexes bearing chiral diphosphine ligands, such as (S)-BINAP, (S)-DM-SEGPHOS, and (S)-DTBM-SEGPHOS, producing cationic triply chloride bridged dinuclear rhodium(III) complexes ( 1 a : (S)-BINAP; 1 b : (S)-DM-SEGPHOS) and a neutral mononuclear monohydride-dichloro rhodium(III) complex ( 1 c : (S)-DTBM-SEGPHOS) in high yield and high purity. Their solid state structure and solution behavior were determined by crystallographic studies as well as full spectral data, including DOSY NMR spectroscopy. Among these three complexes, 1 c has a rigid pocket surrounded by two chloride atoms bound to the rhodium atom together with one tBu group of (S)-DTBM-SEGPHOS for fitting to simple olefins without any coordinating functional groups. Complex 1 c exhibited superior catalytic activity and enantioselectivity for asymmetric hydrogenation of exo-olefins and olefinic substrates. The catalytic activity of 1 c was compared with that of well-demonstrated dihydride species derived in situ from rhodium(I) precursors such as [Rh(cod)Cl]₂ and [Rh(cod)₂]⁺[BF₄]⁻ upon mixing with (S)-DTBM-SEGPHOS under dihydrogen.     

Supramolecular gold(I) compounds with trithiocyanuric acid: Self‐assembly and luminescent properties

[(N₃S₃)Au(AuPMe₃)₂]₂ ( 1 ) and [(N₃S₃)Au(AuPEt₃)₂]₂ ( 2 ) were prepared by treating AuCl(PMe₃) or AuCl(PEt₃) with H₃N₃S₃ upon deprotonation by trimethylamine to give respective Au₆ supermolecules. Using dppm(AuCl)₂ instead of AuCl(PMe₃) or AuCl(PEt₃) to react with H₃N₃S₃ in a similar reaction condition led to a rare heptanuclear supermolecule of [(N₃S₃)₂Au₇(dppm)₄]Cl ( 3 ). It is noted that besides short intramolecular gold(I)?gold(I) distances, both compounds 1 and 2 also show intermolecular gold(I)?gold(I) distances of 3.067(1) and 3.241(1) Å, resulting in two‐dimensional and one‐dimensional polymeric gold(I) solid, respectively. In fact, compound 1 shows a similar two‐dimensional polymeric gold(I) solid to that of the reported [(N₃S₃)Au(AuPPhMe₂)₂]₂ with an intermolecular gold(I)?gold(I) distance of 3.130(2) Å. Significantly, these intermolecular gold(I)?gold(I) distances are well correlated with their cone angles and emission energies. For example, intermolecular gold(I)?gold(I) distances increase in the order of 3.067(1) Å < 3.130(2) Å < 3.241(1) Å for PMe₃ (118°), PPhMe₂ (122°), and PEt₃ (132°), and their emission energies also increase in the order of 542 nm < 530 nm < 504 nm, respectively. This work highlights a very good correlation between intermolecular aurophilic interactions and emission energies for a series of Au₆ supermolecules, where the cone angle plays a vital role in the self‐assembly process as well. Finally, the emissions for 1 – 3 are tentatively assigned to the S → Au charge‐transfer transition, whereas they are most probably modified by gold(I)?gold(I) interactions.     

单分散水溶性金纳米团簇的制备及表征

采用改进的Brust方法,用硼氢化钠还原氯金酸,并以巯基丁二酸(MSA)、氮乙酰基半光胺酸(NAC)作为包裹剂,成功制备了单分散的水溶性金纳米团簇。高分辨透射电镜(HRTEM)结果表明,增大硫醇与氯金酸的比例并增加氯金酸的初始浓度,有利于得到尺寸更小的金纳米粒子。当氯金酸的浓度(C_Au)为9.3 mmol·L^-1,C_Au:C_S为1:30时,得到了直径约为1 nm、标准偏差为0.2 nm的Au@MSA纳米团簇。结合紫外(UV)、热重(TG)和X射线光电子能谱(XPS)分析结果,可以推测出单分散金纳米簇的化学式为[Au₃₈(MSANa)₂₆]或[Au₃₉(MSANa)₂₇]。     

Synthese,Kristallstruktur und spektroskopische Charakterisierung von [Au12(PPh)2(P2Ph2)2(dppm)4Cl2]Cl2

Synthesis, Crystal Structure and Spectroscopic Characterization of [Au₁₂(PPh)₂(P₂Ph₂)₂(dppm)₄Cl₂]Cl₂ The reaction of [(AuCl)₂dppm] (dppm = Ph₂PCH₂PPh₂) with P(Ph)(SiMe₃)₂ in CHCl₃ results in the formation of [Au₁₂(PPh)₂(P₂Ph₂)₂(dppm)₄Cl₂]Cl₂ ( 1 ), the crystal structure of which was determined by single crystal X‐ray analysis (space group P2₁/c, a = 1425.3(3) pm, b = 2803.7(6) pm, c = 2255.0(5) pm, β = 95.00(3)°, V = 8977(3)·10⁶ pm³, Z = 2). The dication in 1 consists of two Au₆P₃ units built by highly distorted Au₃P and Au₂P₂ heterotetrahedra, connected via four bidentate phosphine ligands. Additionally, the compound was characterized by IR‐, UV‐ and NMR spectroscopy. The ³¹P{¹H} NMR spectrum is discussed in detail.     

Unraveling the Impact of Gold(I)–Thiolate Motifs on the Aggregation-Induced Emission of Gold Nanoclusters

Aggregation-induced emission (AIE) provides an efficient strategy to synthesize highly luminescent metal nanoclusters (NCs), however, rational control of emission energy and intensity of metal NCs is still challenging. This communication reveals the impact of surface Au^I-thiolate motifs on the AIE properties of Au NCs, by employing a series of water-soluble glutathione (GSH)-coordinated Au complexes and NCs as a model ([Au₁₀SR₁₀], [Au₁₅SR₁₃], [Au₁₈SR₁₄], and [Au₂₅SR₁₈]⁻, SR=thiolate ligand). Spectroscopic investigations show that the emission wavelength of Au NCs is adjustable from visible to the near-infrared II (NIR-II) region by controlling the length of the Au^I-SR motifs on the NC surface. Decreasing the length of Au^I-SR motifs also changes the origin of cluster luminescence from AIE-type phosphorescence to Au⁰-core-dictated fluorescence. This effect becomes more prominent when the degree of aggregation of Au NCs increases in solution.     

Chemisorption of the [AuCl4]− anion by cadmium cyclo-pentamethylenedithiocarbamate and the resulting bound-gold(III) species: The supramolecular structure and thermal behavior of the polynuclear complexes ([Au{S2CN(CH2)5}2]2[CdCl4]) n and ([Au{S2CN(CH2)5}Cl2]) n

The interaction between cadmium cyclo-pentamethylenedithiocarbamate (chemisorbent Ia) and the [AuCl₄]^? anion in 2 M HCl has been investigated. The state of the chemisorbent in contact with AuCl₃ solutions has been probed by ¹¹³Cd MAS NMR spectroscopy. The heterogeneous reactions in the system, including gold(III) chemisorption from the solution and partial ion exchange, yield the gold(III)-cadmium heteropolynuclear complex ([Au{S₂CN(CH₂)₅}₂]₂[CdCl₄]) _n (I) and the polynuclear mixed-ligand complex ([Au{S₂CN(CH₂)₅}Cl₂]) _n (II). The crystal and molecular structures of these compounds have been determined by X-ray crystallography. The main structural units of the compounds are the complex cation [Au{S₂CN(CH₂)₅}₂]⁺, [CdCl₄]^2? anion (in I), and Au{S₂CN(CH₂)₅}Cl₂ molecule (in II). The further structural self-organization of the complexes at the supramolecular level is due to secondary Au...S and Au...Au bonds. [Au₂{S₂CN(CH₂)₅}₄]²⁺ dinuclear cations form in the structure of I, which then polymerize into ([Au₂{S₂CN(CH₂)₅}₄]²⁺) _n chains. In the structure of II, adjacent Au{S₂CN(CH₂)₅}Cl₂ molecules join by forming pairs of asymmetric secondary Au...S bonds, producing polymer chains with alternating antiparallel monomer units. The chemisorption capacity values calculated for cadmium cyclo-pentamethylenedithiocarbamate from gold(III) binding reactions are 455 and 910 mg of gold per gram of sorbent. The gold recovery conditions have been determined by investigating the thermal behavior of I and II by synchronous thermal analysis. The multistep thermal destruction of ionic complex I includes the thermolysis of its carbamate moiety and [CdCl₄]_2? (which liberates gold metal and cadmium chloride and yield some amount of CdS) and CdCl₂ and CdS evaporation. The thermolysis of II proceeds via the formation of Au₂S and AuCl as intermediate compounds. In both cases, the ultimate pyrolysis product is elemental gold.     

Coordination Behavior of a D‐Penicillaminato Aurate(I) Metalloligand Toward Coblat(III) Centers

Treatment of (NH₄)[Au(D‐Hpen‐S)₂](D‐H₂pen = D‐penicillamine) with CoCl₂·6H₂O in an acetate buffer solution, followed by air oxidation, gave neutral Au^ICo^III and anionic Au^I₃Co^III₂ polynuclear complexes, [Au₃Co₃(D‐pen‐N,O,S)₆]([ 1 ]) and [Au₃Co₂(D‐pen‐N,S)₆]^3? ([ 2 ]^3?), which were separated by anion‐exchange column chromatography. Complexes [ 1 ] and [ 2 ]^3? each formed a single isomer, and their structures were determined by single‐crystal X‐ray crystallography. In [ 1 ], each of three [Au(D‐pen‐S)₂]^3?metalloligands coordinates to two Co^III ions in a bis‐tridentate‐N,O,S mode to form a cyclic Au^I₃Co^III₃ hexanuclear structure, in which three [Co(D‐pen‐N,O,S)₂]^? octahedral units and six bridging S atoms adopt trans(O) geometrical and R chiral configurations, respectively. In [ 2 ]^3?, each of three [Au(D‐pen‐S)₂]^3? metalloligands coordinates to two Co^III ions in a bis‐bidentate‐N,S mode to form a Au^I₃Co^III₂ pentanuclear structure, in which two [Co(D‐pen‐N,S)₃]^3? units and six bridging S atoms adopt ∧ and R chiral configurations, respectively.     

Seed free high yield gold nanorods synthesis from single precursor gold(I) dithiophosphate complex

In this work, we demonstrate a simple, one pot and seed free synthetic route for the formation of gold nanorods (Au NRs) via thermal decomposition of gold(I) dithiophosphate {[Au₂{S₂P(OⁱPr)₂}₂]_n,} 1 complex as a molecular precursor in presence of 4′‐amino‐biphenyl‐4‐carboxylic molecule. Here [Au₂{S₂P(OⁱPr)₂}₂]_n, complex functioned as gold (Au) source and 4′‐amino‐biphenyl‐4‐carboxylic molecule stabilized gold (Au) nanorods (NRs) through the unidirectional coating of Au surface during its growth in the reaction medium.     

A square‐planar hydrated cationic tetrakis(methimazole)gold(III) complex

The cationic pseudo‐square‐planar complex tetrakis(1‐methyl‐2,3‐dihydro‐1H‐imidazole‐2‐thione‐κS)gold(III) trichloride sesquihydrate, [Au(C₄H₆N₂S)₄]Cl₃·1.5H₂O, was isolated as dark‐red crystals from the reaction of chloroauric acid trihydrate (HAuCl₄·3H₂O) with four equivalents of methimazole in methanol. The Au^III atoms reside at the corners of the unit cell on an inversion center and are bound by the S atoms of four methimazole ligands in a planar arrangement, with S—Au—S bond angles of approximately 90°.