Synthèse et réactivité de complexes à ligand iminophosphorane : des métaux de transition aux actinides

For the past decades, organometallic and coordination chemistry have proven to be fields of major importanceby allowing the preparation of catalysts that are able to perform unpreceded chemical reactions, in addition with the discovery of unusual species with physical and chemical properties that are very interesting. All these studies are underlining the primordial role of the ligand, which allows fine-tuning of the properties of such species. Our laboratory has gained considerable experience in the synthesis and the study of the coordination chemistry of ligands bearing the iminophosphorane moieties (RN=PR’3). These ligands, still poorly studied in the literature, present electronic properties that are strongly deviating from those of their carbon-analogues, i.e. imines. This thesis is focused on the synthesis of a new family of (un)symmetrical, lutidine-based iminophosphorane ligands. Initially, the coordination chemistry of these ligands with transition metals is described with a focus on copper. Hemilabile behaviour is highlighted and shown to be related to the oxidation state of the copper metal centre, furnishing a redox-switchable system. These complexes are then shown to be useful in a number of catalytic reactions. Then, the coordination chemistry of these ligands is explored with lanthanides, more particularly divalent. These metals are strong reductants and are able to activate a variety of substrates like carbon dioxide for example, however such reactivities must be restrained by an appropriate ligand set. In particular, the study of the coordination chemistry of the new ligand family with metallocenes of ytterbium(II) is exhibiting lability phenomena, either of the iminophosphorane ligand or of the phospholyl ligand on the ytterbium centre. Moreover, the coordination chemistry of these ligands with uranium is briefly described. The synthesis and the coordination chemistry of mixed iminophosphorane-phosphine ligands are described subsequently. These ligands exhibit properties of dearomatization of the central pyridine scaffold. This phenomenon is studied with palladium(II) complexes, as the reactivity of these species with boranes. The reactivity of these new mixed ligands is also studied with ruthenium. Particularly, the presence of a hydride leads to the formation of an organometallic bond between the ligand and the ruthenium centre with the loss of hydrogen. In the last part, a new family of ligands bearing phenoxide moieties is studied. The oxidative and reductive chemistry of the copper and uranium complexes are explored and show a large divergence in comparison with the imines analogues of these ligands. Finally, the use of their nickel complexes as catalysts for the dimerization of ethylene is presented. All the results are supported by solid-state analysis, mainly by X-ray diffraction experiments; in solution the behavior of the species are studied by means of multinuclear NMR studies; finally some compounds are also investigated in silico by DFT calculations.La chimie organométallique et de coordination a prouvé dans les dernières décennies son importance enpermettant l’obtention de catalyseurs capables d’effectuer des réactions chimiques sans précèdent mais permettant aussi la découverte d’espèces présentant des propriétés physiques et chimiques très intéressantes. Il ressort de ces études que les ligands jouent un rôle primordial en modulant finement les propriétés de telles espèces. Notre laboratoire a acquis une grande expérience dans la synthèse et l’étude de la chimie de coordination de ligands présentant la fonctionnalité iminophosphorane (RN=PR’3). Ces ligands, encore peu étudiés dans la littérature, présentent des propriétés électroniques divergeant fortement de leurs analogues carbonés, les imines. Ce travail de doctorat est centré sur la synthèse d’une nouvelle famille de ligands iminophosphoranes symétriques ou non, comportant le motif de lutidine. Dans un premier temps, la chimie de coordination de ces espèces avec les métaux de transition et, plus particulièrement, avec le cuivre est décrite. Des phénomènes d’hémilabilité du ligand, liés à l’état d’oxydation du métal, sont mis en évidence , fournissant ainsi un système commutable par un stimulus redox. Ces espèces sont aussi employées dans le cadre de quelques réactions catalytiques. La chimie de ces nouveaux ligands symétriques est ensuite explorée avec les lanthanides, plus particulièrement divalents. Ces métaux fortement réducteurs sont capables d’activer de nombreux substrats comme le dioxyde de carbone, mais leurs réactivités doivent être souvent canalisées par des ligands appropriés. L’étude de la chimie de coordination de la nouvelle famille de ligands iminophosphoranes avec les métallocènes d’ytterbium(II) permet de mettre en évidence des phénomènes de labilité, soit du ligand iminophosphorane, soit des ligands phospholes de l’ytterbium. L’étude de la chimie de coordination de ces espèces avec l’uranium est enfin brièvement abordée. Par la suite, la synthèse et la chimie de coordination de ligands mixtes iminophosphoranes-phosphines sont abordées. Ces ligands présentent des propriétés de déaromatisation de la pyridine centrale. La chimie de coordination et l’étude du phénomène de déaromatisation avec le palladium(II) sont présentés, ainsi que la réactivité de ces espèces vis-à-vis des boranes. La réactivité de ces nouveaux ligands vis-à-vis du ruthénium est aussi explorée. En particulier la présence d’un hydrure conduit à la formation d’une liaison organométallique entre le ligand et le ruthénium et le départ de dihydrogène. Dans une dernière partie, des ligands iminophosphoranes présentant une fonctionnalité phénolate sont étudiés. La chimie d’oxydation et de réduction des complexes de cuivre et d’uranium est explorée et met en évidence une forte divergence par rapport aux analogues imines de ces ligands. Enfin, l’utilisation de complexes de nickel(II) pour catalyse de dimérisation de l’éthylène est décrite. L’ensemble des résultats est soutenu par des analyses à l’état solide, principalement par diffraction des rayons X ; en solution, par des études RMN multinoyaux mais aussi in silico par des calculs DFT

Uncontrolled Donation after Circulatory Death: European practices and recommendations for the development and optimization of an effective programme.

Shortage of organs has made a global interest for donation after circulatory death (DCD) to re-emerge. While controlled DCD (cDCD) has been progressively increasing, uncontrolled DCD (uDCD) has only been developed in a few settings.1 This activity is quantitatively important in France and Spain, although it has also been reported in other European countries, as Austria, Belgium, Italy, the Netherlands, and recently in Russia.2,3 uDCD protocols have allowed the transplantation of a significant number of kidneys, livers and lungs at these countries.3 Excellent graft survival has been reported in kidney transplantation from uDCD, in spite of an increased incidence of delayed graft function (DGF).4,5,6,7,8,9,10,11,12,13,14,1516 Albeit promising, results with liver transplants obtained in uDCD protocols do not consistently provide similar outcomes compared with livers from donors after brain death (DBD), mainly due to a higher incidence of primary graft dysfunction and non-function and biliary complications.17,18,19,20,21,22 Lung transplantation is still facing limited experience, but preliminary results are encouraging.pre-print938 K

Achieving a Preoperative Target HbA1c of < 69 mmol/mol in Elective Vascular and Orthopedic Surgery: A Retrospective Single Center Observational Study

Introduction Diabetes mellitus (DM) is present in 10–15% of the surgical population. It is a known risk factor for adverse postoperative outcomes. UK perioperative guidance recommends optimizing glycemic control preoperatively, aiming for a target glycated hemoglobin (HbA1c) of < 69 mmol/mol. However, real-world compliance with this guidance remains unknown. The aim of our study was to determine how many patients with DM undergoing elective orthopedic and vascular surgery had a preoperative HbA1c of < 69 mmol/mol. We also reviewed the surgical reasons for non-concordance with the recommended preoperative HbA1c target. Methods This was a retrospective observational study of 1000 consecutive patients who had been referred for elective vascular and orthopedic surgery at a large tertiary center. Data were collected on these patients, both those with and without DM, between January 2016 and February 2017. Electronic databases were used to collect information on the patients’ preoperative HbA1c concentration and to determine whether there was a resulting delay in surgery when the preoperative HbA1c target of < 69 mmol/mol was exceeded. Results Of the 1000 patients referred for surgery (500 orthopedic and 500 vascular patients) included in the study, 201 (20%) had diabetes. Among these 201 people with DM, 155 (77%) had a preoperative HbA1c < 69 mmol/mol. Among the 46 people with DM whose HbA1c exceeded the recommended target, 41 were operated on despite the high HbA1c level, and only five had their surgery deferred or canceled due to suboptimal preoperative glycemic control. Conclusions Our data shows that the majority (77% ) of people undergoing elective vascular and orthopedic surgery were able to achieve a target HbA1c of < 69 mmol/mol. The current preoperative guidance is therefore achievable in a real-life setting. However, as is stated in the national guidance, this target should only be used where it is safe to do so and a degree of clinical discretion is necessary

Une image satirique de Jacques Chaban-Delmas

Cheisson Anne. Une image satirique de Jacques Chaban-Delmas. In: Gaullisme et anti-gaullisme en Aquitaine. Bordeaux : Presses Universitaires de Bordeaux, 1990. pp. 149-160. (Institut d'études politiques de Bordeaux, 2