Design aspects of viologen molecular wires

Abstract

AB3:Työ kuuluu VTT:n tutkimushankkeeseen "Ultra Fine Particles Basic Research"sekä SA:n MATRA-ohjelmaan kuuluvaan hankkeeseen "Organic Thin Films withFunctional Activity".

This thesis describes the adsorption of molecular wires on modified gold surfaces and the different molecular aspects of these molecules which may be of relevance to the adsorption process. Conjugation-extended bipyridinium compounds (viologens and conjugationextended viologens) are very versatile compounds. They have interesting, nonlinear optical, fluorescence, solvatochromic and electrochromic properties and are also effective intrinsic conductors. Their application is mainly envisaged in molecular electronics devices and (bio)chemical sensors.In this study the adsorption of various pyridinium compounds onto self-assembled layers of octadecylmercaptan on gold was investigated with secondary ion mass spectroscopy (SIMS) and atomic force microscopy (AFM). The salient structural features of the viologens were also examined with semiempirical molecular modelling using MOPAC/AM1.