- DNA binding studies of a series of cis-[Pt(Am)2X2] complexes (Am = inert amine, X = labile carboxylato ligand)
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A series of platinum(II) complexes of formulae cis-[Pt(Am) 2X2] (where Am represents an inert amine and X a labile (carboxylato) ligand) have been prepared and characterized by elemental analysis, ESI-MS, IR and 1H NMR spectroscopy. The single-crystal molecular structures were determined for cis-[Pt(opea)(cbdca-2H)], cis-[Pt(hmpy)(cbdca-2H)], cis-[Pt(NH3)2(bzmal-2H)] and cis-[Pt(hmpy)(μ-dcch-2H)2] (where opea is picolylamine, hmpy represents 4-hydroxymethylpyridine, cbdca-2H, is 1,1-cyclobutanedicarboxylate anion, bzmal-2H stands for benzylmalonate anion and dcch-2H is trans-1,2-cyclohexanedicarboxylate anion). The interaction of all compounds with DNA was investigated with different techniques: viscosity measurements and emission fluorescence spectroscopy were used to investigate the changes induced by the binding of the platinum compounds to calf-thymus DNA, while atomic force microscopy and electrophoretic mobility allowed evaluating the potential alterations of pBR322 plasmid DNA. The cytotoxic behavior of the platinum compounds on human leukemia HL-60 tumor cell lines was also examined.
- Escribano, Esther,Font-Bardia, Mercè,Calvet, Teresa,Lorenzo, Julia,Gamez, Patrick,Moreno, Virtudes
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- Synthesis, multinuclear magnetic resonance and crystal structures of Pt(II) complexes containing amines and bidentate carboxylate ligands
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A novel synthetic method for the synthesis of the complexes cis-Pt(amine)2R(COO)2 is compared to two other methods involving the use of either barium dicarboxylate or sodium carboxylate. Pt(II) compounds with monodentate and bidentate amines were studied. The reaction involves the use of a silver dicarboxylato complex, which is the intermediate in the new synthetic procedure. The crystal structure of the silver intermediate with the ligand 1,1-cyclobutanedicarboxylate (1,1-CBDCA) was determined by X-ray diffraction. The crystal Ag2(1,1-CBDCA) has a very interesting 3-D extended structure. The complexes cis-Pt(amine)2R(COO)2 were studied in solution by multinuclear (1H, 13C and 195Pt) magnetic resonance spectroscopy, but the solubilities are very low. D2O was found to be the best solvent. In 195Pt NMR, the complexes containing bidentate amines forming five-membered chelates were observed at higher fields than those containing monodentate amines. The resonances of the NH3 compounds were also found at lower fields than the primary amine complexes. All the dicarboxylato ligands form six-membered chelates except 1,2-CBDCA, whose Pt(II) compounds were observed at lower fields than the others. The crystal structures of Pt(en)(1,1-CBDCA), Pt(Meen)(1,1-CBDCA) and Pt(en)(benzylmalonato) were confirmed by X-ray diffraction methods. Several compounds are disordered. The crystals are stabilized by intermolecular hydrogen bonds between the -NH2 groups and the carboxylato O atoms.
- Rochon, Fernande D.,Massarweh, Gassan
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p. 4095 - 4104
(2008/10/09)
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- Synthesis and characterization of Pt(II) complexes with amine and carboxylato ligands. Crystal structure of (1,1-cyclobutanedicarboxylato)di(ethylamine)platinum(II)·H2O
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Two methods for the synthesis of compounds of the type cis-PtA2X2 (A2 = bidentate amine or two monodentate amines and X2 = bidentate or two monodentate carboxylato ligands) were evaluated. The compounds were characterized by multinuclear NMR and IR spectroscopies. The 195PT NMR chemical shifts were in the range - 1615 to - 1976 ppm, the higher field values corresponding to the complexes containing bidentate ligands. The coupling constants 3J(195Pt-1H) are approximately 35 Hz, while the 2J(195Pt-1HN) are about 70 Hz. One coupling constant 2J(195Pt-13C) (53 Hz) was also measured. The crystal structure of the compound, cis-Pt(1,1-cyclobutanedicarboxylato)(C2H5NH2)2·H2O belongs to the P21/n space group with a=9.468(5), b =9.365(4), c = 16.473(7) A?, β = 105.08(3)°, Z = 4 and R1 = 0.0576. The Pt-N bond distances are 1.992(5) and 2.020(5) A?, while the Pt-O bonds are 2.000(4) and 2.015(4) A?. The molecules are held together by intermolecular H-bonds involving the lattice water molecules and the two free carbonyl O atoms and between the amino H atoms and the Pt-bonded C-O groups. (C) 2000 Elsevier Science S.A.
- Rochon, Fernande D.,Gruia, Letitia M.
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p. 193 - 204
(2008/10/08)
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