Synthesis, structure and properties of some new dihydrotetrathiafulvalenes

Abstract

Eighteen novel, norbornene-fused dihydrotetrathiafulvalenes derived from various alkyne reagents were prepared to form a library of compounds. They were fully characterised using nuclear magnetic resonance and infrared spectroscopy. Additionally, cyclic voltammetry and ultraviolet-visible spectroscopy were used to establish trends. Crystal structures were obtained for three compounds within the series, including a polymorph of a previously reported compound that was isolated.

Three novel pyridazine-4,7-diones were prepared out of interest in their ability as donor-acceptor compounds, in addition to their hydrogen-bonding capabilities. The first trimeric crystal structure of a related product was produced. A total of three polymorph crystal structures of one compound were obtained. The pyridazine-4,7-dione unit was of interest for future field-effect transistor applications due to its ability to form nano-objects and the trimeric crystal structure obtained based on its tautomeric form supported this possibility.

A novel norbornadiene-fused maleic hydrazide was achieved, and a novel hydrazine-functionalised norbornene biproduct was identified in another reaction. A new crystal structure of norbornadiene dicarboxylic acid was produced, along with the full characterisation by nuclear magnetic resonance of the previously misreported norbornadiene-2,3-dicarboxylic anhydride. While attempting to prepare novel dihydrotetrathiafulvalenes from n-butyl cyclic imide starting materials to increase product solubility, instead two unexpected products were formed and fully characterised.

To form novel dihydrotetrathiafulvalenes of potential interest in surface science studies, new adsorptive ligands were sought out. This included aryl amidoxime and N-heterocyclic carbene functionalities. Aryl-amidoxime dihydrotetrathiafulvalenes were successfully formed, and in the process six novel products were prepared and fully characterised. In conclusion, N-heterocyclic carbene derivatives were not fully realised, however, several dihydrotetrathiafulvalene dimers were formed, in this process a total of eight novel products were prepared and fully characterised.