M. Concepción Gimeno

Synthesis and characterisation of copper complexes with N-ferrocenoyl-N′-aryl(alkyl)thioureas

Abstract The treatment of CuCl 2 ·2H 2 O with ferrocenoyl-substituted thioureas of the type FcC(O)NHC(S)N′HR (Fc=ferrocenyl; R=C 6 H 5 ; C 6 H 4 - p -OMe; C 6 H 4 - p -C(O)Me; C 6 H 4 - o -Me; C 6 H 4 - o -Cl; C 6 H 4 - o -NO 2 ; i -Pr) gives the corresponding copper(I) derivatives with the metallic centre in an unusual coordination mode. The complexes were characterised by spectroscopic methods and X-ray diffraction studies. The electrochemical behaviour of these compounds was also investigated.

Simple and efficient synthesis of [MCI(NHC)] (M = Au, Ag) complexes

A facile and efficient synthetic route leading to catalytically relevant N-heterocyclic carbene (NHC) gold complexes is described. The method consists of one pot synthesis starting from readily available imidazolium salts and [AuCl(tht)], in the presence of K2CO3. Using the same protocol NHC silver complexes have been synthesised starting from AgNO3.

The Lowest Excited State of Brightly Emitting Gold(I) Triphosphine Complexes

The strongly luminescent neutral gold(I) triphosphine complexes [Au(dipnc)(PPh(3))] and [Au(dppnc)(PPh(3))] with dipnc = 7,8-bis(diisopropylphosphino)-nido-carborane ([(PiPr(2))(2)B(9)H(10)C(2))](-)) and dppnc = 7,8-bis(diphenylphosphino)-nido-carborane ([(PPh(2))(2)B(9)H(10)C(2)](-)) are studied in a wide range of temperatures of 1.5 <or= T <or= 300 K. Analysis of the emission decay dynamics provides detailed information about the lowest triplet state. In particular, the magnitude of zero-field splitting of the emitting state is determined to be 47 and 29 cm(-1) for [Au(dipnc)(PPh(3))] and [Au(dppnc)(PPh(3))], respectively. The emission decay times of the individual triplet substates lie in the range of 4 to 130 mus. The observed photophysical properties suggest that the molecular orbitals involved in the lowest electronic transitions exhibit, beside gold orbitals, considerable contributions from nonmetallic ligand orbitals. OLED or sensor application of these complexes is suggested.

Synthesis, structure and redox behaviour of gold and silver complexes with 3-ferrocenylpyridine

Abstract 3-Ferrocenylpyridine (Fcpy) reacts with gold(I) derivatives to afford neutral, [AuR(Fcpy)] (R=Cl, C6F5), or cationic complexes, [Au(Fcpy)(PPh3)]OTf. Reaction with [Au(C6F5)2(OEt2)2]ClO4 or [Au(C6F5)3(OEt2)] gives the gold(III) complexes [Au(C6F5)2(Fcpy)2]ClO4 or [Au(C6F5)3(Fcpy)], respectively. The silver derivatives [Ag(Fcpy)(PPh3)]OTf and [Ag(OTf)(Fcpy)2] have also been synthesised.

Synthesis of silver(I) complexes with 1,1′-bis(diphenyl-phosphino)ferrocene (dppf). Crystal structures of [Ag(dppf)(PPh3)]ClO4·2CH2Cl2, [Ag(dppf)2]ClO4·2CHCl3 and [Ag(dppf)(phen)]ClO4(phen = 1,10-phenanthroline)

Addition of 1,1′-bis(diphenylphosphino)ferrocene (dppf) to a solution of AgClO4 in 1 : 1 molar ratio led to the complex [Ag(OClO3)(dppf)]1. Substitution of the perchlorate anion in 1 by monodentate ligands gave [Ag(dppf)(L)]ClO4(L = PPh32 or SPPh33), or with the less sterically demanding phosphine PPh2Me the four-co-ordinate silver(I) complex [Ag(dppf)(PPh2Me)2]ClO44. Direct reaction of dppf with [Ag(OClO3)(PPh3)] also affords complex 2. The homoleptic derivative [Ag(dppf)2]ClO45 can be synthesized by reaction of dppf and AgClO4 using a molar ratio of 2 : 1, or by substitution of the ClO4– by dppf in complex 1. Treatment of 1 with other bidentate ligands such as 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy) or bis(diphenylphosphino)methane disulfide (SdppmS) gave mixed cationic four-co-ordinate complexes [Ag(dppf)(L–L)]ClO4(L–L = phen 6, bipy 7 or SdppmS 8); with sodium dithiocarbamates Na(S2CNR2) the neutral species [Ag(S2CNR2)(dppf)](R = Et 9 or Me 10) were obtained. The crystal structures of complexes 2, 5 and 6 have been established by X-ray diffraction. Compound 2 shows a trigonal-planar silver(I) centre, whereas in complexes 5 and 6 the silver atom exhibits a tetrahedral geometry.

Heteropolynuclear Gold Complexes with Metallophilic Interactions: Modulation of the Luminescent Properties

Metalloligands of stoichiometry [AuCl(P-N)] have been obtained by the reaction of the heterofunctional phosphines P-N = PPh(2)py, PPh(2)CH(2)CH(2)py, or PPhpy(2) with [AuCl(tht)] (tht = tetrahydrothiophene). Reactions of these metalloligands with several metal compounds have afforded heteropolynuclear species which exhibit luminescent properties. The stoichiometries depend on the molar ratio and the heterometal. Thus, the reaction with [Cu(NCMe)(4)](+) in a molar ratio 2:1 gives the trinuclear compounds [Au(2)CuCl(2)(P-N)(2)](+), in which the structure and Au···Cu interactions depend on the phosphine ligand. With rhodium and iridium derivatives the reactivity is different leading to complexes of the type [AuMCl(2)(cod)(P-N)] for P-N = PPh(2)py, PPhpy(2), and [Au(2)M(2)Cl(cod)(2)(P-N)(2)]Cl with PPh(2)CH(2)CH(2)py. Using [MCl(2)(NCPh)(2)] (M = Pd, Pt) in a 2:1 molar ratio yields [Au(2)MCl(4)(P-N)(2)] and in a 1:1 molar ratio [AuPdCl(3)(μ(3)-PPhpy(2))]. Several compounds have been characterized by X-ray diffraction showing in many cases short Au···M distances. The luminescence of these derivatives has been studied. The metalloligands display bands assigned to intraligand (IL) transitions. For the bimetallic (Au/M) systems the luminescence depends on the heterometal present and on the metallophilic interactions. The most important excitations in the relevant energy range were assigned essentially a MMLCT character (from Rh/Ir and Au to ligands) based on density functional theory (DFT) calculations in selected complexes. The luminescence behavior in Rh/Ir [AuMCl(2)(cod)(PPh(2)py)] complexes was interpreted on the basis of the different nature of the half occupied orbitals in the triplet state.

Conjugates of ferrocene with biological compounds. Coordination to gold complexes and antitumoral properties

Several bioconjugates of ferrocene with biological compounds such as aminoacid esters and related species have been prepared by reaction of chlorocarbonyl ferrocene with the corresponding amino acid ester (histidine methyl ester, tryptophan methyl ester, methionine methyl ester and lysine ethyl ester) or histamine or prolinamide in the presence of NEt(3). The reaction of the tryptophan or prolinamide ferrocene conjugates with [Au(acac)(PR(3))] (acac=acetylacetonate) results in the substitution of the proton of the cyclic NH groups by the fragment AuPR(3)(+) affording the complexes [Au(FcCO-tryptophan-OMe)(PR(3))] or [Au(FcCO-prolinamide)(PR(3))] (Fc=ferrocenyl group). The reaction of FcCO-Met-OMe with [Au(OTf)(PR(3))] (OTF=trifluoromethysulfonate) or [Au(C(6)F(5))(3)(OEt(2))] yields the gold(I) or gold(III) derivatives [Au(FcCO-Met-OMe)(PR(3))]OTf or [Au(C(6)F(5))(3)(FcCO-Met-OMe)], respectively. Cytotoxicity studies towards several cancer lines such as MCF-7, HeLa or NIE-115 have been performed. The ferrocene bioconjugates show no activity whereas the gold complexes exhibit antiproliferative effect. Preliminary studies of interaction of compounds with cells were carried out with the goal of increasing our knowledge on the mechanism of action of these potential drugs.

Synthesis of dithiolate gold(III) complexes by dithiolate transfer reactions. X-ray structure of [Au(C6F5)(S2C6H4)(PPh3)]

Abstract The reaction of ethanolic solutions of Na 2 (SS) {SS &.dbnd; 1,2-S 2 C 6 H 4 or 3,4-S 2 C 6 H 3 (CH 3 )} with [Sn(CH 3 ) 2 Cl 2 ] or (PPN) 2 [ZnCl 4 ] gives [Sn(CH 3 ) 2 (SS)] and (PPN) 2 [Zn(SS) 2 ], respectively. The tin derivative with 1,3-dithiol-2-thione-4,5-dithiolate (dmit), [Sn(CH 3 ) 2 (dmit)], is obtained by reaction of [Sn(CH 3 ) 2 Cl 2 ] with (NEt 4 ) 2 [Zn(dmit) 2 ]. The tin and zinc complexes further react with the gold(III) derivatives cis -[Au(C 6 F 5 )Cl 2 L] giving rise to dithiolate gold(III) complexes [Au(C 6 F 5 )(SS)L]. The structure of [Au(C 6 F 5 )(S 2 C 6 H 4 )(PPh 3 )] has been established by an X-ray diffraction study, and shows a square-planar coordination of the gold with the dithiolate chelating.

Strong inhibition of thioredoxin reductase by highly cytotoxic gold(I) complexes. DNA binding studies

Biological properties of a series of aminophosphine-thiolate gold(I) complexes [Au(SR)(PPh2NHpy)] [Ph2PNHpy=2-(diphenylphosphinoamino)pyridine; HSR=2-mercaptopyridine (2-HSpy) (3), 2-mercaptonicotinic acid (2-H2-mna) (4), 2-thiouracil (2-HTU) (5) or 2-thiocytosine (2-HTC) (6)] and [Au(SR){PPh2NH(Htrz)}] [Ph2PNH(Htrz)=3-(diphenylphosphinoamino)-1,2,4-triazole]; HSR=2-mercaptopyridine (2-HSpy) (7), 2-thiocytosine (2-HTC) (8) or 6-thioguanine (6-HTG) (9) have been studied. Their antitumor properties have been tested in vitro against two tumor human cell lines, HeLa (derived from cervical cancer) and MCF-7 (derived from breast cancer), using a metabolic activity test (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide, MTT). Some of them showed excellent cytotoxic activity. With the aim to obtain more information about the mechanisms of action of these derivatives, the interactions of complexes 3, 5, 7 and 9 with thioredoxin reductase in HeLa cells were studied. They showed a potent inhibition of thioredoxin reductase activity. In order to complete this study, interactions of the complexes with calf thymus (CT-) DNA and with different bacterial DNAs, namely the plasmid pEMBL9 and the promoter region of the furA (ferric uptake regulator A) gene from Anabaena sp. PCC 7120 were investigated. Although interactions of complexes with CT-DNA have been verified, none of them cause significant changes in its structure.

Gold and silver complexes with the diselenium ligand [Ph2P(Se)NP(Se)Ph2]-

Abstract The treatment of potassium diselenoimidodiphosphinato with silver(I) or gold(III) derivatives leads to the synthesis of three-coordinated, [Ag{(SePPh2)2N}(PPh3)], tetranuclear, [Ag4{(SePPh2)2N}3]OTf (4) (OTf=OSO2CF3), or square-planar, [Au(C6F5)2{(SePPh2)2N}] (5), complexes. The crystal structures of [Au2{(SePPh2)2N}(PPh3)2]OTf (2), 4 and 5 have been established by X-ray diffraction. Complex 2 is associated by gold–gold interactions forming tetranuclear dimers. In complex 4 four silver atoms forming a distorted tetrahedron are bridged by three ligands, and 5 shows the expected square-planar coordination at gold.