51 - Using Metathesis to Achieve Water Solubility of Nanoparticles
One fundamental issue facing nanochemistry research today is the practical application of nanoparticles created in organic solvents but destined for use in water-based systems. The presence of organic solvents and surfactants allows for the high temperatures required for synthesis, and yields monodisperse nanoparticles. However, as a result of synthesis in organic solvent, nanoparticles are left with coronas of long hydrophobic surfactant molecules. Current methods for improving water solubility, such as ligand exchange, do not exhibit equivalent efficacy for all nanoparticle systems. A unique opportunity to overcome this problem lies in the exploitation and manipulation of the chemistry of the surfactant molecules, which are frequently unsaturated fatty acids. The double bond functionality provides a pathway for access to many polar functional groups, and it is this bond that will be targeted. Using the Grubbs€ metathesis reaction, a ruthenium catalyst will be used to cleave the surfactant molecules at the double bond and attach another molecule with a double bond at that site. The reaction allows for precise control of the resultant structure of the ligand. Subsequently, species of nanoparticles and unsaturated surfactants will be varied to showcase the universality and scope of this method.