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Herein we report the synthesis and characterization of a new copper(I) complex with triphenylphosphine (PPh3) and N‐(2‐thiophenecarbonyl)‐N'‐(3‐Cl, 4‐F‐phenyl)thiourea (HL), as ligands. The complex was characterized by vibrational (FTIR and FT‐Raman) and multinuclear (1H, 13C {1H}, 31P{1H}) NMR spectroscopies. The crystalline structure of the complex was determined by single‐crystal X‐ray diffraction, confirming that a neutral binuclear compound, identified as [Cu(PPh3)(L‐κ2‐N,μ‐S)]2, was obtained. The anionic thiourea ligand coordinates to the metal through the sulfur and nitrogen atoms in an unusual bidentate κ2‐N,μ‐S coordination mode. The complex is a dimer sited on a crystallographic center of symmetry. Each Cu2(μ‐S)2 cation bridges trough the sulfur atoms of two symmetry related thiourea moieties and is also coordinated to the nitrogen atom of the thiourea ligand and the phosphorus atom from PPh3 co‐ligand, forming a slightly distorted tetrahedral geometry. An intramolecular N−H⋅⋅⋅O=C hydrogen bond is observed in the anionic ligand, forming a six‐membered ring that stabilizes the N−H thioamide group. Hirshfeld surface analysis shows that the molecules are connected by weak intermolecular contacts C⋅⋅⋅C, H⋅⋅⋅C and H⋅⋅⋅H which add to the stability of the crystalline packing. The in vitro cytotoxicity study of the complex indicates that it is more active against human lung carcinoma cells (A549), when compared to the free ligand. [ABSTRACT FROM AUTHOR]

Organometallic ruthenium complexes as potential anticancer agents have been explored due to their suitable properties, such as stability in the solid state and in solution, water solubility and low toxicity. In this study, eight metal complexes of this class were synthesized, characterized and their important biological activities against a human breast tumor cell line (MDA-MB-231) were studied. Complexes 1–8 were obtained in good yields and have been characterized by satisfactory elemental analyses, IR, 1D and 2D 1H and 13C{1H} NMR, UV-Vis spectroscopy, cyclic voltammetry, ESI-MS and X-ray diffractometry (1, 2, 3 and 6). All complexes exhibit growth inhibition on human breast and lung tumor cell lines, with IC50 values ranging from 6.0 to 45.0 μM in 48 h. Four compounds were selected to evaluate the changes in the morphology, clonogenic, migration, cell cycle arrest and cell death in MDA-MB-231 cells. The complexes are able to induce morphological changes and inhibit the size, number of colonies and cell migration, and induce cell cycle arrest in the sub-G1 phase and apoptosis cell death. The interaction of the complexes with DNA was determined by performing spectroscopic titration, a competitive assay with thiazole orange, circular dichroism, gel electrophoresis and interactions with guanosine or guanosine monophosphate by 1H NMR, indicating the non-covalent interaction. The HSA binding affinity measured by spectrophotometric titration, revealed the hydrophobic and spontaneous association with the human protein. Overall, the studies indicated that these metal complexes are potential agents against MDA-MB-231 cells, encouraging us to continue studies of these types of compounds. [ABSTRACT FROM AUTHOR]

Three new homodinuclear complexes containing substituted phenolate-type ligands based on the N5O2 donor (2-(N,N-Bis(2-pyridylmethyl)aminomethyl)-6-(N′,N′-(2-hydroxybenzyl)(2-pyridylmethyl))aminomethyl)-4-methylphenol (H2L-H) were synthesized and characterized by X-ray crystallography. Potentiometric titration studies in 70% (v/v) aqueous ethanol show that all three complexes exhibit a common {CuII(µ-phenoxo)(µ-OH)CuII(OH)} core in solution. Kinetic studies on the oxidation reaction of 3,5-di-tert-butylcatechol revealed that the catalytic activity of the metal complexes increases toward the ligand containing an electron-donating group. In addition, these complexes also carried out DNA cleavage by hydrolytic and oxidative pathways. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Two copper(II) complexes, [Cu(sac)2(4-cypy)2(H2O)], 1 and [Cu(sac)2(4-Ampy)2(H2O)], 2 (4-cypy: 4-cyanopyridine; 4-Ampy: 4-aminopyridine) were prepared. Physicochemical properties of the complexes were studied by spectroscopic (solution UV–vis, diffuse reflectance and IR) techniques. Structural X-ray diffraction data could be obtained only for [Cu(sac)2(4-cypy)2(H2O)] that it crystallized in the tetragonal space group P4cc with a=b=15.313(1), c=13.240(1)Å, and Z=4 molecules per unit cell. The complex was cited on a crystallographic C 2-axis with the Cu(II) ion in a square–pyramidal environment, coordinated at the pyramid basis to the nitrogen atom of two saccharine anions [d(Cu–N)=2.011(3)Å] and the pyridine N-atom of two 4-cyanopyridine ligands [d(Cu–N)=2.038(4)Å]. The coordination was completed by a water molecule at the pyramid apex [d(Cu–Ow)=2.189(5)Å]. Elemental and spectroscopic analyses revealed an O-saccharinate coordination mode for complex 2 and a square–pyramidal structure. Only complex 2 retained its structure in methanolic solution. However, both complexes were able to catalyze the dismutation of superoxide anion (O2 −) (pH 7.5) at micromolar concentrations. Therefore, these complexes behaved as useful SOD-mimetic compounds. [Copyright &y& Elsevier]

Abstract: The hydrolysis of pyridoxalrhodanine in a basic medium containing the dimethylthallium(III) cation afforded the compound [TlMe2(L)]·H2O (1·H2O) [HL=5-(hydroxymethyl)-8-methyl-3-thiol-7-azacoumarin]. This compound was characterized in solid state by IR spectroscopy and in solution by 1 H and 13 C{ 1 H} NMR spectrometry. X-ray diffraction showed that the crystal consists of associated TlMe2(L) units and hydrogen bonded water molecules. The L− anion is bound to the metal mainly by a bridging S atom [Tl–S=2.9458(18) Å; 2.9616(16) Å], although secondary interactions through O atoms (Tl–O: 2.861(5); 2.900(5) Å)] are also present. The longer Tl–O interaction and the hydrogen bonds of the water molecules give rise to a tridimensional polymeric structure. [Copyright &y& Elsevier]

Abstract: A polymeric complex [Eu(α-tpc)3(α-Htpc)2] n and its characterization by single crystal X-ray and thermal analysis, infrared and photoluminescence spectroscopies are described. The compound crystallizes in the monoclinic Cc space group. The asymmetric unit is formed from a europium ion bonded to one carboxyl oxygen of five different thiophene carboxylic moieties. Three of these moieties are deprotonated and bridge between neighboring europium ions giving rise to an infinite polymer along the c axis. Besides the europium characteristic emission lines, the emission spectra show unambiguously the crystal size effect on the 5D0 → 7F0 transition. The complex thermal decomposition at 220°C leads to a stable luminescent complex in which the 5D0 → 7F4 transition reveals a monomeric characteristic. The Judd–Ofelt intensity parameters to the polymeric and the monomeric compound with the same ligand and coordination number were compared. [Copyright &y& Elsevier]

Abstract: 2-Benzoylpyridine semicarbazone (H2BzPS) and its complexes [Cu(H2BzPS)Cl2] (1) and [Zn(H2BzPS)Cl2] (2) have been synthesized and their spectral properties have been studied. The electrochemical behaviour of [Cu(H2BzPS)Cl2] (1) has been investigated. [Cu(H2BzPS)Cl2] (1) crystallizes in the triclinic P-1 space group, a=9.278(1), b=12.848(1), c=13.923(1) Å, α=84.54(1), β=71.91(1), γ=85.14(1)°, with two complexes per asymmetric unit (Z=4) and a disordered methanol solvent molecule (occupancy=1/4). [Zn(H2BzPS)Cl2] (2) crystallizes in the orthorhombic P212121 space group with a=11.983(1), b=14.067(1), c=18.706(1) Å, and two independent molecules per asymmetric unit (Z=8). In both cases, the neutral semicarbazone acts as a tridentate ligand which coordinates the metal through the pyridine and imine nitrogen atoms and the carbonyl oxygen. Two chloride ions occupy the fourth and fifth coordination positions. [Copyright &y& Elsevier]

The new complexes of Pd(II) with N , N -disubstituted- N ′-acylthioureas:[( 1 ) [Pd(dppf)( N , N -dimethyl- N ′-benzoylthioureato-k 2 O,S)]PF 6 , ( 2 ) [Pd(dppf)( N , N -diethyl- N ′-benzoylthioureato-k 2 O,S)]PF 6 , ( 3 ) [Pd(dppf)( N , N -dibuthyl- N ′-benzoylthioureato-k 2 O,S)]PF 6 , ( 4 ) [Pd(dppf)( N , N -diphenyl- N ′-benzoylthioureato-k 2 O,S)]PF 6 , ( 5 ) [Pd(dppf)( N , N -diethyl- N ′-furoylthioureato-k 2 O,S)]PF 6 , ( 6 ) [Pd(dppf)( N , N -diphenyl- N ′-furoylthioureato-k 2 O,S)]PF 6 , ( 7 ) [Pd(dppf)( N , N -dimethyl-N′- thiophenylthioureato-k 2 O,S)]PF 6 , and ( 8 ) [Pd(dppf)( N , N -diphenyl-N′-thiophenylthioureato-k 2 O,S)]PF 6 , were prepared and characterized by elemental analysis, and spectroscopic techniques. The structures of complexes ( 2 ), ( 3 ), ( 5 ), ( 6 ) and ( 8 ) had their structures determined by X-ray crystallography, confirming the coordination of the ligands with the metal through sulfur and oxygen atoms, forming distorted square-planar geometries. These complexes have shown antibacterial activity against anti- Mycobacterium tuberculosis H37Rv ATCC 27294. The complexes exhibited antiparasitic activity against Trypanosoma cruzi , while the metal-free thioureas did not. The results demonstrated that the compounds described here can be considered as promising anti- Mycobacterium tuberculosis and anti- T. cruzi agents, since in both cases their in vitro activity were better than reference drugs available for the treatment of both diseases. [ABSTRACT FROM AUTHOR]

Three new mixed and mononuclear Ru(II) complexes containing 1,3-thiazolidine-2-thione (tzdtH) were synthesized and characterized by spectroscopic analysis, molar conductivity, cyclic voltammetry, high-resolution electrospray ionization mass spectra and X-ray diffraction. The complexes presented unique stereochemistry and the proposed formulae are: [Ru(tzdt)(bipy)(dppb)]PF6 ( 1 ), cis -[Ru(tzdt) 2 (PPh 3 ) 2 ] ( 2 ) and trans -[Ru(tzdt)(PPh 3 ) 2 (bipy)]PF 6 ( 3 ), where dppb = 1,4-bis(diphenylphosphino)butane and bipy = 2,2′-bipyridine. These complexes demonstrated strong cytotoxicity against cancer cell lines when compared to cisplatin. Specifically, complex 2 was the most potent cytotoxic agent against MCF-7 breast cells, while complexes 1 and 3 were more active in DU-145 prostate cells. Binding of complexes to ctDNA was determined by UV–vis titration and viscosity measurements and revealed binding constant (K b ) values in range of 1.0–4.9 × 10 3 M − 1 , which are characteristic of compounds possessing weak affinity to ctDNA. In addition, these complexes presented antiparasitic activity against Trypanosoma cruzi . Specifically, complex 3 demonstrated strong potency, moderate selectivity index and acted in synergism with the approved antiparasitic drug, benznidazole. Additionally, complex 3 caused parasite cell death through a necrotic process. In conclusion, we demonstrated that Ru(II) complexes have powerful pharmacological activity, while the metal-free tzdtH does not provoke the same outcome. [ABSTRACT FROM AUTHOR]

In this work, group 10 transition metal complexes bearing dppe [1,2- bis (diphenylphosphino)ethane] and acylthiourea ligands were evaluated for their cytotoxic and antiparasitic activities. Six new complexes with a general formula [M(L n)(dppe)]BF 4 [where M = NiII, PdII or PtII; L n = N , N ′-dimethyl-N-benzoyl thiourea (L 1) or N , N ′-dimethyl-N-tiofenyl thiourea (L 2) were synthesized and characterized by infrared, NMR (31P{1H}, 1H and 13C{1H}) spectroscopies, elemental analysis and molar conductivity. The structures of the complexes were confirmed by X-ray diffraction technique. The biological activity of the complexes was evaluated on breast cancer cells (MDA-MB-231 and MCF-7) and causative agents of chagas disease and leishmaniasis. The complexes presented higher cytotoxicity for breast cancer cell lines compared to non-tumor cells. Nickel complexes stood out when evaluated against the triple-negative breast cancer line (MDA-MB-231), presenting considerably lower IC 50 values (about 10 to 22×), when compared to palladium and platinum complexes, and the cisplatin drug. When evaluated on the triple-negative line (MDA-MB-231), the complexes [Ni(L 2)(dppe)]BF 4 (2), [Pd(L 2)(dppe)]BF 4 (4) and [Pt(L 2)(dppe)]BF 4 (6) were able to induce cell morphological changes, influence on the cell colony formation and the size of the cells. The complexes inhibit cell migration and cause changes to the cell cytoskeleton and nuclear arrangement. In the same cell line, the compounds caused cell arrest in the Sub-G1 phase of the cell cycle. The compounds were also tested against the Trypanosom Cruzi (T. cruzi) and Leishmania sp. parasites, which cause Chagas and leishmaniasis disease, respectively. The compounds showed good anti-parasitic activity, mainly for T. cruzi, with lower IC 50 values, when compared to the commercial drug, benznidazole. The compounds interact with CT-DNA, indicating that interaction occurs by the minor groove of the biomolecule. Phosphinic complexes of group 10 metals with acylthioureas ligands were evaluated for their cytotoxic and antiparasitic activities. Complexes were active against breast cancer tumor cells, Trypanosome Cruzi (T. cruzi), and Leishmania sp. parasites. Compounds 2 , 4, and 6 altered the cytoskeleton, induced nuclear alterations, and caused cell arrest in the Sub-G1 phase of the cell cycle in MDA-MB-231 cells. Studies indicated the interaction of compounds in the DNA minor groove. [Display omitted] • New metal-acylthiourea complexes were synthesized. • The complexes interact with the DNA, through the minor groove, and with the HSA. • The cytotoxicity of the compounds was significant in breast tumor cell lines. • The compounds were active against Chagas disease and leishmaniasis. • Complexes 2, 4 and 6 caused cell arrest in the Sub-G1 phase of the cell cycle, in MDA-MB-231 cells. [ABSTRACT FROM AUTHOR]

Herein, we report the synthesis and characterization of the new di-iron(III) complex [(bbpmp)(H 2 O)(Cl)Fe III ( μ -O phenoxo )Fe III (H 2 O)Cl)]Cl ( 1 ), with the symmetrical ligand 2,6-bis{[(2-hydroxybenzyl)(pyridin-2-yl)methylamino]methyl}-4-methylphenol (H 3 bbpmp). Complexes 2 with the unsymmetrical ligand H 2 bpbpmp — {2-[[(2-hydroxybenzyl)(2-pyridylmethyl)]aminomethyl]-6-bis(pyridylmethyl) aminomethyl}-4-methylphenol and 3 with the ligand L 1 = 4,11-dimethyl-1,8-bis{2-[N-(di-2-pyridylmethyl)amino]ethyl}cyclam were included for comparison purposes. Complex 1 was characterized through elemental analysis, X-ray crystallography, magnetochemistry, electronic spectroscopy, electrochemistry, mass spectrometry and potentiometric titration. The magnetic data show a very weak antiferromagnetic coupling between the two iron centers of the dinuclear complex 1 ( J = − 0.29 cm − 1 ). Due to the presence of labile coordination sites in both iron centers the hydrolysis of both the diester model substrate 2,4-BDNPP and DNA was studied in detail. Complex 1 was also able to catalyze the oxidation of the substrate 3,5-di- tert -butylcatechol (3,5-DTBC) to give the corresponding quinone, and thus it can be considered as a catalytically promiscuous system. [ABSTRACT FROM AUTHOR]

Abstract: The new mononuclear copper(II) complex [CuII(H2LDA)(ClO4)](ClO4) (1) ([H2LDA= N,N′-[bis-(2-hydroxy-3-formyl-5-methylbenzyl)(dimethyl)]-ethylenediamine]) with an unusual coordination mode of a salen derivative ligand is reported. The most interesting feature of 1 is that the ligand is doubly protonated and presents significant intermolecular π-stacking interactions, contributing to the dimer structure stabilization in the solid state and in CH3CN and methanolic solutions. The complex was characterized by X-ray crystallography and shows catecholase-like activity in the oxidation of the substrate 3,5-di-tert-butylcatechol (3,5-dtbc), with the formation of H2O2, which kinetic parameters are similar to those observed in conventional dinuclear bridged CuII complexes. [Copyright &y& Elsevier]

Abstract: This study describes the synthesis of a new ruthenium nitrosyl complex with the formula [RuCl2NO(BPA)] [BPA = (2-hydroxybenzyl)(2-methylpyridyl)amine ion], which was synthesized and characterized by spectroscopy, cyclic voltammetry, X-ray crystallography, and theoretical calculation data. The biological studies of this complex included in vitro cytotoxic assays, which revealed its activity against two different tumor cell lines (HeLa and Tm5), with efficacy comparable to that of cisplatin, a metal-based drug that is administered in clinical treatment. The in vivo studies showed that [RuCl2NO(BPA)]is effective in reducing tumor mass. Also, our results suggest that the mechanism of action of [RuCl2NO(BPA)] includes binding to DNA, causing fragmentation of this biological molecule, which leads to apoptosis. [Copyright &y& Elsevier]

Abstract: Complexes of the type trans-[PdX2(isn)2] {X = Cl (1), N3 (2), SCN (3), NCO (4); isn = isonicotinamide} were synthesized and evaluated for in vitro antimycobacterial and antitumor activities. The coordination mode of the isonicotinamide and the pseudohalide ligands was inferred by IR spectroscopy. Single crystal X-ray diffraction determination on 2 showed that coordination geometry around Pd(II) is nearly square planar, with the ligands in a trans configuration. All the compounds demonstrated better in vitro activity against Mycobacterium tuberculosis than isonicotinamide and pyrazinamide. Among the complexes, compound 2 was found to be the most active with MIC of 35.89 μM. Complexes 1–4 were also screened for their in vitro antitumor activity towards LM3 and LP07 murine cancer cell lines. [ABSTRACT FROM AUTHOR]

Abstract: The “Ru(P–P)” unit (P–P=diphosphine) is recognized to be an important core in catalytic species for hydrogenation of unsaturated organic substrates. Thus, in this study we synthesized six new complexes containing this core, including the binuclear complex [(dppb)(CO)Cl2Ru-pz-RuCl2(CO)(dppb)] (pz=pyrazine) which can be used as a precursor for the synthesis of cationic carbonyl species of general formula [RuCl(CO)(dppb)(N–N)]PF6 (N–N=diimine). Complexes with the formula [RuCl(py)(dppb)(N–N)]PF6 were synthesized by exhaustive electrolysis of these carbonyl compounds or from the precursors [RuCl2(dppb)(N–N)]. The new complexes were characterized by microanalysis, conductivity measurements, IR and 31P{1H} NMR spectroscopy, cyclic voltammetry and X-ray crystallography. [Copyright &y& Elsevier]

Abstract: Complexes [RuCl(H4NO2Fo4M)(bipy)(dppb)]PF6 (1), [RuCl(H4NO2Fo4M)(Mebipy)(dppb)]PF6 (2), [RuCl(H4NO2Fo4M)(phen)(dppb)]PF6 (3), [RuCl(H4NO2Ac4M)(bipy)(dppb)]PF6 (4), [RuCl(H4NO2Ac4M)(Mebipy)(dppb)]PF6 (5) and [RuCl(H4NO2Ac4M)(phen)(dppb)]PF6 (6) with N4 -methyl-4-nitrobenzaldehyde thiosemicarbazone (H4NO2Fo4M) and N4 -methyl-4-nitroacetophenone thiosemicarbazone (H4NO2Ac4M) were obtained from [RuCl2(bipy)(dppb)], [RuCl2(Mebipy)(dppb)], and [RuCl2(phen)(dppb)], (dppb = 1,4-bis(diphenylphospine)butane; bipy = 2,2′-bipyridine; Mebipy = 4,4′-dimethyl-2,2′-bipyridine; phen = 1,10-phenanthroline). In all cases the thiosemicarbazone is attached to the metal center through the sulfur atom. Complexes (1–6), together with the corresponding ligands and the Ru precursors were evaluated for their ability to in vitro suppress the growth of Trypanosoma cruzi. All complexes were more active than their corresponding ligands and precursors. Complexes (1–3) and (5) revealed to be the most active among all studied compounds with ID50 = 0.6–0.8 μM. In all cases the association of the thiosemicarbazone with ruthenium, dppb and bipyridine or phenanthroline in one same complex proved to be an excellent strategy for activity improvement. [Copyright &y& Elsevier]

Abstract: In the present work 2-formylpyridine-para-chloro-phenyl hydrazone (H2FopClPh) and 2-formylpyridine-para-nitro-phenyl hydrazone (H2FopNO2Ph) were obtained, as well as their copper(II) and zinc(II) complexes [Cu(H2FopClPh)Cl2] (1), [Cu(2FopNO2Ph)Cl] (2), [Zn(H2FopClPh)Cl2] (3) and [Zn(H2FopNO2Ph)Cl2] (4). Upon re-crystallization in DMSO:acetone conversion of 2 into [Cu(2FopNO2Ph)Cl(DMSO)] (2a) and of 4 into [Zn(2FopNO2Ph)Cl(DMSO)] (4a) occurred. The crystal structures of 1, 2a, 3 and 4a were determined. [Copyright &y& Elsevier]

Abstract: The reaction of cis-[RuCl2(P–P)(N–N)] type complexes (P–P=1,4-bis(diphenylphosphino)butane or (1,1′-diphenylphosphino)ferrocene; N–N=2,2′-bipyridine or 1,10-phenantroline) with monodentate ligands (L), such as 4-methylpyridine, 4-phenylpyridine and benzonitrile forms [RuCl(L)(P–P)(N–N)]+ species. Upon characterization of the isolated compounds by elemental analysis, 31P{1H} NMR and X-ray crystallography it was found out that the type of the L ligand determines its position in relation to the phosphorus atom. While pyridine derivatives like 4-methylpyridine and 4-phenylpyridine coordinate trans to the phosphorus atom, the benzonitrile ligand (bzCN), a good π acceptor, coordinates trans to the nitrogen atom. A 31P{1H} NMR experiment following the reaction of the precursor cis-[RuCl2(dppb)(phen)] with the benzonitrile ligand shows that the final position of the entering ligand in the complex is better defined as a consequence of the competitive effect between the phosphorus atom and the cyano-group from the benzonitrile moiety and not by the trans effect. In this case, the benzonitrile group is stabilized trans to one of the nitrogen atoms of the N–N ligand. A differential pulse voltammetry experiment confirms this statement. In both experiments the [RuCl(bzCN)(dppb)(phen)]PF6 species with the bzCN ligand positioned trans to a phosphorus atom of the dppb ligand was detected as an intermediate complex. [Copyright &y& Elsevier]

Abstract: 2-Benzoylpyridine-methyl hydrazone (HBzMe) has been obtained as well as its copper(II) [Cu(HBzMe)Cl2] (1) and zinc(II) [Zn(HBzMe)Cl2] (2) complexes. Upon re-crystallization in 1 – 9 DMSO:acetone conversion of 1 into dimeric [Cu(BzMe)Cl]2 (1a) occurred. The crystal structures of HBzMe, 1, 1a, and 2 were determined. HBzMe adopts the ZE conformation in the solid. In all complexes the hydrazone adopts the E configuration to attach to the metal through the Npy ph name="sbnd" />O chelating system. In 1 and 2 a neutral hydrazone coordinates to the metal center while in 1a deprotonation occurs with coordination of an anionic ligand. 1a presents a dimeric structure, having two copper(II) ions per asymmetric unit. Two chlorides are also present in the copper coordination sphere, which act as bridging ligands and connect the copper centers to each other. [Copyright &y& Elsevier]

Abstract: The synthesis and characterization of trans/cis-[RuCl2(dppf)(diimines)], dppf=1,1′-bis(diphenylphosphino)ferrocene; diimines=2,2′-bipyridine (trans/cis-(1)), the new complexes with 4,4′-dimethyl-2,2′-bipyridine (trans/cis-(2)) and 1,10-phenanthroline (cis-(3)) are presented. The complexes were synthesized using two routes and the trans/cis-isomer formation is dependent upon conditions and the precursor applied. The trans-isomer (kinetic) readily isomerizes to the cis-isomer (thermodynamic) when exposed to light (fluorescent) and this process was followed by cyclic voltammetry and UV–vis. The electrochemical studies on these complexes reveal that Fe(III)/Fe(II) couples are insensitive to the isomer (trans/cis) formed, but the Ru(III)/Ru(II) couples are dependent on the isomer. Transfer-hydrogenation reactions for reduction of acetophenone were conducted using complexes cis-(1) and cis-(2) and the results are compared with that obtained for similar complexes. X-ray structure for cis-(3) are presented and discussed. [Copyright &y& Elsevier]

Herein we describe the synthesis of a new heterodinuclear FemCuu model complex for the active site of purple acid phosphatases and its binding to a polyamine chain, a model for the amino acid residues around the active site. The properties of these systems and their catalytic activity in the hydrolysis of bis(2,4-dinitrophenyl)phosphate are compared, and conclusions regarding the effects of the second coordination sphere are drawn. The positive effect of the polymeric chain on DNA hydrolysis is also described and discussed. [ABSTRACT FROM AUTHOR]