Helical Channels in Molecular Co-Crystals

Science Center A255

Idealized crystalline solids are those in which the positions of all of the atoms can be described by the repeated stacking of a building block known as the unit cell. That said, most real solids with potential technological applications do not adhere to such a simple definition. Our research group studies the complex packing of propeller-shaped molecules that tend to crystallize with nanometerscale channels capable of adsorbing other small molecules or ions. The ‘guest’ molecules are often disordered with respect to the structure of the ‘host’ material, which challenges our understanding of their positions, orientations and chemical interactions. My project involves the study of crystals formed by combining two propeller-shaped molecules, one bearing a positive charge. Xray diffraction analysis of the prototype material revealed a columnar structure assembled from helices that enclose channels containing disordered negative ions. My investigations suggest the possibility of exchanging these negative ions for others, making the host material potentially capable of sequestering toxic ions from natural waters.