Sandra E. Martín

Efficient solvent-free iron (III) catalyzed oxidation of alcohols by hydrogen peroxide

Selective oxidation of secondary and benzylic alcohols was efficiently accomplished by H2O2 under solvent-free condition catalyzed by FeBr3. Secondary alcohols are selectively oxidized even in the presence of primary ones. This method is high yielding, safe and operationally simple.

Catalytic aerobic oxidation of alcohols by Fe(NO3)3–FeBr3

Selective aerobic oxidation of secondary and benzylic alcohols was efficiently accomplished by the binary catalyst system Fe(NO3)3–FeBr3 under air at room temperature. The oxidation developed in mild conditions and showed good yields. A secondary alcohol even in the presence of a primary one was selectively oxidized.

An efficient and selective aerobic oxidation of sulfides to sulfoxides catalyzed by Fe(NO3)3–FeBr3

Abstract The binary system Fe(NO 3 ) 3 –FeBr 3 is a very efficient catalyst for the selective air-oxidation of sulfides to sulfoxides. Since the oxidation is selective, it may be applied to any type of dialkyl and alkyl aryl sulfide, as well as to substrates of biological interest. It develops in mild conditions, giving a high yield in the presence of different functional groups on the sulfide. Other binary systems such as Fe(NO 3 ) 3 –FeBr 2 and Cu(NO 3 ) 2 –CuBr 2 are also effective catalysts for sulfoxidation. In contrast to previous oxygenation methods, this oxidation requires neither an aldehyde nor a transition metal complex.

Oxidation of organic sulphides to sulphoxides by nitric acid catalyzed by FeBr3 and (FeBr3)2(DMSO)3

Abstract The selective oxidation of organic sulphides to sulphoxides by 9.5 % (∼1.5 M) nitric acid was catalyzed by FeBr 3 and the coordination compound (FeBr 3 ) 2 (dimethylsulphoxide) 3 .

Possible role of nitrate/nitrite redox cycles in catalytic and selective sulfoxidation reaction. Metallic nitrates and bromides as redox mediators: a comparative study

Abstract Different combinations of metallic nitrates and bromides were used as redox mediators in the conversion of sulfides to sulfoxides. The metal salts were used in catalytic amounts in the oxidation reaction. It is suggested that in the oxidation and oxygenation processes are involved species originated from the nitrate/nitrite redox cycles and/or the dissolved atmospheric dioxygen and/or coordinated water molecules, all in combination with the redox couple 2Br − ⇄Br 2 +2e − . The utilized metallic centers showed distinct reactivity; Fe III appears as the best metallic center.

One-pot palladium-catalyzed phosphination of aryl iodides with Ph2PSnR3

Abstract We found a very efficient one-pot phosphination reaction starting with Ph 3 P, which by reaction with Na metal in liquid ammonia gives Ph 2 P − ions that reacted with R 3 SnCl to afford (trialkylstannyl)diphenylphosphine. The palladium-catalyzed coupling reaction of these stannanes with aryl iodides yield functionalized phosphines in high yield (69–97%). The use of Ph 3 P as starting reagent, the endurance of the reaction to a wide variety of functional groups and the easiness of a one-pot reaction make this method a useful and versatile approach to tertiary phosphine oxides.

Electrochemical synthesis of palladium nanoparticles in PVP solutions and their catalytic activity in Suzuki and Heck reactions in aqueous medium

Fil: Uberman, Paula Marina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Cordoba. Instituto de Investigaciones en Fisico-quimica de Cordoba. Universidad Nacional de Cordoba. Facultad de Ciencias Quimicas. Instituto de Investigaciones en Fisico-quimica de Cordoba; Argentina

Synthesis of biphenyl-based arsine ligands by Suzuki–Miyaura coupling and their application to Pd-catalyzed arsination

A versatile and efficient approach for the synthesis of new biphenyl-based arsine ligands, by a Pd-catalyzed arsination to introduce the -AsPh(2) moiety, and then a Suzuki-Miyaura cross-coupling for biaryl construction is reported. By Pd-catalyzed arsination with n-Bu(3)SnAsPh(2) (1), (2-bromophenyl)diphenylarsine (2, 83%) was obtained. The Suzuki-Miyaura reaction between the bromoarsine 2 and aryl boronic acids bearing different substituents provided biarylarsine ligands (80-99%). The efficiency of catalysts derived from the new biarylarsine ligands was evaluated in the Pd-catalyzed arsination with perfluoroalkyl iodides (R(f)I). Outstanding activities of catalysts derived from Pd/methoxybiarylarsine ligands were found in this coupling reaction affording perfluoroalkyl arsines in very good yields (57-100%).

PVP-Pd nanoparticles as efficient catalyst for nitroarene reduction under mild conditions in aqueous media

The catalytic activity of PVP-Pd nanoparticles synthesized by electrochemical methods was explored in nitroaromatic hydrogenation reaction. In this transformation, the colloidal nanocatalyst proved to have outstanding catalytic activity under sustainable reaction conditions. This mild process efficiently reduced the nitroaromatic group at room temperature, without high pressure of molecular hydrogen and in aqueous medium. Furthermore, several functional groups were tolerated, given the corresponding substituted arylamines in excellent yields and with high TOF. In addition, one-pot reactions and tandem process were explored, in which nitroaromatic hydrogenation reaction was included in the synthesis of modified amines. This methodology was effectively incorporated in tandem reactions and one-pot procedures, achieving N-arylamines functionalized in good isolated yields. Finally, comparison of sustainable chemistry metrics analysis demonstrated that this methodology is a reliable approach to perform the nitro compound hydrogenation process.

Synthesis, Characterization, and Nanocatalysis Application of Core–Shell Superparamagnetic Nanoparticles of Fe3O4@Pd

There is a wide number of different synthetic methods to obtain magnetite (Fe3O4) superparamagnetic nanoparticles (SPNPs). However, only a few are able to produce very small and well defined SPNPs with narrow size distribution. We report a modification of the metal-complex decomposition in organic media method in which we replace iron(iii) acetylacetonate (Fe(Acac)3) with an iron–urea complex (Fe-Urea) as metal source for the synthesis. With this modification we were able to obtain small particle sizes with a good control in size distribution. The Fe-Urea complex is easy to prepare with excellent yields. Core–shell nanoparticles are then prepared using palladium(ii) acetylacetonate as a Pd source, to obtain a Pd0 shell stabilised by oleylamine. The core–shell superparamagnetic nanoparticles of Fe3O4@Pd-OA are extensively characterized by FT-IR, powder X-ray diffraction, transmission electron microscopy, UV-vis, thermogravimetric analysis/differential scanning calorimetry, and magnetic susceptibility measurements, and tested in a palladium-catalyzed cross-coupling Suzuki–Miyaura reaction with promising results.