Silica-Supported Silver Nitrate as a Highly Active Dearomatizing Spirocyclization Catalyst: Synergistic Alkyne Activation by Silver Nanoparticles and Silica

In contrast to the rapidity with which scientific information is published, the application of new knowledge often remains slow, and we believe this to be particularly true of newly developed synthetic organic chemistry methodology. Consequently, methods to assess and identify robust chemical reactions are desirable, and would directly facilitate the application of newly reported synthetic methodology to complex synthetic problems. Here, we describe a simple process for assessing the likely scope and limitations of a chemical reaction beyond the idealized reaction conditions initially reported. Using simple methods and common analytical techniques we demonstrate a rapid assessment of an established chemical reaction, and also propose a simplified analysis that may be reported alongside new synthetic methodology.

In this work, we investigate the catalytic properties of silver nanoparticles supported on silica spheres. The technique to support silver particles on silica spheres effectively avoids flocculation of nanosized colloidal metal particles during a catalytic process in the solution, which allows one to carry out the successful catalytic reduction of dyes. The effects of electrolytes and surfactants on the catalytic properties of silver particles on silica have been investigated. It is found that the presence of surfactants depresses the catalytic activity of the silver particles to some extent by inhibiting the adsorption of reactants onto the surface of the particles. Electrolytes either increase the migration rate of reactants in the solution resulting in an increase in the catalytic reaction rate or inhibit the adsorption of reactants onto the surface of the silver particles leading to a loss in the activity of the metal particles.