Three new copper(II) complexes of formula [Cu(Memal)(H2O)]n (1), [Cu2(pyz)(Memal)2] (2) and [Cu2(4,4′-bpy)(Memal)2(H2O)2] (3) (Memal = methylmalonate, pyz = pyrazine and 4,4′-bpy = 4,4′-bipyridine) were obtained and structurally characterized by X-ray diffraction. Complex 1 is a square grid of aquacopper(II) units which are linked by carboxylate-methylmalonate groups in the anti–syn (equatorial–equatorial) coordination mode. The crystal structures of 2 and 3 consist of corrugated layers of copper(II) (2) and aquacopper(II) (3) units with intralayer carboxylate-methylmalonate bridges in the anti–syn (equatorial–apical) coordination mode which are linked through pyrazine (2) and 4,4′-bipyridine (3) ligands; to build up a 3-D network. Magnetic susceptibility measurements of complexes 1–3 in the temperature range 2–300 K show the occurrence of an overall ferromagnetic behaviour with a weak intralayer ferromagnetic coupling (J = +1.61(1) cm−1) in 1 whereas two opposite magnetic interactions occur in 2 and 3, one ferromagnetic through the anti–syn carboxylate (2 and 3) and the other antiferromagnetic through pyz (2) and 4,4′-bpy) (3).

Crystal engineering of 3-D coordination polymers by pillaring ferromagnetic copper(II)-methylmalonate layers

Characterization and DNA interaction of the Pt(II)(pq)(bdt) complex: A theoretical and experimental research

Synthesis, characterization, DFT studies and DNA binding of mixed platinum (II) complexes containing quinoxaline and 1,2-dithiolate ligands.

A dinuclear palladium-based complex (Pd(2) -Spm) was synthesized and compared with cisplatin (cDDP) on two different human breast cancer cell lines (MCF-7 and MDA-MB-231) as well as toward an untransformed cell line (BJ fibroblasts). The results obtained show that Pd(2) -Spm is more effective against the estrogen receptors [ER(-)] cell line MDA-MB-231, while cDDP displayed better results for the ER(+) MCF-7 cell line. It was shown that, like cDDP, Pd(2) -Spm triggers phosphorylation of H2AX, indicating that this compound damages DNA. Apart from DNA, Pd(2) -Spm also targets the cytoskeleton having a greater impact on cell morphology than cDDP. Pd(2) -Spm and cDDP have opposite antiproliferative activities in the presence of the PI3K inhibitor wortmannin. Furthermore, Pd(2) -Spm at an optimized concentration displays a rapid antiproliferative effect as opposed to cDDP, which seems to have a slower kinetics. The results point to a distinct mechanism of action for each of these complexes, which may explain their synergistic action when coadministrated.

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Biologic activity of a dinuclear Pd(II)-spermine complex toward human breast cancer.

The synthesis, crystal structure and variable-temperature magnetic measurements of compounds [M 2 (μ-Hade) 2 (μ-mal) 2 -(H 2 O) 2 ]•2H 2 O [M = Ni (1), Co (2)], [Co 2 (μ-Hade 2 (μ-mal) 2 -(H 2 O) 2] (3), {(H 2 ade) 2 [Cu(μ-mal) 2 ]•2H 2 O} n (4) and (H 2 ade) 2 -[Cu(mmal) 2 (H 2 0)] (5; H 2 ade = adeninium, Hade = adenine, mal = malonato, mmal = methylmalonato) are reported. Compounds 1-3 contain neutral paddle-wheel [M 2 ( μ -Hade) 2 ( μ -mal) 2 (H 2 O) 2 ] [M = Ni (1), Co (2 and 3)] units where the 7H-tautomeric form of the nucleobase and the malonate dianion act as μ-KN3:KN9 and μ-K 2 O1,O2:κO1 bridging ligands, respectively. The supramolecular crystal structures of 1-3 are essentially maintained by hydrogen-bonding interactions involving the nucleobases, the carboxylate groups and crystallisation water molecules (in compounds 1 and 2). Compounds 4 and 5 show a hybrid inorganic-organic lamellar structure containing layers of anionic metal-malonato complexes and supramolecular aggregates of the 1H,9H-adeninium cation. Their overall three-dimensional architectures are controlled, in addition to electrostatic forces, by supramolecular recognition processes between the inorganic and organic frameworks. Compound 4 contains one-dimensional anionic copper-malonato chains in which the copper atoms are doubly bridged by μ-K 2 O1 ,O2:KO2' malonato ligands and the cationic nucleobases form dimeric entities sustained by Hoogsteen-Hoogsteen hydrogen-bonding interactions. Compound 5 is built up of anionic [Cu(mmal) 2 (H 2 O)] 2- monomeric entities and planar, hydrogen-bonded, one-dimensional, ribbon-like aggregates of protonated adenine. Variable-temperature magnetic susceptibility measurements of compounds 1-4 show the preponderance of ferromagnetic interactions between the paramagnetic centres. DFT calculations have been performed to evaluate the magnetic behaviour of these compounds and to analyze the interaction between two adeninium cations in compound 4.

http://www.ehu.eus/proman/documents/20090828PerezSonia-5AdenineMetalMalonatoComplexes2009EURJIC26-3889-3899.pdf

Analysis of the Interaction between Adenine Nucleobase and Metal-Malonato Complexes

Synthesis, characterization, solution equilibria and DNA binding of some mixed-ligand palladium(II) complexes. Thermodynamic models for carboplatin drug and analogous compounds

The formation of complexes of Zn(II), Cd(II), Hg(II), and Pb(II) and N-carboxymethyl-D,L-threonine (H2CMT, H2L) in aqueous solutions has been studied by spectrophotometric and potentiometric methods. The complexation model for each system has been established by the HYPERQUAD program from the potentiometric data. Three different behaviors are found: ML2H, MLH, ML, MLOH, and ML2 complexes are formed by Zn(II) and Cd(II) ions, ML2H, ML, MLOH, and ML2 are formed by Hg(II) ion, and only 1/1 complexes MLH, ML, and MLOH are formed by the Pb(II) ion. The formation constants determined for all these complexes allow simulation of experimental titration curves with good agreement. The speciation of multimetal systems with H2CMT shows that this compound is a good and selective ligand at low pH for the Hg(II) ion.

M. A. Sanjuan

Papers

Synthesis, characterization, solution equilibria and DNA binding of some mixed-ligand palladium(II) complexes. Thermodynamic models for carboplatin drug and analogous compounds

Zinc(II), Cadmium(II), Mercury(II), and Lead(II) Complexes of N-Carboxymethyl-D,L-threonine in Aqueous Solution