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Arkadiusz Frąckowiak - One of the best experts on this subject based on the ideXlab platform.
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mixed valence trimers in cation radical salts of tmttf with the planar bis 6 sulfo 8 quinolato Platinum Complex pt qs 2 2
New Journal of Chemistry, 2020Co-Authors: Arkadiusz Frąckowiak, Boleslaw Barszcz, Iwona Olejniczak, Mikolaj Tomasik, Natalia Jarzyniak, Roman świetlik, Pascale Aubansenzier, Marc Fourmigue, Olivier JeanninAbstract:Electrocrystallization of TMTTF (tetramethyltetrathiafulvalene) in the presence of the dianionic [Pt(qS)2]2− Platinum Complex (qS: 5-sulfo-8-quinolinol) afforded simultaneously two phases. Phase A with isolated dicationic (TMTTF)22+ species is fully insulating and characterized by C–H hydrogen bonds with the anionic sulfonate moieties. Phase B is a mixed valence salt formulated as (TMTTF)3[Pt(qS)2]. It is organized into strongly trimerized chains, with a notably higher conductivity (σRT = 4 × 10−5 S cm−1). The charge distribution within the TMTTF trimers has been evaluated from the intramolecular bond distances, and IR and Raman spectra, converging all to a +0.5/+1/+0.5 motif, which is not modified at lower temperatures. Spectroscopic studies of such trimeric structures are scarce and the doublet (or triplet) structure expected in the IR of trimers is clearly identified here in the EMV-activated ν8(ag) mode associated with the totally symmetric vibration of methyl groups, in relation to the weak C–H⋯O hydrogen bonds between the radical cation and the dianionic [Pt(qS)2]2− Platinum Complex.
Daniel P. Bezerra - One of the best experts on this subject based on the ideXlab platform.
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A novel Platinum Complex containing a piplartine derivative exhibits enhanced cytotoxicity, causes oxidative stress and triggers apoptotic cell death by ERK/p38 pathway in human acute promyelocytic leukemia HL-60 cells
Elsevier, 2019Co-Authors: Maiara De S. Oliveira, Marília I.f. Barbosa, Thiago Belarmino De Souza, Diogo R.m. Moreira, Felipe Terra Martins, Wilmer Villarreal, Rafael P. Machado, Antônio Carlos Doriguetto, Milena B.p. Soares, Daniel P. BezerraAbstract:Piplartine (piperlongumine) is a plant-derived compound found in some Piper species that became a novel potential antineoplastic agent. In the present study, we synthesized a novel Platinum Complex containing a piplartine derivative cis-[PtCl(PIP-OH)(PPh3)2]PF6 (where, PIP-OH = piplartine demethylated derivative; and PPh3 = triphenylphosphine) with enhanced cytotoxicity in different cancer cells, and investigated its apoptotic action in human promyelocytic leukemia HL-60 cells. The structure of PIP-OH ligand was characterized by X-ray crystallographic analysis and the resulting Platinum Complex was characterized by infrared, molar conductance measurements, elemental analysis and NMR experiments. We found that the Complex is more potent than piplartine in a panel of cancer cell lines. Apoptotic cell morphology, increased internucleosomal DNA fragmentation, without cell membrane permeability, loss of the mitochondrial transmembrane potential, increased phosphatidylserine externalization and caspase-3 activation were observed in Complex-treated HL-60 cells. Treatment with the Complex also caused a marked increase in the production of reactive oxygen species (ROS), and the pretreatment with N-acetyl-L-cysteine, an antioxidant, reduced the Complex-induced apoptosis, indicating activation of ROS-mediated apoptosis pathway. Important, pretreatment with a p38 MAPK inhibitor (PD 169316) and MEK inhibitor (U-0126), known to inhibit ERK1/2 activation, also prevented the Complex-induced apoptosis. The Complex did not induce DNA intercalation in cell-free DNA assays. In conclusion, the Complex exhibits more potent cytotoxicity than piplartine in a panel of different cancer cells and triggers ROS/ERK/p38-mediated apoptosis in HL-60 cells. Keywords: Piplartine, Piperlongumine, Platinum Complex, Leukemia, Apoptosis, ROS, p38, ER
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a novel Platinum Complex containing a piplartine derivative exhibits enhanced cytotoxicity causes oxidative stress and triggers apoptotic cell death by erk p38 pathway in human acute promyelocytic leukemia hl 60 cells
Redox biology, 2019Co-Authors: Maiara De Souza Oliveira, Marília I.f. Barbosa, Thiago Belarmino De Souza, Diogo R.m. Moreira, Felipe Terra Martins, Wilmer Villarreal, Rafael P. Machado, Antônio Carlos Doriguetto, Milena B.p. Soares, Daniel P. BezerraAbstract:Piplartine (piperlongumine) is a plant-derived compound found in some Piper species that became a novel potential antineoplastic agent. In the present study, we synthesized a novel Platinum Complex containing a piplartine derivative cis-[PtCl(PIP-OH)(PPh3)2]PF6 (where, PIP-OH = piplartine demethylated derivative; and PPh3 = triphenylphosphine) with enhanced cytotoxicity in different cancer cells, and investigated its apoptotic action in human promyelocytic leukemia HL-60 cells. The structure of PIP-OH ligand was characterized by X-ray crystallographic analysis and the resulting Platinum Complex was characterized by infrared, molar conductance measurements, elemental analysis and NMR experiments. We found that the Complex is more potent than piplartine in a panel of cancer cell lines. Apoptotic cell morphology, increased internucleosomal DNA fragmentation, without cell membrane permeability, loss of the mitochondrial transmembrane potential, increased phosphatidylserine externalization and caspase-3 activation were observed in Complex-treated HL-60 cells. Treatment with the Complex also caused a marked increase in the production of reactive oxygen species (ROS), and the pretreatment with N-acetyl-L-cysteine, an antioxidant, reduced the Complex-induced apoptosis, indicating activation of ROS-mediated apoptosis pathway. Important, pretreatment with a p38 MAPK inhibitor (PD 169316) and MEK inhibitor (U-0126), known to inhibit ERK1/2 activation, also prevented the Complex-induced apoptosis. The Complex did not induce DNA intercalation in cell-free DNA assays. In conclusion, the Complex exhibits more potent cytotoxicity than piplartine in a panel of different cancer cells and triggers ROS/ERK/p38-mediated apoptosis in HL-60 cells.
Olivier Jeannin - One of the best experts on this subject based on the ideXlab platform.
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mixed valence trimers in cation radical salts of tmttf with the planar bis 6 sulfo 8 quinolato Platinum Complex pt qs 2 2
New Journal of Chemistry, 2020Co-Authors: Arkadiusz Frąckowiak, Boleslaw Barszcz, Iwona Olejniczak, Mikolaj Tomasik, Natalia Jarzyniak, Roman świetlik, Pascale Aubansenzier, Marc Fourmigue, Olivier JeanninAbstract:Electrocrystallization of TMTTF (tetramethyltetrathiafulvalene) in the presence of the dianionic [Pt(qS)2]2− Platinum Complex (qS: 5-sulfo-8-quinolinol) afforded simultaneously two phases. Phase A with isolated dicationic (TMTTF)22+ species is fully insulating and characterized by C–H hydrogen bonds with the anionic sulfonate moieties. Phase B is a mixed valence salt formulated as (TMTTF)3[Pt(qS)2]. It is organized into strongly trimerized chains, with a notably higher conductivity (σRT = 4 × 10−5 S cm−1). The charge distribution within the TMTTF trimers has been evaluated from the intramolecular bond distances, and IR and Raman spectra, converging all to a +0.5/+1/+0.5 motif, which is not modified at lower temperatures. Spectroscopic studies of such trimeric structures are scarce and the doublet (or triplet) structure expected in the IR of trimers is clearly identified here in the EMV-activated ν8(ag) mode associated with the totally symmetric vibration of methyl groups, in relation to the weak C–H⋯O hydrogen bonds between the radical cation and the dianionic [Pt(qS)2]2− Platinum Complex.
Weiguo Zhu - One of the best experts on this subject based on the ideXlab platform.
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synthesis and optoelectronic properties of a novel dinuclear cyclometalated Platinum ii Complex containing triphenylamine substituted indolo 3 2 b carbazole derivative in the single emissive layer wpleds
Tetrahedron, 2014Co-Authors: Jian Luo, Qing Chen, Yafei Wang, Haigang Jiang, Hua Tan, Fanyuan Meng, Xianping Deng, Weiguo ZhuAbstract:Abstract A novel bi-picolinic acid derivative of H 2 dipic-BTICz containing binary triphenylamine-substituted indolo[3,2- b ]carbazole (BTICz) unit and its dinuclear Platinum(II) Complex of (dfppy) 2 Pt 2 (dipic-BTICz) were synthesized as a single-component emitter used in the white polymer light-emitting diodes (WPLEDs), where dfppy is 2-(2,4-difluorophenyl)pyridine and dipic-BTICz is an anion of H 2 dipic-BTICz. The photophysical and electrochemical properties of (dfppy) 2 Pt 2 (dipic-BTICz) were investigated. Compared with the reported mononuclear Platinum Complex of (dfppy)Pt(pic), (dfppy) 2 Pt 2 (dipic-BTICz) exhibited a red-shifted photoluminescent peak at 434 nm in dilute dichloromethane (10 −5 M), but a weakened and red-shifted aggregation emission peak at 640 nm besides its intrinsic emission at 445 nm in its neat films. Stable pure white emissions with CIE coordinates of (0.325±0.005, 0.345±0.015) and a maximum brightness of 208 cd/m 2 were observed in the (dfppy) 2 Pt 2 (dipic-BTICz)-doped single-emissive-layer (SEL) PLEDs using a blend of poly(vinylcarbazole) and 2-(4-biphenyl)-5-(4- tert -butylphenyl)-1,3,4-oxadiazole as a host matrix at 1 wt % dopant concentrations under applied voltages from 9 to 14 V. It indicates that the intrinsic and aggregation emissions of this dinuclear Platinum Complex were effectively tuned by inserting a new BTICz fluorophore in the dual picolinic acid derivative. Therefore, it is a promising single-component emitter to get white emission in SEL PLEDs.
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novel cyclometalated Platinum ii Complex containing carrier transporting groups synthesis luminescence and application in single dopant white pleds
Dyes and Pigments, 2013Co-Authors: Weiguo Zhu, Yafei Wang, Aihui Liang, Fei Huang, Yong CaoAbstract:Abstract In order to investigate the influence of carrier-transporting groups on the luminescent properties, especially on excimer/aggregation emission, and to obtain single emissive dopants used in white polymer light-emitting diodes with a single emissive-layer structure, two novel Platinum Complexes derived from a Platinum(II) (2-(4′,6′-difluorophenyl)pyridinato-N,C2′)(picolinate) unit containing carrier-transporting groups were synthesized and characterized, where a triphenylamino or an oxadiazole-triphenylamino functionalized unit was pending into the picolinate by non-conjugated linkage, respectively. Their optophysical, electrochemical and electroluminescent properties were investigated. Compared to their parent Platinum Complex, both functionalized Platinum Complexes exhibited a significantly red-shifted photoluminescent profile in neat film and higher photoluminescent quantum efficiency in dichloromethane at room temperature. Furthermore, the Platinum Complex with oxadiazole-triphenylamino ambipolar transporting group exhibited better photoluminescent properties and offered potential application as a single dopant in a single emissive-layer-based white polymer light-emitting diode. More stable white light emissions were observed in this Platinum Complex-doped devices at dopant concentrations of 4–8 wt%. The maximum luminous efficiency of 1.01 cd A−1 and the maximum brightness of 2177 cd m−2 were obtained in the polyfluorene-hosted devices.
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synthesis optoelectronic properties of a dinuclear Platinum ii Complex containing a binary cyclometalated ligand in the single emissive layer pleds
Dalton Transactions, 2013Co-Authors: Jian Luo, Gangtie Lei, Yu Liu, Qing Chen, Danyan Shi, Ying Huang, Yafei Wang, Zhiyong Zhang, Weiguo ZhuAbstract:A novel dinuclear Platinum Complex of (dfppy-mhb-dfppy)Pt2(acac)2 was synthesized and characterized, where dfppy-mhb-dfppy is a binary C^N cyclometalated ligand containing two bridged 2,4-difluorophenylpyridine (dfppy) units and acac is 2,4-pentanedione anion. Compared to previously reported dinuclear Platinum Complexes with a binary ancillary ligand, this dinuclear Platinum Complex showed more intense excimer emission, peaking at 617 nm, besides its intrinsic emission in dilute dichloromethane solution. Single-emissive-layer (SEL) polymer light-emitting devices (PLEDs) using (dfppy-mhb-dfppy)Pt2(acac)2 as dopant and a blend of poly (N-vinylcarbazole) (PVK) and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) as host matrix exhibited stable white emission at 1 wt% doping concentration under applied voltages from 7 V to 11 V. The stable white emission observed in the (dfppy-mhb-dfppy)Pt2(acac)2-doped SEL PLEDs indeed implies that the dinuclear Platinum Complex constructed by a binary cyclometalated ligand has a potential application in white-emitting SEL PLEDs.
Giannis Spyrou - One of the best experts on this subject based on the ideXlab platform.
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analysis of the inhibition of mammalian thioredoxin thioredoxin reductase and glutaredoxin by cis diamminedichloroPlatinum ii and its major metabolite the glutathione Platinum Complex
Free Radical Biology and Medicine, 2001Co-Authors: Hajime Nakamura, Junji Yodoi, Tetsuro Sasada, Giannis SpyrouAbstract:Abstract Several studies have demonstrated a correlation between cellular toxicity of cis-diamminedichloroPlatinum (II) (cisplatin, CDDP) and inhibited intracellular activity of the thioredoxin system, i.e., thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. Conversely, increased cellular activity of the Trx system confers resistance to CDDP. In this study, we have analyzed the interaction of CDDP with Trx and TrxR in order to clarify the mechanism. The inhibition with time-dependent kinetics by CDDP of NADPH-reduced (but not oxidized) TrxR was irreversible, strongly suggesting covalent modification of the reduced selenocysteine-containing active site. Assuming second order kinetics, the rate constant of TrxR inhibition by CDDP was 21 ± 3 M−1s−1. Transplatin was found to be an even more efficient inhibitor, with a second order rate constant of 84 ± 22 M−1s−1, whereas carboplatin (up to 1 mM) gave no inhibition of the enzyme under the same conditions. Escherichia coli Trx or human or bacterial glutaredoxin (Grx) activities were in comparison only slightly or not at all inhibited by either CDDP, transplatin, or carboplatin. However, glutaredoxins were found to be inhibited by the purified glutathione adduct of cisplatin, bis-(glutathionato)Platinum(II) (GS-Platinum Complex, GS-Pt), with an IC50 = 350 μM in the standard β-hydroxyethyl disulfide-coupled assay for human Grx. Also the mammalian Trx system was inhibited by GS-Pt with similar efficiency (IC50 = 325 μM), whereas neither the E. coli Trx system nor glutathione reductase were inhibited. Formation of GS-Pt is a major route for cellular elimination of CDDP. The fact that GS-Pt inhibits the mammalian Trx as well as Grx systems shows that CDDP may exert effects at several stages of its metabolism, including after conjugation with GSH, which are intimately linked with the cellular disulfide/dithiol redox regulatory systems.
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analysis of the inhibition of mammalian thioredoxin thioredoxin reductase and glutaredoxin by cis diamminedichloroPlatinum ii and its major metabolite the glutathione Platinum Complex
Free Radical Biology and Medicine, 2001Co-Authors: Hajime Nakamura, Junji Yodoi, Tetsuro Sasada, Giannis SpyrouAbstract:Several studies have demonstrated a correlation between cellular toxicity of cis-diamminedichloroPlatinum (II) (cisplatin, CDDP) and inhibited intracellular activity of the thioredoxin system, i.e., thioredoxin (Trx), thioredoxin reductase (TrxR), and NADPH. Conversely, increased cellular activity of the Trx system confers resistance to CDDP. In this study, we have analyzed the interaction of CDDP with Trx and TrxR in order to clarify the mechanism. The inhibition with time-dependent kinetics by CDDP of NADPH-reduced (but not oxidized) TrxR was irreversible, strongly suggesting covalent modification of the reduced selenocysteine-containing active site. Assuming second order kinetics, the rate constant of TrxR inhibition by CDDP was 21 +/- 3 M(-1) x s(-1). Transplatin was found to be an even more efficient inhibitor, with a second order rate constant of 84 +/- 22 M(-1) x s(-1), whereas carboplatin (up to 1 mM) gave no inhibition of the enzyme under the same conditions. Escherichia coli Trx or human or bacterial glutaredoxin (Grx) activities were in comparison only slightly or not at all inhibited by either CDDP, transplatin, or carboplatin. However, glutaredoxins were found to be inhibited by the purified glutathione adduct of cisplatin, bis-(glutathionato)Platinum(II) (GS-Platinum Complex, GS-Pt), with an IC50 = 350 microM in the standard beta-hydroxyethyl disulfide-coupled assay for human Grx. Also the mammalian Trx system was inhibited by GS-Pt with similar efficiency (IC(50) = 325 microM), whereas neither the E. coli Trx system nor glutathione reductase were inhibited. Formation of GS-Pt is a major route for cellular elimination of CDDP. The fact that GS-Pt inhibits the mammalian Trx as well as Grx systems shows that CDDP may exert effects at several stages of its metabolism, including after conjugation with GSH, which are intimately linked with the cellular disulfide/dithiol redox regulatory systems.