Self-Assembled multiple molecular layers of Cobalt Phthalocyanines, /

Abstract

The chemical and electrochemical properties of self-assembled monolayers on gold electrodes constructed from pyridine tagged alkanethiols were explored by cyclic voltammetry. A pyridine tagged alkanethiol chain was used as an anchoring group in the construction of the self assembled monolayer. The monolayer was subsequently extended into multi-layer films using cobalt phthalocyanine with pyrazine spacer groups. 1-(1 O-mercaptodecyl)isonicotinate was synthesized in a four step process prior to the formation of the monolayers. Cleaned and polished gold electrodes were allowed to soak in a stirred 1mM aqueous solution of I-(IO-mercaptodecyl)isonicotinate for 24 hours to promote self assembly onto the gold surface. Subsequent attachment of cobalt phthalocyanine moieties to the pyridine was accomplished via axial ligation from a 1.0 mM solution of cobalt phthalocyanine in methylene chloride. The resulting layers were further extended using a pyrazine spacer, followed by attachment of cobalt phthalocyanine or cobalt octafluorophthalocyanine to yield homogeneous and/or heterogeneous multi-layer films. Multi-layer films were constructed in this manner in hopes of creating molecular electronic and optical devices. Films were characterized via cyclic voltammetry after the addition of each new layer. This system was found to be air, water and thermodynamically stable for several weeks.