The chemistry of some heteroaryltin compounds.

The objective of this study was to prepare a series of previously unreported heteroaryl organotin compounds bearing thienyl and furyl substituents, where the heteroaryl group is bound to tin via a heteroaromatic ring carbon atom. In particular, compounds bearing, respectively, two and three heteroaryl groups were of greater interest, as diorgano- and triorganotin compounds have previously been found to be significant in terms of their biological applications. The desired compounds have been prepared and subsequently characterised by spectroscopic, chemical, and analytical techniques. (Some of the compounds are being evaluated for potential usefulness in the areas of pest control and chemotherapy). Chapter 1 provides an insight into the present uses of organotin compounds. The electronic properties of the chosen heterocyclic substituents are also reviewed and their possible influence on the properties of the proposed organotin compounds discussed. A survey of the literature relating to heteroaryltin compounds is present. Chapter 2 commences with an overview of probable synthetic methods for the desired compounds based, in particular, on the chemistry of related phenyltin compounds. The di- and tri(2-heteroaryl)tin compounds are found to be unstable to the atmosphere and attempts have therefore been made to characterise them immediately following their preparation. In contrast, the 3-heteroaryl analogues are found to be more stable. [119m]Sn Mossbauer, [119]Sn nmr and mass spectrometry studies have been carried out and the results of these studies are discussed. Chemical characterisation has also been employed and results provided for derivatives of greater stability which can be more accurately analysed and characterised. In Chapter 3 the solid state structures of tri(3-thienyl)tin bromide and its triphenylphosphine oxide adduct are reported and discussed in conjunction with previously obtained Mossbauer data. An introduction to Mossbauer spectroscopy is provided in an appendix to this thesis.