Electrochemical attachment of a conjugated amino-ferrocifen complex onto carbon and metal surfaces

International audienceThe attachment of a pi-conjugated amino-ferrocifen complex was electrochemically achieved either by direct oxidation of the amino group or via the oxidation of the ferrocene moiety. In the first case, the modification consists in oxidizing, at +0.70V/SCE, the amino moiety to its radical cation, which upon deprotonation from the amino group, yields all aminyl radical that may add onto the electrode surface. Alternatively, it is demonstrated that the amine moiety can be indirectly oxidized through an intramolecular electron transfer from the amino moiety to the ferrocenyl group after oxidation of the ferrocene part at +0.40 V. This can occur thanks to the conjugated pi system of the complex. More importantly. it is demonstrated that the covalent attachment of the complex can be achieved on glassy carbon, gold, and platinum surfaces whatever the approach used. The possible mechanisms for the covalent attachment are discussed. Interestingly, it is also shown that the amino-ferrocene compound adsorbs very well likely via pi stacking between grafted and non-grafted molecules. Nevertheless, the adsorbed molecules could be easily removed after passing the electrode in an ultrasonic bath. The electrode coverage was determined under various conditions by integration of the corresponding voltammograms. (C) 2008 Elsevier B.V. All rights reserved

Minyon’un düğünü

Johann Wolfgang Goethe'nin Sabah'ta yayımlanan Minyon'un Düğünü adlı romanının ilk ve son tefrikalarıTefrikada yazarın adı belirtilmemiştir

Tamoxifen-like metallocifens target thioredoxin system determining mitochondrial impairment leading to apoptosis in Jurkat cells

Tamoxifen-like metallocifens (TLMs) of the group-8 metals (Fe, Ru, and Os) show strong anti-proliferative activity on cancer cell lines resistant to apoptosis, owing to their unique redox properties. In contrast, the thioredoxin system, which is involved in cellular redox balance, is often overexpressed in cancer cells, especially in tumour types resistant to standard chemotherapies. Therefore, we investigated the effect of these three TLMs on the thioredoxin system and evaluated the input of the metallocene unit in comparison with structurally related organic tamoxifens. In vitro, all three TLMs became strong inhibitors of the cytosolic (TrxR1) and mitochondrial (TrxR2) isoforms of thioredoxin reductase after enzymatic oxidation with HRP/H2O2 while none of the organic analogues was effective. In Jurkat cells, TLMs inhibited mainly TrxR2, resulting in the accumulation of oxidized thioredoxin 2 and cell redox imbalance. Overproduction of ROS resulted in a strong decrease in the mitochondrial membrane potential, translocation of cytochrome c to the cytosol and activation of caspase 3, thus leading to apoptosis. None of these events occurred with organic tamoxifens. The mitochondrial fraction of cells exposed to TLMs contained a high amount of the corresponding metal, as quantified by ICP-OES. The lipophilic and cationic character associated with the singular redox properties of the TLMs could explain why they alter the mitochondrial function. These results provide new insights into the mechanism of action of tamoxifen-like metallocifens, underlying their prodrug behaviour and the pivotal role played by the metallocenic entity in their cytotoxic activity associated with the induction of apoptosis

4-(3-Methoxy­phen­oxy)butyric acid

In the title compound, C11H14O4, an inter­mediate for the synthesis of a new kind of estrogen receptor modulator, all non-H atoms lie on a common plane (r.m.s. deviation = 0.0472 Å). All C—C bonds in the side chain are in a trans conformation, and the hydroxyl group is also trans to the methyl­ene chain. In the crystal structure, mol­ecules form centrosymmetric dimers showing a head-to-head arrangement which is stabilized by O—H⋯O hydrogen bonds. A weak C—H⋯O contact is also present

Effective field and universal mobility in high-k metal gate UTBB-FDSOI devices

session 1: parameter extractionInternational audienceThis paper aims at reviewing experimental and theoretical behaviors of universal mobility in high-k metal gate UTBB-FDSOI devices. Based on split-CV mobility measurements, the parameter η, characterizing the effective field, has been extracted for a large range of back voltages and temperatures in devices with various equivalent oxide thicknesses. We demonstrated that a nearly universal trend for the mobility with respect to the effective field can be obtained in the front inversion regime but is difficult to obtain in the back channel inversion regime. Keywords—FDSOI, universal mobility, effective field, coefficient η

(Eta6-arene) ruthenium(II) complexes and metallo-papain hybrid as Lewis acid catalysts of Diels-Alder reaction in water.

International audienceCovalent embedding of a (eta(6)-arene) ruthenium(II) complex into the protein papain gives rise to a metalloenzyme displaying a catalytic efficiency for a Lewis acid-mediated catalysed Diels-Alder reaction enhanced by two orders of magnitude in water

Nanoparticles loaded with ferrocenyl tamoxifen derivatives for breast cancer treatment.

International audienceFor the first time, two organometallic triphenylethylene compounds (Fc-diOH and DFO), with strong antiproliferative activity in breast cancer cells, but insoluble in biological fluids, were incorporated in two types of stealth nanoparticles (NP): PEG/PLA nanospheres (NS) and nanocapsules (NC). Their physicochemical parameters were measured (size, zeta potential, encapsulation and loading efficiency), and their biological activity was assessed. In vitro drug release after high dilution of loaded NPs was measured by estradiol binding competition in MELN cells. The influence of the encapsulated drugs on the cell cycle and apoptosis was studied by flow cytometry analyses. Notwithstanding potential drug adsorption at the NP surface, Fc-diOH and DFO were incorporated efficiently in NC and NS, which slowly released both compounds. They arrested the cell cycle in the S-phase and induced apoptosis, whose activity is increased by loaded NS. A decrease in their antiproliferative activity by the antioxidant alpha-tocopherol indicated that reactive oxygen species (ROS) may be involved. Therefore, nanosystems, containing for the first time a high load of anticancer organometallic triphenylethylenes, have been developed. Their small size and delayed drug release, combined with their enhanced apoptotic potential, are compatible with an increased persistence in the blood and a promising antitumour activity

A [3]Ferrocenophane polyphenol showing a remarkable antiproliferative activity on breast and prostate cancer cell lines

International audienc