Darren L. Pearson

Potential molecular wires and molecular alligator clips

The synthesis of oligo(2-ethylphenylene-ethynylene)s, oligo(2-(-ethylheptyl)phenylene-ethynylene)s, and oligo(3-ethylthiophene-ethynylene)s is described via an iterative divergent convergent approach. Synthesized were the monomer, dimer, tetramer, octamer and 16-mer of the oligo(3-ethylthiophene-ethynylene)s and oligo(2--ethylheptyl)phenylene-ethynylene)s. The 16-mers are 100 A and 128 A long, respectively. At each stage in the iteration, the length of the framework doubles. Only three sets of reaction conditions are needed for the entire iterative synthetic sequence; an iodination, a protodesilylation, and a Pd/Cu-catalyzed cross coupling. The oligomers were characterized spectroscopically and by mass spectrometry. The optical properties are presented which show the stage of optical absorbance saturation. The size exclusion chromatography values for the number average weights, relative to polystyrene, illustrate the tremendous differences in the hydrodynamic volume of these rigid rod oligomers versus the random coils of polystyrene. These differences become quite apparent at the octamer stage. The preparation of thiol-protected end groups is described. These may serve as molecular alligator clips for adhesion to gold surfaces. These oligomers may act as molecular wires in molecular electronic devices and they also serve as useful models for understanding related bulk polymers.

Molecular scale electronics. Syntheses and Testing

The syntheses of conjugated molecules that are over 100 A long are presented. They are based on oligo(thiophene-ethynylene)s and oligo(phenylene-ethynylene)s. A method for attachment of molecular-sized alligator clips is presented. These serve as bonding locations to gold probes.

Synthesis of well-defined conjugated oligomers for molecular electronics

Described are methods for the rapid syntheses of conjugated oligomers of precise length and constitution by an iterative divergentkonvergent approach. The syntheses can be carried out in solution or on a polymer support. The properties of the conjugated oligomers are presented as well there potential to act as molecular wires.

Copper-Coated Self-Assembled Monolayers: Alkanethiols and Prospective Molecular Wires

The study of the effects of metal overlayers on organic self-assembled monolayers (SAMs) is of interest in many scientific areas. The self-assembly process leads to a well-defined substrate whereas the numerous combinations of end-groups and metals allows for the fine-tuning of the chemistry at the monolayer/metal interface. These unique features make metal/SAM interfaces a valuable tool for probing fundamental processes. SAM/metal interfaces, have been proposed as templates to elucidate details on, for example, metal/“organic host” interactions which are known to occur in biologically active metallic reaction sites [1]; reaction mechanisms at organic/metal/gas interfaces, such as those involved in heterogeneous catalysis and environmental chemistry [2]; the solvation and electron-transfer reactions of metals in molecular solvents or within molecular clusters [3, 4]; and the insertion of zero-valent metals into chemical bonds frequently found in homogeneous catalysis reactions [3, 4, 5, 6].