Investigations concerning the reactions of small molecules with a series of pentacoordinate manganese complexes and the characterization of a solvent refined coal

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Virginia Tech


Manganese(II) complexes with linear potentially pentadentate Schiff base ligands have been prepared and characterized. Their reactions with dioxygen and nitric oxide has been studied. The ligands were synthesized from substituted salicylaldehydes and selected hiamines containing a central nitrogen donor. The five-coordinate complexes assume a distorted trigonal bipyramidal structure.

The manganese(II) complexes are unstable in the air and all of them react with dioxygen in solution. Intro cases dimeric µ-peroxo dioxygen adducts were formed which are stable in air. These two complexes demonstrate reversible coordinating ability for dioxygen under mild conditions.

The manganese(II) complexes react with nitric oxide when in solution when no steric problems are presented by the central donor. All the manganese(I) nitrosyls so formed demonstrate reversible coordinating ability for nitric oxide under mild conditions.

Some steps in the characterization of a Solvent Refined Coal has been presented. A novel chromatographic column design has been developed which allows the rapid quantitative GPC separation of coal liquid products on a preparative scale, Among several packings that were examined Bio-Beads S-X4 proved to be the superior material. Molecular weights on each fraction were determined.

Quantitative determination of metal content in the Solvent Refined Coal were made using flameless atomic absorption spectrometry. The Solvent Refined Coal was shown to contain substantial quantities of catalytic metals and metals of environmental concern.

Electron Spin Resonance measurements yielded signals assignable to organic free radicals and iron(III) were observed.