Chalcogen-carbon-nitrogen rings, chains and coordination compounds

Abstract

This thesis describes the general area of chalcogen-carbon-nitrogen compounds. The first part of Chapter 1 provides an introduction to chalcogen donor ligands. The second part of Chapter 1 considers the literature reports on polythiocyanogen and related compounds. Chapter 2 details the synthesis and characterisation of a series of homoleptic, heteroleptic and dimeric cyanodithioimidocarbonate complexes prepared by the reaction of dipotassium cyanodithioimidocarbonate with the appropriate transition metal starting materials. Chapter 3 describes the synthesis and characterisation of the cyanodiselenoimidocarbonate complexes. In Chapter 4 we report a convenient one pot synthesis for the preparation of triselenocarbonate complexes. We have prepared mononuclear, binuclear and tetranuclear complexes of this ligand including the first crystallographically characterised example of a triselenocarbonate complex. In Chapter 5 we have prepared a series of 1,2,4- thiadiazole compounds for spectroscopic comparison with (SCN)ₓ. We also report the synthesis of model compounds for (SCN)ₓ composed of two 1,2,4- dithiazole rings linked by a sulfur bridge. Chapter 6 describes the synthesis and full characterisation of polythiocyanogen (SCN)ₓ the related small molecules Sₓ(CN)₂ (x = 1, 2, 3) and the selenium analogues. Using the data obtained and comparison with the 1,2,4-thiadiazole model compounds reported in Chapter 5 as well as literature compounds we have determined the structure of polythiocyanogen.