Aris Terzis

Anti-inflammatory drugs interacting with Zn(II), Cd(II) and Pt(II) metal ions

Complexes of Zn(II), Cd(II) and Pt(II) metal ions with the anti-inflammatory drugs, 1-methyl-5-(p-toluoyl)-1H-pyrrole-2-acetic acid (Tolmetin), alpha-methyl-4-(2-methylpropyl)benzeneacetic acid (Ibuprofen), 6-methoxy-alpha-methylnaphthalene-2-acetic acid (Naproxen) and 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid (indomethacin) have been synthesized and characterized. In the structurally characterized Cd(naproxen)2 complex the anti-inflammatory drugs acts as bidentate chelate ligand coordinatively bound to metal ions through the deprotonated carboxylate group. Crystal data for 1: [C32H26O8Cd], orthorhombic, space group P22(1)2(1), a = 5.693(2) (A), b = 8.760(3) (A), c = 30.74(1) (A), V = 1533(1) A3, Z = 2. Antibacterial and growth inhibitory activity is higher than that of the parent ligands or the platinum(II) diamine compounds.

Low temperature measurements of the electrical conductivities of some charge transfer salts with the asymmetric donors MDT-TTF, EDT-TTF and EDT-DSDTF. (MDT-TTF)2AuI2, a new superconductor (Tc=3.5 K at ambient pressure)

Abstract The electrical and x-ray structural properties of the new superconductor (MDT-TTF) 2 AuI 2 with a T c of 3.5 K at ambient pressure were studied (MDT-TTF = methylenedithio-tetrathiafulvalene). Low temperature measurements of the electrical conductivities of two new metals, (EDT-TTF) 2 IBr 2 and (EDT-DSDTF) 2 AuI 2 are reported (EDT-TTF = ethylenedithio-tetrathiafulvalene, EDT-DSDTF = ethylenedithio-diselenadithiafulvalene).

Thegem-Diol Form of (py)2CO as a Ligand in Cobalt(II) Carboxylate Clusters: A Cubane Complex and a Novel Nonanuclear Species with a Vertex-Sharing Double Square Pyramidal Structure

A vertex-sharing double square pyramid of cobalt(II) ions (see picture) is present in the nonanuclear complex 1, obtained by treating cobalt acetate with 0.5 equivalents of (py2 )CO. The corresponding 1:1 reaction gave 2, which has a central core with a cubane structure. py=pyridine.

Coordinating properties of 2-acetylpyridine thiosemicarbazone. Palladium(II) complexes with neutral and deprotonated ligand. X-ray structure of bromo(2-acetylpyridine thiosemicarbazonato) palladium(II)

Abstract The preparation of the complexes PdLX, [Pd(HL) 2 ]X 2 and PdL 2 (X = Cl, Br; HL and L the neutral and deprotonated ligand) is described. The new complexes have been characterized by elemental analyses, conductivity measurements and spectroscopic (IR and UV-vis) studies and the crystal and molecular structure of PdLBr has been determined by single-crystal X-ray diffraction. The palladium atom has a square planar geometry with three donor atoms (NNS) coming from L to form a planar tricyclic ligating system, and one bromide atom. All data are discussed in terms of assigned structural type and the nature of the bonding. The protonation constants of the ligand, K a1 and K a2 , were determined by spectrophotometry and the logarithms of their values were found to be equal to 11.43 ± 0.02 and 3.98 ± 0.02.

Synthesis and characterization of tetrakis-μ-2-[(2,6dichlorophenyl) amino] benzeneacetodiaquodicopper(II) dihydrate and tetrakis-μ-2-[(2,6dichlorophenyl)amino]benzeneaceto dimethylformamidodicopper(II)

Abstract Complexes of diclofenac (L), [CuL2(H2O)]22H2O, and [CuL2(DMF)]2 were prepared by the reaction of the sodium salt of this potent antiinflammatory drug with CuCl2. The new symmetric binuclear copper(II) complex [CuL2(DMF)]2 crystallizes in the monoclinic space group P21/n with cell constants a = 10.807(1), b = 15.429(2), c = 19.360(2), β = 92.508(3), V = 3225(1) A 3 , and Z = 2 . The structure was determined from 5456 out of a total of 5768 unique reflections. The final values for R1, wR2, and GOF for all data are 0.0602, 0.1066, and 1.030, respectively. The crystal structure consists of a binuclear quadruply bridged neutral molecule. The four carboxylato groups from four ligands are in the familar bidentate syn,syn η1:η1:μ2 bridging mode. The metal coordination geometry is described as a perfect square bipyramid with a water or dimethyloformamide oxygen occupying both apical positions. Optical, infrared, electron paramagnetic resonance, magnetic, and electrochemical properties of these complexes are also reported.

Synthesis, spectroscopic, and structural characterization of the first aqueous cobalt(II)-citrate complex: toward a potentially bioavailable form of cobalt in biologically relevant fluids.

Abstract Citric acid represents a class of carboxylic acids present in biological fluids and playing key roles in biochemical processes in bacteria and humans. Its ability to promote diverse coordination chemistries in aqueous media, in the presence of metal ions known to act as trace elements in human metabolism, earmarks its involvement in a number of physiological functions. Cobalt is known to be a central element of metabolically important biomolecules, such as B12, and therefore its biospeciation in biological fluids constitutes a theme worthy of chemical and biological perusal. In an effort to unravel the aqueous chemistry of cobalt in the presence of a physiologically relevant ligand, citrate, the first aqueous, soluble, mononuclear complex has been synthesized and isolated from reaction mixtures containing Co(II) and citrate in a 1 :2 molar ratio at pH∼8. The crystalline compound (NH4)4[Co(C6H5O7)2] (1) has been characterized spectroscopically (UV/vis, EPR) and crystallographically. Its X-ray structure consists of a distorted octahedral anion with two citrate ligands fulfilling the coordination requirements of the Co(II) ion. The magnetic susceptibility measurements of 1 in the range from 6 to 295 K are consistent with a high-spin complex containing Co(II) with a ground state S=3/2. Corroborating this result is the EPR spectrum of 1, which shows a signal consistent with the presence of a Co(II) system. The spectroscopic and structural properties of the complex signify its potential biological relevance and participation in speciation patterns arising under conditions consistent with those employed for its synthesis and isolation.

Lead–citrate chemistry. Synthesis, spectroscopic and structural studies of a novel lead(II)–citrate aqueous complex

Abstract The interaction of lead with biologically relevant ligands, such as citrate, constitutes a major research thrust relating to toxic effects exerted on humans. Reaction of Pb(NO3)2 with citric acid in water at pH 2 and various ratios (1:1–1:3) yielded the first Pb–citrate species, which was characterized analytically and spectroscopically (FT-IR). X-ray crystallographic studies were carried out and showed the novel compound to be [Pb(C6H6O7)]n·nH2O. The geometry around Pb2+ appears to be distorted trigonal bipyramidal with PbO distances ranging from 2.397(7) to 2.527(6) A and the lone pair on Pb2+ occupying one of the three basal plane positions. Citrate binds Pb2+ forming rhomboidal Pb2O2 units, while it subtends its terminal carboxylate onto a proximal Pb2+, thus linking adjacent Pb2O2 units into a chain along the a axis. The involvement of citrate in hydrogen bonds with water molecules and abutting Pb–citrate moieties leads to a stable structure. The stability of the species formed and eventually isolated from aqueous solutions as well as its reactivity toward bases present useful information on the chemistry in biological media and its relevance to the known biotoxicity of lead.

Structural and Electronic-Properties of the Natural Quantum-Well System (C6h5ch2ch2nh3)2sni4

Abstract The structural and electronic properties of the natural multi-quantum-well system (C 6 H 5 CH 2 CH 2 NH 3 ) 2 SnI 4 were investigated by determining its single crystal x-ray structure, measuring its dc-electrical-conductivity and electronic spectra, as well as by calculating its electronic band structure and its excitonic binding energy.

Di-2-pyridyl ketone oxime [(py)2CNOH] in manganese carboxylate chemistry: mononuclear, dinuclear and tetranuclear complexes, and partial transformation of (py)2CNOH to the gem-diolate(2-) derivative of di-2-pyridyl ketone leading to the formation of NO3-

The use of di-2-pyridyl ketone oxime, (py)2CNOH, in manganese carboxylate chemistry has been investigated. Using a variety of synthetic routes complexes [Mn(O2CPh)2{(py)2CNOH}2].0.25H2O (1.0.25H2O), Mn4(O2CPh)2{(py)2CO2}2{(py)2CNO}2Br2].MeCN (2.MeCN), [Mn4(O2CPh)2{(py)2CO2}2{(py)2CNO}2Cl(2)].2MeCN (3.2MeCN), [Mn4(O2CMe)2{(py)2CO2}2{(py)2CNO}2Br2].2MeCN (4.2MeCN), [Mn4(O2CMe)2{(py)2CO2}2{(py)2CNO}2(NO3)2].MeCN.H2O (5.MeCN.H2O) and [Mn2(O2CCF3)2(hfac)2{(py)2CNOH}2] (6) have been isolated in good yields. Remarkable features of the reactions are the in situ transformation of an amount of (py)2CNOH to yield the coordination dianion, (py)2CO2(2-), of the gem-diol derivative of di-2-pyridyl ketone in 2-5, the coordination of nitrate ligands in 5 although the starting materials are nitrate-free and the incorporation of CF3CO2- ligands 6 in which was prepared from Mn(hfac)(2).3H2O (hfac(-)= hexafluoroacetylacetonate). Complexes 2-4 have completely analogous molecular structures. The centrosymmetric tetranuclear molecule contains two MnII and two MnIII six-coordinate ions held together by four mu-oxygen atoms from the two 3.2211 (py)2CO2(2-) ligands to give the unprecedented [MnII(mu-OR)MnIII(mu-OR)2MnIII(mu-OR)MnII]6+ core consisting of a planar zig-zag array of the four metal ions. Peripheral ligation is provided by two 2.111 (py)2CNO-, two 2.11 PhCO2- and two terminal Br- ligands. The overall molecular structure 5 of is very similar to that of 2-4 except for the X- being chelating NO3-. A tentative reaction scheme was proposed that explains the observed oxime transformation and nitrate generation. The CF3CO2- ligand is one of the decomposition products of the hfac- ligand. The two Mn(II) ions are bridged by two neutral (py)2CNOH ligands which adopt the 2.0111 coordination mode. A chelating hfac- ligand and a terminal CF3CO2- ion complete a distorted octahedral geometry at each metal ion. The CV of complex reveals irreversible reduction and oxidation processes. Variable-temperature magnetic susceptibility studies in the 2-300 K range for the representative tetranuclear clusters 2 and 4 reveal weak antiferromagnetic exchange interactions, leading to non-magnetic ST = 0 ground states. Best-fit parameters obtained by means of the program CLUMAG and applying the appropriate Hamiltonian are J(Mn(II)Mn((III))=-1.7 (2), -1.5 (4) cm(-1) and J(Mn(III)Mn(III))=-3.0 (2, 4) cm(-1).

Synthesis and characterization of copper(I) halide complexes with heterocyclic thiones and triphenylphosphine as ligands. The X-ray crystal structure of copper(I) 1-methyl-1,3-imidazoline-2-thione bis(triphenylphosphine)bromide, [Cu(PPh3)2-meimtH)Br]

Abstract Following our earlier reports on copper(I) mixed-ligand complexes with heterocyclic thiones and triphenylphosphine, we now report the isolation of 12 new complexes of the general formula [Cu(PPh3)2(L)X] [L = 1-methyl-1,3-imidazoline-2-thione (meimtH), 5-methyl-2-benz-1,3-imidazoline-2-thione (mebzimtH2), purine-6-thione (pur6SH), quinoline-2-thione (qn2SH) and X = Cl, Br, I], and their characterization by various physico-chemical methods. The crystal structure of the complex [Cu(PPh3)2(meimtH)Br] is also reported. Crystals are prisms, space group P 1 with a = 9.988(3), b = 10.212(2), c = 21.066(5) A, α = 94.86(2), β = 91.70(2), γ = 119.16(2)° and Z = 2. The metal ion has a distorted tetrahedral geometry with bond lengths CuS = 2.375(1), CuBr = 2.509(0), CuP(1) = 2.268(1) and CuP(2) = 2.281(1) A. The structure has been solved by single-crystal X-ray diffraction methods with a final R of 0.0330 for observed reflections with Fo ⩾ 6.0β(Fo).