'A Twisted Backbone' - The Synthesis of Interesting Metallosupramolecular Assemblies Through Steric Control.
Degree GrantorUniversity of Canterbury
Degree NameMaster of Science
This study investigates the self-assembly of ligands consisting of sterically hindered backbones. Ligands synthesised in this study took advantage of the twisted nature of benzil-2,3-dihydrazone brought about by the steric repulsion between two neighbouring phenyl groups. Synthesis of all ligands used a simple imine condensation reaction, where benzil-2,3-dihydrazone was combined with a chosen aromatic aldehyde. Coordination studies were conducted using first row transition metals and described in text are the solid state structures of twelve new discrete supramolecular complexes, characterised by single crystal X-ray crystallography. Chapter 1 outlines an introduction to the topics discussed in this text, while providing examples drawn from literature and nature. Chapter 2 details the modified synthesis of bis-2-pyridyliminohydrazono-1,2-diphenylethane, L1, and the in-depth background of previous studies with the ligand. The complexes of L1 with Mn(II), Fe(II), Co(II), Cu(I) and Zn(II) determined by single X-ray crystallography are presented, noting the structural effects different metal ion sources have upon L1. In chapter 3 the modified synthesis and characterisation of bis-2-imidazolyliminohydrazono-1,2-diphenylethane, L2, is presented. Crystallographically characterised complexes from the combination of L2 with Mn(II), Ni(II), Co(II) and Zn(II) show the formation of interesting topologies which are compared to structures previously determined. Chapter 4 begins with a brief introduction to clusters, followed by the synthesis and characterisation of a recently synthesised ligand, bis-2-salicyliminohydrazono-1,2-diphenylethane, L3,. The formation of a Ni(II) cluster with L3 is further discussed in detail, and outlines the future scope for the work with these ligands. The synthesis and characterisation of L4, and the discussion of mononuclear complex formed between L4 and Cu(II) is also introduced. The chapter concludes with a discussion with the potential future direction of this work with these ligands and their related compounds. Chapter 5 concludes the results and discussion with a brief summary of these results. Chapter 6 outlines the synthesis and characterisation of all ligands and complexes used in this study as well as potential ligands for future studies.