Consecutive Reactions with Sulfoximines: Straightforward Synthesis of Substituted 5,5-Spiroketals

International audienceAn efficient sysnthesis of 5,5-spiroketals, i.e. 1,6-dioxaspiro[4.4]nonane derivatives, is described from 2-(sulfonimidoylmethylene)tetrahydrofurans involving a consecutive epoxide opening / oxa-Michael spiroketalization sequence. This methodology was applied to the very direct synthesis of chalcogran, a beetle pheromone

Synthesis of bromo- and carboxylic acid-substituted methylenepyrans

International audienceIn this contribution we describe a series of pyranylidene derivatives bearing bromine atoms in various positions. Some of these bromo derivatives have been converted in carboxylic acid by halogen-metal exchange reaction using gaseous CO2 as electrophile. Selected compounds have been studied by UV-visible absorption and cyclic voltametry to study the influence of the substituent on the pyranylidene core

New 8-substituted BODIPY-based chromophores: synthesis, optical and electrochemical properties

International audienceBODIPY-based chromophores, in which an electron withdrawing difluoro-boraindacene fragment is connected via position 8 to different donor fragments, were synthesized. Their electrochemical and photophysical properties were studied. All compounds exhibit a quasi-reversible oxidation corresponding to the formation of a BODIPY p-radical cation at around 0.8 V vs. FeCp2+/FeCp2 that is slightly sensitive to the nature of the electron donating group. A reversible reduction is observed around - 1.6 V vs. FeCp2+/FeCp2 corresponding to the formation of the BODIPY p-radical anion. Cyclic voltammetry analysis of a gamma-methylenepyran substituted BODIPY indicates the formation of redox bistable system with high bistability. In dichloromethane solution, the chromophores exhibit an intense absorption band around 502 nm and an emission in the 516-528 nm range. A significant emission quench is observed in case of amino and gamma-methylenepyran substituents

Studing of Polithermal Solubility of Tris-Acetylacetonat Chrome (III) and Cobalt (III) in Water-Propanol and Isopropanol Solvents

В работе представлены данные по растворимости трис-ацетилацетонатов кобальта(III) и хрома(III) в водно-пропанольных растворах, в широком диапазоне температур и концентраций спиртов. Проведена статистическая обработка полученных данных, рассчитаны термодинамические параметры процесса растворения. На зависимостях растворимости от концентрации обнаружена точка инверсии, соответствующая изменению механизма гидратации при перестроении растворителя от структуры воды к структуре спиртового раствора. Положение точки инверсии зависит от температуры, природы и содержания спирта.The data of solubility of tris-acetylacetonats cobalt (III) and chrome (III) in water and water-propanol and water-isopropanol solutions in a wide range of temperature and concentration of alcohol is presented. Statistical processing of the received data is spent. Thermodynamics parameters of process dissolution are calculated. Оn dependences solubility inversion point corresponding to change of the mechanism of gidration at evolution from structure of water to structure of alcoholic solution is found out on concentration. Position inversion point depends on temperature, content of alcohol and its nature

Studing of Polithermal Solubility of Tris-Acetylacetonat Chrome (iii ) and Cobalt (iii ) in Water-Methanol Solvents

В работе представлены данные по растворимости трис-ацетилацетонатов кобальта(III) и хрома(III) в воде и водно-метанольных растворах в широком диапазоне температур и концентраций спирта. Проведена статистическая обработка полученных данных, и рассчитаны термодинамические параметры процесса растворения. На зависимостях растворимости от концентрации обнаружена точка инверсии, соответствующая изменению механизма гидратации при перестроении растворителя от структуры воды к структуре спиртового раствора. В области высоких концентраций >0,8-0,9 мольные доли, зависимости lgS - Cсп, почти параллельны оси абсцисс.The data of solubility of tris-acetylacetonats cobalt (III) and chrome (III) in water and water-methanol solutions in a wide range of temperature and concentration of alcohol is presented. Statistical processing of the received data is spent. Thermodynamics parameters of process dissolution are calculated. Оn dependences solubility inversion point corresponding to change of the mechanism of gidration at evolution from structure of water to structure of alcoholic solution is found out on concentration. Dependences lgS-Cаl are almost parallel to an axis of abscises in the field of high concentration > 0.8-0.9 mole fraction

Studing of Polithermal Solubility of Tris-Acetylacetonat Chrome (iii ) and Cobalt (iii ) in Water-Methanol Solvents

В работе представлены данные по растворимости трис-ацетилацетонатов кобальта(III) и хрома(III) в воде и водно-метанольных растворах в широком диапазоне температур и концентраций спирта. Проведена статистическая обработка полученных данных, и рассчитаны термодинамические параметры процесса растворения. На зависимостях растворимости от концентрации обнаружена точка инверсии, соответствующая изменению механизма гидратации при перестроении растворителя от структуры воды к структуре спиртового раствора. В области высоких концентраций >0,8-0,9 мольные доли, зависимости lgS - Cсп, почти параллельны оси абсцисс.The data of solubility of tris-acetylacetonats cobalt (III) and chrome (III) in water and water-methanol solutions in a wide range of temperature and concentration of alcohol is presented. Statistical processing of the received data is spent. Thermodynamics parameters of process dissolution are calculated. Оn dependences solubility inversion point corresponding to change of the mechanism of gidration at evolution from structure of water to structure of alcoholic solution is found out on concentration. Dependences lgS-Cаl are almost parallel to an axis of abscises in the field of high concentration > 0.8-0.9 mole fraction

Methylenepyran based dipolar and quadrupolar dyes: synthesis, electrochemical and photochemical properties

International audienceThis paper presents the synthesis of a series of push-pull and quadrupolar π-conjugated structures incorporating pro-aromatic methylenepyran electron-donor groups and various electron-attracting groups. Some of the methylenepyran derivatives were oxidized by I2 to give, after reduction by Na2S2O3, bismethylenepyran compounds via successive steps. The electrochemical redox properties of methylenepyrans 5-9 and extended bismethylenepyrans 10, 14, and 15 determined by cyclic voltammetry indicate the formation of redox bistable systems with high bi-stability. Oxidation of the dimers obtained from 5 to 9 was also described. All compounds are colored and slightly fluorescent (except some bismethylenepyran derivatives). Some compound second-order nonlinear optical properties were investigated, and large positive values of μβ were obtained. A positive dimer effect was also observed for bispyran derivatives

Studing of Polithermal Solubility of Tris-Acetylacetonat Chrome (III) and Cobalt (III) in Water-Propanol and Isopropanol Solvents

В работе представлены данные по растворимости трис-ацетилацетонатов кобальта(III) и хрома(III) в водно-пропанольных растворах, в широком диапазоне температур и концентраций спиртов. Проведена статистическая обработка полученных данных, рассчитаны термодинамические параметры процесса растворения. На зависимостях растворимости от концентрации обнаружена точка инверсии, соответствующая изменению механизма гидратации при перестроении растворителя от структуры воды к структуре спиртового раствора. Положение точки инверсии зависит от температуры, природы и содержания спирта.The data of solubility of tris-acetylacetonats cobalt (III) and chrome (III) in water and water-propanol and water-isopropanol solutions in a wide range of temperature and concentration of alcohol is presented. Statistical processing of the received data is spent. Thermodynamics parameters of process dissolution are calculated. Оn dependences solubility inversion point corresponding to change of the mechanism of gidration at evolution from structure of water to structure of alcoholic solution is found out on concentration. Position inversion point depends on temperature, content of alcohol and its nature

Selective formation of a unique diphosphonium-diphosphine from a tetraphosphine double protonation induced by zirconium salts

International audienc

Converging and Diverging Synthetic Strategies to Tetradentate (<i>N</i>,<i>N</i>′)-Diaminomethyl,(<i>P</i>,<i>P</i>′)-Ferrocenyl Ligands: Influence of <i>tert</i>-Butyl Groups on Ferrocene Backbone Conformation

Hexasubstituted hybrid tetradentate (<i>N</i>,<i>N</i>′,<i>P</i>,<i>P</i>′)-ferrocenes bearing phosphino and aminomethyl groups, plus hindering <i>tert</i>-butyl moieties, were synthesized by using two different strategies: a “diverging” synthesis involving successive functionalization of preformed di-<i>tert</i>-butylated ferrocene and a “converging” assembly of the species from appropriately substituted cyclopentadienyl rings. While the new cyclopentadienyl salts formed are of interest, their assembly with iron dichloride used as a “converging” way to produce tetradentate ferrocene ligands presented several drawbacks. Conversely, the synthesis of new <i>tert</i>-butylated (aminomethyl)­ferrocene derivatives was found convenient to further form (<i>N</i>,<i>N</i>′)-aminomethyl,(<i>P</i>,<i>P</i>′)-<i>tert</i>-butylated-ferrocenyl diphosphines by N-directed <i>ortho</i>-metalation. The novel N₂-didentate and N₂P₂-tetradentate <i>tert</i>-butylated ferrocene compounds were all synthesized in good to high yields (48–96%) and tolerated aryl, alkyl, and heteroaryl phosphino groups as substituents on nitrogen and phosphorus atoms. They were characterized by X-ray diffraction and multinuclear NMR (¹H, ¹³C, ³¹P, ¹⁵N). We observed the conformation control provided to <i>rac</i>-(<i>N</i>,<i>N</i>′)-diaminomethyl-(<i>P</i>,<i>P</i>′)-<i>tert</i>-butylated-ferrocenyldiphosphines with in particular the systematic near-eclipsed conformation of aminomethyl groups. This conformation is at the origin of the unexpected formation at RT of a zwitterionic cyclopalladate from an (aminomethyl)­ferrocene derivative, arising from intramolecular Cp-proton transfer to the proximate free amino group by simple C–H activation reaction in the presence of palladium dichloride