- A Pt(IV)-based mononitro-naphthalimide conjugate with minimized side-effects targeting DNA damage response via a dual-DNA-damage approach to overcome cisplatin resistance
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Platinum(Pt)(II) drugs and new Pt(IV) agents behave the dysregulation of apoptosis as the result of DNA damage repair and thus, are less effective in the treatment of resistant tumors. Herein, mononitro-naphthalimide Pt(IV) complex 10b with minimized side-effects was reported targeting DNA damage response via a dual-DNA-damage approach to overcome cisplatin resistance. 10b displayed remarkably evaluated antitumor (70.10percent) activities in vivo compared to that of cisplatin (52.88percent). The highest fold increase (FI) (5.08) for A549cisR cells and the lowest (0.72) for A549 indicated 10b preferentially accumulated in resistant cell lines. The possible molecular mechanism indicates that 10b targets resistant cells in a totally different way from the existing Pt drugs. The cell accumulation and the Pt levels in genomic DNA from 10b is almost 5 folds higher than that of cisplatin and oxaliplatin, indicating the naphthalimide moiety in 10b exhibits preferentially DNA damage. Using 5′-dGMP as a DNA model, the DNA-binding properties of 10b (1 mM) with 5′-dGMP (3 mM) in the presence of ascorbic acid (5 mM) deduced that 10b was generated by the combination of cisplatin with 5′-dGMP after reduction by ascorbic acid. Moreover, 10b promoted the expression of p53 gene and protein more effectively than cisplatin, leading to the increased anticancer activity. The up-regulated γH2A.X and down-regulated RAD51 indicates that 10b not only induced severe DNA damage but also inhibited the DNA damage repair, thus resulting in its higher cytotoxicity in comparison to that of cisplatin. Their preferential accumulation in cancer cells (SMMC-7721) compared to the matched normal cells (HL-7702 cells) demonstrated that they were potentially safe for clinical therapeutic use. In addition, the higher therapeutic indices of 10b for 4T1 cells in vivo indicated that naphthalimide-Pt(IV) conjugates behaved a vital function in the treatment of breast cancer. For the first time, our study implies a significant strategy for Pt drugs to treat resistance cancer targeting DNA damage repair via dual DNA damage mechanism in a totally new field.
- Li, Linrong,Li, Yingguang,Liu, Hanfang,Ma, Jing,Niu, Jie,Xie, Songqiang,Yue, Kexin
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- Solid-Phase Reaction of Tetraammineplatinum(II) Chloride with Ammonium Heptamolybdate
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Abstract: The solid-phase reaction of [Pt(NH3)4]Cl2 and (NH4)6Mo7O24 under argon in the temperature range from 50 to 500°C was studied by thermal analysis and mass spectrometry.
- Buslaeva, T. M.,Fesik, E. V.,Melnikova, T. I.,Tarasova, L. S.
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p. 1020 - 1024
(2020/07/27)
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- trans-Platinum(iv) pro-drugs that exhibit unusual resistance to reduction by endogenous reductants and blood serum but are rapidly activated inside cells:1H NMR and XANES spectroscopy study
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Recent results have confirmed that protection of transplatin from reactions on the path to cancer cells substantially increases their activity, suggesting that such complexes have greater potential than previously thought. In this study we have investigated the use of the platinum(iv) oxidation state and the tetracarboxylate coordination sphere to determine whether these features could impart the same stability totrans-diammineplatinum complexes that they do tocis-diam(m)ineplatinum complexes. Theciscomplexes exhibit resistance to reduction byl-ascorbate and human blood serum, but are readily reduced inside cancer cells. Studies of reduction monitored by1H NMR revealed that oxidation oftrans-diammineplatinum(ii) complexes does not always result in significant stabilisation, but the complexestrans, trans, trans-[Pt(OAc)4(NH3)2] (OAc = acetate) andtrans, trans, trans-[Pt(OPr)2(OAc)2(NH3)2] (OPr = propionate) exhibit second order half-lives of 33 h and 5.9 days respectively in the presence of a ten-fold excess ofl-ascorbate. XANES spectroscopy studies of reduction in blood models showed thattrans, trans, trans-[Pt(OAc)4(NH3)2] is stable in blood serum for at least 24 hours, but is reduced rapidly in whole blood and was observed to have a half-life of approximately 4 hours in DLD-1 colon cancer cells. Consequently, the tetracarboxylatoplatinum(iv) moiety has the properties required to enable the delivery oftrans-diammine platinum complexes to cancer cells.
- Chen, Catherine K. J.,Gibson, Dan,Hambley, Trevor W.,Kappen, Peter
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supporting information
p. 7722 - 7736
(2020/06/26)
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- Nucleolar Stress Induction by Oxaliplatin and Derivatives
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Platinum(II) compounds are a critical class of chemotherapeutic agents. Recent studies have highlighted the ability of a subset of Pt(II) compounds, including oxaliplatin but not cisplatin, to induce cytotoxicity via nucleolar stress rather than a canonical DNA damage response. In this study, influential properties of Pt(II) compounds were investigated using redistribution of nucleophosmin (NPM1) as a marker of nucleolar stress. NPM1 assays were coupled to calculated and measured properties such as compound size and hydrophobicity. The oxalate leaving group of oxaliplatin is not required for NPM1 redistribution. Interestingly, although changes in diaminocyclohexane (DACH) ligand ring size and aromaticity can be tolerated, ring orientation appears important for stress induction. The specificity of ligand requirements provides insight into the striking ability of only certain Pt(II) compounds to activate nucleolar processes.
- Sutton, Emily C.,Mcdevitt, Christine E.,Prochnau, Jack Y.,Yglesias, Matthew V.,Mroz, Austin M.,Yang, Min Chieh,Cunningham, Rachael M.,Hendon, Christopher H.,Derose, Victoria J.
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supporting information
p. 18411 - 18415
(2019/11/19)
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- Development of an Efficient Dual-Action GST-Inhibiting Anticancer Platinum(IV) Prodrug
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The cytotoxicity of cisplatin (cDDP) is enhanced when co-administered with ethacrynic acid (EA), a glutathione S-transferase (GST) inhibitor. A PtIV–EA conjugate containing a cDDP core and two axial ethacrynate ligands (compound 1) was shown to be an excellent inhibitor of GST, but did not readily release a PtII species to exert a synergistic cytotoxic effect. In this study, a redesigned PtIV construct composed of a cDDP core with one axial ethacrynate ligand and one axial hydroxido ligand (compound 2) was prepared and shown to overcome the limitations of compound 1. The EA ligand in 2 is readily released in vitro together with a cytotoxic PtII species derived from cisplatin, working together to inhibit cell proliferation in cDDP-resistant human ovarian cancer cells. The in vitro activity translates well in vivo with 2, showing effective (~80 %) inhibition of tumor growth in a human ovarian carcinoma A2780 tumor model, while showing considerably lower toxicity than cisplatin, thus validating the new design strategy.
- Lee, Keefe Guang Zhi,Babak, Maria V.,Weiss, Andrea,Dyson, Paul J.,Nowak-Sliwinska, Patrycja,Montagner, Diego,Ang, Wee Han
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p. 1210 - 1217
(2018/06/04)
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- Coordination-drIVen self-assembly of a Pt(IV) prodrug-conjugated supramolecular hexagon
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This article presents a new strategy to engage coordination-driven self-assembly for platinum drug delivery. The self-assembled supramolecular hexagon is conjugated with three equivalents of Pt(iv) prodrugs and displays a superior therapeutic index compared to cisplatin against a panel of human cancer cell lines.
- Yue, Zhizhou,Wang, Han,Li, Yiming,Qin, Yi,Xu, Lin,Bowers, David J.,Gangoda, Mahinda,Li, Xiaopeng,Yang, Hai-Bo,Zheng, Yao-Rong
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supporting information
p. 731 - 734
(2018/02/06)
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- The effect of geometric isomerism on the anticancer activity of the monofunctional platinum complex: Trans -[Pt(NH3)2(phenanthridine)Cl]NO3
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A trans-DDP based monofunctional phenanthridine Pt(ii) complex was synthesized and characterized. Its anticancer activity was studied in vitro on a panel of human cancer cell lines and mouse intestinal cancer organoids. This complex displays significant antitumor properties, with a different spectrum of activity than that of classic bifunctional cross-linking agents like cisplatin.
- Zhou, Wen,Almeqdadi, Mohammad,Xifaras, Michael E.,Riddell, Imogen A.,Yilmaz, ?mer H.,Lippard, Stephen J.
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supporting information
p. 2788 - 2791
(2018/03/21)
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- Reduction of Cisplatin and Carboplatin Pt(IV) Prodrugs by Homocysteine: Kinetic and Mechanistic Investigations
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Pt(IV) anticancer active complexes are commonly regarded as prodrugs, and the reduction of the prodrugs to their Pt(II) analogs is the activation process. The reduction of a cisplatin prodrug cis-[Pt(NH3)2Cl4] and a carboplatin prodrug cis,trans-[Pt(cbdca)(NH3)2Cl2] by dl-homocysteine (Hcy) has been investigated kinetically in a wide pH range in this work. The reduction process follows overall second-order kinetics: ?d[Pt(IV)]/dt = k′[Hcy]tot[Pt(IV)], where [Hcy]tot stands for the total concentration of Hcy and k′ pertains to the observed second-order rate constants. The k′ versus pH profiles have been established for both prodrugs. Spectrohotometric titrations reveal a stoichiometry of Δ[Pt(IV)]:Δ[Hcy]tot = 1:2; homocystine is identified as the major oxidation product of Hcy by high-resolution mass spectrometry. A reaction mechanism has been proposed, which involves all the four protolysis species of Hcy attacking the Pt(IV) prodrugs in parallel. Moreover, these parallel attacks are the rate-determining steps, resulting in a Cl+ transfer from the Pt(IV) prodrugs to the attacking sulfur atom. Rate constants of the rate-determining steps have been derived, indicating that the two prodrugs are reduced with a very similar rate in spite of the difference between the coordination ligands in their equatorial positions. The reactivity analysis in the case of cis,trans-[Pt(cbdca)(NH3)2Cl2] unravels that one species of Hcy (form III) is almost exclusively responsible for the reductions at the physiological pH (7.4), although it is existing only 5.2% of the total Hcy. On the other hand, the dominant existing form II of Hcy virtually does not make a contribution to the overall reactivity at pH 7.4.
- Tian, Hongwu,Dong, Jingran,Chi, Xueru,Xu, Liyao,Shi, Hongmei,Shi, Tiesheng
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supporting information
p. 681 - 689
(2017/08/01)
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- Characterization of the mechanism of reduction of trans-diamminetetrachloroplatinum(IV) by l-cysteine and dl-homocysteine
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The interactions between Pt(IV) anticancer prodrugs incorporating two ammines/amines in trans positions in their equatorial planes and some important thiols have not been exploited to date. In this work, the reduction of one such Pt(IV) prodrug, namely trans-[Pt(NH3)2Cl4], by two thiol-containing amino acids l-cysteine (Cys) and dl-homocysteine (Hcy) which are prevalent in human plasma has been characterized by stopped-flow spectroscopic and ESI high-resolution mass spectral methods. The reduction process obeys overall second-order kinetics. The dependencies of the observed second-order rate constants k′ on pH have been established between pH 4.03 and 11.24. Mass spectral analysis indicates that cystine and homocystine are the dominant products for the Cys and Hcy oxidations, respectively. The suggested reaction mechanism involves all possible protolytic species of Cys/Hcy, which attack one of the two apically coordinated chlorides in parallel (all as rate-determining steps), leading to a Cl+ transfer to the attacking sulfur atom. The rate expression has been derived, and the rate constants for the rate-determining steps have been calculated. Features of the reduction process are discussed based on the obtained rate constants. The overall kinetic and mechanistic picture enables an in-depth understanding of the reduction process of this type of Pt(IV) anticancer prodrug.
- Lu, Taotao,Dong, Jingran,Nan, Chunxia,Huo, Shuying,Shen, Shigang,Sun, Sufang,Shi, Tiesheng
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p. 869 - 875
(2015/10/20)
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- A Keggin-type polyoxotungstate-coordinated diplatinum(II) complex: Synthesis, characterization, and stability of the cis-platinum(II) moieties in dimethylsulfoxide and water
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The synthesis of a Keggin-type polyoxotungstate-coordinated diplatinum(II) complex, [(CH3)4N]3[α-PW 11O39{cis-Pt(NH3)2}2], obtained by reaction of Keggin-type mono-lacunary polyoxotungstate, [α-PW11O39]7-, with cis- diamminedichloroplatinum(II) in an aqueous solution is described. The complex was characterized by elemental analysis, thermogravimetric/differential thermal analysis (TG/DTA), Fourier transform infrared (FTIR), ultraviolet-visible (UV-vis), and solution 1H, 31P, and 183W nuclear magnetic resonance (NMR) spectroscopy. The two cis-platinum(II) moieties, [cis-Pt(NH3)2]2+, were coordinated each to two oxygen atoms in a mono-vacant site of [α-PW11O 39]7- with Cs symmetry, and the cis-conformation was highly stable in dimethylsulfoxide and water.
- Kato, Masao,Kato, Chika Nozaki
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p. 982 - 985
(2011/08/05)
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- Conversion of Magnus salt into diamminedichloroplatinum(II) isomers in aqueous solution
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The conditions inducing conversion of Magnus salt into diamminedichloroplatinum(II) isomers were studied. Syntheses of cis-diamminedichloroplatinum(II) and trans-diamminedichloroplatinum(II), which are used to prepare potassium or ammonium amminetrichloroplatinate(II), are described. The identity and structure of diamminedichloroplatinum(II) isomers were verified by elemental analysis, X-ray powder diffraction, and IR and UV spectroscopy. A workflow for preparing potassium or ammonium amminetrichloroplatinate(II) from diamminedichloroplatinum(II) isomers was developed. This workflow appreciably increases the product yield due to the return of unused Magnus salt to the main synthesis flow.
- Starkov,Kozhukhovskaya
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p. 1426 - 1429
(2009/05/06)
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- Synthesis of the isomers of dichlorodiammineplatinum(II) from the magnus salt
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The synthesis of the isomers of dichlorodiammineplatinum (II) from the Magnus salt is described. The Magnus salt is added to an aqueous solution of ammonium acetate. The reaction mixture is heated for an hour and then cooled. hydrochloric acid is added an
- Starkov,Kazbanov,Kozhukhovskaya,Olado
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p. 692 - 692
(2008/10/09)
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- Coordination complexes, and methods for preparing by combinatorial methods, assaying and using the same
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The present invention provides novel coordination complexes, methods for synthesizing and identifying coordination complexes using combinatorial techniques, and assaying for their activity. In certain embodiments, the subject coordination complexes contain platinum,
- -
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Page/Page column 52
(2010/02/08)
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- Kinetics and mechanism for reduction of halo- and haloam(m)ine platinum(IV) complexes by L-ascorbate
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Reduction of the model platinum(IV) complexes cis-[PtCl4(NH3)2] (1), trans-[PtCl4(NH3)2] (2), trans-[PtCl2(en)2]2+ (3), trans-[PtBr2(NH3)4]2+ (4), [PtCl6]2- (5), and [PtBr6]2- (6) with L-ascorbic acid (H2Asc) in 1.0 M aqueous medium at 25°C in the region 1.75≤pH≤7.20 has been investigated using stopped-flow spectrophotometry. The redox reactions follow the rate law: -d[Pt(IV]/dt=k[H2Asc]tot[Pt(IV)] where k is a pH-dependent second-order rate constant and [H2Asc]tot, the total concentration of ascorbic acid. The pH-dependence of k is attributed to parallel reduction of Pt(IV) by the protolytic species HAsc- and Asc2-. Analysis of the kinetics data reveals that the ascorbate anion Asc2- is up to seven orders of magnitude more reactive than HAsc- while H2Asc is unreactive. Electron transfer from HAsc-/Asc2- to the Pt(IV) compounds is suggested to take place by a mechanism involving a reductive attack on any one of the mutually trans-halide ligands by Asc2- and/or HAsc- forming a halide-bridged activated complex. The rapid reduction of these complexes supports the assumption that ascorbate Asc2- might be an important reductant at physiological conditions for anticancer active Pt(IV) pro-drugs capable of undergoing reductive trans elimination. The parameters ΔH≠ and ΔS≠ for reduction of Pt(IV) with Asc2- have been determined from the study of the temperature dependence of k.
- Lemma, Kelemu,House, Donald A.,Retta, Negussie,Elding, Lars I.
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- Synthesis, characterization, and reactivity of trans-[PtCl(R′R″SO)(A)2]NO3 (R′R″SO = ME2SO, MeBzSO, MePhSO; A = NH3, py, pic). Crystal structure of trans-[PtCl(Me2SO)(py)2]+
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Trans complexes such as trans-[PtCl2(NH3)2] have historically been considered therapeutically inactive. The use of planar ligands such as pyridine greatly enhances the cytotoxicity of the trans geometry. The complexes trans-[PtCl(R′R″SO)(A)2]NO3 (R′R″SO = substituted sulfoxides such as dimethyl (Me2SO), methyl benzyl (MeBzSO), and methyl phenyl sulfoxide (MePhSO) and A = NH3, pyridine (py) and 4-methylpyridine or picoline (pic)) were prepared for comparison of the chemical reactivity between ammine and pyridine ligands. The X-ray crystal structure determination for trans-[PtCl(Me2SO)(py)2]NO3 confirmed the geometry with S-bound Me2SO. The crystals are orthorhombic, space group P212121, with cell dimensions a = 7.888(2) A, b = 14.740(3) A, c = 15.626(5) A, and Z = 4. The geometry around the platinum atom is square planar with l(Pt-Cl) = 2.304(4) A, l(Pt-S) = 2.218(5) A and l(Pt-N) = 2.03(1) and 2.02(1) A. Bond angles are normal with Cl-Pt-S = 177.9(2)°, Cl-Pt-N1 = 88.0(4)°, Cl-Pt-N2 = 89.3(5)°, S-Pt-N1 = 93.8(4)°, S-Pt-N2 = 88.9(4)°, and N1-Pt-N2 = 177.2(6)°. The intensity data were collected with Mo Kα radiation with a λ = 0.710 69 A. Refinement was by full-matrix least-squares methods to a final R value of 3.80%. Unlike trans-[PtCl2(NH3)2], trans-[PtCl2(A)2] (A = py or pic) complexes do not react with Me2SO. The solvolytic products of cis-[PtCl2(A)2] (A = py or pic) were characterized. Studies of displacement of the sulfoxide by chloride were performed using HPLC. The sulfoxide was displaced faster for the pyridine complex relative to the ammine complex. Chemical studies comparing the reactivity of trans-[PtCl(R′R″SO)(amine)2]NO3 with a model nucleotide, guanosine 5′-monophosphate (GMP), showed that the reaction gave two principal products: the species [Pt(R′R″SO)(amine)2(N7-GMP)], which reacts with a second equivalent of GMP, forming [Pt(amine)2(N7- GMP)2]. The reaction pathways were different, however, for the pyridine complexes in comparison to the NH3 species, with sulfoxide displacement again being significantly faster for the pyridine case.
- Fontes,Oskarsson,Loevqvist,Farrell
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p. 1745 - 1750
(2008/10/08)
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- Uracil quartet formation through non-covalent interaction with a neutral metal ammine complex
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Cocrystallization of 1-methyluracil (Hmura) and trans[PtCl4(NH3)2] yields an adduct of composition [PtCl4(NH3)2·2 Hmura with two types of uracil quartets, one of which is relevant to that formed in tetraplex RNA.
- Witkowski, Holger,Freisinger, Eva,Lippert, Bernhard
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p. 1315 - 1316
(2007/10/03)
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- Conversion of Acetonitrile into Acetamide in the Co-ordination Spheres of cis- and trans-M(II)(amine)2 (M = Pt or Pd). Solution and Crystal Structural Studies
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The preparation and solution behaviour of mono- and bis-acetonitrile complexes of cis, (en = ethane-1,2-diamine) and trans- has been investigated.The nitrile complexes are hydrolysed to acetamidate, acetamidate-bridged and mixed acetamidate-acetonitrile species.It is shown that an essential feature of monomeric acetamidate complexes with cis configuration is their tendency to dimerize to dinuclear platinum compounds having bridging amidate ligands.The resulting dimers undergo a facile head-to-tail to head-to-head rearrangement without any detectable intermediate.Solution studies of the mononitrile complex trans-(1+) at around neutral pH reveal the formation of trans-(1+), suggesting a preceding ligand exchange.The reactions of platinum with MeCN are compared with those of the kinetically labile palladium.The nitrile complex cis-ClO4 and the mixed-ligand complex trans-ClO4 were characterized by X-ray crystallography: cis-ClO4, monoclinic, space group P21/c, a = 10.618(10), b = 10.625(8), c = 9.176(7) Angstroem, β = 111.20(6) deg, Z = 4; trans-ClO4, monoclinic, space group P21/c, a = 8.601(6), b = 19.508(19), c = 7.625(4) Angstroem, β = 115.29(5) deg, Z = 4.
- Erxleben, Andrea,Mutikainen, Ilpo,Lippert, Bernhard
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p. 3667 - 3676
(2007/10/02)
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- EFFECTS OF THE FOUR IN-PLANE LIGANDS ON THE RATES OF INNER-SPHERE OXIDATION REACTIONS OF TETRAAMINE- AND DIAMMINEDIAMINEPLATINUM(II) COMPLEXES
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The oxidation reactions of platinum(II) complexes of the type trans and/or cis-(2+) (R = Me, Et, Prn, Pri, Bui, Bus, CH2But, CH2Ph, C6H11cyclo) and (2+) (R = H, Me, Et, Prn) by trans- in the presence of chloride ions have been kinetically investigated in aqueous solution.The reactions obey a third-order rate law: Rate = k3.The rates are sensitive to changes of the ligands in such a way that the overall steric hindrance of the four in-plane ligands appears to be mainly responsible for the reactivity trend observed.Conversely, the ?-electron donor ability of these ligands appears to play only a minor role in affecting the reactivity of platinum(II) towards oxidation.A roughly linear relationship is found to correlate the activation free energy and the standard free energy of the reactions.
- Peloso, Arnaldo
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p. 625 - 632
(2007/10/02)
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- Effects of Geometric Configuration and Steric Hindrance on Rates and Mechanisms of Oxidation of Diaminedichloroplatinum(II) Complexes by Tetrachloroaurate(III) Ions
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The oxidation reactions of trans- and/or cis- by - in the presence of Cl have been kinetically investigated in acetonitrile (R=H,Me,Et,Prn,Pri,Bun,Bui,Bus,But,CH2But,CH2Ph, or cyclo-C6H11).The rate law for the oxidation of the trans complexes consists mainly of a third-order rate term, kc->->, whereas an additiona rate term, ka->->/(1+kb->), operates in the case of the cis complexes.A reaction scheme is proposed.The oxidation rates of both cis and trans complexes appear to be reduced by increasing the steric hindrance of the amine, cis complexes being more sensitive towards changes of steric hindrance than trans analogues.Approximate linear relationships correlate the reactivities (log k) of both cis and trans complexes with an amine steric hindrance parameter.
- Peloso, Arnaldo
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p. 1285 - 1290
(2007/10/02)
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- Crystal structures of trans-dichloroammine(1-methylcytosine-N3)platinum(II) hemihydrate, PtCl2(NH3)(C5H7N 3O)·1/2H2O, and trans-diamminebis(1-methylcytosine-N3)platinum(II) dinitrate. Evidence for the unexpected lability of NH3 in a cis-diammineplatinum(II) complex
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Two trans-ligand-platinum(II) complexes have been isolated and investigated. trans-Dichloroammine(1-methyl-cytosine-N3)platinum(II) hemihydrate, [Pt(NH3)Cl2(C5H7N 3O)·1/2H2O (A), has the space group C2/c with a = 14.697 (6) A?, b = 6.816 (1) A?, c = 23.225 (4) A?, β = 112.03 (2)°, and eight formula units in the unit cell. trans-Diammine-bis(1-methylcytosine-N3)platinum(II) dinitrate, [Pt(NH3)2(C5H7N3O) 2](NO3)2 (B), has space group P21/c with a = 6.834 (2) A?, b = 10.315 (2) A?, c = 13.349 (3) A?, β = 107.90 (2)°, and two formula units in the unit cell. Data for both compounds were collected with use of Mo Ka radiation and a Syntex P21 diffractometer. Both crystal structures were determined by standard methods. A was refined to R1 = 0.0612 and R2 = 0.0775 on the basis of 2503 independent reflections. The final R1 = 0.0346 and R2 = 0.0410 for B were based on 1687 independent reflections. A has normal bond distances (Pt-Cl = 2.288 (5), 2.296 (5) A?; Pt-N(pyrimidine) = 2.03 (1) A?; Pt-N(ammonia) = 2.04 (1) A?) and angles, and the pyrimidine ring is at an angle of 64° to the ligand square plane. A is formed from chloro-cis-diammine(1-methylcytosine-N3)platinum(II) chloride in aqueous solution at room temperature. A mechanism is proposed for its formation, and possible implications with regard to the binding properties of cis-Pt(NH3)2Cl2 are discussed. B also has normal bond distances (Pt-N(ammonia) = 2.067 (10) A?; Pt-N(pyrimidine) = 2.023 (8) A?) and angles; the pyrimidine-square-plane dihedral angle is larger (78°).
- Lippert,Lock,Speranzini
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p. 808 - 813
(2008/10/08)
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