University of Illinois Urbana-Champaign

Studies of the mechanism of oxygen atom transfer from molecular oxygen to iridium-coordinated cyclooctadiene

Lockledge, Scott Potter

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Description

Title
Studies of the mechanism of oxygen atom transfer from molecular oxygen to iridium-coordinated cyclooctadiene
Author(s)
Lockledge, Scott Potter
Issue Date
1990
Doctoral Committee Chair(s)
Klemperer, Walter G.
Department of Study
Chemistry
Discipline
Chemistry
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Chemistry, Inorganic
Language
eng
Abstract
  • The cyclooctadiene complex ((C$\sb8$H$\sb{12}$)Ir(P$\sb3$O$\sb9$)) ((n-C$\sb4$H$\sb9$)$\sb4$N) $\sb2$, a, reacted in solution at ambient temperature with O$\sb2$ to form ((C$\sb8$H$\sb{11}$OH)Ir(P$\sb3$O$\sb9$)) ((n-C$\sb4$H$\sb9$)$\sb4$N) $\sb2$, f. Sealed tube $\sp{31}$P NMR spectroscopic experiments established the presence of three additional species in this reaction and the relationship between them. One of these intermediates, the oxametallacyclobutane complex ((C$\sb8$H$\sb{12}$O)Ir(P$\sb3$O$\sb9$)) ((n-C$\sb4$H$\sb9$)$\sb4$N) $\sb2$, e, was isolated and structurally characterized. Pseudo-octahedral coordination geometry at the Ir(III) center is defined by three terminal (P$\sb3$O$\sb9$)$\sp{3-}$ oxygen atoms, an olefinic C=C bond, and the carbon and oxygen atoms of an oxametallacyclobutane ring. The structures a and e are related by insertion of an O atom into a C-Ir bond of a. The structures of e and f are related by proton transfer from the allylic carbon of e to the oxygen atom of the oxametallacyclobutane ring. Oxygen uptake experiments indicated that both atoms of O$\sb2$ are incorporated into a molecule of a.
  • Two other species were observed by $\sp{13}$C and $\sp{31}$P NMR spectroscopy and structures for these complexes are proposed. On the basis of these observations, a mechanism is proposed detailing the incorporation of the oxygen atoms from O$\sb{2}$ into a and its subsequent reactivity.
Type of Resource
text
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http://hdl.handle.net/2142/21894
Copyright and License Information
Copyright 1990 Lockledge, Scott Potter

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Graduate Theses and Dissertations at Illinois
Dissertations and Theses - Chemistry