Author

Graham Turner

Date of Award

8-1976

Degree Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Supervisor

C.J.L. Lock

Abstract

In the higher oxidation states (V, VI and VII) the outstanding feature of the chemistry of rhenium is the tendency to form compounds containing rhenium-oxygen multiple bonds. This thesis examines the nature of these Re-O multiple bonds, and in particular, derives a correlation between the bond length and the Re-O stretching force constant. The validity of this empirical correlation is tested over a limited range of compounds. The crystal structure of KReO₄ was redetermined to a high precision to test the predictions of this correlation. A normal coordinate analysis of the ReO₂ (CN)₄³ ion was performed, including data from ¹³C suhbtituted and ¹⁸O enriched complex ions. Some new infrared data for complexes of type ReO(OR)L₄ are reported (R = hydrogen atom or alkyl group), and the rhenium-oxygen stretching frequencies are assigned. Force constants are calculated for complexes of type Re₂O₃L₈ and ReO(OR)L₄.

The crystal structures of [ReO₂en₂]Cl and [ReO₂py₄]Cl.2H₂O were redetermined, to provide some accurate data on Re-O double bonds. The structure of the compound [ReO(OH)en₂][CIO₄]₂ was also redetermined and an accurate bond length for the Re-O(H) bond was finally obtained. The structure of the compound Re₂O₃py₄Cl₄ was determined, and was found to be different from that predicted in the literature. The nature of the intramolecular interactions in this compound were examined in an effort to explain the unusual stereochemistry, and the asymmetry of the compound. Pyridine groups were found to play a dominant role in the structure of the compound. The structure of ReO(OEt)py₂Cl₂ was also determined, giving a value for the Re-O(Et) bond length. Pyridine groups were again the dominant factor in the stereochemistry of the complex. The rhenium-oxygen bonding in complexes of type ReO(OR)L₄ was found to be similar to that found in Re₂O₃L₈ type complexes.

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