Structural Conformers of (1,3-Dithiol-2-ylidene)ethanethioamides: The Balance Between Thioamide Rotation and Preservation of Classical Sulfur-Sulfur Hypervalent Bonds

The reaction of N-(2-phthalimidoethyl)-N-alkylisopropylamines and S2Cl2 gave 4-N-(2-phthalimidoethyl)-N-alkylamino-5-chloro-1,2-dithiol-3-thiones that quantitatively cycloadded to dimethyl or diethyl acetylenedicarboxylate to give stable thioacid chlorides, which in turn reacted with one equivalent of aniline or a thiole to give thioanilides or a dithioester. Several compounds of this series showed atropisomers that were studied by a combination of dynamic NMR, simulation of the signals, conformational analysis by DFT methods, and single crystal X-ray diffraction, showing a good correlation between the theoretical calculations, the experimental values of energies, and the preferred conformations in the solid state. The steric hindering of the crowded substitution at the central amine group was found to be the reason for the presence of permanent atropisomers in this series of compounds and the cause of a unique disposition of the thioxo group at close-to-right angles with respect to the plane defined by the 1,3-dithiole ring in the dithiafulvene derivatives, thus breaking the sulfur–sulfur hypervalent bond that is always found in this kind of compounds.Ministerio de Economıá y Competitividad, Spain (Project CTQ2012- 31611), Junta de Castilla y León, Consejería de Educación y Cultura y Fondo Social Europeo (Project BU246A12-1), and the European Commission, Seventh Framework Programme (Project SNIFFER FP7-SEC-2012-312411

Housing (In)Equity and the Spatial Dynamics of Homeownership in France: A Research Agenda

First published: 11 August 2020 (online)Print: Februray 2021International audienceThis paper advances a research agenda on how asset-based welfare policies, residential marketvolatility, stratified accumulation and vulnerability impinge upon the geography of inequality inproperty markets. Since the mid-1990s, housing prices have increased faster than the incomeof buyers, becoming a driver of social polarisation and household vulnerability. Few studieshave however explicitly linked socio-spatial inequality to asset capitalisation, instability andvulnerability in residential housing markets. We employ an empirically-grounded investigationof the factors driving and reinforcing these dynamics, what we conceptualise as a feedback loopmediating particular housing finance regimes. Drawing on three French cities (Paris, Lyon,and Avignon) our study develops a comparative framework to interpret the relational effectsof price, equity and homeowner vulnerability on the production of inequality across differentgeographical scales. Our approach puts into conversation debates concerning housing markets,social inequality, and ordinary financialisation in the period since the Global Financial Crisis.Cet article développe un agenda de recherche portant sur la la géographie des inégalités sur les marchés immobiliers, influencée par les politiques de protection sociale fondées sur les actifs, la volatilité du marché résidentiel, les logiques d’accumulation socialement et spatialement stratifiées, et la vulnérabilité induite des ménages. Depuis le milieu des années 1990, les prix des logements ont augmenté plus rapidement que les revenus des acheteurs, devenant un facteur de polarisation sociale et de vulnérabilité des ménages devant l’accès au logement. Peu d'études ont cependant explicitement établi un lien entre l'inégalité socio-spatiale et la capitalisation des actifs d’une part, l'instabilité et la vulnérabilité des marchés immobiliers résidentiels d’autre part. Partant d’un étude empirique des facteurs qui entraînent et renforcent ces dynamiques, notre cadre conceptuel est celui d’une boucle de rétroaction entre des régimes particuliers de financement du logement. En s'appuyant sur trois villes françaises (Paris, Lyon et Avignon), notre étude développe un cadre comparatif pour interpréter les effets du prix, de la valeur nette et de la vulnérabilité des propriétaires sur la production d'inégalités à différentes échelles géographiques. Notre approche met en débat les analyses du marchés du logement, l'inégalité sociale et la financiarisation ordinaire dans la période qui a suivi la crise financière mondiale

Self-assembled lamellar complexes of siRNA with lipidic aminoglycoside derivatives promote efficient siRNA delivery and interference

RNA interference requires efficient delivery of small double-stranded RNA molecules into the target cells and their subsequent incorporation into RNA-induced silencing complexes. Although current cationic lipids commonly used for DNA transfection have also been used for siRNA transfection, a clear need still exists for better siRNA delivery to improve the gene silencing efficiency. We synthesized a series of cationic lipids characterized by head groups bearing various aminoglycosides for specific interaction with RNA. siRNA complexation with such lipidic aminoglycoside derivatives exhibited three lipid/siRNA ratio-dependent domains of colloidal stability. Fluorescence and dynamic light-scattering experiments showed that cationic lipid/siRNA complexes were formed at lower charge ratios, exhibited a reduced zone of colloidal instability, and had smaller mean diameters compared with our previously described guanidinium-based cationic lipids. Cryo-transmission electron microscopy and x-ray-scattering experiments showed that, although the final in toto morphology of the lipid/siRNA complexes depended on the aminoglycoside type, there was a general supramolecular arrangement consisting of ordered lamellar domains with an even spacing of 67 Å. The most active cationic lipid/siRNA complexes for gene silencing were obtained with 4,5-disubstituted 2-deoxystreptamine aminoglycoside derivatives and were characterized by the siRNA being entrapped in small particles exhibiting lamellar microdomains corresponding to siRNA molecules sandwiched between the lipid bilayers. These results clearly show that lipidic aminoglycoside derivatives constitute a versatile class of siRNA nanocarriers allowing efficient gene silencing