Synthesis and Langmuir−Blodgett Film Formation of Amphiphilic Zwitterions Based on Benzothiazolium Tricyanoquinodimethanide

Abstract

Five zwitterions based on a coupling reaction between 2-methylbenzothiazole and its selenium and tellurium analogues with the lithium salt of tetracyanoquinodimethane were designed and synthesized, bearing long alkyl tails to facilitate Pockels−Langmuir film formation at the air−water interface. Stable monolayers were formed at the air−water interface. Z-type and Y-type Langmuir−Blodgett multilayers were formed on Al and Si substrates. A test for molecular rectification for the most promising molecule in the series was negative.

Current–voltage characteristics of an LB monolayer of didecylammonium tricyanoquinodimethanide measured between macroscopic gold electrodes

“…The rectification was explained by a modified If the molecules in the LB film are in an orientation such that the molecular dipole moment is perpendicular to the applied electric field, then the I-V characteristics would not be rectifying [19]. Fig.…”

Unimolecular electronics

“…16, as expected. Not all compounds tested rectified, [217][218][219] because of their chemical structure and/or monolayer assembly. Table 3 summarizes the characteristics of the measured rectifiers.…”

Materials Research Society Symposium Proceedings Volume 582. Molecular Electronics. Symposium held November 29-December 2, 1999, Boston, Massachusetts, U.S.A.

“…However, since 1 is not a molecule whose components have low ionization potentials (the molecule decomposes upon oxidation in solution [14]) or high electron affinity (its reversible reduction puts it on a par with p-benzoquinone), therefore one should probably consider its mechanism of action as that linking a state with high dipole moment with one with low dipole moment, through an allowed electronic transition. Another zwitterionic molecule, whose dipole moment was in the plane of the monolayer, instead of normal to it, and which did not exhibit hypsochromism, did not rectify [29]. Another molecule with an unpromising structure did, however, rectify [30].…”