Gold Nanomolecules : Developing Synthetic Protocols, Characterization And Investigation Of Ligand Effects On Structure And Properties

The term "Nano" in chemistry refers to particles/molecules in the size range 1 to 100 nm. Gold nanoparticles were used in ancient times in making decorative glass as they produce vibrant, size dependent, colors upon interaction with light. Gold is a preferred choice of metal for the synthesis of nanoparticles mainly due to its inertness to atmospheric conditions and most chemicals. Gold thiolate nanomolecules, which is the primary focus of this dissertation research, are chemical molecules with a fixed number of gold atoms and organo-thiolate ligands. They are of the form Aux(SR)y and possess molecule-like properties as a result of distinctive quantum confinement effects occurring at the nanoscale size. The optical and electronic properties of these molecules change as a function of "x" and "y" in the formulation Aux(SR) y. The stability of these nanomolecules can be attributed due in part to their symmetrical geometry as evidenced by the X-ray crystallography. Recent research in the field has focused on exploiting the size-dependent properties of gold nanomolecules in applications like nano-electronics, biological sensing and catalysis. But much of the hindrance to these advances come from the lack of established protocols to synthesize monodisperse nanomolecules in high yields. Brust-schiffrin protocol for the synthesis of nanomolecules yields stable products in a two-phase system which can be dried and re-dispersed without affecting the stability. But the protocol has a major drawback of producing a polydisperse mixture of different sizes of nanomolecules. A major portion of my dissertation focuses on addressing this issue of polydispersity of products. In this regard, I have investigated the one-phase synthesis protocol for synthesis of gold-thiolate nanomolecules wherein the gold salt and the capping ligands are essentially dissolved in a single solvent system. This protocol is peculiar in that it yields various sizes which are otherwise not observed.

Name thesis:degree_name

Ph.D. in Chemistry

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry and Biochemistry

Year dc:date.available

2015

Author dc:creator

• Nimmala, Praneeth Reddy

Contributors dc:contributor

• Amala Dass
• Joseph R. Gladden
• James Cizdziel

• Aromatic
• Chemistry
• Gold
• Nanomolecules
• Nanoparticles
• Phenylethanethiol

Repository record dc:identifier

https://egrove.olemiss.edu/etd/412

OAI identifier oai:identifier

oai:egrove.olemiss.edu:etd-1411