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1.
Yosi Kratish Dr. Arseni Kostenko Alexander Kaushansky Dr. Boris Tumanskii Dr. Dmitry Bravo‐Zhivotovskii Prof. Dr. Yitzhak Apeloig 《Angewandte Chemie (International ed. in English)》2018,57(27):8275-8279
The first persistent platinum(I)‐centered radical was generated by homolytic cleavage of a Pt?HgSiR3 bond of a mercury‐substituted platinum(II) complex. The PtI radical was characterized by EPR spectroscopy, chemical trapping experiments, and density functional theory (DFT) calculations. 相似文献
2.
A.V. Kalinkin A.V. Pashis V.I. Bukhtiyarov 《Reaction Kinetics and Catalysis Letters》2002,77(2):255-261
The reaction of CO oxidation over thin films of rhodium and platinum prepared by vacuum evaporation of the metals on an inert support has been investigated at low pressures (P < 2×10-5 mbar). Rhodium has been found to be more active than platinum in this reaction. The reasons of the higher activity of Rh are discussed. 相似文献
3.
Standard enthalpies of formation of amorphous platinum hydrous oxide PtH2.76O3.89 (Adams' catalyst) and dehydrated oxide PtO2.52 at T=298.15 K were determined to be -519.6±1.0 and -101.3 ±5.2 kJ mol-1, respectively, by micro-combustion calorimetry. Standard enthalpy of formation of anhydrous PtO2 was estimated to be -80 kJ mol-1 based on the calorimetry. A meaningful linear relationship was found between the pseudo-atomization enthalpies of platinum
oxides and the coordination number of oxygen surrounding platinum. This relationship indicates that the Pt-O bond dissociation
energy is 246 kJ mol-1 at T=298.15 K which is surprisingly independent of both the coordination number and the valence of platinum atom. This may provide
an energetic reason why platinum hydrous oxide is non-stoichiometric.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
István Bakos 《Journal of Solid State Electrochemistry》2000,4(2):80-86
Occlusion of hydrogen in platinized platinum electrodes has been studied in 1 mol/dm3 H2SO4 electrolyte. It has been found that the amount of hydrogen dissolved in the platinum layer depends on the structure of the
Pt deposit, which is determined by the parameters of electrodeposition. Composition of the platinizing solution as well as
the potential of Pt deposition are decisive parameters. On the basis of experimental results it is assumed that occlusion
of hydrogen takes place in special structural elements of the platinum layer which are formed in the course of Pt deposition.
Hydrogen dissolution versus H-deposition potential, H-deposition time and Pt layer thickness relationships are also presented.
Received: 2 March 1999 / Accepted: 25 May 1999 相似文献
5.
Inorganic ion-exchangers with a layered structure such as γ-zirconium and γ-titanium phosphates, intercalated with organic
diamines, are able to exchange Pt2+ ions to give new intercalation compounds that can be utilized in heterogeneous catalysis. The experiments performed at different
temperatures (25 and 45°C), show different ion uptakes, greater at 45°C and for the materials derived from γ-zirconium phosphate.
After platinum exchange, all the materials show an amorphization in the XRD if compared with their precursors. The thermal
behaviour of the platinum materials is specific, depending on the exchanger used and the ligand inside the exchanger. Pt2+ ion has a catalytic effect on ligand elimination in the γ-zirconium phosphate platinum compounds, but not in those derived
from γ-titanium. All the obtained yellow materials show a small step in the TG curves and simultaneously we have the Pt2+→Pt0 reduction: this is confirmed by XRD registered at the temperatures of the thermal effect, showing peaks at dhkl=2.27 and 1.95 Å.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Bioinspired Hierarchical Nanotubular Titania Immobilized with Platinum Nanoparticles for Photocatalytic Hydrogen Production
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Dr. Xiaoyan Liu Jiao Li Dr. Yiming Zhang Prof. Jianguo Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7345-7349
A bioinspired nanocomposite composed of platinum nanoparticles and nanotubular titania was fabricated in which the titania matter was templated by natural cellulose substance. The composite possesses three‐ dimensional hierarchical structures, and ultrafine metallic platinum particles with sizes of ca. 2 nm were immobilized uniformly on the surfaces of the titania nanotubes. Such a nanocomposite with 1.06 wt % of platinum content shows the optimal photocatalytic hydrogen production activity from water splitting of 16.44 mmol h?1 g?1, and excessive loading of platinum results in poorer photocatalytic performance. The structural integrity of the nanocomposite upon cyclic water‐splitting processes results in its sufficient photocatalytic stability. 相似文献
7.
Dr. Grégory Thiabaud Dr. Jonathan F. Arambula Prof. Zahid H. Siddik Prof. Jonathan L. Sessler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(29):8942-8947
In an effort to increase the stability and control the platinum reactivity of platinum–texaphyrin conjugates, two PtIV conjugates were designed, synthesized, and studied for their ability to form DNA adducts. They were also tested for their anti‐proliferative effects using wild‐type and platinum‐resistant human ovarian cancer cell lines (A2780 and 2780CP, respectively). In comparison to an analogous first‐generation PtII chimera, one of the new conjugates provided increased stability in aqueous environments. Using a combination of 1H NMR spectroscopy and FAAS (flameless atomic‐absorption spectrometry), it was found that the PtIV center within this conjugate undergoes photoinduced reduction to PtII upon exposure to glass‐filtered daylight, resulting in an entity that binds DNA in a controlled manner. Under conditions in which the PtIV complex is reduced to the corresponding PtII species, these new conjugates demonstrated potent anti‐proliferative activity in both test ovarian cancer cell lines. 相似文献
8.
Leticia Cubo Dr. Angela Casini Dr. Chiara Gabbiani Dr. Guido Mastrobuoni Dr. Luigi Messori Prof. Jesús Jiménez‐Barbero Prof. Carmen Navarro‐Ranninger Prof. Adoración G. Quiroga Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(36):9139-9146
A novel trans‐platinum(II) complex bearing one dimethylamine (dma) and one methylamine (ma) ligand, namely trans‐[PtCl2(dma)(ma)], recently synthesised and characterised in our laboratory, displayed relevant antiproliferative properties in vitro, being more active than the parent complex, trans‐[PtCl2(dma)(ipa)], which has isopropylamine (ipa) in place of methylamine. We have analysed comparatively the solution behaviour of these two complexes under various experimental conditions, and investigated their reactivity with horse heart cytochrome c by mass spectrometry, inductively coupled plasma–optical emission spectroscopy (ICP‐OES), 2D [1H,15N],[1H,13C] HSQC and [1H,1H] NOESY NMR. Some important changes that occurred in the [1H,13C] HSQC NMR spectrum of cytochrome c treated with trans‐[PtCl2(dma)(ma)] in water, after two days’ incubation, most probably arose from direct platinum coordination to the protein side chain; this was proved conclusively by [1H,1H] NOESY NMR and [1H,15N] HSQC NMR measurements. Met65 was identified as the primary Pt binding site on cytochrome c. Electrospray mass spectrometry (ESIMS) results provided evidence for extensive platinum–protein adduct formation. A fragment of the [Pt(amine)(amine′)] type was established to be primarily responsible for protein metalation. ICP‐OES analysis revealed that these trans‐platinum(II) complexes bind preferentially to the serum proteins albumin and transferrin rather than to calf thymus DNA. Pt binding to DNA was found to be far lower than in the case of cisplatin. The implications of the results for the mechanism of action of novel cytotoxic trans‐platinum complexes are discussed. 相似文献
9.
Human Serum Albumin Conjugated Nanoparticles for pH and Redox‐Responsive Delivery of a Prodrug of Cisplatin
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Hongdong Shi Qinqin Cheng Siming Yuan Xin Ding Prof. Yangzhong Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(46):16547-16554
Platinum anticancer drugs are particularly in need of controlled drug delivery because of their severe side effects. Platinum(IV) agents are designed as prodrugs to reduce the side effects of platinum(II) drugs; however, premature reduction could limit the effect as a prodrug. In this work, a highly biocompatible, pH and redox dual‐responsive delivery system is prepared by using hybrid nanoparticles of human serum albumin (HSA) and calcium phosphate (CaP) for the PtIV prodrug of cisplatin. This conjugate is very stable under extracellular conditions, so that it protects the platinum(IV) prodrug in HSA. Upon reaching the acidic and hypoxic environment, the platinum drug is released in its active form and is able to bind to the target DNA. The Pt–HSA/CaP hybrid inhibits the proliferation of various cancer cells more efficiently than cisplatin. Different cell cycle arrests suggest different cellular responses of the PtIV prodrug in the CaP nanocarrier. Interestingly, this delivery system demonstrates enhanced cytotoxicity to tumor cells, but not to normal cells. 相似文献
10.
A. A. Shubin R. S. Mitchenko T. V. Bezbozhnaya A. N. Vdovichenko 《Russian Chemical Bulletin》2005,54(10):2456-2459
A procedure was developed for the synthesis of previously unknown β-chlorovinyl derivatives of PtIV chloride complexes by chloroplatination of terminal alkynes catalyzed by PtII chloride complexes. The reaction is highly stereoselective and gives only the products of trans-anti-addition of platinum and chlorine atoms. The regioselectivity of the catalytic reaction formally corresponds to Markovnikov’s
rule, e.g., in alkynes containing electron-donating substituents, platinum attacks the terminal carbon atom. The σ-vinyl derivatives
of PtIV chloride complexes were characterized by IR spectroscopy and 1H and 13C NMR spectroscopy.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2380–2384, October, 2005. 相似文献
11.
As part of our continuing interest in the chemistry of cationic antimony Lewis acids as ligands for late transition metals, we have now investigated the synthesis of platinum complexes featuring a triarylstibine ligand substituted by an o-[(dimethylamino)methyl]phenyl group referred to as ArN. More specifically, we describe the synthesis of the amino stibine ligand Ph2SbArN (L) and its platinum dichloride complex [LPtCl]Cl which exists as a chloride salt and which shows weak coordination of the amino group to the antimony center. We also report the conversion of [LPtCl]Cl into a tricationic complex [LHPt(SMe2)]3+ which has been isolated as a tris-triflate salt after reaction of [LPtCl]Cl with SMe2, HOTf and AgOTf. Finally, we show that [LHPt(SMe2)][OTf]3 acts as a catalyst for the cyclization of 2-allyl-2-(2-propynyl)malonate. 相似文献
12.
Savinova D. V. Molodkina E. B. Danilov A. I. Polukarov Yu. M. 《Russian Journal of Electrochemistry》2004,40(7):683-687
The oxidation of polycrystalline platinum in perchloric acid is studied by cyclic voltammetry at a potential scan rate of 0.1 V s–1 in various potential cycling ranges. The earlier model for the formation of a barrier layer of strong complexes consisting of subsurface oxygen Oss, platinum atoms, and anions adsorbed on the latter is shown to correctly describe experimental results on the platinum oxidation in sulfuric and perchloric acids. The regularities in these acids are on the whole similar. A weaker adsorption of perchlorate anions as compared with bisulfate facilitates chemisorption of oxygen at 0.7–0.85 V and hinders exchange by sites Pt O at 0.85–1.35 V. A prolonged potential cycling with a cathodic limit of 0.27 V and low anodic limits leads to the accumulation of surface complexes Oss–Pt
n
–ClO4, which hinder both the oxygen chemisorption and the exchange Pt O below 1 V. At more positive potentials, the complexes are destroyed and oxygen penetrates into subsurface platinum layers. 相似文献
13.
14.
Dr. Tony Chave Nathalie M. Navarro Serge Nitsche Dr. Sergey I. Nikitenko 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(13):3879-3885
Sonochemical synthesis of platinum nanoparticles (Pt NPs) in formic acid solutions and pure water was investigated using a 20 kHz ultrasonic irradiation. The obtained results gave new insights on the underneath PtIV reduction mechanism in formic acid media under argon and in pure water under Ar/CO atmosphere. It was shown that in pure water sonochemical reduction of platinum ions occurs by hydrogen issued from homolytic water molecule split. PtIV ion reduction appears to be a very slow process under argon atmosphere in pure water due to formation of oxidizing species like OH radicals and H2O2 leading to reoxidation of intermediate PtII ions. Sonochemical reduction is accelerated manifold in the presence of formic acid or Ar/CO gas mixture. Solution and gas‐phase analyses reveal that both CO and HCOOH act as OH. radical scavenger and reducing agent under ultrasonic irradiation. Their ability to reduce platinum ions at room temperature is enhanced due to the local heating in the liquid shell surround the cavitation bubble. An innovative synthesis route for monodispersed Pt NPs in pure water without any templates or capping agents in the presence of Ar/CO gas mixture is then proposed. Obtained Pt NPs within the range of 2–3 nm exhibited a strong stability towards sedimentation in water. Since Ar/CO atmosphere is the only restriction of the process, this procedure can be applied in various media and is also compatible with a large array of experimental conditions. 相似文献
15.
16.
Nucleotide Binding Preference of the Monofunctional Platinum Anticancer‐Agent Phenanthriplatin
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Dr. Imogen A. Riddell Dr. Timothy C. Johnstone Dr. Ga Young Park Prof. Stephen J. Lippard 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(22):7574-7581
The monofunctional platinum anticancer agent phenanthriplatin generates covalent adducts with the purine bases guanine and adenine. Preferential nucleotide binding was investigated by using a polymerase stop assay and linear DNA amplification with a 163‐base pair DNA double helix. Similarly to cisplatin, phenanthriplatin forms the majority of adducts at guanosine residues, but significant differences in both the number and position of platination sites emerge when comparing results for the two complexes. Notably, the monofunctional complex generates a greater number of polymerase‐halting lesions at adenosine residues than does cisplatin. Studies with 9‐methyladenine reveal that, under abiological conditions, phenanthriplatin binds to the N1 or N7 position of 9‐methyladenine in approximately equimolar amounts. By contrast, comparable reactions with 9‐methylguanine afforded only the N7‐bound species. Both of the 9‐methyladenine linkage isomers (N1 and N7) exist as two diastereomeric species, arising from hindered rotation of the aromatic ligands about their respective platinum–nitrogen bonds. Eyring analysis of rate constants extracted from variable‐temperature NMR spectroscopic data revealed that the activation energies for ligand rotation in the N1‐bound platinum complex and the N7‐linkage isomers are comparable. Finally, a kinetic analysis indicated that phenanthriplatin reacts more rapidly, by a factor of eight, with 9‐methylguanine than with 9‐methyladenine, suggesting that the distribution of lesions formed on double‐stranded DNA is kinetically controlled. In addition, implications for the potent anticancer activity of phenanthriplatin are discussed herein. 相似文献
17.
Kamil Wawrowicz Agnieszka Majkowska-Pilip Damian Gawe Ewelina Chajduk Tadeusz Piekowski Aleksander Bilewicz 《Molecules (Basel, Switzerland)》2021,26(7)
193mPt and 195mPt radionuclides are therapeutically attractive Auger electron emitters with notably high Auger electron yield per decay. The present paper summarizes the first step of research on the applications of core-shell (Au@Pt) nanoparticles for electron Auger therapy of HER2+ (human epidermal growth factor receptor 2) breast cancer and hepatocellular carcinoma. Gold nanoparticles (30 nm) were synthesized covered with a platinum shell at high efficiency (>80%) and were further evaluated for in vitro studies such as binding affinity, internalization and cytotoxicity. To find the mechanism(s) responsible for platinum cytotoxicity in HepG2 cells, the platinum concentration in isolated cell nuclei and cytoplasm was determined using ICP-MS (inductively coupled plasma mass spectrometry). Lack of platinum in cell nuclei suggests that the cytotoxic effect is associated with the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS). Studies carried out on the SKOV-3 cell line with the use of a synthesized targeting bioconjugate (Au@Pt-PEG-trastuzumab) revealed a high affinity of this preparation to HER2+ cells, its internalization, its placement in the perinuclear area and partial intranuclear location. The specific binding for HER2 negative cells, MDA-MB-231, was negligible and Au@Pt-PEG-trastuzumab did not enter these cells. The results obtained are promising and warrant future investigation of Auger electron therapy using 193mPt and 195mPt based radiopharmaceuticals. 相似文献
18.
A novel one‐pot synthesis of dimethyl(1,5‐cyclooctadiene)platinum(II), i.e. [(COD)Pt(CH3)2] (complex 1), was developed in 92% yield using platinum acetylacetonate, 1,5‐cyclooctadiene and trimethylaluminium. Complex 1 was fully characterized by 1H and 13C NMR, mass spectrometry, cell dimensions and elemental analysis. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
19.
Prof. Jana Kasparkova Dr. Hana Kostrhunova Dr. Olga Novakova Dr. Radka Křikavová Dr. Ján Vančo Prof. Zdeněk Trávníček Prof. Viktor Brabec 《Angewandte Chemie (International ed. in English)》2015,54(48):14478-14482
We report toxic effects of a photoactivatable platinum(IV) complex conjugated with suberoyl‐bis‐hydroxamic acid in tumor cells. The conjugate exerts, after photoactivation, two functions: activity as both a platinum(II) anticancer drug and histone deacetylase (HDAC) inhibitor in cancer cells. This approach relies on the use of a PtIV pro‐drug, acting by two independent mechanisms of biological action in a cooperative manner, which can be selectively photoactivated to a cytotoxic species in and around a tumor, thereby increasing selectivity towards cancer cells. These results suggest that this strategy is a valuable route to design new platinum agents with higher efficacy for photodynamic anticancer chemotherapy. 相似文献
20.
Ping Wang Dr. Chung‐Hang Leung Dr. Dik‐Lung Ma Dr. Wei Lu Prof. Chi‐Ming Che 《化学:亚洲杂志》2010,5(10):2271-2280
Platinum(II) complexes bearing acetylide ligands containing nucleobase motifs are prepared and their impact on human topoisomerase II (TopoII) is evaluated. Both platinum(II) complexes [PtII(C^N^N)(C≡CCH2R)] ( 1a , 1b , 1c ) and [PtII(tBu3terpy)(C≡CCH2R)]+ ( 2a , 2b , 2c ) (C^N^N=6‐phenyl‐2,2′‐bipyridyl, tBu3terpy = 4,4′,4′′‐tri‐tert‐butyl‐2,2′:6′,2′′‐terpyridyl, and R=( a ) adenine, ( b ) thymine, and ( c ) 2‐amino‐6‐chloropurine) are stable in aqueous solutions for 48 hours at room temperature. The binding constants (K) for the platinum(II) complexes towards calf thymus DNA are in the order of 105 dm3 mol?1 as estimated by using UV/Vis absorption spectroscopy. Of the complexes examined, only complexes 1a , 1b , 1c are found to behave as intercalators. Both complexes 1a , 1b , 1c and 2a , 2b , 2c inhibit TopoII‐induced relaxation of supercoiled DNA, while 2c is the most potent TopoII inhibitors among the tested compounds. Inhibition of DNA relaxation is detected at nanomolar concentrations of 2c . All of the platinum(II) complexes are cytotoxic to human cancer cells with IC50 values of 0.5–13.7 μM , while they are less toxic against normal cells CCD‐19 Lu. 相似文献