New Metallosupramolecular Assemblies Involving Silver-Alkene Interactions

• Main Author: Wasseyehun Kelemu, Solomon
• Language: en
• Published: University of Canterbury. Chemistry 2013
• Online Access: http://hdl.handle.net/10092/7871

This thesis describes the silver(I) coordination chemistry of forty two ligands containing alkene functional group. The synthesis of thirty nine ligands is described, fourteen of which were previously unreported compounds. These ligands are classified into three major categories containing allyloxy, diallylamine and allyl groups. The ligands containing allyloxy groups were designed by changing the number of allyloxy arms from one to six, which allows investigation of the influence of the number of allyloxy arms within a ligand on the overall structure of the complex. Ligands containing one allyloxy arm generally form rectangular shaped discrete assemblies that involve the coordination of the nitrogen atom of the core and the allyloxy arm of the ligand with silver. Ligands containing two and three allyloxy arms gave 1D and 2D polymeric structures. Some of these 2D polymers contain cavities filled by the counter anion and the solvent used to grow crystals of the complex. Some of the ligands containing four allyloxy arms gave discrete M₂L or M₄L₂ type coordination complexes. One of these ligands gave a rare type of 1D-1D polycatenane by intercalating two ladders. A ligand containing six allyloxy arms forms a 1D polymeric assembly by using the six allyloxy arms and four silver atoms. Four of these allyloxy arms chelated, while the other two are bridging. Ligands containing two, four and six allyl arms were designed by using diallylamine groups. Introducing additional functional groups in the core structure of the ligand showed the co-existence of silver(I)-alkene interactions with other strong interactions, such as silver(I)-nitrogen. Ligands containing one diallyamine group with different silver(I) salts resulted in 1D polymeric assemblies, while two and three diallylamine groups inclined to form M₂L, M₃L and M₄L₂ discrete assemblies. Ligands containing allyl groups with a urea core structures showed the coexistence of silver(I)-alkene interaction with other moderate interactions such as silver(I)-carbonyl oxygen. The use of ligands containing allyl group allowed the formation of 1D polymeric ladders and helical structures as well as discrete assemblies. ¹H NMR spectroscopy, ¹³C NMR spectroscopy, mass spectrometry, IR, melting point and X-ray crystallography were used to study the compounds synthesised. The crystal structure of six ligands, forty-six complexes and two salts are discussed.