Ferrocene‐Alkynyl Conjugated Molecular Wires: Synthesis, Characterization, and Conductance Properties

Abstract

A novel series of 1,2,3-substituted ferrocene-based wires a1-a2 and b4-b5 have been synthesized by using an iterative Pd-mediated Sonogashira cross-coupling methodology. The molecular structures of a2 and b3 were determined by single-crystal X-ray analysis. Electrochemical data showed that there was a strong electronic communication among the ferrocenyl moieties in b1-b5. The UV absorption spectra indicated that replacing the 1,1'-substituted ferrocene unit with a 1,2,3-substituted ferrocene moiety causes delocalization of electrons in the extended π orbitals. The self-assembled monolayers of wire a1 and a2 on Au surfaces have been comprehensively characterized by electrochemistry and scanning tunneling microscopy break junction. The data demonstrated that 1,2,3-substituted ferrocene-based wires reduced the intermolecular π-π stacking, and furthermore solved the rotation problem in the 1,1'-substituted ferrocene-based wires.

Improving Gating Efficiency of Electron Transport through Redox‐Active Molecular Junctions with Conjugated Chains

“…A Clavilier‐type Au (111) half‐bead single crystal (∼2 mm diameter) was used as work electrode to perform the cyclic voltammograms (CVs) test in BMIPF 6 under the protection of high purity N 2 . As shown in Figure a and b, there are pairs of well‐defined reversible peaks at about 0.5 V, which are correspond to redox of Fc + /Fc in the molecules similar to reported ferrocene‐based derivatives . Plotting current density of oxidation (black square) or reduction (red circle) with the scan rate, a linear correlation is shown in the insert panels, which proves that the C−C−Fc−Py and C=C−Fc−Py indeed self‐assemble onto the Au(111) surface.…”

On‐Surface Synthesis of Polyferrocenylene and its Single‐Chain Conformational and Electrical Transport Properties

“…[ 10 ] Materials derived from (poly)ferrocene that undergo reversible, low‐potential, single‐electron redox processes [ 35 ] are undoubtedly attractive to molecular electronics. Indeed, the number of studies on ferrocene‐based devices, ranging from molecular wires [ 36–39 ] to models of quantum cellular automata, [ 40–42 ] is steadily growing.…”

“…The discovery of the iconic ferrocene 1 molecule (Figure 1) in 1951, [1,2] whose sandwich structure contains an iron atom between two cyclopentadienyl rings, has revolutionized our view of the nature of the metal-carbon bond. [3,4] However, the preparation of its polymeric form, i.e., heteroannular poly(1,1′ferrocenylene) 2, as a well-defined, ultimately monodispersed Indeed, the number of studies on ferrocene-based devices, ranging from molecular wires [36][37][38][39] to models of quantum cellular automata, [40][41][42] is steadily growing.…”

A review of oligo(arylene ethynylene) derivatives in molecular junctions

“…Wire 46 and analogues with longer and shorter OAE units were used to show that the incorporation of ferrocene units into the backbone enhanced conductance relative to analogous OPEs. 232 True OAEs, where one of the cyclopentadienyl ligands of a ferrocene moiety acts as an arylene unit in the OAE backbone, such as 47, have also been studied, 233 but a direct comparison with species resembling 46 does not yet appear to have been made.…”