(Phosphine)gold(I) Complexes of Benzenedithioles. Crystal structures of 1,2-benzenedithiolato-bis[triphenyl-phosphinegold(I)] and bis(triethylphosphine)gold(I) bis(1,2-benzenedithiolato)gold(III)

The reaction of 1,2- and 1,3-benzenedithiol C₆H₄(SH)₂ with chloro(phosphine)gold(I) complexes R₃PAuCl (R = Et, Ph) in the presence of triethylamine in tetrahydrofuran gives stable gold(I) complexes 1,2-C₆H₄(SAuPR₃)₂ [R = Et ( 1 ) and Ph ( 2 )] or 1,3-C₆H₄(SAuPPh₃)₂ ( 3 ), respectively, in high yield. The compounds have been characterized by analytical and NMR spectroscopic data. From the reaction of 1,2-C₆H(SH)₂ with Et₃P? AuCl a by-product [(Et₃P)₂Au]⁺ [Au(1,2? C₆H₄S₂)₂]^? ( 4 ) has also been isolated in low yield. The crystal structures of compounds 2 and 4 have been determined by single crystal X-ray diffraction. The gold(I) atoms in complex 2 are two-coordinate with bond angles S? Au? P of 175.2(1) and 159.5(1)°, Au? S bond distances of 2.304(1) and 2.321(1) å, and a short Au…?Au contact of 3.145(1) Å. The gold(I) atom in the cation of complex 4 is also linearly two-coordinate with a P? Au? P angle of 170.1(1) Å and Au? P distances of 2.296(3) and 2.298(3) Å. The geometry of the anion in 4 shows a square-planar coordination of gold(III) by two chelating 1,2-benzenedithiolate ligands with Au? S distances between 2.299(3) and 2.312(3) Å (for two crystallographically independent, centrosymmetrical anions in the unit cell).     

Structural studies of two-coordinate complexes of tris(2-methoxylphenyl)phosphine and tris(4-methoxyphenyl)phosphine with gold(I) halides

A series of five gold(I) halide complexes with the two isomeric methoxy-substituted triarylphosphines, tris(2-methoxyphenyl)phosphine [P(oanis)₃], [AuP(oanis)₃X] [for X = Cl, (1); X = Br, (2) and X = I, (3)] and tris(4-methoxyphenyl)phosphine [P(panis)₃], [AuP(panis)₃X] [for X = Br (4) and X = I (5)] have been synthesized and characterized by single crystal X-ray diffraction and solution ³¹P{¹H} NMR spectroscopy. The structure determinations confirm the expected presence of linear two-coordination about the gold centres in all five complexes with bond distance and angle data typical of this type of compound [Au–P, 2.239(2)–2.259(3) Å; Au–Cl, 2.294(2) Å; Au–Br, 2.385(2)–2.402(2) Å; Au–I, 2.546(1)–2.554(1) Å; P–Au–X; 175.3(1)–180°]. All analogues except the iodo complex 5 crystallize with one complex molecule in the crystallographic asymmetric unit. The bromo and iodo complexes 2 and 3 constitute a trigonal isomorphous set while the bromo complex 4 is also isomorphous with the previously determined chloro complex [AuP(panis)₃Cl]. The 2-methoxy analogues are stabilized by significant methoxy-O?Au interactions.     

冠醚环化二硫烯双核Au(I)配合物的合成、结构及电化学性质

合成了含有冠醚环化二硫烯的双核Au(I)配合物[(30-C2S4)Au2(PPh3):](1),[(40-C2S4)Au2·(PPh3)2](2),[(30一C6-S8)Au2(Pph3)2](3)和[(40-C6-S8)Au2(PPh3)2](4)以及富硫配合物[(btdt)Au2·(PPh3)2](5).通过x射线...     

Solution and solid state NMR studies of some selenium analogues of auranofin (an anti-arthritic gold drug)

Three mixed ligand complexes of gold(I) with phosphines and selenones, [Et₃PAuSe=C<]Br as analogues of auranofin (Et₃PAuSR) have been prepared and characterized by elemental analysis, IR and NMR methods. A decrease in the IR frequency of the C=Se mode of selenones upon complexation is indicative of selenone binding to gold(I) via a selenone group. An upfield shift in ¹³C NMR for the C=Se resonance of the selenones and downfield shifts in ³¹P NMR for the R₃P moiety are consistent with the selenium coordination to gold(I). ¹³C solid state NMR shows the chemical shift difference between free and bound selenone to gold(I) for ImSe and DiazSe to be ca 10 and 17?ppm respectively. Large ⁷⁷Se NMR chemical shifts (55?ppm) upon complexation in the solid state for [Et₃PAuDiazSe]Br compared to [Et₃PAuImSe]Br (10?ppm) indicates the former to be more stable and the Au–Se bond to be stronger than in the latter complex.     

The specific detection of Cu(Ⅱ) using an AIE-active alanine ester

Cu(Ⅱ) detection is important because it plays crucial role in several biological processes and ecological systems.Fluorescent techniques have attracted more and more attention in Cu(Ⅱ) detection.In this report,we contribute a novel strategy to use fluorescence spectroscopy for Cu(Ⅱ) specific detection.The specificity relies on the fact that,of the many metal cations,only Cu(Ⅱ) can catalyze the hydrolyzation of a-amino acid ester.The novelty originates from the unique aggregation-induced emission(AIE) property of the fluorescent label.We designed a model a-amino acid ester(TPE-Ala) constructed with alanine and tetraphenylethene-functionalized methanol(TPE-methanol).In comparison with the precursor TPE-Ala, TPE-methanol has lower solubility and is easy to form aggregates in water,thereby displaying a higher fluorescent response.Thus,the Cu(Ⅱ) catalyzed hydrolyzation can be monitored by recording the fluorescence enhancement and fluorescent detection Cu(Ⅱ) is rationally achieved.     

In vitro biological studies of heteroleptic Ag(I) and Cu(I) unsymmetrical N,N′-diarylformamidine dithiocarbamate phosphine complexes; the effect of the metal center

A series of five dithiocarbamate and their respective Ag(I) and Cu(I) triphenylphosphine complexes of the general formula [Ag/Cu(PPh₃)₂L] were synthesized and characterized. The dithiocarbamate ligands were synthesized from formamidines with substituents in the 2 and/or 6 positions of the phenyl rings, intentionally keeping substituents on one ring different from those of the second phenyl ring while investigating the structure-activity relationship of Ag(I) and Cu(I) dithiocarbamate complexes. All Ag(I) and Cu(I) complexes with the general formula [Ag(PPh₃)₂L] (1–5) or [Cu(PPh₃)₂L] (6–10), displayed distorted tetrahedral geometry around the metal centers with coordination via two S atoms of the dithiocarbamate ligand and two P atoms from the PPh₃ units. Complexes 1–5 showed better inhibition values against Gram-positive, Staphylococcus aureus (methicillin resistant) and Staphylococcus aureus than the standard used, ciprofloxacin. Complexes 1 and 2 generally had good activity against all bacterial strains but were not active against Salmonella typhimurium. All Cu(I) complexes were either of low activity or inactive against all bacterial strains tested. Complex 2 was found to be more active with IC₅₀ values of 1.34 × 10⁻³ mM and 0.25 mM as agents for antioxidant activity against DPPH and NO free radical scavengers, respectively. The metal center played a vital role in their biological activity as the Ag(I) complexes displayed better antibacterial and antioxidant activity than Cu(I) complexes.     

Synthesis, characterization and bromination of bis(phosphinoferrocenyl) gold(I) compounds

Reaction of [(dppf)Au₂Br₂] (3) {dppf = 1,1′-bis(diphenylphosphino)ferrocene} and [(dippf)Au₂Br₂] (4) {dippf = 1,1′-bis(diisopropylphosphino)ferrocene} with excess bromine yields two new complexes [(C₅H₄Br₃)(PR₂)AuBr] (R = Ph, 5; R = i-Pr, 6). Bromination of the free diphosphinoferrocene ligands produces the expected brominated cyclopentenes (C₅H₄Br₃)(PR₂) (R = Ph, 7; R = i-Pr, 8) in good yields; however, these compounds could not be complexed to gold due to reduced basicity of 7 and 8. When the bromination is performed under wet aerobic conditions the oxidized pseudo-centrosymmetric product, [doppf][FeBr₄] (9) {doppf = 1,1′-bis(oxodiphenylphosphino)ferrocene, is formed as the major product. Solid-state structures of 1, 2, 4, 6, and 9 have been established by means of single-crystal X-ray crystallography.     

基于铜纳米簇的聚集诱导发光检测铅离子

基于谷胱甘肽保护的非贵金属铜纳米簇(Cu NCs@GSH)的聚集诱导发光现象,建立了快速检测铅离子(Pb2+)的“Turn on”型荧光分析方法.Cu NCs@GSH溶液荧光强度很弱,当存在pb2+时,荧光强度可显著增强,溶液显示明亮的橙黄色.基于此原理建立了检测pb2+的荧光方法,线性范围为200～700 μmol/L,检出限为106 μmol/L,常见金属离子不干扰pb2+的测定.本方法简单快速、选择性高,可实现对pb2+的可视化定性检测.     

Crystal structures,DNA-binding ability and influence on cellular viability of gold(I) complexes of thiosemicarbazones

The present study reports the synthesis and crystal structure of four novel gold(I) complexes with di-2-pyridyl ketone N(4)-ethylthiosemicarbazone (L¹) and 2-acetylfuran-4-methyl-3-thiosemicarbazone (L²). All the gold(I) complexes were observed with monodentate thiosemicarbazones and exhibited gold(I) ions with linear geometries, bound to a sulfur atom of the ligand and a halogen ion (Br^? or Cl^?). The crystal structures of gold complexes with Br^? and thiosemicarbazone are the first examples reported. Interestingly, 2[AuBr(HL¹)]2Br was observed to have a Au?Au length of 3.155(8) Å, and this distance suggests an unusual Au?Au interaction in the solid state. The ability of the thiosemicarbazones and the corresponding gold(I) complexes to bind to DNA was studied by UV-vis and emission spectroscopy. The effect on cell viability of the compounds was evaluated against human breast cancer cell lines. The results show that the gold(I) complexes exhibit more potent inhibition of tumor growth than the free ligands.     

Unveiling the Potential of Innovative Gold(I) and Silver(I) Selenourea Complexes as Anticancer Agents Targeting TrxR and Cellular Redox Homeostasis

A series of NHC-based selenourea Ag(I) and Au(I) complexes were evaluated for their anticancer potential in vitro, on 2D and 3D human cancer cell systems. All NHC-based selenourea complexes possess an outstanding cytotoxic potency, which was comparable or even better than that of the reference metallodrug auranofin, and were also able to overcome both platinum-based and multi-drug resistances. Intriguingly, their cytotoxic potency did not correlate with solution stability, partition coefficient or cellular uptake. On the other hand, mechanistic studies in cancer cells revealed their ability to strongly and selectively inhibit the redox-regulating enzyme Thioredoxin Reductase (TrxR), being even more effective than auranofin, a well-known TrxR inhibitor, without affecting other redox enzymes such as Glutathione Reductase (GR). The inhibition of TrxR in H157 human cancer cells caused, in turn, the disruption of cellular thiol-redox homeostasis and of mitochondria pathophysiology, ultimately leading to cancer cell death through apoptosis.     

Gold versus silver-catalyzed amination of allylic alcohols

Direct substitution of the hydroxy group in allylic alcohols by different nitrogenated nucleophiles is performed using low loadings of cationic gold(I) or silver salts as catalysts. Sulfonamides, carbamates and aromatic amines can be used as nucleophiles. Comparative studies between the best catalysts, cationic (triphenylphosphite)gold(I) complex and silver triflate, demonstrate that the former catalyst shows, in general, better performance than silver, working at lower loadings, in shorter reaction times and at lower temperatures. Representative allylic alcohols are used giving good γ-regioselectivity, specially in the case of penta-1,4-dien-3-ol and (E)-1-phenylbut-2-en-1-ol affording the corresponding allylic sulfonamides with total regio and stereoselectivity by a hydroamination mechanism. In the case of crotyl alcohol and (E)-4-phenylbut-3-en-2-ol mainly and exclusively α-substituted sulfonamides were obtained, respectively, by a cationic mechanism.     

Syntheses and molecular structures of some phosphine-gold(I) derivatives of 1,3-diynes

The syntheses of several diynylgold(I) phosphine complexes, including Au(CCCCH){P(tol)₃} (1), Au(CCCCSiMe₃)(PR₃) (R = Ph 2-Ph, tol 2-tol), Au(CCCCFc)(PPh₃) (3), {(tol)₃P}Au(CC)_nAu{P(tol)₃} [n = 2 (4), 3 (6), 4 (7)], {(Ph₃P)Au}CCCC{Au[P(tol)₃]} (5), [ppn][Au{CCCCAu[P(tol)₃]}₂] (8), [Au₂(μ-I)(μ-dppm)₂][Au(CCCCSiMe₃)₂] (9), Hg{CCCCAu(PR₃)}₂ (R = Ph 10-Ph, tol 10-tol) and {(triphos)Cu}CCCC{Au[P(tol)₃]} (11) are described. Of these, the X-ray molecular structures of 1, 2-tol, 3, 4 and 9 have been determined.     

Zur Charakterisierung von 1,1,2,3,3-Pentacyanopropenid als Komplexligand in ein- und zweizähniger Funktion. Darstellung von Komplexen des Typs [MX(PPh3)n] (M = CuI,AgI; X = NCC{C(CN)2}2; n = 2, 3)

Pseudoelement Compounds. XII. [1] On the Characterization of 1,1,2,3,3-Pentacyanopropenide in Unidentate and Bidentate Function. Syntheses of Complexes of the Type [MX(PPh₃)_n] (M = Cu^I, Ag^I; X = NCC{C(CN)₂}₂; n = 2, 3) 1,1,2,3,3-Pentacyanopropenide is characterized as unidentate and bidentate ligand. For that reason compounds of the types [MX(PPh₃)₃] ( 6 ) and [MX(PPh₃)₂]₂ ( 8 ) (M = Cu^I, Ag^I) are synthesized. In the complexes 6 the ionic ligand is coordinated unidentately through an end-on nitrile group of a C(CN)₂ unit and in the dimeric complexes 8 bidentately bridging through the N atoms of a C(CN)₂ moiety too. The compounds are characterized by ¹³C NMR, ³¹P NMR and IR spectroscopy. The crystal structure of [AgX(PPh₃)₃] is presented and the structural parameters of the anion in this complex and in [CuX(PPh₃)₂]₂ [X = NCC{C(CN)₂}₂] are compared.     

Darstellung und Struktur von Tetraethylcyclotetraarsoxan-Komplexen von Kupfer(I)-Halogeniden

Preparation and Structure of Tetraethylcyclotetraarsoxane Complexes of Copper(I) Halides The polymeric complexes [Cu₄Cl₄{cyclo-(C₂H₅AsO)₄}₃]_n ( 1 ), [Cu₃Br₃{cyclo-(C₂H₅AsO)₄}₂]_n ( 2 ) and [Cu₆I₆{cyclo-(C₂H₅AsO)₄}₃]_n ( 3 ) were prepared by the reaction of (C₂H₅AsO)_n and CuX (X = Cl, Br, I) in acetonitrile and characterised by X-ray analysis. All three complexes contain only tetramers (C₂H₅AsO)₄ as ligands, in which the As₄O₄ ring systems coordinate between two and four Cu-atoms. In each case one As₄O₄ ring with a crown-shaped conformation is observed, which coordinates either four (in 1 ) or three (in 2 and 3 ) axially sited Cu-atoms. In addition there are further (C₂H₅AsO)₄ ligands, which display either a boat-chair- (in 1 ) or a twist-chair-conformation (in 1–3 ). The individual building units are connected to one another via Cu? X? Cu bridges (in 2 and 3 ) and/or centrosymmetric As₄O₄ ring systems (in 1–3 ) into chain ( 1 ) or layer structures ( 2 und 3 ).     

(R,R,R)-Tris(2-hydroxy-1-methylethyl)- and (S,S,S)-tris(2-hydroxy-2-methylethyl)phosphine: water-soluble chiral trialkylphosphines with C3-symmetry

The first α- and β-chiral water-soluble trialkylmonophosphines, 1 and 2, respectively, both with C₃ symmetry, were synthesised from sodium phosphide and chiral mesylates, accessible from (S)-ethyl lactate. X-ray structures of a corresponding 2:1 gold(I) complex [1₂Au(I)]OTf and of a borane complex 2·BH₃ were determined.     

Thermal decomposition of silver(I) and mercury(I) anthranilates and salicyloaldoximates

The processes of thermal decomposition of silver(I) and mercury(I) anthranilates and salicyloaldoximates were studied. Thermal, chemical and X-ray analyses and infrared spectroscopy were used to determine the mechanisms of decomposition of these complexes. The factor determining the decomposition is the character of the Ag⁺ and Hg ₂ ²⁺ ions, which are easily reduced to free metals. The final reaction product of the compounds of silver is the pure metal; the compounds of mercury are volatilized completely when heated.     

Heterometallic complexes containing 1,1′-(CC)2Fc′ units linking two different metal centres

Proto-desilylation of 1-(Me₃SiCC)-1′-{Cp^∗(dppe)RuCC}Fc′ (1) afforded the corresponding ethynyl derivative 2, from which the green Co₂(μ-dppm)_n(CO)_8−2n (n = 0, 1) adducts 3 and 4 were obtained. Replacement of the ethynyl proton in reactions between 2 and AuCl(PPh₃), Hg(OAc)₂ or FeCl(dppe)Cp^∗ gave complexes 1-(RCC)-1′-{Cp^∗(dppe)RuCC}Fc′ [R = Au(PPh₃) 5, 1/2Hg 6, Fe(dppe)Cp^∗8]; the latter gave bis-vinylidene 9 with MeI, characterised (as was 2) by a single crystal X-ray study. Oxidative coupling of 2 (CuCl/tmeda/acetone, air) gave diyne 10, while coupling of 5 with Co₃(μ₃-CBr)(μ-dppm)(CO)₇ afforded 1-{Cp^∗(dppe)RuCC}-1′-{(OC)₇(μ-dppm)Co₃(μ₃-CCC)}Fc′ (11). Cyclic voltammetric measurements indicated that there was no significant electronic coupling between the end-groups through the ferrocene centre in any of these compounds.