- Reaction of chlorine with platinum(IV) triamine containing N,N-dimethylethylenediamine. the crystal structure of [Pt{(CH3) 2N(CH2)2NH2}PyCl3] Cl·H2O[Pt{(CH3)2N(CH2) 2NCl}PyCl3], and [Pt{(CH3)2N(CH 2)2NH2...
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Full title: Reaction of chlorine with platinum(IV) triamine containing N,N-dimethylethylenediamine. the crystal structure of [Pt{(CH3) 2N(CH2)2NH2}PyCl3] Cl·H2O[Pt{(CH3)2N(CH2) 2NCl}PyCl3], and [Pt{(CH3)2N(CH 2)2NH2}PyCl4]. The Platinum(II) diamine with N,N-dimethylethylenediamine (N,N-dimeEn) [Pt{(CH3)2N(CH2)2NH 2}Cl2] (I) was synthesized. The reaction of the diamine with pyridine gave Pt(II) tetramine [Pt{(CH3)2N(CH 2)2NH2}Py2]Cl2 (II), which was oxidized with chlorine to give Pt(IV) triamine Pt{[(CH 3)2N(CH2)2}PyCl3]Cl ? H2O (III). The reaction of III with chlorine (chloroamidation) yielded chloroimide [Pt{(CH3)2N(CH2) 2NCl}PyCl3] (IV). The IR spectra of complexes I-IV and UV/Vis spectra of III and IV were studied. X-Ray diffraction analysis was performed for III (monoclinic crystals, space group P21/c, a = 7.7437(6), b = 8.1100(7), c = 28.52992(2) A?, β = 93.7280(10)°, Z = 4, R hkl = 0.0420) and IV (orthorhombic crystals, space group Pna21, a = 15.7825(12), b = 7.4447(6), c = 12.3099(6) A?, Z = 4, R hkl = 0.0539). During oxidation of Pt(II) tetramine with chlorine, the pyridine molecule is removed from the cis position relative to the (CH 3)2N group (trans position relative to the NH2 group) of N,N-dimethylethylenediamine. The reaction of chloroimide complex IV with concentrated HCl (dechloroamidation) at 20°C afforded the initial complex III; that at 100°C, gave triamine III together with Pt(IV) diamine [Pt(N,N-dimeEn)Cl4] (V) (monoclinic crystals, space group P2 1/n, a = 7.1278(5), b = 11.5384(8), c = 12.7501(9) A?, β = 93.23(10)°, Z = 4, R hkl = 0.0239).
- Fedotova,Aleksandrov,Kuznetsova
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- Synthesis and reactions of platinum(IV) complexes with sodium ascorbate
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The platinum(IV) complexes [PtCl2(OH)2(N∩N)] (N∩N=en, N,N-dmen, N,N′-dmen) were prepared by oxidation of [PtCl2(N∩N)] with hydrogen peroxide. The complexes were characterized by multinuclea
- Arendse, Malcolm J.,Anderson, Gordon K.,Majola, Raquel N.,Rath, Nigam P.
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- Trend in cytotoxic activity of a series of cis-[APtCl2] (A = ethylenediamine methylated at different positions) complexes
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The study of a series of cis-[APtCl2] complexes (A = ethylenediamine, en, methylated at different positions) was carried out to evaluate the effect of different methyl substitutions on the cytotoxic properties of the resulting derivatives. As expected, differentially methylated complexes were found to differ widely in their cytotoxic effects on human cultured ovarian carcinoma cells (A2780). Molecular mechanics (MM) calculations have been performed to assess the relationship between differential diamine methylation and the repulsive energy of the corresponding complexes when interacting with DNA. Compounds that bind DNA at high energetic cost relative to cisplatin, due to the steric hindrance of additional methyl groups, have shown high values for IC50 (concentration inhibiting tumour cell growth by 50%). Semi-quantitative analyses with a DNA electrochemical biosensor confirm that the interaction between cis-[APtCl2] complexes and ds-DNA deposed onto the electrode is stronger for the non-methylated derivative with respect to the fully methylated congener. In addition, MM calculations were used to investigate the interactions between DNA and cis-[(P-L-A)PtCl2] complexes [A = en group linked to an antiestrogen-like pharmacophore, P, via a -(CH2)n- spacer (n = 2, 4, 6, 8 and 10), L].
- Milanesio, Marco,Monti, Elena,Gariboldi, Marzia Bruna,Gabano, Elisabetta,Ravera, Mauro,Osella, Domenico
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p. 2803 - 2814
(2009/02/03)
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- Stereospecific hydrogen-bonding in mononucleotide adducts of platinum anticancer complexes in aqueous solution
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The ammine and amine N-H 1H NMR resonances of Pt(II) complexes containing 5′-phosphate derivatives of nucleobases undergo significant low-field shifts in aqueous solution consistent with stereospecific H-bonding between Pt-NH protons and cis nucleotide 5′-phosphate groups. The effects are strongest for NH protons held rigidly in a chelate ring (ethylenediamine, en, complexes), when the phosphate is fully deprotonated, and when rotation about Pt-N7 (head-to-tail isomerism) is slow, as in [Pt(en)(5′-AMP-N7)2]2+. The temperature dependences of Pt-NH 1H NMR resonances for these complexes are low (3| ppm K-1) but not simply diagnostic of H-bonding. The nucleobase complexes investigated were cis-[Pt(X)(Y)(15NH3)(15NH2CH 3)]2+, [Pt(15N-en)(X)(Y)]2+, and [Pt(N,N-Me2-en)(X)(Y)]2+ where X = Y = 5′-GMP, 5×-dGMP, 3×-GMP, G, 5×-AMP, or 3×-AMP or Y = Cl or H2O. Data for the complexes trans-[Pt(X)(Y)(NH3)2]n+, X, Y = 5′-GMP, Cl, H2O are reported for comparison with the cis analogues, and the shifts are rationalized in terms of cis and trans influences.
- Berners-Price, Susan J.,Frey, Urban,Ranford, John D.,Sadler, Peter J.
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p. 8649 - 8659
(2007/10/02)
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- Atom-transfer and outer-sphere reductions of platinum(IV) complexes. A comparative kinetic investigation
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Reductions of platinum(IV) complexes of the type (N-N=en, meen, dmen, tmen, 1,2-pn, 1,3-pn) by FeCp2, Bu4NI and (ClO4)2 in the presence of Et4NCl have been kinetically investigated in methanol solution.The reactions with FeCp2 or Bu4NI obey e second-order rate law reductant), whereas the rate law for the reactions with (ClO4)2 in the presence of Et4NCl is: rate = Pt(II)+kPt(II)->2+4>.The reactivity of the complexes is enhanced by an increased steric hindrance of the N-N ligand.Such a reactivity trend is likely to be related to a parallel increased thermodynamic tendency of platinum(IV) towards reduction.The effect of steric hindrance on the rate is less pronounced in the reaction with 2+ probably due to a direct interaction between the N-N and the NH2Et ligands in the activated complex
- Peloso, Arnaldo,Mohamud, Sacid Issa
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p. 349 - 354
(2007/10/02)
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