Self-assembly of large high symmetry coordination assemblies: Design, synthesis, and supramolecular chirality

The rational approach toward the synthesis of high symmetry coordination assemblies is being developed both to answer fundamental questions about self-assembly of large, multi-component supermolecules, and to fulfill the practical need for large and chiral supramolecular hosts that enable new host-guest chemistries. In Chapter One, a literature review of self-assembly in coordination chemistry is presented. The focus is on discrete oligonuclear complexes composed of multiple ligands and metal ions. The review of this rapidly growing branch of supramolecular chemistry provides the critical background and context for the subsequent chapters.; An outline of the motivation and goals of this research project is introduced in Chapter Two. A design plan for large M4L6 tetrahedral coordination assemblies, with cavity volumes in excess of 1 nm3, is developed. The discussion focuses not only on idealized geometric and symmetry requirements for the M4L6 structure but also on practical and empirically determined parameters that can affect self-assembly. In addition, a practical approach for the determination of cavity volume inside the M 4L6 tetrahedron is described.; Chapter Three presents the synthesis of eight bis-catecholamide ligands that are based on the design for the M4L6 coordination tetrahedron presented in Chapter Two. The first section introduces a modular synthetic strategy utilizing Suzuki-Miyaura cross-coupling in the key step for the rapid synthesis of a small library of ligands. The next section describes the synthesis of aryl boronic esters as critical components in this synthetic strategy. The final section covers the synthesis of eight bis-catecholamide ligands.; Self-assembly of metal-ligand coordination complexes from large bis-bidentate catecholate ligands is the focus in Chapter Four. The synthesis and characterization of four new metal-ligand complexes is presented. From these results, the predictive design strategy described in Chapter Two is tested and refined.; The Fifth Chapter presents the design and synthesis of tetrahedral M 4L4 coordination assemblies. There are several important structural and dynamic differences between the M4L4 tetrahedra described in this chapter and the M4L6 tetrahedra described earlier. Size and shape selective guest encapsulation is observed. The M4L4 face-on approach for cavity containing supermolecules is a viable alternative to the M4L6 design.; The final chapter focuses on intermolecular chiral induction in dinuclear triple stranded helicates. Intermolecular asymmetric interaction in the both the M4L6 and M4L4 tetrahedra occur by a similar mechanism. The first section introduces the concept of supramolecular chirogenesis. The second section describes chiral induction in a variety of helicates using three different chiral cations. The third part of this chapter covers the mechanism of chiral induction in one particular helicate.