Exploration of Active Roles of Water in Aqueous Supramolecular Chemistry

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Hydrophobic effect-caused self-assembly (HE-SA) is conventionally defaulted as a process of hydrophobic interaction (HI) of non-polar groups. This default is one reason for the perplexity of HE-SA behavior in many cases, including biological systems, because the roles of water are neglected. Computer simulations have proposed that HEs stem from the free energy of water structure (dynamic hydrogen bonding network). The water structures are different between bulk water and the water hydrating hydrophobic molecules, known as hydrophobic hydration (HH), which cause an energy difference driving HE-SA. Consequently, the HH water is either repelled to gain entropy (conventional HE-SA) or reserved to act as an assembling component involved within the assemblies via an enthalpy/entropy compensation. The latter scenario is commonly observed in biological systems and the water component is responsible for the functions, which is the inspiration and motivation to advance the conventional HE-SA. The goal of my research is to experimentally understand the role of water in the construction and function of self-assembled colloids, which will promote supramolecular synthesis for water-mediated functions and industrial innovation of aqueous materials and technologies. My team and I have (1) explored the synthesis and aqueous self-assembly of water-insoluble metal carbonyl compounds with various structures, (2) discovered the first aqueous assembly without HI, which involves water as a major assembling component and (3) developed a number of practical techniques for water characterizations. Building on this progress, the proposed research program will target three objectives towards the comprehensive knowledge of HE-SA: (O1) Examine the possibility to transfer the knowledge already learned from the metal carbonyl organometallic to organic systems, which is essential to promote extensive studies to advance HE-SA; (O2) Explore the water component within the discovered organometallic assembly to learn its role in the construction of functional colloids; (O3) Elucidate water behavior in the HE-SA in relation to the chemical structure of the organometallic building blocks, including small molecules, linear and cyclic macromolecules. The research will advance the conventional knowledge of HE-SA and create a new niche to explore water-mediated functions for self-assembled colloids, which will promote Canada's position in research internationally, strengthen the R & D capacity for the innovation of aqueous biomedical, agricultural and household products, etc. and thus contribute to Canada's pillar industries. The students will be trained in relevant technical skills, research interests and, particularly, scientific vision, so they will be expected to take a leadership role after the training to further advance the field, create high tech jobs and establish Canada as an innovation hub.