Monday, 22 November 4:00pm – 5:00pm

This seminar will be delivered via Zoom – Please email chemistry.researchsupport@sydney.edu.au for zoom link and password.

Speaker: Mr. Hunter Windsor; The University of Sydney

Host: Professor Cameron Kepert

Title: Supramolecular Control over Spin Crossover in Benzothiadiazole-Based Nanoporous Frameworks

Abstract: The targeted engineering of multifunctional devices displaying facile switching behaviours is a pervasive yet difficult problem to solve. One solution is to develop spin crossover (SCO) nanoporous metal–organic frameworks (MOFs) that couple a reversible and fatigue-resistant electronic rearrangement with other modalities such as redox activity, luminescence, or molecular recognition, thereby producing multistimuli responsive switches. Materials which display such dynamic responsiveness to a range of stimuli have already seen widespread use as nanomechanical actuators, thermochromic pigments, optical display devices, and pressure sensors within materials science.

2,1,3-Benzothiadiazole (2,1,3-BTZ) is one heterocyclic unit known to be redox-active and exhibit high fluorescence quantum yields. The aim therefore of this thesis is to synthesise a family of nanoporous SCO MOFs that incorporate pillaring ligands based on the 2,1,3-BTZ moiety; to then characterise their thermal spin-state dependence via magnetometry and diffraction techniques; and to probe the interplay between spin, redox, and fluorescent states. The study also seeks to investigate the effect that guest molecule encapsulation within the pore structures of these MOFs has on their SCO behaviour. These will primarily include electron-rich polycyclic aromatic hydrocarbons (PAHs) and perfluorinated aryliodides. Such guest molecule encapsulation in other host–guest systems has been proven to be an effective methodology towards modulating the electronic band and resonance structures of the host compound and has applications within designing new semiconductors