TETRAHEDRON LETTERS Tetrahedron Letters 44 (2003) 6699–6702 Pergamon Synthesis of thiol substituted oligoanilines for molecular device candidates  Austen K. Flatt and James M. Tour* Department of Chemistry and Center for Nanoscale Science and Technology, Rice University, MS -222, 6100 Main Street, Houston, TX 77005, USA Received 23 June 2003; accepted 29 June 2003 Abstract—The synthesis of thioacetate derivatized oligoanilines designed for molecular electronic device purposes is described. Reversible oxidation between the non-conductive leuco base and conductive emeraldine salt forms of these compounds may produce switching effects and device behavior. The targeted compounds contain a sulfur moiety as a means to connect the molecules to metallic electrodes. © 2003 Elsevier Ltd. All rights reserved. Increasing costs and physical barriers attributed with silicon based solid-state computing technology have given way to substantial work in the field of molecular electronics. 1–3 It has been shown that single molecules can undergo reversible switching behavior in solid-state testbeds. 4 We have designed and synthesized oligoani- line-based molecules as a new class of potential switch- ing and memory type devices. Oligoanilines offer the possibility to reversibly oxidize between different con- ductivity states in a controlled fashion, 5 namely between the non-conductive leuco base and the conduc- tive emeraldine salt giving rise to a potential on–off ‘memory-like’ effect. Extensive research on couplings of aryl halides with anilines by Buchwald and Hartwig 6,7 has facilitated the synthesis of oligoanilines. We introduce a new series of oligoanilines for use as potential molecular electronic devices by incorporating a sulfur moiety into the molecule, which allows contact between the molecule and a metal electrode. We also synthesized oligomers with methylated nitrogen atoms to ensure oxidation only to the highly conductive emeraldine salt and not to the non-conductive emeraldine base or leuco salt, pro- vided pH is controlled. 8 Additionally, each nitrogen atom is capable of losing one electron, therefore the structures here could offer multiple independent elec- tronic states. The structures of the oligoaniline targets (1–5) are shown in Figure 1. The synthesis of oligomer 1 is shown in Scheme 1. Employing Buchwald’s conditions, 6 N -phenyl-p - phenylenediamine was coupled to 2-(trimethylsil- yl)ethyl-4-bromophenyl sulfide, 9 to afford 6. Due to the harsh coupling conditions, the robust ethyl- trimethylsilyl protecting group was employed rather Figure 1. Oligoaniline targets for device assembly and testing.  Supplementary data associated with this article can be found at doi:10.1016/S0040-4039(03)01626-5 * Corresponding author. Tel.: 713-348-6246; fax: 713-348-6250; e-mail: tour@rice.edu 0040-4039/$ - see front matter © 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0040-4039(03)01626-5