Determinação sexual e maturação gonadal de fêmeas da tartaruga-verde (Chelonia mydas) e tartaruga-cabeçuda (Caretta caretta) no extremo sul do Brasil

 Determinação sexual e maturação gonadal de fêmeas da tartaruga-verde (Chelonia mydas) e tartaruga-cabeçuda (Caretta caretta) no extremo sul do Brasil</htm

One-Step Ruthenium-Catalysed Transformation of 1,7-Enynes into Strained Bicyclic Amino Esters

International audienceThe reaction of 1,7-enynes, synthesised from α-amino acids, carried out with diazo compounds in the presence of the Cp*RuCl(cod) catalyst allowed the one-step preparation of various strained bicyclic pipecolic acid derivatives in good yields under mild conditions. The stereoselectivity of the created double bond depends on the nature of the diazoalkane, and the diastereoselectivity arises essentially from steric factors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Catalyse asymétrique au laboratoire de travaux pratiques : Synthèse d'un alcol chiral à partir de réactifs courants.

National audienc

Cp*RuCl(COD) in Catalysis : a Unique Role in the Addition of Diazoalkane Carbene to Alkynes

International audienceThe catalytic transformations of functional alkynes with diazoalkanes in the presence of the catalyst precursor RuCl(COD)Cp* are presented. They show the unique role played by the Ru(X)Cp* moiety in catalysis and that the nature of the formed products strongly depends on the alkyne functionality. Simple alkynes generate dienes via double diazoalkane carbene addition to the triple bond. Enynes with terminal triple bond lead to alkenyl bicyclo[x.1.0]alkanes, including bicyclic aminoacid derivatives. 1,6-enynes with disubstituted propargylic carbon produce in priority alkenyl alkylidene cyclopentanes. 1,6-Allenynes offer the direct access to alkenyl alkylidene bicyclo[3.1.0]hexanes. Propargylic carboxylates lead to conjugated dienes by coupling of the diazoalkane carbene with the alkyne terminal carbon and 1,2-shift of the carboxylate. All catalytic reactions can be explained by the initial formation of the 16 electron RuCl(double bond; length as m-dashCHR)Cp* moiety giving first a 2+2 cycloaddition with the alkyne triple bond

Ruthenium-Catalyzed Synthesis of Functionalized Dienes from Propargylic Esters : Formal Cross-Coupling of Two Carbenes

International audienc

Self-erasable inkless imprinting using a dual emitting hybrid organic-inorganic material

International audienceSmart emissive materials that can react to external stimuli in a reversible way are challenging to develop and have been the subject of considerable interest. Here, we present a printable hybrid material that can withstand numerous writing-erasing cycles. This material is based on a poly(methyl methacrylate) host matrix embedding by copolymerization of a red NIR phosphorescent metal cluster and a blue green 3-oxindole emitter. Irradiation of the homogeneous and stable hybrid films changes the emission color from white to deep red because of the oxygen perturbed energy transfer from the organic dye to the metal cluster. Because of the low PMMA gas permeability, encrypted data lifetime can be tuned from minutes to days, can be self-erased, and be rewritten at will. This material represents a key stepping stone for anticounterfeiting, optoelectronic, data recording, and many other technologies © 2019 Elsevier Lt

Travaux du groupe de normalisation français (AFNOR) sur les odeurs : révision de la norme sur la mesure de l'intensité d'odeur et élaboration d'une nouvelle norme pour le prélèvement d'émissions surfaciques

International audienceIn the frame of the French regulation evolution and the European standardisation on odour issues, two French technical groups were created 3 years ago. They deal with : - the update of the French standard for the measurement of odour intensity to take account of the publication of the European standardisation (EN 13725); - the elaboration of a new standard for the measurement of odour flow rate from area sources by a direct measurement approach, the enclosure approach using an emission flux chamber