14 research outputs found
Photoredox reactions applied to the valorisation of carbon monoxide and 1,3-butadiene
Le domaine de la photocatalyse connait un intĂ©rĂȘt important car il permet le dĂ©veloppement de procĂ©dĂ©s Ă©co-compatibles et lâemploi de conditions douces. De nombreux photocatalyseurs organiques ou organomĂ©talliques tels que les xanthĂšnes, les complexes de ruthĂ©nium ou dâiridium ont Ă©tĂ© dĂ©veloppĂ©s. A ce jour, trĂšs peu dâexemples dĂ©crivent la valorisation de gaz tels que le monoxyde de carbone et le 1,3-butadiĂšne dans des rĂ©actions de catalyse photorĂ©dox. Dans ce contexte, les travaux prĂ©sentĂ©s dans la thĂšse ont reportĂ© la synthĂšse dâacides arylcarboxyliques et la fonctionnalisation en α dâaldĂ©hydes photocatalysĂ©es respectivement par le ruthĂ©nium tris(bipyridine) et lâĂ©osine Y, sous pression de monoxyde de carbone. La valorisation du 1,3-butadiĂšne est Ă©galement dĂ©crite par arylation de Meerwein Ă partir de sels dâaryldiazonium, associĂ©e Ă la rĂ©action de Ritter photocatalysĂ©e par le ruthĂ©nium tris(bipyridine). Lâarylation de Meerwein a Ă©galement Ă©tĂ© associĂ©e Ă dâautres nuclĂ©ophiles tels que les isonitriles, de mĂȘme quâĂ des Ă©tapes de cyclisation pour les synthĂšses de dihydroisoquinolĂ©ines et dâisochromanones. Enfin, la synthĂšse de phtalides par cyclisation intramolĂ©culaire et photocatalysĂ©e par le 4CzIPN a Ă©tĂ© effectuĂ©e.Photocatalysis field is of great interest because it allows development of eco-friendly processes and use of mild conditions. Many organic and organometallic photocatalysts, such as xanthenes, as well as ruthenium and iridium complexes were then developed. To date, very few examples describe recovery of gases such as carbon monoxide and butadiene by photoredox catalysis. Therefore, the work presented in this thesis has reported synthesis of arylcarboxylic acids and fonctionalisation in position α of aldehydes, photocatalysed respectively by ruthenium tris(bipyridine) and eosin Y, under pressure of carbon monoxide. Valorisation of butadiene has also been described using Meerwein arylation from aryl diazonium salts, associated with Ritter reaction, photocatalysed by ruthenium tris(bipyridine). Meerwein arylation has also been conjugated to nucleophiles other than nitriles, as well as cyclisation steps for dihydroisoquinoleines and isochromanones synthesis. Finally, phtalides synthesis was carried out by intramolecular cyclisation, photocatalysed by 4CzIPN
Visible-Light-Mediated Hydroxycarbonylation of Diazonium Salts
International audienceA visible lightâpromoted catalytic photoredox hydroxycarbonylation was achieved on aryl diazonium salts whether preformed or generated inâ
situ from the corresponding anilines. This strategy allows a straightforward access to a variety of carboxylic acids under mild conditions
Photocatalyzed Synthesis of 3-Substituted Phthalides: A Key Access to (+/-)-Herbaric Acid
International audienceAn efficient organophotocatalyzed protocol was developed for the preparation of 3-substituted phthalides. The presented transformation was performed under particularly mild conditions within 6â
h and was ultimately applied to a precursor of the herbaric acid
Multi-platform observations of a representative springtime case of Bodélé and Sudan dust emission, transport and scavenging over West Africa
26-30 november
A new series of trivalent lanthanide (Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy) coordination polymers with a 1,2-cyclohexanedicarboxylate ligand: synthesis, crystal structure, luminescence and catalytic properties
International audienc
Detection of hepatitis C virus antibodies and RNA among medicolegal autopsy cases in Northern France
International audienceForensic medical personnel are at risk of exposure to blood-borne viruses including hepatitis C virus (HCV). The aim of this study was to determine prevalence of HCV markers among a cadaver population at the medicolegal institute in Lille. Seventy-seven consecutive cadavers were screened for antibodies to HCV and for HCV RNA. Positive results were confirmed by an immunoblot assay. Fifty-three cadavers had a histopathologic study. Anti-HCV was detected in 13 (16.9%) and accompanied by HCV RNA in 7 (9%) cases. The rate of HCV RNA detection among seropositive cases was 53.8%. Five cases had histopathologic lesions suggestive of hepatitis. This is the first HCV RNA screening in forensic cadavers. The results highlight the high prevalence rate of HCV cases in medicolegal practice in Lille. All forensic specimens should be treated as potentially infectious and universal precautions should be taken
Multi-platform observations of a springtime case of Bodele and Sudan dust emission, transport and scavenging over West Africa
The structure of the Saharan air layer over Niger and Benin during a major springtime dust event from the Bodele region and Sudan is investigated using airborne lidar and dropsonde measurements. Aircraft operations were conducted on 13 and 14 June 2006, within the framework of the African Monsoon Multidisciplinary Analysis Special Observing Period. Complementary ground-based and satellite observations, as well as European Centre for Medium-range Weather Forecasts analyses are used to investigate the regional aspects of emission, transport and deposition in the period from 9 to 14 June 2006, to provide a framework for the interpretation of the airborne measurements. The study details the transport patterns of dust from eastern Saharan sources towards the southwest in the springtime, and highlights the role of the intertropical discontinuity and the Darfur mountains in injecting the aerosols from Bodele and Sudan, respectively, over the monsoon flow, and in the African easterly jet (AEJ) region. It also illustrates the impact of the daily variability of the emissions in the source regions on the dust load advected westward by the AEJ and observed over Benin. The impact of a mesoscale convective system (MCS) on the dust load and vertical distribution observed over Benin and southern Niger was also investigated, nearly 12 hours after its passage over Benin. The only discernible impact on the dust distribution is observed to be associated with widespread subsidence in the wake of the MCS, over northern Benin and Niger. Wet scavenging related to convective or stratiform rain could not be observed, as processed air masses were replaced by fresh dust transported in the upper Saharan air layer by the AEJ. Over southern Benin, the dust distribution appeared to be mostly controlled by processes affecting the planetary boundary layer upstream, i.e. over Nigeria or Chad. Because springtime dust from remote eastern sources (such as observed in this case) is mainly transported into the AEJ, it could impact on the radiation budget in the AEJ region, thereby possibly modifying the West African weather at the synoptic scale