A mild, selective and facile synthesis of vinylsilanes via a recyclable platinum nanoparticle catalysed hydrosilylation of alkynes is reported. Various functionalized alkynes are selectively hydrosilylated to furnish functional β-E vinylsilanes in high yields. The catalytic effectiveness, ease of catalyst recovery and recyclability of the polysiloxane stabilized Pt-nanoparticle catalyst are the major achievements of this work. Detailed in situ characterization using Electron Microscopy and controlled poisoning experiments supports the participation of Pt-nanoparticles as active catalysts.
The utilization of nanoparticles for a variety of applications has raised much interest in recent years as new knowledge has emerged in nanochemistry. New and diverse methods for synthesis, characterization, and application of these particles have been discovered with differing degrees of ease and reproducibility. Post-synthetic modification of nanoparticles is often a required step to facilitate their use in applications. The reaction conditions and chemical environment for the nanoparticle synthesis may not support or may conflict with further reactions. For this reason, it is beneficial to have phase transfer methods for nanoparticles to allow for their dispersion in a variety of solvents. Phase transfer methods are often limited in the types and sizes of particles that can be effectively dispersed in an immiscible solvent. Currently, general transfer methods for a wide variety of nanoparticles have not been identified. New routes for phase transfer allow for utilization of a larger range of particles in applications which were previously limited by solubility and reactivity issues. In this work, we will describe the fundamental methods for the phase transfer of metallic nanoparticles. We will look at the major problems and pitfalls of these methods. The applications of phase transfer will also be reviewed, mainly focusing on catalysis and drug delivery.
17 December 2009 in Applied Organometallic Chemistry
In this work, a NIR emitting dye, p-toluenesulfonate (IR-813) was explored as a model precursor to develop red emissive carbon dots (813-CD) with solvatochromic behavior with a red-shift observed with increasing solvent polarity. The 813-CDs produced had emission peaks at 610 and 698 nm, respectively, in water with blue shifts of emission as solvent polarity decreased. Subsequently, 813-CD was synthesized with increasing nitrogen content with polyethyleneimine (PEI) to elucidate the change in band gap energy. With increased nitrogen content, the CDs produced emissions as far as 776 nm. Additionally, a CD nanocomposite polyvinylpyrrolidone (PVP) film was synthesized to assess the phenomenon of solid-state fluorescence. Furthermore, the CDs were found to have electrochemical properties to be used as an additive doping agent for PVP film coatings.