Optimization of self-assembly processes that incorporate directional bonding of geometrically predisposed building blocks has led to the development of a plethora of molecular superstructures in the literature. Molecular polyhedra are of high interest due to potential applications of highly symmetric cage-like architectures as molecular containers and reaction flasks. Typically, polygonal metallacycles are inhibited from undergoing further reactions at the metal vertices because of coordinative saturation and non-labile �capping� ligands, but we have in hand a family of supramolecular anion-p templated metallacycles with two labile acetonitrile ligands per vertex. Bridging the vertices of pentagonal metallacyclic building blocks with linear bis-bidentate linkers or tripodal tris-bidentate linkers is predicted to lead to truncated icosahedral and rhombicosidodecahedral architectures respectively. In this vein, we are preparing molecular polyhedra by reacting anion-p templated pentagonal metallacycles with bis-bidentate organic linkers including terephthalic acid and tetrapyrido[3,2-a:2',3'-c:3�,2�-h:2�',3�'-j]phenazine. Thermodynamic control over the formation of the polyhedral structures is critical for synthesizing closed, symmetrical architectures with a uniform diameter. Characterization is being performed using TEM, AFM, and STM imaging methods and molecular mechanics and DFT calculations are being carried out to determine the plausibility of using various molecular linkers vis-�-vis geometric and thermodynamic considerations. By optimizing the polyhedral structures using an MM potential, we aim to be able to qualitatively estimate via DFT the overall thermodynamic stability for the organic bis- and tris-bidentate linkers. Successful shape control through self-assembly reactions and qualitative thermodynamic analysis of pentagon-linker interactions is leading to targeted polyhedral assemblies exhibiting unique structural and physical properties.

Extended superstructures developed from supramolecular anion-p templated metallacycles

247th National Meeting (2014)

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