New Chemistry of Mercaptoazulenes and Low-Valent Complexes of Isocyanoarenes

Abstract

Aryl mercaptans and their coordination complexes contribute to a number of diverse applications including pharmaceutical, surface science, and molecular electronics, and light emitting diodes. Recently the Barybin group has begun to explore the coordination chemistry of mercaptoazulenes. Prior to the work done by Barybin et al. there were no examples of coordination complexes of featuring mercaptoazulenes. Other mercaptoarenes have been utilized in the formation of thin films and featured in materials with luminescent capabilities. Thiolates have also been studied as junction groups used to attach organic compounds with extended π systems to electrodes. Linear asymmetric dimercaptoarenes are rare, but are intriguing for electronics and construction of molecular electronic components such as diodes. In this dissertation coordination chemistry of mercaptoazulenes, synthesis of azulenic derivatives to probe the charge transport dynamics of the asymmetric 2,6-molecular axis of azulene, and the coordination of isocyanoarenes with low valent transition metal complexes will be discussed. Chapter 1 of the thesis describes the synthesis of the first example of a dimercaptoazulene. Two different synthetic routes were developed for the preparation of this dimercaptan and regioselective metallation was demonstrated for the generation of its mono-nuclear coordination complex. Additionally metallation of the second thiolate termini is also discussed. Chapter 2 describes the synthesis of isomeric mercaptazulenes featuring cyano substituents. The 6-cyano-2-mecaptoazulene has been prepared. These isomeric molecules offer an opportunity to probe the charge transport dynamics of the asymmetric 2,6-molecular axis of azulene. The cyano substituent could serve as a spectroscopic reporter for additional spectroscopic characterization of these molecules in surface studies. Chapter 3 describes the coordination studies of iscyanoarenes with electron rich low valent Mo and W metal centers. This investigation focused on whether substitution variations in non-benzenoid aromatic isocyanides would result in the formation of either cis- or trans- [M(dppe)2(CNAr)2] and related complexes.