Observation of current rectification by the new bimetallic iron(iii) hydrophobe [Fe III2(LN4O6)] on Au|LB-molecule|Au devices

Abstract

Targeting the development of stimulus-responsive molecular materials with electronic functionality, we have synthesized and studied the redox and electronic properties of a new bimetallic iron hydrophobe [Fe^III₂(L^N4O6)] (1). The new H₆L^N4O6 ligand displays bicompartmental topology capable of accomodating two five-coordinate ^HSFe^III ions bridged by tetraaminobenzene at a close distance of ca. 8 Å. We show that the metal-based reduction processes in (1) proceed sequentially, as observed for electronically coupled metal centers. This species forms a well-defined Pockels-Langmuir film at the air–water interface, with collapse pressure of 32 mN m⁻¹. Langmuir–Blodgett monolayers were deposited on gold substrates and used to investigate current–voltage (I–V) measurements. This unprecedented bimetallic hydrophobe [Fe^III₂(L^N4O6)] (1) shows unquestionable molecular rectification and displays a rectification ratio RR between 2 and 15.