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1.
《Inorganica chimica acta》1986,124(2):101-114
The Pt L3 X-ray absorption spectra of a series of Pt compounds have been recorded and their extended fine structure (EXAFS) analysed to investigate the sensitivity of EXAFS to non-first-shell PtPt distances. The Pt L3 EXAFS spectra of complexes formed between [(NH3)2Pt(OH)2Pt(NH3)2]2+ and calf thymus DNA were also recorded. PtPt vectors could not be detected in these spectra. When combined with the model compound studies, this result rules out Pt dimer structures for the PtDNA complex which involve rigidly bridged, adjacent Pt atoms. Such structures, based on dimeric bonding of a hydroxo dimer intermediate to DNA, have been proposed as models for cisplatin antitumor activity. These types of models now seem unlikely. 相似文献
2.
Wojciech P. Ozimiński Piotr Garnuszek Jan Cz. Dobrowolski 《Inorganica chimica acta》2007,360(6):1902-1914
The Pt(II) and Pt(IV) complexes with histamine were calculated by using more than 20 DFT functionals and various basis sets. Based on the comparison between the X-ray and theoretical geometrical parameters of the Pt(II)(Hist)Cl2 complex the MPW1PW91, OPW91 and SVWN5 functionals combined with the 6-311G∗∗ basis set for non-metallic and SDD (ECP) basis set for platinum were found to yield the most satisfactory agreement. The structure of the Pt(II) complex with iodohistamine important for pharmacy, so far isolated only in minute amounts, was predicted by using the MPW1PW91 functional. Comparison of the theoretical NMR chemical shifts of the Pt(II)(Hist)Cl2 complex with those found experimentally have shown that the theoretical 1H and 13C NMR chemical shifts are in plausible agreement with the experimental ones, whereas the theoretical 195Pt chemical shifts fit the experimental values only when the relativistic approach is applied within the ZORA formalism. We confirmed suitability of the three selected functionals for reproduction of the experimental structure of Pt complexes at fourth oxidation state by using the cis- and ions as models. Finally, with the selected theoretical methods, the structures and stabilities of four Pt(IV)(Hist)2Cl2 complex isomers were predicted. 相似文献
3.
Gregory J. Grant Andrea M. Goforth William T. Pennington 《Inorganica chimica acta》2004,357(7):2107-2114
The synthesis, spectroscopy, electrochemistry, and crystal structures of two new mononuclear homoleptic Pt(II) and Pd(II) complexes with the crown trithioether 1,5,9-trithiacyclododecane (12S3) are reported. In contrast to behavior with analogous smaller ring trithiacrowns, both metal complexes exhibit exodentate axial sulfur donors, a consequence of the preferred conformation of the 12S3 ligand. The lack of two axial metal-sulfur interactions correlates with the observed electronic spectroscopy and oxidative electrochemistry displayed by the complexes and contrasts with properties exhibited by complexes containing smaller polythioether macrocycles. The two complexes have electronic spectra dominated by charge transfer, not d-d bands and show no M2+/M3+ couples. Both complexes show a fluxional 12S3 ligand in solution due to a 1,5-metallotropic shift, an uncommon observation of this particular type of intramolecular ligand exchange. The 195Pt NMR chemical shift of −4201 ppm for [Pt(12S3)2]2+ is consistent with an alternating positioning of the four sulfur lone pairs on the coordinated thioethers. Although 12S3 is poorly pre-organized for facial complexation, its flexibility to position a sulfur in an exodentate fashion enables it to form stable complexes with d8 metal ions such as Pt(II) and Pd(II). 相似文献
4.
Jean-Pierre Girault Jean-Claude Chottard Eric R. Guittet Jean-Yves Lallemand Tam Huynh-Dinh Jean Igolen 《Biochemical and biophysical research communications》1982,109(4):1157-1163
The stoichiometric reaction between d-TpGpGpCpCpA (d(T-G-G-C-C-A)) and -[Pt(NH3)2(H2O)2](NO3)2 (8.4 × 10?6 to 1.3 × 10?4M in water at pH 5.5–6) gives a single complex. High pressure gel permeation chromatography and pH-dependent 1H NMR analyses of the nonexchangeable base protons, show that it is a platinum chelate with the -PtII(NH3)2 moiety bound to the two N7 atoms of the adjacent guanines. A 3 × 10?3M reaction gives the same platinum chelate, via the formation of intermediate complexes, together with unsoluble adducts. 相似文献
5.
Shi Y Liu SA Kerwood DJ Goodisman J Dabrowiak JC 《Journal of inorganic biochemistry》2012,107(1):6-14
The antitumor effects of platinum(IV) complexes, considered prodrugs for cisplatin, are believed to be due to biological reduction of Pt(IV) to Pt(II), with the reduction products binding to DNA and other cellular targets. In this work we used pBR322 DNA to capture the products of reduction of oxoplatin, c,t,c-[PtCl2(OH)2(NH3)2], 3, and a carboxylate-modified analog, c,t,c-[PtCl2(OH)(O2CCH2CH2CO2H)(NH3)2], 4, by ascorbic acid (AsA) or glutathione (GSH). Since carbonate plays a significant role in the speciation of platinum complexes in solution, we also investigated the effects of carbonate on the reduction/DNA-binding process. In pH 7.4 buffer in the absence of carbonate, both 3 and 4 are reduced by AsA to cisplatin (confirmed using 195Pt NMR), which binds to and unwinds closed circular DNA in a manner consistent with the formation of the well-known 1, 2 intrastrand DNA crosslink. However, when GSH is used as the reducing agent for 3 and 4, 195Pt NMR shows that cisplatin is not produced in the reaction medium. Although the Pt(II) products bind to closed circular DNA, their effect on the mobility of Form I DNA is different from that produced by cisplatin. When physiological carbonate is present in the reduction medium, 13C NMR shows that Pt(II) carbonato complexes form which block or impede platinum binding to DNA. The results of the study vis-à-vis the ability of the Pt(IV) complexes to act as prodrugs for cisplatin are discussed. 相似文献
6.
Timothy C. Johnstone Stephen J. Lippard 《Journal of biological inorganic chemistry》2014,19(4-5):667-674
The Pt(IV) complex c,c,t-[Pt(NH3)2Cl2(OH)2] is an important intermediate in the synthesis of Pt(IV) anticancer prodrugs and has been investigated as an anticancer agent in its own right. An analysis of the vibrational spectroscopy of this molecule was previously reported (Faggiani et al., Can. J. Chem. 60:529, 1982), in which crystallographic determination of the structure of the complex permitted a site group approach. The space group, however, was incorrectly assigned. In the present study we have redetermined at high resolution crystal structures of c,c,t-[Pt(NH3)2Cl2(OH)2] and c,c,t-[Pt(NH3)2Cl2(OH)2]·H2O2, which makes possible discussion of the effect of hydrogen bonding on the N–H and O–H vibrational bands. The correct crystallographic site symmetry of the platinum complex in the c,c,t-[Pt(NH3)2Cl2(OH)2] structure is used to conduct a new vibrational analysis using both group-theoretical and modern density functional theory methods. This analysis reveals the nature and symmetry of the “missing band” described in the original publication and suggests a possible explanation for its disappearance. 相似文献
7.
Pt(II) complexes of the types K[Pt(R2SO)X3], NR4[Pt(R2SO)X3] and Pt(R2SO)2Cl2 (where X = Cl or Br) were characterized by multinuclear magnetic resonance spectroscopy (195Pt, 1H and 13C). In 195Pt NMR, the chloro ionic compounds have shown signals between −2979 and −3106 ppm, while the cis disubstituted complexes were observed at higher fields, between −3450 and −3546 ppm. The signal of the compound trans-Pt(DPrSO)2Cl2 was found at higher field (−3666 ppm) than its cis analogue (−3517 ppm), since π-back-donation is considerably less effective in the trans geometry. In 1H NMR, a single signal was observed for the sulfoxide in [Pt(DMSO)Cl3]−, but for the other more sterically hindered ligands, two series of resonances were observed for the protons in α and β positions. The coupling constant 3J(195Pt-1H) are between 15 and 33 Hz. The 13C NMR results were interpreted in relation to the concept of inversed polarization of the π sulfoxide bond. The 2J(195Pt-13C) values vary between 35 and 66 Hz, while a few 3J(195Pt-13C) couplings were observed (13-26 Hz). The crystal structures of five monosubstituted ionic compounds N(n-Bu)4[Pt(TMSO)Cl3], N(Me)4[Pt(DPrSO)Cl3], K[Pt(EMSO)Cl3], K[Pt(TMSO)Br3] · H2O and N(Et)4[Pt(DPrSO)Br3] and one disubstituted complex cis-Pt(DBuSO)2Cl2 were determined. The trans influence of the different ligands is discussed. 相似文献
8.
Jeroen H.J. den Hartog Hans van den Elst Jan Reedijk 《Journal of inorganic biochemistry》1984,21(1):83-92
Reaction products of 9-methyladenine (mAde) with [Pt(dien)Cl]Cl and cis-Pt(NH3)2Cl2 have been separated using CM-Sephadex C25 cation exchange chromatography. NMR and UV characteristics are presented; the platinum binding sites were established by studying the pH dependence of the 1H-NMR chemical shifts and of UV difference absorption. It is shown that the N 1 atom of the ligand can be protonated in Pt(mAde-N7) adducts, while the N7 atom can be protonated in Pt(mAde-N1). 相似文献
9.
Adriana Bakalova Hristo Varbanov Stancho Stanchev Darvin Ivanov 《Inorganica chimica acta》2010,363(7):1568-1576
Platinum(II) and platinum(IV) complexes with 3-amino-5-methyl-5-(4-pyridyl)-2,4-imidazolidenedione (L) with general formulaе cis-[PtL2X2]·nH2O and [PtL2Cl4], where X = Cl−, Br−, I− and n = 2-4) were synthesized. The novel compounds were fully characterized by elemental analysis, IR, 1H, 13C, 195Pt NMR spectra, thermal analysis and molar conductivity. The geometry of Pt(II) complexes and of the organic ligand in the gas phase were optimized using the hybrid DFT method B3LYP with LANL2DZ and 6-31G** basis sets. Some physicochemical parameters as dipole moment, HOMO, LUMO energies and ESP charges were calculated. The comparison of the bond length and angles, obtained from the X-ray analysis and DFT calculations is realized. The cytotoxic effects of these complexes in human T-cell leukemia KE-37 (SKW-3) are reported. 相似文献
10.
Mrinal Kanti Paira Durbadal Ojha Edward R.T. Tiekink Chittaranjan Sinha 《Inorganica chimica acta》2011,370(1):175-186
3-(2-(Alkylthio)phenylazo)-2,4-pentanedione (HL), an O, N, S donor ligand, is used for the synthesis of Ni(II), Pd(II) and Pt(II) complexes. The spectroscopic (IR, UV-Vis, and NMR) data determine the structure. The single crystal X-ray diffraction measurement of [Ni(L)2] and [Pt(L)Cl] has confirmed the structures. Coulometric oxidation of [Ni(L)2] and EPR spectra thereof show formation of Ni(III) state. DFT computation has calculated the electronic configuration and has explained the spectral and redox properties of the complexes. The compounds are screened for their in vitro anti-bacterial activity using Gram-positive and Gram-negative bacteria (Bacillus subtilis UC564, Escherichia coli TG1, Staphylococcus aureus Bang25, Pseudomonas aeruginosa C/1/7, Salmonella typhi NCTC62, Salmonella paratyphi NCTC A2, Shigella dysenteriae 8NCTC599/52, Streptococcus faecalis S2, Vibrio cholerae DN7 and Mricococcus luteusAGD1). The minimum inhibitory concentration is determined for the compounds. The effect of the structure of the investigated compounds on the antibacterial activity is discussed. 相似文献
11.
《Inorganica chimica acta》1988,147(1):27-31
The electrochemistry for the reduction of tetrakis(dialkyl- and diphenyldithiocarbamato)-μ-oxodioxodirhenium complexes trans-Re2O3(S2CNR2)4 (R = methyl, ethyl, propyl, butyl and phenyl) was investigated in seven nonaqueous solvents. The complexes underwent a reversible reduction involving one- electron at a platinum electrode to [Re2O3(S2CNR2)4]−, which decomposed with the cleavage of the μ-oxo bridge to form ReO(S2CNR2)2, R2CNS2− and other rhenium complexes. The redox potential Eo′ of [Re2O3(S2CNR2)4]0/− couples and the stability of the reduction product [Re2O3(S2CNR2)4]− depend on the R group. The Eo′ are appreciably solvent-dependent. The difference in Eo′ with solvents could be interpreted in terms of the solubility parameters. 相似文献
12.
The synthesis of new platinum bipy (bipy = 2,2′-bipyridyl) complexes containing phenoxide ligands is reported, together with kinetic studies of their oxidative addition reactions with MeI to produce phenoxo platinum(IV) complexes. Complexes of the form [(bipy)Pt(OC6H4-4-X)2] (X = OCH3, CH3, H, Br, Cl) are prepared by the reaction of the chloro complex [(bipy)PtCl2] with substituted phenols and KOH in a two phase system of water and chloroform in the presence of benzyl triphenylphosphonium chloride. Platinum(IV) complexes are formed by oxidative addition of MeI to the platinum(II) complexes obtained. The complexes are characterized by elemental analysis, UV-Vis, IR, mass spectrometry and 1H and 13C NMR spectroscopy.The reaction of methyl iodide with [(bipy)Pt(OC6H4-4-OMe)2] to give [(bipy)PtMe(I)(OC6H4-4-OMe)2] follows the rate law rate = k2[(bipy)Pt(OC6H4-4-OMe)2][MeI]. The values of k2 increase with increasing polarity of the solvent, suggesting a polar transition state for the reaction. 相似文献
13.
Reactions of RuCl2(PR3)3 [PR3 = PPh3 or P(p-tolyl)3 with several monomeric phosphine complexes of rhodium(III), iridium(III) and platinum(IV) have been studied. The reactions with mer-MCl3(P′R3)3 (M = Rh, P′R3 = PEt2Ph, PMe2Ph, PMe2Ph; M = Ir, P′R3 = PBuPh2, PMePh2, PEt2Ph) involves a phosphine ligand transfer between metal atoms to afford novel dark coloured heterobimetallic complexes containing a triple chloro-bridge. The reactions of RuCl2(PR3)3 with PtCl4(P′R3)2 (P′R3 = PEt2Ph, PBu2Ph), however, do not give evidence for the formation of dinuclear complexes containing the (RuCl3Pt) unit, but a reduction of PtIV to PtII occurs with transfer of phosphine ligands between the two metals. The formulation of these complexes has been established by 31P NMR spectroscopy. 相似文献
14.
《Journal of inorganic biochemistry》1987,29(3):217-223
The products obtained from the reaction of Pt(IV)Cl4(LL) compounds (LL denotes the chelating ligands ethylenediamine (en) and 2,2-dimethyl-1,3-diaminopropane (dmdap), or two cis- or trans-coordinated ammines) with 9-methylhypoxanthine (mHyp) at high temperature (80°C) have been characterized by proton NMR spectroscopy. It appeared that both platinum(II) and platinum(IV) adducts were present in the reaction mixtures. After cation-exchange chromatography, the Pt(II) compound could be characterized as Pt(II)(LL)(mHyp)2, whereas the Pt(TV) fractions appeared to contain mainly one or two adducts for the chelating diamine compound but more adducts for the ammine compounds. A 3J(195Pt-1H) coupling was observed for the Pt(IV), but not for the Pt(II) compounds at the used spectrometer frequency. This supplies a useful tool to discriminate between these two types of platinum adducts. 相似文献
15.
Yasuo Nakabayashi Minoru Tashiro Masako Takani Takeshi Motoyama Osamu Yamauchi 《Inorganica chimica acta》2009,362(3):777-2703
Adduct formation of ternary Pt(II) complexes composed of an amino acid and an aromatic diimine, [Pt(A)(DA)] (A = glycinate (Gly), alaninate (Ala), valinate, or arginine (Arg); DA = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)), with flavin mononucleotide (FMN) and anthraquinone-2-sulfonate (AQS) were investigated by spectroscopic, X-ray diffraction, and electrochemical methods. The Pt(II) complexes formed 1:1 [Pt(A)(DA)]-FMN adducts by stacking with the aromatic moiety of FMN, and the stability constants, log K, for the systems with [Pt(A)(phen)] (A = Gly, Ala, and Arg) and [Pt(Arg)(bpy)] were determined to be 2.83(8)-3.42(6) from 1H NMR spectra at 25 °C in D2O (I = var.). The structure of the adduct [Pt(Ala)(phen)](AQS) (1) was determined by X-ray analysis to involve a π-π stacking interaction between coordinated phen and AQS with the distance of 3.400(7) Å and a hydrogen bond between the sulfonate moiety of AQS and the amino group of coordinated Ala. Cyclic voltammetry of the 1:1 [Pt(A)(DA)]-FMN systems in a phosphate buffer (pH 7.0) showed that the potentials, E1/2, for the two-electron redox process of FMN shifted to higher values by 18-31 mV as compared with the value for free FMN. 相似文献
16.
Jung Rae KimJy-Yeon Kim Sang-Beom HanKyung-Won Park G.D. SarataleSang-Eun Oh 《Bioresource technology》2011,102(1):342-347
Co-naphthalocyanine (CoNPc) was prepared by heat treatment for cathode catalysts to be used in microbial fuel cells (MFCs). Four different catalysts (Carbon black, NPc/C, CoNPc/C, Pt/C) were compared and characterized using XPS, EDAX and TEM. The electrochemical characteristics of oxygen reduction reaction (ORR) were compared by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The Co-macrocyclic complex improves the catalyst dispersion and oxygen reduction reaction of CoNPc/C. The maximum power of CoNPc/C was 64.7 mW/m2 at 0.25 mA as compared with 81.3 mW/m2 of Pt/C, 29.7 mW/m2 of NPc/C and 9.3 mW/m2 of carbon black when the cathodes were implemented in H-type MFCs. The steady state cell, cathode and anode potential of MFC with using CoNPc/C were comparable to those of Pt/C. 相似文献
17.
The 1:1 adduct formed from cis-[(PMePh2)2Pt(NO3)2] and 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (bpytdz) in chloroform crystallizes out as a 1D coordination polymer built up of cis-(PMePh2)2Pt units connected by the bpytdz ligand, an unusual self-assembly for a complex formed from a (phosphine)2PtII entity and a N,N linker. 相似文献
18.
The reaction products of adenosine with [Pt(NH3)3Cl]Cl or cis-Pt(NH3)2Cl2 have been studied using high performance liquid chromatography and uv spectroscopy. The reaction of [Pt(NH3)3Cl]Cl with adenosine (pH = 7.0, Pt/base = 0.5) gives four products. Two of them, mononuclear complexes in which platinum is bound to adenosine through N(7) or N(1), comprise more than 90% of all the products. The N(1) and N(7) sites on adenosine indicate almost equal binding affinity for [Pt(NH3)3Cl]Cl. The reaction of cis-Pt(NH3)2Cl2 with adenosine has been studied in the presence of a large excess of adenosine (Pt/base ? 0.05). The reaction gives four products. One is the monomeric 2:1 complex with cis-Pt(NH3)22+ bound to two adenosine molecules through the N(7) site and the N(1) site, and another is the monomeric 2:1 complex with cis-Pt(NH3)22+ bound to two adenosine molecules through the N(7) sites. cis-Pt(NH3)2Cl2 is stronger affinity to the N(7) site than of adenosine to the N(1) site. 相似文献
19.
Annalese F. Maddox Arnold L. Rheingold W. Scott Kassel 《Inorganica chimica acta》2008,361(11):3283-3293
The oxidative electrochemistry of chiral, bidentate ferrocenylphosphines, five Taniaphos and seven Walphos ligands, was studied in methylene chloride. In general, two waves of varying reversibility were observed. Complexes of the general type [(phosphine)MCl2] (phosphine = Taniaphos or Walphos; M = Pd or Pt) were prepared and characterized by NMR. Upon coordination, the oxidative electrochemistry of the ligands was greatly simplified. The X-ray structures of a Taniaphos platinum complex as well as a palladium and a platinum complex with a Walphos ligand were determined. 相似文献
20.
Complexes of the type [Pt(amine)4]I2 were synthesized and characterized mainly by multinuclear (195Pt, 1H and 13C) magnetic resonance spectroscopy. The compounds were prepared with different primary amines, but not with bulky amines, due to steric hindrance. In 195Pt NMR, the signals were observed between −2715 and −2769 ppm in D2O. The coupling constant 3J(195Pt-1H) for the MeNH2 complex is 42 Hz. In 13C NMR, the average values of the coupling constants 2J(195Pt-13C) and 3J(195Pt-13C) are 18 and 30 Hz, respectively. The crystal structure of [Pt(EtNH2)4]I2 was determined by X-ray diffraction methods. The Pt atom is located on an inversion center. The structure is stabilized by H-bonding between the amines and the iodide ions. The compound with n-BuNH2 was found by crystallographic methods to be [Pt(n-BuNH2)4]2I3(n-BuNHCOO). The crystal contains two independent [Pt(CH3NH2)4]2+ cations, three iodide ions and a carbamate ion formed from the reaction of butylamine with CO2 from the air. When the compound [Pt(CH3NH2)4]I2 was dissolved in acetone, crystals identified as trans-[Pt(CH3NH2)2(H3CNC(CH3)2)2]I2 were isolated and characterized by crystallographic methods. Two trans bonded MeNH2 ligands had reacted with acetone to produce the two N-bonded Schiff base Pt(II) compound. 相似文献