Selective Hydrogenations and Dechlorinations in Water Mediated by Anionic Surfactant-Stabilized Pd Nanoparticles.

We report a facile, inexpensive, and green method for the preparation of Pd nanoparticles in aqueous medium stabilized by anionic sulfonated surfactants sodium 1-dodecanesulfonate 1a, sodium dodecylbenzenesulfonate 1b, dioctyl sulfosuccinate sodium salt 1c, and poly(ethylene glycol) 4-nonylphenyl-3-sulfopropyl ether potassium salt 1d simply obtained by stirring aqueous solutions of Pd(OAc)2 with the commercial anionic surfactants further treated under hydrogen atmosphere for variable amounts of time. The aqueous Pd nanoparticle solutions were tested in the selective hydrogenation reactions of aryl-alcohols, -aldehydes, and -ketones, leading to complete conversion to the deoxygenated products even in the absence of strong Brønsted acids in the reduction of aromatic aldehydes and ketones, in the controlled semihydrogenation of alkynes leading to alkenes, and in the efficient hydrodechlorination of aromatic substrates. In all cases, the micellar media were crucial for stabilizing the metal nanoparticles, dissolving substrates, steering product selectivity, and enabling recycling. What is interesting is also that a benchmark catalyst like Pd/C can often be surpassed in activity and/or selectivity in the reactions tested by simply switching to the appropriate commercially available surfactant, thereby providing an easy to use, flexible, and practical catalytic system capable of efficiently addressing a variety of synthetically significant hydrogenation reactions.

Pyrrolidine-Containing Bisphosphonates as Potential Anti-Resorption Bone Drugs.

Bisphosphonates, particularly those with N-substituted groups, are currently the most popular drugs for the treatment of osteoporosis. However, their chemical structures are still rather simple and new synthetic methods are needed to expand their molecular complexity and also improve their specificity of action towards other targets as anticancer, antibacterial, and antimalarial drugs. Herein, we report a new class of potential antiresorption bisphosphonate drugs that have a pyrrolidine unit with different substituents, obtained through a simple dipolar cycloaddition reaction between azomethine ylides and vinylidenebisphosphonate derivatives as precursors. The methodology led to the efficient preparation of a wide range of (1-methylpyrrolidine-3,3-diyl)bis(phosphonic esters) derivatives with different substituents in position 4.

Substrate selective amide coupling driven by encapsulation of a coupling agent within a self-assembled hexameric capsule.

Encapsulation of a cationic carbodiimide condensing agent within a self-assembled hexameric capsule made of resorcin[4]arene units provides a nano-environment that efficiently steers the substrate selectivity in the amide synthesis reaction between carboxylic acids and primary amines. While in solution pairs of acids react similarly with a given amine, in the presence of the capsule the formation of the shorter amide is greatly favored.

Electrochemical measurement of mercury concentration profiles in the pore-waters of sediments of the Venice Lagoon by ion-exchange voltammetry at polymer modified electrodes.

Glassy carbon electrodes modified with coatings of poly-[1-methyl-3-(pyrrol-1-ylmethyl)pyridinium], poly-MPP, were employed for preconcentrating and detecting the anionic complex HgCl4(2-), which is the prevailing inorganic Hg(II) species in salt waters such as the pore-waters of sediments here examined. The application of ion-exchange voltammetry at poly-MPP coated electrodes in combination with an in situ pore-water sampler allowed the measurement of concentration vs. depth profiles for mercury dissolved in the pore-waters of a salt-marsh and of a mud-flat located in a polluted area of the Venice Lagoon. The trends of the mercury profiles are discussed in comparison with the trends measured from the same location for other trace metals (Zn, Cd, Cu and Pb) and reduced species such as S(-II) and Fe(II).