Radicaux libres nitronyl nitroxyde chiraux (synthèse et propriétés de coordination)

La synthèse d'aimants moléculaires et plus généralement de matériauxmoléculaires magnétiques repose essentiellement sur des porteurs de spin adéquats. Il ne fait aucun doute que les radicaux libres organiques ont apporté des possibilités synthétiques inégalées grâce à une variété structurale qui se reflète au niveau des complexes et de leurs propriétés. Les nitroxydes en particulier, ont été l'objet de nombreuses études qui ont montré la variété des matériaux qu'il est possible d'élaborer:ferroaimants organiques, ferriaimants, molécules à haut spin, complexes cuivriques à transition de spin moléculaires. Toutes ces études ont montré l'importance de la chiralité sur la dimension des espèces et l'empilement cristallin, deux paramètres importants pour le comportement magnétique. De plus, de manière plus prospective, le sujet de recherche se développe vers la synthèse de matériaux bi-fonctionnels où des propriétés optiques sont associées au magnétisme.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Nitroxide radicals appended to phthalonitriles: synthesis, structural characterization and photo-physical properties

PubMed: 33664164The syntheses of 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl-2-yl)phenoxy]phthalonitrile (3, C21H19N4O3) and 4-[4-(4,4,5,5-tetramethyl-2-imidazoline-1-oxyl-2-yl)phenoxy]phthalonitrile (4) were carried out by microwaveassisted nucleophilic aromatic substitution of 4-nitrophthalonitrile (2) by the pre-formed 2-(4-hydroxyphenyl)-4,4,5,5-tetramethyl-2- imidazoline-3-oxide-1oxyl (1). Compounds 3 and 4 were characterized unambiguously by a rich array of analyses, such as melting point, FT-IR, MALDI-TOF MS, elemental analysis, UV-Vis, CV, EPR, magnetic measurements and single-crystal X-ray diffraction. Structural studies demonstrate that the C-H center dot center dot center dot X and C-X center dot center dot center dot(X = O and N) interactions in the radical nitronyl nitroxide groups play an important role in the assembly of the crystal structures. Moreover, cyclic voltammetry analyses show that the phthalonitrile substituent retains the redox properties of the Ullman radicals

Bromine-lithium exchange as a straightforward method to obtain meso-tetrakis(4-formylphenyl)porphyrin: a versatile intermediate

International audienceA three step, one-pot reaction has been developed for the introduction of the formyl functional group to the mesa position of porphyrins. Symmetric meso-tetrakis(4-formylphenyl)porphyrin ((CHO)(4)TPPH2), an important cornerstone in porphyrin chemistry, was obtained selectively in good yields via bromine-lithium exchange and subsequent Bouveault reaction. The meso-tetrakis(4-formylphenyl)porphyrin was fully characterized by HR-ESI, UV-vis, NMR, and single crystal X-ray diffraction. (C) 2015 Elsevier Ltd. All rights reserved

Hyperporphyrin effect on oxygen sensitivity of free meso-tetraphenylporphyrins

A series of dyes; three symmetric free meso-tetraphenylporphyrins, bearing phenylacetylide (H2-TPA), hexyloxy (H2-OHex) or without peripheral substituent (H2-TPP) were chosen as luminophore to explore the effect of meso-substitution on the oxygen sensing ability. These dyes were incorporated into poly(trimethylsilylpropyne) [poly(TMSP)], polymethylmethacrylate (PMMA) and silicone matrices along with additives such as perfluorododecanoic acid (PFC) to improve the oxygen sensitivity as well as ionic liquid to favor the microfiber preparation by electrospinning. The pH of the medium is affected by the composition of the cocktail, a non-trivial effect which induce protonation of the free meso-tetraphenylporphyrin derivatives bearing electron donor (H2-OHex) and withdrawing substituents (H2-TPA), which results in absorbance and emission spectroscopic modifications called elsewhere hyperporphyrin effect. Spectrophotometric titrations were carried out by using HClO4 in THE solution and PFC in [poly(TMSP)]-based thin film to study the hyperporphyrin effect of H2-TPA, H2-OHex and H2-TPP showing the influence of the substituent bn the pKa of the inner nitrogen's. The ratio of PFC/dyes optimization was prospected and the influence of the pH/protonation on the steady-state oxygen sensitivity was studied. (C) 2017 Elsevier Ltd. All rights reserved

Through the challenging synthesis of tetraphenylporphyrin derivatives bearing nitroxide moieties

Hirel, Catherine/0000-0002-6297-5650; LUNEAU, Dominique/0000-0002-1831-7693Tetraphenylporphyrin derivatives a synthetic heterocycles with convenient preparation and a richness of properties which make them attractive in broad fields such as energy, life and materials sciences. Thus, in the quest for new radical architectures, tetraphenylporphyrins are prime candidates. To this end, we designed free-base tetraphenylporphyrins bearing nitronyl and imino nitroxide moieties covalently bonded to the para-position of the meso-phenyl substituent. Their detailed synthesis and characterization arc reported here.Scientific and Technological Research Council of Turkey-TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113Z005]Financial support from the Scientific and Technological Research Council of Turkey-TUBITAK (project 113Z005) is gratefully acknowledged. The authors declare no competing financial interest