Conjugated Macrocycles and Supramolecular Chemistry / Abstract

conjugated macrocycles and supramolecular chemistry

The predictable and directional bonding of linear, aromatic ligands such as pyridine and its derivatives allows for the design and preparation of a variety of supramolecular coordination complexes with extraordinary structures and functional properties. We have been intrigued with the synthesis of conjugated macrocycles that can function in a manner analogous to that of linear, pyridine-derived ligands. Specifically, our efforts have focused on the incorporation of pyridyl groups into the framework of cross-conjugated macrocycles such that the orientation of the pyridine nitrogen(s) outward from the core allows for the preparation of a variety of hybrid metal-organic structures and organized materials. As such, we have prepared a series of highly functionalized, pyridine-containing macrocycles and demonstrate their ability to bind to transition metals via the preparation of a variety of coordination complexes, many of which form highly ordered, porous solids.[1-7] The study of porosity in many of these systems can be evaluated using hyperpolarized 129Xe NMR of the solids, something we do in collaboration with the group of Prof. Rod Wasylishen.[1-2]

The design and synthesis of conjugated macrocyclic systems with novel shapes and architectures is a research area that has recently attracted a great deal of attention. These compounds are attractive targets due to their potential as new materials with shape-persistent structures, desirable physical characteristics and photophysical properties. Particularly interesting is the ‘tunability’ of these highly conjugated scaffolds. The covalent modification of a cross-conjugated, macrocyclic framework to incorporate functionality such as aromatic and/or heteroaromatic rings allows us to tailor the shape, as well as the conformational properties and association behavior of these systems. To probe this structure-property relationship, we have prepared a series of macrocycles based on the incorporation of meta-, para-, and ortho-diethynylbenzene into a cross-conjugated enyne framework, including the helically chiral macrocycle 3.