The preparation of organosulfur derived electron transfer salts

Abstract

The concept of this thesis is to effect greater control over the crystalline state of radical cation salts in order to enhance electron transport, and to allow for the incorporation of additional functionality such as optical activity or magnetism. The salts formed are based on the bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) framework, and are produced using the technique of electrocrystallisation. In attempts to control the crystal packing arrangements observed, a number of approaches have been explored including the incorporation of chirality, hydrogen bonding interactions and coordinate bonding interactions. These properties have been installed on the electron donor molecule and/ or the charge stabilising anion component. This thesis presents a novel radical cation salt that has been prepared from ET and the sulfamate anion, and which exhibits ordered channels of hydrogen bonded anions and water molecules extending in one crystallographic dimension. This research has also discovered an unusual chiral crystallographic packing observed in a novel semiconducting radical cation salt formed from ET and the bromide anion. Also presented are the synthesis of a family of metal-binding electron donors and the first radical cation salts formed from these, including a perrhenate salt which is both N-protonated and oxidised, giving an overall charge of +2 on the electron donor molecule. A group of novel aldehyde-functionalised donors are discussed, one of which could lead to a Little-type superconductor, and the syntheses towards a bis(donor) molecule containing a spiro centre, and separately a porphyrin appended electron donor are presented