Our approach to the rational design of supramolecular clusters is based on those in nature. We chose the simplest of the regular polyhedra, the tetrahedron. The symmetry numbers of the tetrahedron are 2 and 3. The two fold symmetry is built into the ligand and the three-fold symmetry is imposed by the metal coordination. The chirality and hydrophobic interior make for exotic chemistry and enzyme-like catalysis. The interior has the properties of a non-aqueous solvent and so can be used for organometallic reactions and catalysis in aqueous solution. Because the cluster binds hydrophobic cations preferentially to neutral species, it can change the proton affinity of a substrate by 3 to 5 orders of magnitude. This in turn enables powerful catalysis.<br/>What are the driving forces for the catalytic activity observed in our supramolecular hosts? The large anionic charge of the original Ga(III)-based -12 host is often cited as the driving force for rate accelerations via stabilization of cationic charge. The synthesis of a new, Si(IV)-based host with an identical structure, but only -8 charge, now enables these studies by comparison of reactions which are catalyzed by the different hosts. The latest examples of the differences seen will be discussed.

The inner space environment in coordination chemistry supramolecular clusters

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.