Conductance switching in expanded porphyrins through aromaticity and topology changes

Activity: Talk or presentationTalk or presentation at a conference


Expanded porphyrins are flexible enough to switch between different π-conjugation topologies (Mobius, Hückel and twisted-Hückel) encoding distinct electronic properties and aromaticity.[1] Since the topological switch can be induced by different external stimuli, expanded porphyrins represent a promising platform to develop a novel type of molecular switches for molecular electronic devices.[2] Indeed, aromaticity emerged as the key concept determining the electronic, magnetic and nonlinear optical properties of expanded porphyrins and accordingly, we proposed different methods to quantify the Hückel and Möbius aromaticity.[3]
In this work, we assess computationally the feasibility of conductance switches based on expanded porphyrins for the first time. Accordingly, the electron transport properties of single thiol-terminated expanded porphyrins bound to gold electrodes with different π-conjugation topologies and aromaticity were investigated using DFT methods and Green´s function formalism. This study is particular relevant since the link between transmission and key concepts in chemistry, such as aromaticity and polarizability, will be established allowing a chemical understanding of the physical property conductance.[5] Our results highlight the importance of the macrocyclic aromaticity on determining the transmission functions of the different states an we provide a set of qualitative rules to predict the presence of quantum interference based on a simple model for Hückel and Möbius systems.
Period28 Aug 2017
Event title11th Triennial Congress of the World Association of Theoretical and Computational Chemists (WATOC2017)
Event typeConference
LocationMunich, Germany
Degree of RecognitionInternational