Directional electron transport in electrode|metallosurfactants junctions

"Transporte direcional de elétrons em junções eletrodo|metalosurfactantes" The Verani Group is invested in the development of new concepts in molecular electronics, a field that aims to develop molecule-size electronic components such as transistors, diodes, and resistors. We are developing amphiphilic coordination complexes [M(L)] known as metallosurfactants and capable of forming ordered films. When these species are deposited in between two gold electrodes, they form assemblies described as Au1|(ML)|Au2 junctions that can promote directional electron transport: Au1 +e-|(ML)o|Au2 ? Au1+|(ML) +e- |Au2 ? Au1+|(ML)o|Au2 +e- This transport of electrons is called current rectification, and the metallosurfactants behave as molecular diodes. To date we have synthesized, characterized, and analyzed several metallosurfactants, starting with HS3d5 FeIII, and expanding our research to the understanding of 3d1 VOIV, 3d3 CrIII, 3d4 MnIII, 3d9 CuII. In this talk, we will introduce the methodology, discuss the experimental work, and explain the intricate mechanistic insights obtained for each of these electronic configurations. In the process, we will utilize fundamental concepts of coordination chemistry such as electronic configurations, coordination numbers, redox behavior of metals, ligand fields, and molecular orbital theory. We propose that rectification in metallosurfactants depends on (i) molecular asymmetries enforced by five-coordinate ligand fields associated with orbital distortions; (ii) structural asymmetries enabling localized placement of the LB film closer to one of the electrodes, and (iii) the matching of the energies between electrode Fermi levels and the SOMOs of the metallosurfactant.