Virginia Tech researchers are using the building block approach to synthesis to create supramolecular complexes with multiple capabilities. They will present their research at the 220th national meeting of American Chemical Society Aug. 20-24 in Washington, D.C.
The researchers are using molecule groups known as "ligands" -- specifically, polyazine ligands -- to connect two metal-based molecules forming a bridge. "We are varying the ligands and metals to get the effect we want," says graduate student Elizabeth Bullock.
At the national meeting, chemistry professor Karen Brewer will discuss coupling a light absorber to other metal based subunits to create photochemical molecular devices or complexes. In one project "we link a unit that can collect light and a unit that collects electrons," says Bullock. "The point is to bind sub-units with different properties for an end goal of solar energy conversion -- from light to energy. The energy levels of the units 'tune' or adjust the system to determine the direction of electron movement, for instance, from a high energy ligand to a lower energy metal, or in the other direction when the ligand's energy is less than that of the metal.
"What is different about our approach is the huge array of systems possible by varying the ligands and molecules." Bullock says. "Recently, we have modified part of our molecular design to couple metal centers capable of binding DNA into our supramolecular structures. The ability to change one sub-unit while leaving the others alone and performing their separate function allows for the construction of diverse sets of systems. This is particularly appealing in biological applications such as metal-DNA binding since the relationship between structure and function is critical to many biological processes.
The paper, "Mixed-metal supramolecular complexes as photochemical molecular devices and DNA binding agents (INOR 158)," by Brewer, Bullock, and chemistry graduate
Contact: Karen Brewer