Synthesis and Applications of Unusual Self-assembled Coordination Architectures

Abstract

Biological systems like enzymes have complex structures which help in executing intricate chemical reactions. Endeavoring to replicate such chemical reactions, chemists have crafted discreate molecular structures featuring precise nanocavities. Over the last twenty years, there has been a proliferation of these structures achieved through hydrogen bonding and Dynamic covalent chemistry (DCvC). Concurrently, the concept of Supramolecular Coordination Structures (SCCs) also emerged as a powerful tool for the synthesis of visually appealing 2D and 3D discrete architectures.1 In literature, pyridyl moieties with generally rigid structures have been extensively studied. However, the primary objective of my thesis is to investigate the use of flexible building blocks for creating discrete structures through metal-ligand coordination. This approach is anticipated to yield unique and nontrivial structures. Initially, we examined a new coordinatively flexible imidazole donor which showed aggregation-induced emission (AIE) activity and the barrel could be used for the selective detection of picric acid.2 Further, the self-assembly of tetratopic pyridyl donors with a flexible alkyl spacer was extensively studied. A simple donor with two flexible dipyridyl amine moiety connected to a xylene core led to the formation of an unconventional molecular boat structure. This structure was then utilized for the selective separation of physiochemically similar isomers, specifically phenanthrene from a mixture of anthracene.3 Subsequently, by elongating the ligand, we unveiled the complexity it could generate, resulting in the creation of an intertwined, unusual A-type cube.4 Furthermore, we explored the utilization of a different Ru(II) metal acceptor, which resulted in the formation of a unusual high-order macrocycle. The equilibrium between this large macrocycle and a simpler macrocycle was also investigated.