Abstract
The work in this thesis covers; (a) The preparation of Schiff's bases of different types, and of their cobalt(II) complexes in particular. (b) The preparation of the corresponding mononitrosyls. (c) Investigations of the properties of the complexes by a variety of physical techniques. Most of the complexes investigated were air-sensitive so that it was necessary to prepare and handle there under nitrogen or in vacuum. The bidentate ligands used were variously substituted salicylaldoximes. The cobalt(II) complexes obtained from these were found from magnetic measurements to be low-spin, planar compounds. The oxime-mononitrosyls were essentially diamagnetic, and probably have tetragonal-pyramidal structures,. It X7&.S found that generally electron-withdrawing substituents increased the NO stretching frequency, but this was not as clear cut as in previous works. The cobalt(II) complexes of the quadridentate ligands acetylacetoneethylenediimine, trifluoroacetylacetone-ethylenediimine, and benzoylacetoneethylenediimine were also investigated, but the first could not be obtained pure. The corresponding mononitrosyls and the nitrosyl of dibenzoylmethaneethylenediimine were also prepared. The cobalt(II) and manganese(II) complexes of quadridentate Schiff's bases prepared by condensing salicylaldehyde with 1:3-propanediamine and 1:2-propanediamine were investigated Both cobalt complexes formed mononitrosyls readily. The manganese(II) complex of 1:3-propanediamine has been reported to react reversibly with nitrogen, oxygen and carbon monoxide; and would therefore be expected to react with nitric oxide. In fact neither manganese complex reacted with nitric oxide, and the samples of the 1:3-propanediajaine complex would not react with nitrogen or oxygen either. Some investigations of the cobalt(II) complexes of Schiff's bases derived from sulphonated salicylaldehyde were also carried out.