|M.Sc Student||Gershoni Poranne Renana|
|Subject||Novel Corannulene-Aryl Ethers as Pentagonal Building|
Blocks for Superstructures
|Department||Department of Chemistry||Supervisor||Professor Emeritus Ehud Keinan|
|Full Thesis text|
The notion that molecular containers can be obtained by total synthesis and selfassembly of small molecules is largely inspired by the fascinating architecture of virus particles, and in particular, that of spherical viral capsids. Our proposed general strategy to meet the challenge of constructing non-protein based molecular capsids of icosahedral geometry, is by the synthesis and assembly of twelve pentagonal tiles with appropriate “sticky” moieties. The icosahedron is widely prevalent in Nature for the basic purpose of encapsulation, to which it is highly suited, due to its surface area-to-volume ratio and genetic efficiency of subunit-based symmetric assembly.
For the synthesis of the desired pentagonal tiles we have chosen the corannulene molecule as the core skeleton due to its bowl shape, rigid polyaromatic nature and five-fold symmetry. The choice of the “sticky” functionalities was guided by the dual properties necessary to achieve this goal: the bonds formed between the tiles must be thermodynamically stable, yet kinetically labile. These two complementary properties enable at the same time fast equilibration and movement from the local minima of various aggregates to the global energy minimum of the spherical capsid.
Corannulene was synthesized according to the literature multi-step procedure, and subsequently chlorinated on five positions. The C5-symmetrical 1,3,5,7,9 pentachlorocorannulene was then converted to a wide range of novel pentaaryloxy derivatives with varying functionalities via the Cu-catalyzed Ullmann Condensation reaction. Thus, we have opened new avenues for easy preparation of other symmetrically substituted corannulene derivatives, setting the stage for the design and preparation of new materials and new supramolecular architectures on the basis of pentagonal building blocks.