Principal Investigator Mircea Dinca
Owing to their highly crystalline nature, metal-organic frameworks (MOFS) and covalent-organic frameworks (COFs) can function as perfect scaffolds for controlling the collective properties of electronically non-trivial organic molecules or metal clusters. They are therefore excellent platforms for studying the formation and propagation of excitons. We have also begun taking advantage of the rigidity of MOFs to isolate organic molecules such as tetraphenylethylene (TPE, above) in unusual conformations to study the effect of conformation on photophysics. The ultimate aim is to make turn-on porous sensors for gases, pressure, and viscosity, for instance, by using ligands based on a class of chromophores known as aggregation-induced emission (AIE) chromophores, whose iconic representative is TPE itself. We have shown that TPE forms porous fluorescent MOFs despite being itself non-lfuorescent, and used spectroscopic techniques to derive rules for making turn-on porous sensors using these molecules. Students involved in this project often design and synthesize relatively complicated organic molecules, become profficient in solvothermal synthesis, and a variety of spectroscopic techniques such as fluorescence specotroscopy and solid-state NMR, done in collaboration with the Griffin group. Theoretical calculations also inform our synthetic design. More widely, we are interested in using topological principles to control through novel synthesis the aggregation sequence of molecular chromophores, with potential applications in solar energy conversion and light harvesting constructs.