| As long as chemists have marveled at the specificity of interactions in enzymes, nucleic acids, and other biological motifs that contain an inner cavity, there has been much desire to construct molecules that mimic these in function. Inspired by work performed by Charles J. Pederson on crown ethers, Donald J. Cram conducted seminal research into the construction and the host-guest interactions of a number of molecular architectures, specifically with his work on carcerands and hemicarcerands. Since Cram's early work, the field of cavitand chemistry has taken off, providing endless examples in architecture capable of enclosing the space around a guest molecule. Some common examples of artificial hosts are cryptophanes, cucurbit[n]urils, and calixaranes. Function and application vary as much as structure, and range from stabilizing reactive intermediates and probing fundamental questions in physical organic chemistry, to drug delivery and chiral separations. Meanwhile, in the Badjic Group, the development of cavitands functionalized with dynamic apertures, or gates, have allowed us to probe fundamental questions in the kinetics of encapsulation. These studies have relied upon a single symmetric host. As a result, the group has taken on the challenge of constructing new architectures giving consideration toward the inner space geometry to allow for installation of "gate" moieties onto these architectures. My research efforts have focused on the development of these new molecular architectures, with applications towards molecular recognition. Three journeys will be described, about how the key bicyclic core is transformed to give rise to differently shaped hosts. These synthetic methodologies allow for multi-gram syntheses of desired products and better potential control of their stereochemistry, all the while utilizing more environmentally friendly methodologies. Currently being explored is using these architectures for different possible applications, including studying recognition phenomena, and perhaps building chiroptical sensors capable of reporting on the presence of minute quantities of chiral substances in the environment. |
