Dr. Milena Jovanovic
Physical Chemistry Seminar
Description
Title: “Delocalized Bonding in Extended Systems: From Molecules to Quantum Materials”
Abstract: A long list of words attached to extensions of two-center two-electron bonding, such as
conjugation, aromaticity, electron-deficient, and electron-rich bonding, testifies to the ubiquity of
electron delocalization and its importance in chemistry. Delocalization certainly has consequences – in
spectroscopic, ionization, and magnetic questions the most prominently – both for discrete molecules
and for polymers and extended solids. Moreover, a complex relationship between delocalized bonding
and quantum properties of extended solids has come to light in recent years. Understanding
delocalization mechanisms and how they interact with each other is crucial to designing new quantum
materials.
My talk focuses on two cases of electron delocalization in materials: σ delocalization in
permethylated polysilane and chemical bonding in kagome lattices. In the case of permethylated
polysilane, I will explain how strong conformational dependence of the polymer’s properties arises from
an interplay of two delocalization mechanisms. In the case of compounds featuring the kagome lattice, I
will derive chemical rules to predict if bonding within the lattice is possible and its relation to materials’
properties. Additionally, I will briefly reflect on the other aspects of electron delocalization, namely non-
trivial election localization in crystals and its consequences.
