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Highlights: [•] Synthesis of range of new gold(III) thiourea complexes by simple methodology. [•] ESI MS identifies wide range of other species, demonstrating method generality. [•] Two structural determinations reveal effects of bulky cyclohexyl substitution. [Copyright &y& Elsevier]

Gold complexes of 1,3- bis-pyridylimidazolium chloride ( L1), 1,3-bis-[2,6-diisopropylphenyl]imidazolium chloride ( L2) and 1,3-bis-[benzyl]benzimidazolium chloride ( L3) were synthesized and characterized by . For the complexes, electronic spectral results show that there is a marked difference in the band feature observed in the spectra, ascribed to the greater relativistic effect of gold. In fluorescence studies, the complexes develop emission bands in the visible region (400-600 nm) after excitation at around 350 nm. Au complex-DNA binding was studied, and it was observed that genomic DNA isolated from the U373-GB cell line was fragmented and in some cases degraded by the Au complexes. Furthermore, the intensity of the DNA band increased when concentration of the metal complex was augmented. This study shows that the DNA cleavage is mediated by the Au complex. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The reaction of tetrapropylammonium bis(acetylacetonato)gold(I) with alkyne derivatives of the tris(pyrazolyl)methane and 1,8-naphthalimide functional groups yielded two new compounds, both bridged by the linear C[triple-bond]C-Au-C[triple-bond]C spacer, namely tetrapropylammonium bis{3-[2,2,2-tris(1 H-pyrazol-1-yl)ethoxy]prop-1-yn-1-yl}aurate(I), (C16H28N)[Au(C14H13N6O)2], and tetrapropylammonium {η2-μ-3-[2,4-dioxo-3-azatricyclo[7.3.1.05,13]trideca-1(12),5,7,9(13),10-pentaen-3-yl]prop-1-yn-yl}bis{3-[2,4-dioxo-3-azatricyclo[7.3.1.05,13]trideca-1(12),5,7,9(13),10-pentaen-3-yl]prop-1-yn-1-yl}digold(I) deuterochloroform disolvate, (C16H28N)[Au2(C15H8NO2)3]·2CDCl3. The alkyne-functionalized scorpionate ligand [Au{C[triple-bond]CCH2OCH2C(pz)3}2]− features two potentially tridentate tris(pyrazolyl)methane donor groups oriented in a ` trans' position relative to the C[triple-bond]C-Au-C[triple-bond]C spacer. The naphthalimide-containing compound comprises a σ-bonded NI-CH2-C[triple-bond]C-Au-C[triple-bond]C-CH2-NI unit (NI is the naphthalimide group) π-coordinated to an NI-CH2-C[triple-bond]C-Au neutral fragment. The crystal packing of this compound is supported by π-π stacking interactions of the NI unit, generating a three-dimensional network containing channels accommodating the tetrapropylammonium cations and deuterated chloroform solvent molecules. [ABSTRACT FROM AUTHOR]

Two for one gold: Factors governing the formation of isolable digold(I) σ,π‐acetylide complexes are given (see scheme), indicating the general tendency of phosphine–AuI precatalysts to form this type of complexes, which are involved as reaction intermediates in gold(I)‐catalyzed reactions. Mechanistic insights into the intermolecular hydroamination of aniline and terminal alkynes catalyzed by gold(I) have shown the role of a fluxional, cationic σ,π‐digold alkynide complex as one of the intermediates in the formation of imines. [ABSTRACT FROM AUTHOR]

The oxidative photocyclization reactions of olefins that contain 1 H-phosphindole or dibenzophosphole substituents have been applied to the synthesis of P/N-bi-heterosubstituted dimeric helicenes, as well as of new [6]- and [8]phosphahelicenes. In these photocyclization processes, the configuration of the stereogenic phosphorus center dictates the sense of helical chirality. Thus, by starting from enantiomerically pure P-menthylphosphole-oxide units, this method affords enantiopure helical compounds. The helical phosphine oxides were characterized by X-ray diffraction. After reduction of the phosphine-oxides, the corresponding helical phosphines have been used as ligands in transition-metal complexes. The X-ray crystal structure of a gold chloride complex of a [6]helicene is reported. [ABSTRACT FROM AUTHOR]

Abstract: The antineoplastic potential of a new stable mixed phosphine gold(I) complex containing tris(tert-butyl)phosphine (tBu3P) and bis(diphenylphosphino)ethene (dppet), namely [Au(tBu3P)(dppet)Cl], has been investigated in the human colon cancer HCT-116 cell line. The 31P NMR solution study, confirms the structural features observed in the solid state and, in addition, indicates partial formation of dinuclear cationic [Au(tBu3P)2]+ and [Au(dppet)2]+ species. The ionic character and strong Au–P bonds of this gold(I) species are similar to those of the most active antitumor gold compounds so far studied. The title compound was found to exhibit strong cytotoxicity, showing 85 fold greater toxicity than cisplatin (IC50 =0.45μM vs IC50 =39.16 for cisplatin at 24h) on the HCT-116 line. The cytotoxic effects were, at least partly, mediated by the induction of apoptotic cell death as evidenced by the sub-G1 cell accumulation, oligonucleosomal DNA fragmentation, caspase-3 activation and the release of cytochrome c from the mitochondria. The gold(I) compound showed little interaction with DNA measured through fluorescence quenching studies with calf thymus DNA. The inhibitory effect of the gold(I) compound on intracellular redox proteins has been also observed in pretreated HCT-116 cells. The compound was particularly effective in inhibiting thioredoxin reductase, that is likely responsible for the increased ROS production, and subsequent apoptosis induction via the mitochondrial pathway. [Copyright &y& Elsevier]

Abstract: Treatment of [RuCl2(η 6-p-cymene){κ 1-(P)-PPh2(py-6-tert-amyl)}] (1a) and [RuCl2(η 3:η 3-C10H16){κ 1-(P)-PPh2(py-6-tert-amyl)}] (1b) with [AuCl(SMe2)], in dichloromethane at room temperature, resulted in the formation of the dimethyl sulfide adducts [RuCl2(η 6-p-cymene)(SMe2)] (3a) and [RuCl2(η 3:η 3-C10H16)(SMe2)] (3b), and the Au(I) complex [AuCl{κ 1-(P)-PPh2(py-6-tert-amyl)}] (4). Transmetalation of the pyridyl-phosphine PPh2(py-6-tert-amyl) (2) was also observed when dichloromethane solutions of 1a–b were treated with AgSbF6 in the presence of SMe2, the reactions leading to 3a–b and the dinuclear Ag(I) derivative [Ag2{μ-PPh2(py-6-tert-amyl)}2][SbF6]2 (5). In the absence of SMe2 transmetalation of the phosphine to silver was not observed. Instead, the unexpected protonation of the pyridyl group by HF, generated by partial hydrolysis of the SbF6 − anion, occurred. Compounds [AuCl{κ 1-(P)-PPh2(py-6-tert-amyl)}] (4) and [Ag2{μ-PPh2(py-6-tert-amyl)}2][SbF6]2 (5) were independently synthesized by reacting 2 with [AuCl(SMe2)] and AgSbF6, respectively, and their structures confirmed by means of single-crystal X-ray diffraction techniques, along with those of the protonated species [RuCl2(η 6-p-cymene){κ 1-(P)-PPh2(pyH-6-tert-amyl)}][SbF6] (6a) and [RuCl2(η 3:η 3-C10H16){κ 1-(P)-PPh2(pyH-6-tert-amyl)}][SbF6] (6b). [Copyright &y& Elsevier]

Abstract: Nowadays, gold compounds occupy a relevant position constituting a promising class of experimental anticancer metallodrugs. Several research efforts have been devoted to the investigations of the pharmacological properties of gold(I) complexes bearing phosphine ligands, such as the antiarthritic drug auranofin, that has also been shown to produce anticancer effects in vitro. In spite of the numerous studies that appeared in the literature the biological mechanisms of action of auranofin and analogues are still controversial. Here, we report on the inhibition effects of glutathione S-transferase P1-1 (GST P1-1) exerted by auranofin. The compound was able to inhibit GST P1-1 with a calculated IC50 of 32.9±0.5μM. Interestingly, the inhibition of GST P1-1 and its cysteine mutants by the gold(I) compound is essentially the same, suggesting that probably the cysteine residues are not so essential for enzyme inactivation in contrast to other reported inhibitors. High-resolution electrospray ionisation Fourier transform ion cyclotron mass spectrometry (ESI FT-ICR MS) studies allowed characterising the binding of the compound with GST enzymes at a molecular level, confirming that similar gold binding sites may be present in the wild-type protein and its Cys mutants. [Copyright &y& Elsevier]

Abstract: Three new silyl-substituted phosphaalkenes Mes*P013;Si(Cl)PhR (R = chlorine, 1; R = 9-methylfluoren-9-yl, 2; R = 9-trimethylsilylfluoren-9-yl, 3) were obtained and completely characterized. The coordination compounds 4 and 5, resulting from the reaction between Au(SMe2)Cl and 1 and 3, respectively, are also described. All these compounds are potential precursors of phosphasilaallenes, not stabilized until now and new ligands in transition metal chemistry. [Copyright &y& Elsevier]

Abstract: Reactions of the dinuclear platinum(II) sulfide complex [Pt2(μ-S)2(PPh3)4] with a range of gold(III) dichloride complexes [AuLCl2] containing C, N- or N, N-cycloaurated ligands L gives a new series of dicationic adducts [Pt2(μ-S)2(PPh3)4AuL]2+, isolated as their PF6 − salts. The complexes investigated are [Au{C6–H4(CH2NMe2)-2}Cl2], [Au{C6H3(CH2NMe2)-2-(OMe)-5}Cl2], [Au{NC5H4(CH2C6H4)-2}Cl2], [Au{NC5H4(COC6H4)-2}Cl2] and [Au{NC5H4(CONH)-2}Cl2]. An X-ray structure determination on the picolinamide-derived complex [Pt2(μ-S)2(PPh3)4Au{NC5H4(CONH)-2}](PF6)2 was not of sufficiently high quality for detailed discussion, but confirmed the atom connectivity. Reactions of [Pt2(μ-S)2(PPh3)4] with [AuCl2(bipy)]PF6 (L=bipy=2,2’-bipyridine) and [AuCl2(phen)]Cl (L=phen=1,10-phenanthroline) gives the corresponding tricationic adducts [Pt2(μ-S)2(PPh3)4AuL]3+, also isolated as their PF6 − salts. The complexes are characterised by NMR spectroscopy, electrospray mass spectrometry and microelemental analyses. Biological assay data of a selection of these new complexes towards the P388 murine leukemia cell line, as well as a range of antimicrobial tests, reveals overall low activity compared to other cycloaurated gold(III) complexes. [Copyright &y& Elsevier]

Since their first discovery, N -heterocyclic carbenes have had a significant impact on organometallic chemistry. Due to their nature as strong σ-donor and π-acceptor ligands, they are exceptionally well suited to stabilize Au(I) and Au(III) complexes in biological environments. Over the last decade, the development of rationally designed NHCAu(I/III) complexes to specifically target DNA has led to a new "gold rush" in bioinorganic chemistry. This review aims to summarize the latest advances of NHCAu(I/III) complexes that are able to interact with DNA. Furthermore, the latest advancements on acyclic diamino carbene gold complexes with anticancer activity are presented as these typically overlooked NHC alternatives offer great additional design possibilities in the toolbox of carbene-stabilized gold complexes for targeted therapy.

Abstract: N,N-Diethyl-N′-4-nitrobenzoylselenourea (HL Se ) reacts with the mono- and dinuclear phosphine gold(I) chloro complexes [AuCl(PR3)] (R=Ph, o-tol, Et) and [Au2Cl2(μ-P-P)] (P-P=dppm, dppe, dppp, dppb, dppf) in the presence of base to give gold(I) phosphine selenoureato complexes [Au(LSe)(PR3)] [R=Ph (1), o-tol (2), Et (3)], [Au2(LSe)2(μ-P-P)] [P-P=dppm (4), dppe (5), dppp (6), dppb (7), dppf (8)] in excellent yields. The compounds were fully characterised by spectroscopic methods and, in the case of compounds 1, 5 and 8, by single crystal X-ray diffraction. The compounds consist of a gold atom bound in linear fashion to the phosphine ligand and the selenium atom from the deprotonated acylselenourea. These complexes thus represent the first examples of acylselenoureato metal compounds in which the ligands do not adopt the typical O,Se chelating mode but rather coordinate to the metal only through the selenium atom. [Copyright &y& Elsevier]

Novel double complex salts [M(NH)Br][AuBr]· nHO, M = Rh, Ir, have been synthesized and examined. The processes of thermal decomposition of the compounds in inert and reductive atmospheres have been studied and intermediate products identified. Simultaneous thermal analysis with parallel mass-spectrometric analysis of evolved gases (STA-EGA) has been employed for identification of main gaseous products of thermolysis in inert atmosphere. It has been revealed that the final products of decomposition in inert or reductive atmospheres are fine powders of gold and the corresponding platinum metal with sizes of crystallites 4-40 nm. The possibility of preparation of the metastable solid solution AuIr on thermolysis of [Ir(NH)Br][AuBr]·HO in inert atmosphere has been demonstrated. [ABSTRACT FROM AUTHOR]

Complexes [Au(HGy3DH)]Cl ( 1), [Au(HGy3Me)]Cl ( 2) and [Au(HGy3Et)]Cl ( 3) were obtained with glyoxaldehyde bis(thiosemicarbazone) (HGy3DH) and its N(3)-methyl (HGy3Me) and N(3)-ethyl (HGy3Et) derivatives. The bis(thiosemicarbazones) and their gold(I) and gold(III) complexes exhibited anti-proliferative activity against HL-60, Jurkat (leukemia) and MCF-7 (breast cancer) cells at 10 μmol L. Complex ( 2) was able to in vitro inhibit thioredoxin reductase (TrxR) activity, which suggests that inhibition of TrxR could be part of its mechanism of action. [ABSTRACT FROM AUTHOR]

Abstract: Ligands Ph2P(OAr) (Ar=2,4,6-C6H2Br3, 1; Ar=C6H3(o-OMe)(p-C3H5), 2) were prepared by treating PPh2Cl with tribromo phenol and eugenol, respectively, in good yields. The reaction of Ph2P(OAr) with [Pd(COD)Cl2] in 2:1 molar ratio yielded trans-[Pd{PPh2(OAr)}Cl2] (4) and cis-[Pd{PPh2(OAr)}Cl2] (5), respectively. The chloro-bridged dipalladium complex [Pd2{PPh2(OAr)}2Cl4] (6) was obtained in the 1:1 reaction between 2 and [Pd(COD)Cl2], along with 5 as a minor product. Mononuclear complexes, [Au{PPh2(OAr)}Cl] (Ar=2,4,6-C6H2Br3, 7; Ar=C6H3(o-OMe)(p-C3H5), 8) and [(Ru(η6-p-cym){PPh2(OAr)}Cl2] (9) were prepared by reacting ligands 1 and 2 with [AuCl(SMe2)] and [(Ru(η6-p-cym)Cl2]2, respectively. All the complexes were characterized by 31P, 1H NMR and elemental analyses data. [Copyright &y& Elsevier]

Abstract: Iminophosphoranes with organic groups derived from d-glucose, d-galactose and l-arabinose have been used to prepare gold(III) dichloride complexes via mercurated intermediates, since direct cyclometallation was unsuccessful. Structures and full spectroscopic data are reported. Replacement of one or more of the chloride ligands by PPh3, or by thiosalicylate gave new derivatives. Biological screening showed no enhanced activity relative to other alkyl or aryl analogues. [Copyright &y& Elsevier]

Abstract: The aim of this work was to extend the small library of existing compounds of gold(I) that contain pentafluorophenyl and thiazole ligands and to determine the biological activity of such compounds against a well-known cancer cell line. Seven mono and dinuclear new compounds that contain imidazole, thiazole and tetrazole rings were isolated and characterised. Three of the crystal structures determined indicated Au…Au interactions between constituent complex molecules. A simple adduct, [Au(C6F5)(N-methyl-imidazole)], exhibits a relatively high anti-tumour specificity indicating the viability of selected phosphine-free gold complexes as cytotoxic agents. [Copyright &y& Elsevier]

Abstract: Five new heterocyclic gold carbene complexes were prepared, four chlorido-[1,3-dimethyl-4,5-diarylimidazol-2-ylidene]gold complexes 6a-d and a chlorido-[1,3-dibenzylimidazol-2-ylidene]gold complex 11, and three of them were characterised by X-ray single crystal analyses. They were tested for cytotoxicity against a panel of four human cancer cell lines and non-malignant fibroblasts, for tubulin interaction, and for the pathways of their uptake into 518A2 melanoma cells. All complexes showed cytotoxic activity in the micromolar IC50 range with distinct selectivities for certain cell lines. In stark contrast to related metal-free 1-methyl-4,5-diarylimidazoles, the complexes 6 and 11 did not noticeably inhibit the polymerisation of tubulin to give microtubules. The cellular uptake of complexes 6 occurred mainly via the copper transporter (Ctr1) and the organic cation transporters (OCT-1/2). Complex 11 was accumulated preferentially via the organic cation transporters and by Na+/K+-dependent endocytosis. The new gold carbene complexes seem to operate by a mechanism different from that of the parent 1-methylimidazolium ligands. [Copyright &y& Elsevier]

Abstract: Gold(I) and gold(III) complexes have been previously investigated for potential biomedical applications including as anti-HIV agents. The oxidising nature of some gold(III) complexes yields well-documented cellular toxicity in cell-based assays but the effect in direct biochemical assays has not been fully investigated. In this study, gold(III) complexes were evaluated in HIV-1 reverse transcriptase and HIV-1 integrase biochemical assays. The gold(III) tetrachlorides KAuCl4 and HAuCl4 yielded sub-micromolar IC50’s of 0.947 and 0.983μM in the direct HIV-1 RT assay, respectively, while IC50’s ranging from 0.461 to 8.796μM were obtained for seven selected gold(III) complexes. The gold(III) tetrachlorides were also effective inhibitors of integrase enzymatic activity with >80% inhibition obtained at a single dose evaluation of 10μM. RT inhibition was decreased in the presence of a reducing agent (10mM DTT) and against the M184V HIV-1 RT mutant, while none of the gold(III) complexes were effective inhibitors in cell-based antiviral assays (SI values <5.95). Taken together, the findings of this study demonstrate that gold(III) complexes modify HIV-1 enzyme activity in direct biochemical assays, most likely through protein oxidation. [Copyright &y& Elsevier]

Abstract: Reaction of the metalloligand [Pt2(μ-S)2(PPh3)4] with the N-heterocyclic carbene (NHC) complexes IPrAuCl, IMesAuCl and IMesAgCl in methanol gave the first examples of metal adducts of [Pt2(μ-S)2(PPh3)4] that contain NHC ligands, namely [Pt2(μ-S)2(PPh3)4AuL]+ (L= IPr, IMes) and [Pt2(μ-S)2(PPh3)4AgIMes]+. The complexes were isolated as hexafluorophosphate salts. Reaction of [Pt2(μ-S)2(PPh3)4] with excess IPrAuCl in refluxing methanol yielded only the mono-adduct, in contrast to the behaviour with the gold(I) phosphine complex Ph3PAuCl, which undergoes double addition giving [Pt2(μ-SAuPPh3)2(PPh3)4]2+. The X-ray structure of [Pt2(μ-S)2(PPh3)4AuIPr]PF6 was determined and reveals that the ‘free’ sulfide is substantially sterically protected by the IPr ligand, accounting for the low reactivity towards addition of a second AgIPr+ moiety. [Copyright &y& Elsevier]

Abstract: A series of gold(I) complexes containing diphenylphosphine bridging ligands, dppm, dppe, dpephos, dbfphos and biphep and co-ligands of the type pyrazole have been synthesized. The X-ray crystal structures of [Au2(μ-dpephos)(μ-pz2CH3)][PF6], [Au2(μ-dbfphos)(μ-pz2CH3)][PF6], and of the starting compound [Au2Cl2(μ-biphep)] indicate that the structural and stoichiometric characteristics of the new complexes depend on the diphosphine ligand. The three complexes show Au⋯Au contacts between 3.27 Å and 3.30 Å, with that of the biphep compound being the shortest. Digold (I)-diphosphine derivatives with a bridging pyrazolate ligand are obtained in all cases, except when [Au2Cl2(μ-biphep)] is used as starting material. Surprisingly, in this case, two monodentate neutral pyrazole ligands are attached to the gold atoms. The new complexes are luminescent in the solid state at 77 K and in solution both at room temperature and 77 K. Low energy emission bands related to the presence of Au⋯Au interactions have been identified in some of the compounds in the solid state and/or in solution. [Copyright &y& Elsevier]

Abstract: The self-assembly processes between binuclear [Zn2L n ]2+ complex cations and complex anions, [M(CN)2]− [M(I)=Ag(I), Au(I)], generate new one-dimensional (1-D) coordination polymers: 1 ∞[{L1Zn2(μ3-OH)}2(H2O){μ-[Ag(CN)2]}](ClO4)3 THF 0.5MeOH 1, 1 ∞[{L1Zn2(μ3-OH)}2(H2O){μ-[Au(CN)2]}](ClO4)3 THF H2O 2, 1 ∞[{L2Zn2(μ-OH)}{μ-[Ag(CN)2]}][Ag(CN)2] H2O 3 (H2L n are bicompartmental Schiff-base ligands resulting from condensation reactions between 2,6-diformyl-p-cresol with 2-aminomethyl-pyridine, and 2-aminoethyl-pyridine, respectively). The luminescence properties of the new heterometallic complexes have been investigated. [Copyright &y& Elsevier]

Abstract: A study concerning the gold(I)-catalyzed hydroarylation of N-propargyl-N′-arylhydrazinecarboxylic acid methyl esters is described. The use of the gold complex [XPhosAu(NCCH3)SbF6] as the catalyst in refluxing nitromethane allows the generally rapid and efficient synthesis of a range of functionalized 4-exo-methylene-1,2-dihydrocinnolines. [ABSTRACT FROM AUTHOR]

The series of platinum(II), palladium(II), and nickel(II) complexes [ML2(dppe)] [M = Ni, Pd, Pt; L = 4-SC5H4N or 4-SC6H4OMe; dppe = Ph2PCH2CH2PPh2] containing pyridine-4-thiolate or 4-methoxybenzenethiolate ligands, together with the corresponding gold(I) complexes [AuL(PPh3)], were prepared and their electrospray ionization mass spectrometric behavior compared with that of the thiophenolate complexes [M(SPh)2(dppe)] (M = Ni, Pd, Pt) and [Au(SPh)(PPh3)]. While the pyridine-4-thiolate complexes yielded protonated ions of the type [M + H]+ and [M + 2H]2+ ions in the Ni, Pd, and Pt complexes, an [M + H]+ ion was only observed for the platinum derivative of 4-methoxybenzenethiolate. Other ions, which dominated the spectra of the thiophenolate complexes, were formed by thiolate loss and aggregate formation. The X-ray crystal structure of [Pt(SC6H4OMe-4)2(dppe)] is also reported. [ABSTRACT FROM AUTHOR]

Abstract: Tetrachloroauric acid HAuCl4 reacts with the ionic liquid 1-(2-aminoethyl)-3-methylimidazolium nitrate [NH2(CH2)2ImMe]NO3, (2b) or its dicationic ammonium salt [NH3(CH2)2ImMe][NO3]2, (3) in methanolic solutions to give the novel gold(III)-aminoethyl imidazolium aurate salt [Cl3AuNH2(CH2)2ImMe][AuCl4] (4). The reaction of 4 with [ n Bu4]Cl gives [NH2(CH2)2ImMe][AuCl4] (2c) whereas with acetone the dicationic, iminium-functionalized, imidazolium aurate salt [Me2C=N(H)(CH2)2ImMe][AuCl4]2 (5) has been isolated. The structures in the solid state of 2c, 3, 4, and 5 have been determined by X-ray diffraction. The electrochemical behaviour of 4 has been examined by Cyclic voltammetry in acetonitrile and compared with 2c and KAuCl4. [Copyright &y& Elsevier]

Abstract: [{C7F15CO2}2AgAu(PPh3)]2 is obtained in good yield from the reaction of [C7F15CO2Ag] with [ClAuPPh3] in THF solution. The crystal structure shows a zig-zag Au–Ag–Ag–Au core with fluorocarboxylate ligands bridging the Au–Ag and Ag–Ag bonds and triphenylphosphine groups bound to Au. Electrodeposition from acetonitrile yields Au–Ag alloys. The deposited alloys are Ag rich and the composition varies with deposition potential. [Copyright &y& Elsevier]

Abstract: Gold(I) phosphine complexes have shown promising results as a novel class of anticancer drugs in a variety of biochemical and pharmacological investigations. Studies on pharmacokinetic properties of these species are rare. Here we report the results of a comparative study on the cytotoxicity, cellular and nuclear uptake of a series of chloro gold(I) phosphine complexes (Cl–Au–P(R)3, R=Me, Et, tert-But, Ph) containing different ligands on the phosphor. Cellular and nuclear gold levels in HT-29 colon carcinoma and MCF-7 breast cancer cells were measured by electrothermal atomic absorption spectrometry. All studied complexes exhibited significant antiproliferative effects in both investigated cell lines. Cellular and nuclear gold levels were enhanced especially for Cl–Au–P(Ph)3 indicating a positive influence of larger and more lipophilic substituents. [Copyright &y& Elsevier]

Abstract: Reactions of H[AuCl4] with N-substituted 2-pyridine thiocarboxamide ligands 2-(C5H4N)C(S)NHR (R= p-C6H4Me, CH2Ph, Me, p-C6H4OMe) gave cycloaurated derivatives {(C5H4N)C(S)NR}AuCl2, with the ligand bonded as the thiol tautomer through the deprotonated SH group and the pyridine N atom to give a five-membered metallacyclic ring. The X-ray structure determination of the R=CH2Ph derivative shows a square–planar gold(III) complex that dimerises in the solid state by weak Au···S intermolecular interactions. In contrast, in the reaction of H[AuCl4] with 2-(C5H4N)C(S)NHR where R=2-pyridyl, the ligand was oxidised to give a 1,2,4-thiadiazolo[2,3-a]pyridinium heterocyclic ring that was crystallographically characterised. [Copyright &y& Elsevier]

Abstract: This article reviews the synthesis, structures, reactions and spectroscopic studies of gold complexes containing organoselenium and organotellurium ligands, i.e. compounds containing an Au–Se–C and Au–Te–C unit. The literature up to June 2009 has been covered. Appendix 1 lists important structural data of complexes which have been characterised by X-ray diffraction, whilst Appendix 2 contains a compilation of 77Se and 125Te NMR data for these compounds. [Copyright &y& Elsevier]

Gold monochloride and monobromide can be transformed into monomeric complexes by ligands such as CO, PPh3 or Me2S, and such ligand-stabilized gold monochloride compounds have been investigated as catalysts, luminescent materials and anticancer drugs, especially when coordinated to a lipophilic benzyl-substituted N-heterocyclic carbene (NHC) ligand. The triclinic structures of NHC-Au-Cl {chlorido(1,3-dibenzyl-4,5-diphenylimidazol-2-ylidene)gold, [AuCl(C29H24N2)]} and NHC-Au-Br {bromido(1,3-dibenzyl-4,5-diphenylimidazol-2-ylidene)gold, [AuBr(C29H24N2)]}, determined by X-ray crystallography at 100 K, have one and four molecules, respectively, in their asymmetric units. The chloride compound shows an almost linear C-Au-Cl fragment [179.76 (8)°], with an Au-C distance of 1.976 (3) Å and an Au-Cl distance of 2.3013 (6) Å, while the bromide compound shows surprisingly large geometry deviations, from 1.969 (12) to 2.016 (10) Å for the Au-C distance and from 2.4279 (14) to 2.4796 (12) Å for the Au-Br distance, in the four independent molecules. [ABSTRACT FROM AUTHOR]

Abstract: The reactions of cycloaurated gold(III) dichloride complexes [LAuCl2] (L=2-C6H4CH2NMe2 or 2-C6H4PPh2 monoanionic tripodal oxygen donor Kläui ligands [(η5-C5H5)Co{P(O)(OR)2}3]− (R=Me or Et) results in the formation of cationic gold(III) salts [LAu{OP(OR)2}3Co(η5-C5H5)]+. An X-ray structure determination on [(2-C6H4PPh2 (OR)2}3Co(η5-C5H5)]BF4 shows that the Kläui ligand coordinates strongly to the gold through two oxygen atoms, and weakly through the third, giving the gold(III) a distorted square pyramidal geometry. This is the first structurally characterised example of this geometry for gold(III) with ligands other than those containing rigid bipyridine or phenanthroline backbones. In solution at room temperature there is rapid interchange (on the NMR timescale) between the oxygen atoms of the Kläui ligands, which is frozen out on cooling. [Copyright &y& Elsevier]

We have theoretically studied gold(I) complexes of the type L1-AuI-L2 and HCN-[AuI-CN]n (n = 1–8) using relativistic density functional theory at ZORA-BP86/TZ2P. Our purpose, besides determining structure and stability, is to analyze the bonding in our model systems in the conceptual framework of Kohn–Sham molecular orbital theory in combination with a quantitative bond energy decomposition scheme and analysis of the charge distribution. We focus on the π-bonding interaction for a given ligand-gold coordination bond and how this is affected by the presence of the other ligand. We find pronounced π-electronic communication through the gold(I) valence shell in complexes that involve a π-donor as well as a π-acceptor ligand. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [ABSTRACT FROM AUTHOR]

Transmetallation reactions of ortho-mercurated iminophosphoranes (2-ClHgC6H4)Ph2P＝NR with [AuCl4]− gives new cycloaurated iminophosphorane complexes of gold(III) (2-Cl2AuC6H4)Ph2P＝NR[R=(R,S)- or (S)-CHMePh, p-C6H4F, tBu], characterised by NMR and IR spectroscopies, ESI mass spectrometry and an X-ray structure determination on the chiral derivative R=(S)-CHMePh. The chloride ligands of these complexes can be readily replaced by the chelating ligands thiosalicylate and catecholate; the resulting derivatives show markedly higher anti-tumour activity versus P388 murine leukaemia cells compared to the parent chloride complexes. Reaction of (2-Cl2AuC6H4)Ph2P＝NPh3 with PPh3 results in displacement of a chloride ligand giving the cationic complex [(2-Cl(PPh3)AuC6H4)Ph2P＝NPH]+, indicating that the P＝N strongly bonded to the gold centre. [Copyright &y& Elsevier]

Abstract: Reactions of 2-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L1), 2-(3,5-diphenylpyrazol-1-ylmethyl)pyridine (L2), 2-(3,5-di-tert-butylpyrazol-1-ylmethyl)pyridine (L3) and 2-(3-p-tolylpyrazol-1-ylmethyl)pyridine (L4) with K2[PtCl4] in a mixture of ethanol and water formed the dichloro platinum complexes [PtCl2(L1)] (1), [PtCl2(L2)] (2), [PtCl2(L3)] (3) and [PtCl2(L4)] (4). Complex 1, [PtCl2(L1)], could also be prepared in a mixture of acetone and water. Performing the reactions of L2 and L3 in a mixture of acetone and water, however, led to C–H activation of acetone under mild conditions to form the neutral acetonyl complexes [Pt(CH2COCH3)Cl(L2)] (2a) and [Pt(CH2COCH3)Cl(L3)] (3a). The same ligands reacted with HAuCl4 ·4H2O in a mixture of ethanol and water to form the gold salts [AuCl2(L1)][AuCl4] (5) [AuCl2(L2)][Cl] (6) [AuCl2(L3)][Cl] (7) and [AuCl2(L4)][AuCl4] (8); however, with the pyrazolyl unit in the para position of the pyridinyl ring in 4-(3,5-dimethylpyrazol-1-ylmethyl)pyridine (L5), 4-(3,5-diphenylpyrazol-1-ylmethyl)pyridine (L6) neutral gold complexes [AuCl3(L5)] (9) and [AuCl2(L6)] (10) were formed; signifying the role the position of the pyrazolyl group plays in product formation in the gold reactions. X-ray crystallographic structural determination of L6, 2, 3 3a, 8 and 10 were very important in confirming the structures of these compounds; particularly for 3a and 8 where the presence of the acetonyl group confirmed C–H activation and for 8 where the counter ion is . Cytotoxicity studies of L2, L4 and complexes 1–10 against HeLa cells showed the Au complexes were much less active than the Pt complexes. [Copyright &y& Elsevier]

Abstract: Metal complexes have shown interesting preclinical and clinical results as antitumor drugs and platinum compounds are well established in current cancer chemotherapy. However, the platinum based treatment of tumoral diseases is massively hampered by severe side effects and resistance development. Consequently, the development of novel metallodrugs with a pharmacological profile different from that of the platinum drugs is in the focus of modern medicinal chemistry and drug design. Among the non-platinum antitumor drugs, gold complexes have recently gained considerable attention due to their strong antiproliferative potency. In many cases the cell growth inhibiting effects could be related to anti-mitochondrial effects making gold species interesting drug candidates with a mode of action different from that of the platinum agents. The spectrum of gold complexes described as antiproliferative compounds comprises a broad variety of different species including many phosphine complexes as well as gold in different oxidation states. This presentation gives an overview of the relevant medicinal chemistry of known gold complexes with in vitro and in vivo tumor growth inhibiting properties. [Copyright &y& Elsevier]