N-Substituted Phthalimides; A Highly Diverse and Convenient Family of Ligands for Metal-Organic Framework Design

Abstract

Metal-organic frameworks (MOFs) are a highly diverse class of multicomponent, self-assembling molecular materials. Their functions are extremely diverse, ranging from multi-stimuli responsive switches to extremely high surface area gas-based sorbents. Such a variety of characteristic behaviour is correlated to a monumental assortment of ligands realised by the research community. One group that is yet to be implemented into the greater landscape is N-substituted phthalimides (NxPIs). These versatile family of compounds, and their equally as useful precursor compounds, may unlock unique structures and functionalities yet to be realised. Chapter 3 explores the redox characteristics of nine substituted N-Hydroxyphthalimide (NHPI) based ligands, exploring the effect of coordinative additions upon the redox activity of the N-hydroxyl functional group. Further, the redox activity of the phthalimide ring for pyridyl and alanine substituted NxPIs is explored. Chapter 4 delves into spin-crossover switching behaviour of a MOF incorporating pyridyl substituted NxPI to unveil the structure-function relationship arising from unique ligand symmetry. Additionally, materials utilising polymethyl benzene NxPI precursors are explored for their spin transition behaviour in order to gain insight into modulation of spin switching as a result of minor ligand variation. In Chapter 5, alternate routes to NHPI incorporation into MOFs is explored. To circumvent several challenges in integrating NHPI into the native structure of MOF materials, incorporation of two monofunctionalised NHPI ligand groups via guest and defect mediated methods is explored. Finally, Chapter 6 simply explores several MOFs incorporating NxPIs and their polycarboxyl benzene precursors. Here an insight into the structural ramifications from positional modulation and substitutional alteration are examined