Hydrazone-Based Feedback Loops

Dartmouth College, Hanover NH

Investigators

Abstract

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professor Ivan Aprahamian of Dartmouth College will study how molecular switches can be made to communicate with each other. These studies aim to result in a deeper fundamental understanding of how to control an ensemble of molecules using molecular switches, which in turn will facilitate the understanding of the basic science required to engineer reactions cascades and ensembles, where catalysis, out-of-equilibrium self-assemblies, oscillating systems, among other processes, can be autonomously regulated. The multidisciplinary nature of the project will enable the training and retention of students at different levels of education from high school to undergraduate to graduate students. The group’s public outreach and participation in science, technology, engineering and mathematics (STEM)-related events, such as the annual Science Day at Dartmouth, will help disseminate the group’s work to broader audiences. Moreover, these activities will strengthen and extend the group’s informal and formal science education partnerships and networks with local schools and science museums. In this research, hydrazone-based switches and Zn(II)-initiated negative feedback loops (NFLs) will be used to study how inter-switch communication can be employed for controlling cascade reactions and result in functional products. The straightforward synthesis and modularity of the hydrazone switches and NFL components will allow structure-property analyses for determining the kinetic and thermodynamic factors that control the NFL threshold. With this knowledge at hand, the NFLs will be coupled together in such a way that they can either compete or feed into each other, thus creating interdependency. The NFL will then be used in the synthesis of precise amounts of coordination cages and polymers. Photoreversible ligands will also be developed so light can be used in controlling the concentration of Zn(II) in the solution, while photoacids/bases will be used to tune the solution’s pH. These systems are expected to allow for the clean regulation, using light, of an entire cascade process, thus bringing the approach a step closer to automation. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.