Date of Award
Doctor of Philosophy (PhD)
Chemistry and Biochemistry
Balasubramanian Ramjee (Director)
Richard V. Gregory
Kenneth G. Brown
Jennifer L. Poutsma
Hani E. Elsayed-Ali
In this dissertation, a detailed investigation on the influence of various macrocyclic resorcinarene surfactants in determining the morphology, stabilization and self-assembly of mono- and bi- metallic nanoparticles was undertaken. Chapter 2 describes the influence of resorcinarene surfactants functionalized with amine- and thiol- headgroups in determining the morphology of monometallic Pt nanoparticles synthesized via the Brust-Schiffrin reaction. We found that while resorcinarene benzylthiol can lead to the formation of highly branched Pt nanostructures, resorcinarene amine can lead to the formation of anisotropic crystalline Pt nanoparticles. Further, we have evaluated the influence of resorcinarene ligands in determining the catalytic activity of these nanoparticles.
Chapter 3 evaluates the role of multidentate resorcinarene surfactants in influencing the morphology and composition of catalytic bimetallic nanoparticles synthesized via a Brust-Schiffrin reduction. We have successfully shown the Pt rich V-shaped PdPt nanoparticles and Pd rich spherical PdPt nanoparticles produced in the presence of resorcinarene amine surfactant. Our detailed mechanistic investigations show newer insights into the formation of anisotropic nanostructures under Brust-Schiffrin reaction conditions. These anisotropic Pt rich bimetallic nanoparticles can act as excellent, stable catalysts for Suzuki cross coupling reactions.
Chapter 4 describes the development of novel multidentate resorcinarene quaternary ammonium salts to stabilize metal nanoparticles in both organic and aqueous medium. We have shown that ionic resorcinarene surfactants can phase-transfer citrate stabilized gold colloids from aqueous dispersions into organic solvents, and their long term dispersion stability depends on the nature of the ionic resorcinarene headgroup. To better understand the interaction of resorcinarene quaternary ammonium salts, we have also undertaken direct synthesis of gold nanoparticles employing these surfactants and have evaluated their stability under a variety of conditions.
Chapter 5 explores the synthesis of hollow resorcinarene polymeric nanocapsules via thiol-ene photopolymerization using alkene building blocks of various valencies. We have shown that the thickness and rigidity of hollow polymeric nanocapsules can be varied systematically by altering the valencies of the alkene building blocks. We have employed hollow, polymeric, thiol-ene resorcinarene nanocapsules as 3-D template reaction vessels for the in situ synthesis and assembly of platinum nanoparticle aggregates and have shown their utility as hydrogenation catalysts.
"Synthesis, Morphological Control, Dispersion Stabilization and In Situ Self-Assembly of Noble Metal Nanostructures Using Multidentate Resorcinarene Surfactants"
(2016). Doctor of Philosophy (PhD), dissertation, Chemistry and Biochemistry, Old Dominion University, DOI: 10.25777/6th7-js72