Since the separation of enantiomers by Louis Pasteur we have realized that chirality has many important repercussions in our lives. In the last decades, the chiral properties of organic molecules in solution and adsorbed on surfaces have intensively been explored and analysed. At the same time, new chiral systems have been discovered, such as thiolate protected metal clusters and carbon nanotubes, both of which present intrinsic chirality at the nanoscale. However, the notion and the impact of chirality in these systems are still evolving and the research is mostly concentrating on the structure and optical properties of these materials. In contrast, the aim of the proposed project is to study the creation, amplification and transfer of chirality in thiolate protected gold clusters and carbon nanotubes.
The project clarify fundamental aspects of chiral intermolecular interactions, enantioseparation processes and transfer of chirality at the nanoscale. As such it will have impact on many fields where both systems are crucial, such as in nanotechnology, nanomedicine and molecular electronics. Using clusters and carbon nanotubes with well-defined composition and structure will allow us to gain insight that is difficult to obtain otherwise. Particularly a large part of the project focuses on dynamic aspects of the metal-sulphur interface which plays an important role in many applications but which has been almost completely neglected up to now. Importantly, the project makes use of chiral vibrational spectroscopies extending the application of these techniques to the field of nanotechnology.
Objectives and overview of the action:
The aim of ChiralComm is to study the creation, amplification and transfer of chirality in thiolate protected gold nanoclusters and carbon nanotubes. The achievements of the project will help to understand the principles and possibilities of chiral intermolecular interactions at the 1D nanoscale. Unlike the well-established theory of chirality for simple organic molecules, the notion of chirality at this scale is still evolving, and presents high potential for applications in nanotechnology as well as in the pharmaceutical industry and chiral technology. In particular, toward this aim, the ER (experienced researcher) has defined 3 specific objectives:
Objective 1: Creation of local chirality in a global racemic mixture of AuNCs (Fig. 3). The creation of enantiopure forms, without any interference from chiral seeds, is a fundamental and often challenging problem in chemistry related with the origin of homochirality in life. This problem has been addressed in 2D surfaces and in-solution chemistry, but up to now, it has not been reached with the participation of achiral nanoparticles. The ER will take advantages of the dynamic properties of thiolate protected gold clusters towards the creation of local enantiomers.
Objective 2: To assess quantitative information on the chiral amplification phenomena in AuNCs. Systematic variation of the relative concentration of chiral agents in the nanoclusters will allow the ER to explore chiral amplification phenomena such as “Sergeant and Soldiers” and “Majority Rules” on thiolate-gold surface.
Objective 3: To examine the transfer of chirality between chiral AuNCs and carbon nanotubes. Despite the progress made in the recent years, most of the methods used for their synthesis result in single wall carbon nanotubes (SWNTs) mixtures that have a broad range of diameters and chirality. Indeed, in order to obtain homochiral carbon nanotubes post-synthesis methods like to wrap of SWNTs with chiral molecules have been developed, to achieve a few milligrams of the chiral material. In ChiralComm the ER takes advantage of the size and the chirality of the gold nanoparticles to encapsulate them inside the carbon nanotubes. In such a way, the ER will transfer the chirality from chiral AuNCs to the achiral carbon nanotubes, obtaining SWNTs with defined helicity
