Novel sulfur containing macrocycles and their metal complexes

Abstract

Novel multi-sulfur macrocycles incorporating 4,5- dithio- 1,3- dithiole-2 - thione units connected by a variety of heterocyclic and thioether chains have been prepared and their properties investigated .
Reaction of the dimercapto disodium salt generated in situ from 4,5-bis(benzoylthio)-1,3-dithiole-2-thione with 2,6 - bis(bromomethyl)pyridine lead predominantly to the 2 : 2 product with very small amounts of the 3:3 macrocycle . On the other hand condensation of the dimercapto disodium salt with 4,4' - bis(bromomethyl)-2,2'- bi-1,3 - thiole gave a mixture of macrocycles which were identified by plasma desorption mass spectrometry (PDMS) as the 1:1, 2:2, 3 : 3 and 2:1 macrocycles . Interestingly the same reaction lead to isolation of the 2 : 2 macrocycle in pure form when the 5,5' - bis(ethoxycarbonyl) derivative of the above thiazole was used. When the thioether 1,5- dibromo - 3-thiapentane was employed, the 2:2 and 1:1 macrocycles were produced in the approximate ratio of 16 : 1 respectively.
The macrocycles described above have been used to prepare, via intramolecular coupling, new macrocyclic cage molecules incorporating the electro active tetrathiafulvalene (TTF) moiety and their electrochemical properties have been investigated. These new donor molecules show two reversible one electron oxidation waves similar to other TTF systems , but attempts to grow charge transfer complexes with a variety of acceptors were unsuccessful. The X- ray crystal
structures of the pyridine 2 : 2 macrocycle and its corresponding TTF cage molecule, the 1 :1 macrocycle derived from 1,5-dibromo- 3 - thiapentane, the cage molecule of the 2:2 macrocycle and the 1:1 product prepared from ortho-dibromoxylene are reported.
Attempts have been made to prepare transition metal complexes of the TTF cage molecules and their macrocyclic precursors.
A new ligand, orthoxylenedithiodithiolate (OXDT-DT) has been synthesised and its Ni²⁺, cu²⁺ and Au^{3 +} complexes have been isolated as the mono- tetraalkylammonium salts. An investigation of the solid state properties of these mono anionic complexes has been carried out. The monoanionic complexes have been oxidised to the neutral species by chemical and/or electrochemical methods.

Date of Award	26 Apr 1993
Original language	English
Awarding Institution	University of Wales, Bangor
Sponsors	United Nations Industrial Development Organization & Asmara University, Eritrea
Supervisor	Allan Underhill (Supervisor)