Skip to Content
Merck
  • Growth of Thin, Anisotropic, π-Conjugated Molecular Films by Stepwise "Click" Assembly of Molecular Building Blocks: Characterizing Reaction Yield, Surface Coverage, and Film Thickness versus Addition Step Number.

Growth of Thin, Anisotropic, π-Conjugated Molecular Films by Stepwise "Click" Assembly of Molecular Building Blocks: Characterizing Reaction Yield, Surface Coverage, and Film Thickness versus Addition Step Number.

Journal of the American Chemical Society (2015-06-23)
Abel T Demissie, Greg Haugstad, C Daniel Frisbie
ABSTRACT

We report the systematic characterization of anisotropic, π-conjugated oligophenyleneimine (OPI) films synthesized using stepwise imine condensation, or "click" chemistry. Film synthesis began with a self-assembled monolayer (SAM) of 4-formylthiophenol or 4-aminothiophenol on Au, followed by repetitive, alternate addition of terephthalaldehyde (benzene-1,4-dicarbaldehyde) or 1,4-benzenediamine to form π-conjugated films ranging from 0.6-5.5 nm in thickness. By systematically capping the OPI films with a redox or halogen label, we were able to measure the relative surface coverage after each monomer addition via Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy, spectroscopic ellipsometry, reflection-absorption infrared spectroscopy, and cyclic voltammetry. Nuclear reaction analysis was also employed for the first time on a SAM to calculate the surface coverage of carbon atoms after each stepwise addition. These six different analysis methods indicate that the average extent of reaction is 99% for each addition step. The high yield and molecular surface coverage confirm the efficacy of Schiff base chemistry, at least with the terephthalaldehyde and 1,4-benzenediamine monomers, for preparing high-quality molecular films with π conjugation normal to the substrate.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Acetonitrile solution, contains 10.0% acetone, 0.05% formic acid, 40.0% 2-propanol
Sigma-Aldrich
p-Phenylenediamine, sublimed, ≥99%
Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (v/v) trifluoroacetic acid
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) trifluoroacetic acid, suitable for HPLC
Sigma-Aldrich
p-Phenylenediamine, 98% (GC)
Sigma-Aldrich
p-Phenylenediamine, ≥99.0% (GC/NT)
Sigma-Aldrich
4-Chlorobenzaldehyde, 97%
Sigma-Aldrich
4-Iodobenzaldehyde, 96%
Sigma-Aldrich
4-Fluoroaniline, 99%
Sigma-Aldrich
4-Aminothiophenol, ≥97.0%
Sigma-Aldrich
4-Chlorothiophenol, 97%
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) formic acid, suitable for HPLC
Sigma-Aldrich
Acetonitrile, HPLC Plus, ≥99.9%, poly-coated bottles
Sigma-Aldrich
Acetonitrile, electronic grade, 99.999% trace metals basis
Sigma-Aldrich
Dimethyl sulfoxide, BioUltra, for molecular biology, ≥99.5% (GC)
Sigma-Aldrich
Iodine, anhydrous, beads, −10 mesh, 99.999% trace metals basis
Sigma-Aldrich
Dimethyl sulfoxide, anhydrous, ≥99.9%
Sigma-Aldrich
Acetonitrile, anhydrous, 99.8%
Sigma-Aldrich
4-Iodoaniline, 98%
Sigma-Aldrich
Iodine, ≥99.99% trace metals basis
Sigma-Aldrich
Terephthalaldehyde, ReagentPlus®, 99%
Sigma-Aldrich
Iodine, 99.999% trace metals basis
Sigma-Aldrich
8-Octanoyloxypyrene-1,3,6-trisulfonic acid trisodium salt, suitable for fluorescence, ≥90% (HPCE)
Sigma-Aldrich
Tetrabutylammonium hexafluorophosphate, 98%
Sigma-Aldrich
Dimethyl sulfoxide, meets EP testing specifications, meets USP testing specifications
Sigma-Aldrich
Dimethyl sulfoxide, for molecular biology
Sigma-Aldrich
Dimethyl sulfoxide, sterile-filtered, BioPerformance Certified, meets EP, USP testing specifications, suitable for hybridoma
Sigma-Aldrich
Dimethyl sulfoxide, ≥99.5% (GC), suitable for plant cell culture
Sigma-Aldrich
Dimethyl sulfoxide, PCR Reagent
Sigma-Aldrich
Dimethyl sulfoxide, Hybri-Max, sterile-filtered, BioReagent, suitable for hybridoma, ≥99.7%