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PubMed1998

Interactive modeling of supramolecular assemblies.

The modeling of supramolecular structure presents two major challenges: (1) managing the large amount of sequence, structural and biochemical data, and (2) presenting the data to the user in a flexible and comprehensible manner that addresses these problems. We describe a visualization environment for the creation and analysis of supramolecular models. A set of modular symmetry tools, collectively called SymGen, has been created, providing a flexible platform for the creation of complex assemblies, with interactive control of all symmetry elements and their parameters. A second tool, SymSearch, allows a range of parameters defined within SymGen to be sampled and the resulting conformations to be evaluated. The environment avoids information overload, caused by the large number of atoms in supramolecular complexes, by using a multiresolution spherical harmonic representation that allows the user to display only essential features. Spherical harmonics also enables control of the triangulation level, allowing the user to reduce the complexity of the geometric description to retain interactive speed. The visual fidelity of the surface data is retained by using texture maps that are independent of the resolution of the underlying triangulation. We describe the design and implementation of this environment, and three illustrative examples of its utility.

Capsid↗

PubMed2004

Cation sensors containing a (bpy)Re(CO)3 group linked to an azacrown ether via an alkenyl or alkynyl spacer: synthesis, characterisation, and complexation with metal cations in solution.

Two [(bpy)Re(CO)3L]+ complexes (bpy = 2,2'-bipyridine), where L contains an aza-15-crown-5 ether which is linked to Re via an alkenyl- or alkynyl-pyridine spacer, have been synthesised along with model complexes. Solutions of the complexes in acetonitrile have been studied by UV-Vis absorption spectroscopy, and by 1D and 2D 1H NMR spectroscopy. Strong UV-Vis bands, assigned to intraligand charge-transfer transitions localised at the L ligands, blue shift on protonation of the azacrown nitrogen atom or on complexation of alkali-metal (Li+, Na+ and K+) or alkaline-earth metal (Mg2+, Ca2+ and Ba2+) cations to the azacrown; the magnitude of the blue shift is dependent on the cation, with protonation giving the largest shift of ca. 100 nm. Cation binding constants in the range of log K= 1-4 depend strongly on the identity of the metal cation. Protonation or cation complexation causes downfield shifts in the 1H NMR resonances from most of the azacrown and L ligand protons, and their magnitudes correlate with those of the blue shifts in the UV-Vis bands; shifts in the azacrown 1H NMR resonances report on how the different metal cations interact with the macrocycle. UV-Vis and 1H NMR spectra of the free L ligands enable the effect of the Re centre to be assessed. Together, the data indicate that the alkene spacer gives a more responsive sensor than the alkyne spacer by providing stronger electronic communication across the L ligand.

Journal Article↗

PubMed2001

Mono- and dinuclear five-coordinate cyclometalated palladium(II) compounds.

Reaction of cyclometalated halide-bridged Pd(II) complexes 1-4 with the tertiary triphosphine ligand (Ph2PCH2CH2)2PPh (triphos) yielded complexes [((Ph2PCH2CH2)2PPh-P,P,P)Pd(N(Cy)=(H)C)C6H2(C(H)=N(Cy))Pd((Ph2PCH2CH2)2PPh-P,P,P)][ClO4]2 5, [Pd(C6H4-N=NC6H5)((Ph2PCH2CH2)2PPh-P,P,P)][ClO4] 6, and [Pd(R-C6H3C(H)=NCy)((Ph2PCH2CH2)2PPh-P,P,P)][ClO4] (7; R = 4-CHO, 8; 3-CHO). Spectroscopic and analytic data suggest five-coordination on the palladium atom, which, for complexes 5, 6, and 7, was confirmed by X-ray crystallography. The geometry around palladium may be view as a distorted trigonal bipyramid, with the palladium, nitrogen, and terminal phosphorus atoms in the equatorial plane. Compound 5 is the first doubly cyclometalated palladium(II) compound with two pentacoordinated metal centers. The structure of 6 comprises two discrete cations with slightly different geometries, showing the importance of crystal packing forces in order to determine the coordination arrangement.

Journal Article↗

PubMedDate not supplied

[Structure and electronic properties of heme complexes with various ligands].

The electronic and atomic structures, and the molecular dynamics of the atomic structure at 310 K of a set of heme complexes with His and Gly amino acids in the 5th coordination position and some ligands (O2, NO) in the 6th position were studied by ab initio (3-21G basis set) and semiempirical (PM3) quantum chemistry methods and the method of molecular dynamics. It was shown that the type of coordination of the imidazole ring influences the constant of chemical bonding of molecular oxygen of the complexes. On the other hand, NO and O2 molecules have different transinfluence on the ligand in the 5th coordination position. It was shown that temperature affects profoundly the atomic and electronic structures of the complexes, the tightness of chemical bonding and their reactivity.

Heme↗

PubMed1999

Synthesis, structure, spectroscopic properties and biological activity of mixed diorganotin(IV) complexes containing pyridine-2-carbaldehyde thiosemicarbazonato and diphenyldithiophosphinato ligands.

Reaction of the title ligands (HPyTSC and HS(S)PPh2, respectively) with R2SnO (R = Me, Et, Bu) in ethanol (EtOH) afforded the complexes [SnMe2(PyTSC) (S2PPh2)].EtOH (1) and [SnR2(PyTSC) (S2PPh2)] (R = Et (2), Bu (3)). The structures of 1 and 2 were determined by single-crystal X-ray diffractometry. In both these complexes the tin atom is coordinated to an N,N,S-dentate thiosemicarbazonate ligand, an anisobidentate dithiophosphinato ligand and the two R groups. The coordination polyhedrons can be described as distorted pentagonal bipyramids. A comparative study of the IR spectra of 1, 2 and 3 indicates that the butyl complex has a similar structure. Multinuclear (1H, 13C, 31P and 119Sn) NMR data suggest that the structures of 1 and 2 probably remain in CDCl3 (or DMSO-d6) solution but compound 3 partially decomposes in these media. Preliminary results on the effects of the complexes on the proliferation and differentiation of FLC, CEM, U937, K562 and TOM-1 leukaemia cells, and on the clonogenic activity of K562 cells are also described.

Cell Differentiation↗

PubMed2006

The gas-phase chemistry of cis-diammineplatinum(II) complexes: a joint experimental and theoretical study.

Prior to reactions with DNA, the anticancer drug cisplatin [Pt(II)(NH(3))(2)Cl(2)] forms a series of solvolysis intermediates by successive replacement of the chloro ligands by water or hydroxyl groups. The bonding of water to Pt(II) is weak, and it is easily substituted by donor ligands present in the solution, for example, amines or alcohols. We studied such compounds using high-resolution electrospray mass spectrometry with a linear ion trap and DFT computations. This combination allows for the first time a detailed description of the reactions initiated by the central atom of the complexes. Positively charged cisplatin adducts with primary and secondary alcohols ([Pt(II)(NH(3))(2)(ROH)Cl](+)) show unexpected reactions when fragmented in a linear ion trap. Either water loss is accompanied by formation of the corresponding carbene complex, or loss of the corresponding aldehyde/ketone leads to the formation of the complex [Pt(NH(3))(2)(H(2))Cl](+). Complete loss of the alcohol ligand is not observed for kinetic reasons. A detailed investigation by DFT and molecular dynamics for the cisplatin/methanol complex [Pt(II)(NH(3))(2)(CH(3)OH)Cl](+) allowed identification of the reaction mechanisms leading to the observed fragmentation patterns. The initial step for both fragmentation pathways is activation of the alpha-CH bond and subsequent H transfer within the complex. Direct activation of the OH or CO bond is less favorable. Ligands bound to the Pt(II) center such as the chloro ligand can directly catalyze the reaction by intermediate binding of H atoms. Upon collision activation, adducts without an alpha-H atom such as [Pt(NH(3))(2){(CH(3))(3)COH}Cl](+) show loss of water or the corresponding alkene.

Alcohols↗

PubMed2002

A new class of gadolinium complexes employed to obtain high-phasing-power heavy-atom derivatives: results from SAD experiments with hen egg-white lysozyme and urate oxidase from Aspergillus flavus.

Seven gadolinium complexes are shown to be excellent compounds for the preparation of heavy-atom derivatives for macromolecular crystallography projects. De novo phasing has been carried out using single-wavelength anomalous diffraction (SAD) on a series of gadolinium-derivative crystals of two proteins: hen egg-white lysozyme and urate oxidase from Aspergillus flavus. Lysozyme derivative crystals were obtained by co-crystallizing the protein with the corresponding gadolinium complex at a concentration of 100 mM. Diffraction data were collected to a resolution of 1.7 A using Cu K(alpha) radiation from a rotating-anode generator, making use of the high anomalous signal of gadolinium at this wavelength. Urate oxidase derivative crystals were obtained by soaking native crystals in 100 mM gadolinium complex solutions. Diffraction data were collected to a resolution close to 3 A using X-rays at the Gd L(III) absorption edge, taking advantage of the sharp white line on that edge. For all urate oxidase derivative crystals and three of the lysozyme crystals, SAD phasing led to electron-density maps of very high quality, allowing unambiguous chain tracing. From this study, the binding effectiveness of the gadolinium complexes seems to be related to the nature of the precipitant used for crystallization. These gadolinium complexes represent a new class of high-phasing-power heavy-atom derivatives that may be used for high-throughput structure-determination projects.

Animals↗

PubMed2006

Copper(II) hexaaza macrocyclic binuclear complexes obtained from the reaction of their copper(I) derivates and molecular dioxygen.

Density functional theory (DFT) calculations have been carried out for a series of Cu(I) complexes bearing N-hexadentate macrocyclic dinucleating ligands and for their corresponding peroxo species (1c-8c) generated by their interaction with molecular O2. For complexes 1c-7c, it has been found that the side-on peroxodicopper(II) is the favored structure with regard to the bis(mu-oxo)dicopper(III). For those complexes, the singlet state has also been shown to be more stable than the triplet state. In the case of 8c, the most favored structure is the trans-1,2-peroxodicopper(II) because of the para substitution and the steric encumbrance produced by the methylation of the N atoms. Cu(II) complexes 4e, 5e, and 8e have been obtained by O2 oxidation of their corresponding Cu(I) complexes and structurally and magnetically characterized. X-ray single-crystal structures for those complexes have been solved, and they show three completely different types of Cu(II)2 structures: (a) For 4e, the Cu(II) centers are bridged by a phenolate group and an external hydroxide ligand. The phenolate group is generated from the evolution of 4c via intramolecular arene hydroxylation. (b) For 5e, the two Cu(II) centers are bridged by two hydroxide ligands. (c) For the 8e case, the Cu(II) centers are ligated to terminally bound hydroxide ligands, rare because of its tendency to bridge. The evolution of complexes 1c-8c toward their oxidized species has also been rationalized by DFT calculations based mainly on their structure and electrophilicity. The structural diversity of the oxidized species is also responsible for a variety of magnetic behavior: (a) strong antiferromagnetic (AF) coupling with J = -482.0 cm(-1) (g = 2.30; rho = 0.032; R = 5.6 x 10(-3)) for 4e; (b) AF coupling with J = -286.3 cm(-1) (g = 2.07; rho = 0.064; R = 2.6 x 10(-3)) for 5e; (c) an uncoupled Cu(II)2 complex for 8e.

Journal Article↗

PubMed2001

Synthesis and molecular structures of some new titanium(IV) aryloxides.

The coordination chemistry of model phenolic ligands (pyrocatechol, salicylic acid, and 2,2'-biphenol) that are able to form respectively five-, six-, or seven-membered rings with titanium(IV) alkoxides is investigated. With pyrocatechol, a polynuclear complex containing 10 Ti atoms was characterized with a not very common doubly bridging mu3-(O,O,O',O') coordination mode. With salicylic acid, a monomeric tris(chelate) complex was obtained. With 2,2'-biphenol, a polynuclear complex containing six Ti atoms was obtained showing both mu2-(O,O') and mu2-(O,O,O') coordination modes for the ligands. Intermolecular interactions in the solid state for these three new compounds are also quantitatively discussed using the partial charge model.

Catechols↗

PubMed1997

[Measurement of trace elements in blood serum by atomic absorption spectroscopy with electrothermal atomization].

Describes a method for measuring trace elements Cr, Mn, Co, Fe, Cu, Zn, and Mo in the blood serum using non-flame atomization (KAC 120.1 complex). Optimal conditions for preparing the samples were defined, temperature regimens for analysis of each element selected, and original software permitting automated assays created. The method permits analysis making use of the minimal samples: 0.1 ml per 10 parallel measurements, which is 100 times less than needed for atomic absorption spectroscopy with flame atomization of liquid samples. Metrological characteristics of the method are assessed.

Chromium↗

PubMed2006

Exploring the interaction of ruthenium(II) polypyridyl complexes with DNA using single-molecule techniques.

Here we explore DNA binding by a family of ruthenium(II) polypyridyl complexes using an atomic force microscope (AFM) and optical tweezers. We demonstrate using AFM that Ru(bpy)2dppz2+ intercalates into DNA (K(b) = 1.5 x 10(5) M(-1)), as does its close relative Ru(bpy)2dppx2+ (K(b) = 1.5 x 10(5) M(-1)). However, intercalation by Ru(phen)3(2+) and other Ru(II) complexes with K(b) values lower than that of Ru(bpy)2dppz2+ is difficult to determine using AFM because of competing aggregation and surface-binding phenomena. At the high Ru(II) concentrations required to evaluate intercalation, most of the DNA strands acquire a twisted, curled conformation that is impossible to measure accurately. The condensation of DNA on mica in the presence of polycations is well known, but it clearly precludes the accurate assessment by AFM of DNA intercalation by most Ru(II) complexes, though not by ethidium bromide and other monovalent intercalators. When stretching individual DNA molecules using optical tweezers, the same limitation on high metal concentration does not exist. Using optical tweezers, we show that Ru(phen)2dppz2+ intercalates avidly (K(b) = 3.2 x 10(6) M(-1)) whereas Ru(bpy)3(2+) does not intercalate, even at micromolar ruthenium concentrations. Ru(phen)3(2+) is shown to intercalate weakly (i.e., at micromolar concentrations (K(b) = 8.8 x 10(3) M(-1))). The distinct differences in DNA stretching behavior between Ru(phen)3(2+) and Ru(bpy)3(2+) clearly illustrate that intercalation can be distinguished from groove binding by pulling the DNA with optical tweezers. Our results demonstrate both the benefits and challenges of two single-molecule methods of exploring DNA binding and help to elucidate the mode of binding of Ru(phen)3(2+).

DNA↗

PubMed2005

Highly diastereoselective templated complexation of dipyrromethenes.

[reaction: see text] Bis(dipyrromethene)s with relatively long spacers (>5 atoms) form helical monomeric complexes as the two binding units of the bis(dipyrromethene) chelate around the same tetrahedrally coordinated metal ion. Herein we report the first highly diastereoselective mononuclear helicate-forming complexation reactions of bis(dipyrromethene)s using homochiral binol and tartrate motifs which serve as both linkers and asymmetric templates.

Journal Article↗

PubMed1997

Amino Acid Complexes of Metal Carbonyls: Mechanistic Aspects of the CO-Labilizing Ability of Glycinate Ligands in Zero-Valent Chromium and Tungsten Derivatives.

The amino and phosphino acid derivatives of chromium(0) and tungsten(0), [Et(4)N][Cr(CO)(4)(O(2)CCH(2)NH(2))] (1), [Et(4)N][Cr(CO)(4)(O(2)CCH(2)NHMe)] (2), [Et(4)N][Cr(CO)(4)(O(2)CCH(2)NMe(2))] (3), [Et(4)N][W(CO)(4)(O(2)CCH(C(CH(3))(3))NH(2))] (4), [Et(4)N][W(CO)(4)(O(2)CCH(C(6)H(5))NH(2))], [Et(4)N][W(CO)(4)(O(2)CCH(2)PPh(2))] (5), and [Et(4)N][Cr(CO)(4)(O(2)CCH(2)PPh(2))] have been synthesized from the reaction of the M(CO)(5)THF adduct with the tetraethylammonium salt of the corresponding amino or phosphino acid in THF solution. The complexes have been characterized in solution by (13)C NMR and infrared spectroscopies and in the solid state by X-ray crystallography. The geometry of the metal anion is, in each case, that of a distorted octahedron consisting of four carbonyl ligands and a puckered five-membered glycinate chelate ring, bound through the nitrogen atom and one of its oxygen atoms. Notable about complex 1 is that the crystal obtained exhibited both a different morphology and a different space group than its tungsten analogue. Examination of the packing diagram reveals that this change is due to the different orientation of the chelate ring in 1 relative to the corresponding orientation in the W(CO)(4)(O(2)CCH(2)NH(2))(-) anion. Complexes 1 and 2 exhibit intermolecular hydrogen-bonding interactions between the amine N-H group and the distal oxygen on an adjacent molecule, with N.O distances of 2.828 and 2.821 Å, respectively. Investigations of the lability of the carbonyl ligands have been carried out. The lability is proposed to be due to base-assisted removal of a proton from the amine ligand leading to a substitutionally labile amide transient species. The tungsten analogue of complex 1 was used to obtain evidence in support of this mechanism. The isotope effect (k(H)/k(D)) was measured for W(CO)(4)(O(2)CCH(2)NH(2))(-) using d(5)-glycine and was found to be 2.34. The activation parameters for the intermolecular exchange of CO in the [Et(4)N][W(CO)(4)(O(2)CCH(2)NH(2))] salt were determined and found to be DeltaH() = 15.4 +/- 1.0 kcal/mol and DeltaS() = -23.2 +/- 3.2 eu, values consistent with the proposed mechanism. In addition, the effect of substitution of electron-donating (C(CH(3))(3)) and electron-withdrawing (C(6)H(5)) substituents on the methylene carbon was evaluated. There was little change in the rate of CO exchange observed for W(CO)(4)(O(2)CCH(C(CH(3))(3))NH(2))(-) (5) and W(CO)(4)(O(2)CCH(C(6)H(5))NH(2))(-) vs W(CO)(4)(O(2)CCH(2)NH(2))(-), showing that steric or electronic effects away from the N center are not responsible for the observed CO lability. As anticipated on the basis of the proposed substitutional pathway, the phosphino acid metal carbonyl derivatives did not exhibit facile intermolecular CO exchange.

Journal Article↗

PubMed1991

Crystal structure of a bovine neurophysin II dipeptide complex at 2.8 A determined from the single-wavelength anomalous scattering signal of an incorporated iodine atom.

The crystal structure of a dipeptide complex of bovine neurophysin II has been solved at 2.8 A resolution solely by using single-wavelength anomalous scattering data from a single iodinated derivative. The asymmetric unit is an elongated tetramer of dimensions 110 x 40 x 30 A, composed of two dimers related by pseudo twofold symmetry. Each monomer consists of two homologous layers, each with four antiparallel beta-strands. The two regions are connected by a helix followed by a long loop. Monomer-monomer contacts involve antiparallel beta-sheet interactions, which form a dimer with two layers of eight beta-strands. One peptide per monomer occupies the principal hormone-binding pocket formed by part of the amino-terminal region and parts of the connecting helix and loop, with binding to protein consistent with conclusions drawn from solution studies. Dimer-dimer contacts involve the Tyr49 region adjacent to this site. A fifth dipeptide, of unknown biological significance, helps to stabilize one of the monomer-monomer interfaces and the tetramer-tetramer network in the crystal.

Amino Acid Sequence↗

PubMed1998

New Rydberg-Rydberg Transitions of the ArH and ArD Molecules

We report and rotationally analyze new spectra of the ArH and ArD molecules corresponding to the 0-0 vibrational bands of electronic transitions from the nd and ns states to the 4p Rydberg complex, in united atom notation. In ArD, our observation of the 3ddelta state, along with previous observations of the 3dpi and 3dsigma states, demonstrates that the components of the 3d state are widely separated and can be treated as Hund's case (b) states, unlike the components of the np and 4f states, which form closely coupled case (d) Rydberg complexes. The band 4dsigma --> 4p has also been assigned. The 4dpi component is known from previous work of Lipson, but as yet the 4ddelta component is unknown. Emission from the 6s and 8s states is also analyzed. From the intensities in the rotational structure, there is evidence that the 6s state interacts with the 3dsigma state. In ArH, we analyze the 0-0 bands of the 3dpi --> 4p, 3ddelta --> 4p, 4dsigma --> 4p, and 6s --> 4p transitions. Unlike the rotational levels of the 5s state, which are heavily broadened by predissociation, the 4p levels of ArH are sharp, so we can perform a more accurate and detailed analysis for this isotope than was possible previously. Qualitative features of the ArH spectra essentially mirror those of ArD, except that emission from the 3dsigma state was not identified, possibly due to a perturbation particular to this isotope. Copyright 1998 Academic Press.

Journal Article↗

PubMed1993

Gd(DOTP)5-outer-sphere relaxation enhancement promoted by nitrogen bases.

The relaxation properties of Gd(DOTP)5- (1, 4, 7, 10-tetra-azacyclododecane- N,N',N'',N'''-tetrakis(methylenephosphonic acid)) have been investigated as a function of pH, temperature, concentration, and magnetic field strength. We have found that the complex has one exchangeable water molecule in its inner coordination sphere, at a distance of 3.26 A from the metal ion, and it does not form oligomers in solution in the concentration range 0.2 to 10 mM. The possible presence of two species in solution with an average fractional hydration number is also taken into accounts. The NMRD profiles were recorded at 5 degrees C, 25 degrees C, and 35 degrees C and quantitatively analyzed in terms of the paramagnetic relaxation equations. Interestingly the addition to a solution of the Gd(III)-complex of nitrogen bases results in a marked relaxation enhancement, which shows a strong pH dependence with a maximum around pH = 9. The relaxivity gain has been shown to depend on outer-sphere effects originating from multiple electrostatic interactions between the anionic complex and the organic cations that bring the exchangeable protons of the substrate molecules in to close proximity with the paramagnetic center. High resolution NMR relaxation data for N-methyl-D(-)-glucamine suggest that the hydroxyl group on the beta-carbon plays a role in stabilizing the interaction, presumably through a hydrogen bond with an uncoordinated oxygen atom of the complex.

Chemical Phenomena↗

PubMed2005

Novel copper(II)-dien-imidazole/imidazolate-bridged copper(II) complexes. Crystal structure of [Cu(dien)(Him)](ClO4)2 and of [(dien)Cu(mu-im)Cu(dien)](ClO4)3, a homobinuclear model for the copper(II) site of the CuZn-superoxide dismutase.

The imidazolate-bridged binuclear copper(II)-copper(II) complex [(dien)Cu(mu-im)Cu(dien)](ClO(4))(3) and related mononuclear complexes [Cu(dien)(H(2)O)](ClO(4))(2), [Cu(dien)(Him)](ClO(4))(2) were synthesized with diethylenetriamine (dien) as capping ligand. The crystal structure of mononuclear [Cu(dien)(Him)](ClO(4))(2) and binuclear complex [(dien)Cu(mu-im)Cu(dien)](ClO(4))(3) have been determined by single crystal X-ray diffraction methods. The mononuclear complex [Cu(dien)(Him)](ClO(4))(2) crystallizes in the orthorhombic, Pca2(1) with a = 9.3420(9) A, b = 12.3750(9) A, c = 14.0830(9) A, beta = 90.000(7)(o) and Z = 4 and binuclear complex [(dien)Cu(mu-im)Cu(dien)](ClO(4))(3) crystallizes in the monoclinic space group P2(1)/a, with a = 15.017(7) A, b = 11.938(6) A, c = 15.386(6) A, beta = 110.30(4)(o) and Z = 4. The molecular structures show that copper(II) ions in an asymmetrically elongated octahedral coordination (type 4 + 1 + 1) and in binuclear complex Cu(1) atom has a asymmetrically elongated octahedral coordination (type type 4 + 1 + 1) and Cu(2) atom exhibits a square base pyramidal coordination (type 4 + 1). The bridging ligand (imidazolate ion, im) lies nearly on a straight line between two Cu(2+), which are separated by 5.812 A, slightly shorter than the value in copper-copper superoxide dismutase (Cu(2)-Cu(2)SOD). Magnetic measurements and electron spin resonance (ESR) spectroscopy of the binuclear complex have shown an antiferromagnetic exchange interaction. From pH-dependent cyclic voltametry (CV) and electronic spectroscopic studies the complex has been found to be stable over a wide pH range (7.75-12.50).

Absorption↗

PubMed2006

Synthesis and anticancer activity of certain mononuclear Ru (II) complexes.

Bis(1,10-phenanthroline/2,2'-bipyridine) ruthenium(II)complexes containing TCP, TTZ OPBI, and BTSC ligands (where, TCP = 1-thiocarbamoyl-3,5-diphenyl-2-pyrazoline, TTZ = 2-(3,5-diphenyl-4,5-dihydropyrazol-1-yl)-4-phenylthiazole, OPBI = 2-hydroxyphenyl benzimidazole and BTSC = benzoin thiosemicarbazone) have been prepared and characterized. The spectral data suggested that the ligands were coordinated with the metal through nitrogen, sulfur and oxygen atoms. The target complexes were tested in vivo for anticancer activity against transplantable murine tumor cell line, Ehrlich's Ascitic Carcinoma (EAC). All these complexes increased the life span of the EAC-bearing mice, decreased their tumor volume and viable ascitic cell count as well as improved Hb, RBC and WBC counts. These results suggest that the Ru(II) complexes exhibit significant antitumor activity in EAC-bearing mice. It was also observed that the ruthenium complexes protected red blood cells from 2,2'-azo-bis(2-methylpropionamidine) dihydrochloride (AAPH)- induced hemolysis. The inhibitory effect was dose-dependent at a concentration of 20-120 microg/ml.

Animals↗