A Zinc(II) Tetraphenylporphyrin Peripherally Functionalized with Redox-Active "trans-[(η5-C5H5)Fe(η5-C5H4)C≡C](κ2- dppe)2Ru(C≡C)-" Substituents: Linear Electrochromism and Third-Order Nonlinear Optics

Dedicated to Dr. Claude Lapinte on the occasion of his retirement, in memory of the good times spent together in France and Australia.International audienceA nonametallic organometallic-coordination complex (4), assembled from redox-active ferrocenyl (Fc) and Ru(κ2-dppe)2 fragments (dppe = 1,2-bis(diphenylphosphino)ethane) as peripheral donor groups and a central Zn(II) tetraphenylporphyrin (ZnTPP) core, has been prepared and characterized. Complex 4 is obtained in one step from a pentametallic organometallic porphyrin precursor following substitution of the peripheral chloride ligands by ferrocenylalkynyl moieties (Ctriple bond; length of mdashCFc). The spectroelectrochemistry of 4, and that of previously reported porphyrins featuring related peripheral electron-rich d6-transition metal alkynyl units, has been investigated; the optical and redox properties of 4 are briefly discussed, and its potential, and that of a related pentanuclear tetraferrocenyl ZnTPP complex, to function as redox-switchable chromophores is examined. Preliminary studies of the cubic NLO properties of 4 have been undertaken by Z-scan studies at 560 nm and 630 nm, the results from which are also reported

Estampe dans les institutions

Rémi Mathis : Il existe de multiples manières d’utiliser l’estampe et donc de la collectionner, d’où une certaine dichotomie bibliothèque/musée notamment, qui correspondent à des usages divers. Pouvez-vous rapidement présenter l’institution où vous travaillez ? Corinne Le Bitouzé : Collection nationale d’images fixes multiples, le département des Estampes est l’héritier des collections royales et s’est constitué par agrégation de différentes collections dont la première est celle de l’abbé Ma..

Testing general relativity with accretion onto compact objects

The X-ray emission of neutron stars and black holes presents a rich phenomenology that can lead us to a better understanding of their nature and to address more general physics questions: Does general relativity apply in the strong gravity regime? Is spacetime around black holes described by the Kerr metric? This white paper considers how we can investigate these questions by studying reverberation mapping and quasi-periodic oscillations in accreting systems with a combination of high-spectral and high-timing resolution. In the near future, we will be able to study compact objects in the X-rays in a new way: advancements in transition-edge sensors (TES) technology will allow for electron-volt-resolution spectroscopy combined with nanoseconds-precision timing.Comment: White paper submitted for Astro2020 Decadal Survey. 8 pages, 2 figure

Agricultural intensification and policy interventions: Exploring plausible futures for smallholder farmers in Southern Mali

Assessing how livelihoods in rural sub-Saharan Africa might change given future trends in socio-economic and biophysical conditions helps to identify and direct effective efforts towards poverty reduction. Based on existing literature, hypothetical changes in farmer practices and policy interventions were described and used to build five contrasting scenarios towards the year 2027. A simulation framework was developed to assess food self-sufficiency and income per capita now and in the future for a representative village of 99 households in Southern Mali. In the current situation, 26% of the farms were food self-sufficient and above the 1.9 US$ day−1 poverty line. This percentage would fall to 13% in the “Business as usual” scenario. In the “Dairy development” scenario, with intensification of livestock production and support to the milk sector, 27% of farms would be food self-sufficient and non-poor. Additional policy interventions targeting family planning and job creation outside agriculture would be needed to improve both household food self-sufficiency and income per capita. In this optimistic scenario, 77% of the farms would be non-poor and food self-sufficient in 2027. Additional programs to promote Integrated Pest Management, small-scale mechanization and mineral fertilizer on traditional cereals could allow a drastic increase in productivity and would lift 94% of the farm population out of poverty. Considering the entire heterogeneous farm population was crucial to accurately assess pathways out of poverty. Our study stresses the need for a strategic and multi-sectoral combination of interventions to improve livelihoods