Show simple item record

dc.contributor.advisor Wilson, Lon J.
dc.creatorCoggin, DeAnna Kay
dc.date.accessioned 2009-06-04T00:46:50Z
dc.date.available 2009-06-04T00:46:50Z
dc.date.issued 1990
dc.identifier.urihttps://hdl.handle.net/1911/16333
dc.description.abstract Zinc(II), copper(II), and copper(I) complexes of the pentadentate ligand, ((5-MeimidH)$\sb2$DAP) were prepared and studied as their (BF$\sb4$)$\sp-$ salts. The divalent compounds, (M$\sp{\rm II}$((5-MeimidH)$\sb2$DAP)) (BF$\sb4$)$\sb2$ (M = Zn, Cu), were found to have intermediate geometries between idealized trigonal bipyramidal and square pyramidal structures by x-ray crystallography. It is assumed that (Cu$\sp{\rm I}$((5-MeimidH)$\sb2$DAP)) (BF$\sb4$) is also pentacoordinate as is its parent compound, (Cu$\sp{\rm I}$((imidH)$\sb2$DAP)) (BF$\sb4$). In addition to the x-ray structures, the new compounds have been fully characterized, where appropriate, by a battery of techniques for both the solid and solution states. These studies all suggest that the pentacoordinate structures of the solid state are also retained in solution. Variable-temperature proton NMR studies in non-aqueous solvents were used to extensively probe the intramolecular conformational dynamics of (M((5-MeimidH)$\sb2$DAP)) $\sp{\rm n+}$ (M = Zn(II), Cu(I)) and two related pentacoordinate systems ((M((imidH)$\sb2$DAP)) $\sp{\rm n+}$ and (M((py)$\sb2$DAP)) $\sp{\rm {n+}}$). Computer simulation of the temperature-dependent methylene proton regions were used to observe $\lambda$ and $\delta$ chelate ring conformations. Coalesence rate constants were obtained in four of the six cases. The electron self-exchange rate of the (Cu((5-MeimidH)$\sb2$DAP)) $\sp{+/2+}$ couple was measured in CD$\sb3$CN, as a function of temperature, by dynamic NMR line-broadening techniques. Under controlled conditions ($\mu$ = 25 mM), the observed rate constant ranged from 0.9($\pm$0.1) $\times$ 10$\sp4$ M$\sp{-1}$ s$\sp{-1}$ (243 K) to 3.9($\pm$0.4) $\times$ 10$\sp4$ M$\sp{-1}$ s$\sp{-1}$ (293 K) with activation parameters of $\Delta$H$\sp\ddagger$ = 12.5 kJ mol$\sp{-1}$ and $\Delta$S$\sp\ddagger$ = $-$116 J mol$\sp{-1}$ K$\sp{-1}$. The present electron self-exchange rate constant, together with those for two related Cu(I/II) couples ((Cu((imidH)$\sb2$DAP)) $\sp{+/2+}$ and (Cu((py)$\sb2$DAP)) $\sp{+/2+}$) indicate a possible relationship between intramolecular dynamics of the Cu(I) species and the electron self-exchange rates of the Cu(I/II) couples. Finally, the reactivity of (Cu$\sp{\rm I}$((5-MeimidH)$\sb2$DAP)) $\sp+$ towards O$\sb2$ was investigated and found to be something other than a reversible process. Although an initial uptake stoichiometry of 2Cu:O$\sb2$ was obtained by manometry, a Toepler pump experiment showed that regeneration of Cu(I) proceeded without significant release of O$\sb2$.
dc.format.extent 258 p.
dc.format.mimetype application/pdf
dc.language.iso eng
dc.subjectInorganic chemistry
dc.title Part I. Conformational mobility in pentacoordinate zinc(II) and copper(I) complexes. Part II. Redox chemistry of pentacoordinate copper(I): Reaction with dioxygen and electron transfer properties
dc.type.genre Thesis
dc.type.material Text
thesis.degree.department Chemistry
thesis.degree.discipline Natural Sciences
thesis.degree.grantor Rice University
thesis.degree.level Doctoral
thesis.degree.name Doctor of Philosophy
dc.identifier.citation Coggin, DeAnna Kay. "Part I. Conformational mobility in pentacoordinate zinc(II) and copper(I) complexes. Part II. Redox chemistry of pentacoordinate copper(I): Reaction with dioxygen and electron transfer properties." (1990) Diss., Rice University. https://hdl.handle.net/1911/16333.


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record