dc.contributor.advisor Wilson, Lon J. Coggin, DeAnna Kay 2009-06-04T00:46:50Z 2009-06-04T00:46:50Z 1990 https://hdl.handle.net/1911/16333 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$\sb2$. 258 p. application/pdf eng Inorganic chemistry 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 Thesis Text Chemistry Natural Sciences Rice University Doctoral Doctor of Philosophy 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.
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