University of Illinois Urbana-Champaign

I. An oxygen-17 NMR study on oxygen exchange in yttrium barium(2) copper(3) oxygen(7-x). II. Synthesis of transition metal polysulfide complexes from metal powders

Ramli, Emannuel

This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.

Permalink

https://hdl.handle.net/2142/21567

Description

Title
I. An oxygen-17 NMR study on oxygen exchange in yttrium barium(2) copper(3) oxygen(7-x). II. Synthesis of transition metal polysulfide complexes from metal powders
Author(s)
Ramli, Emannuel
Issue Date
1991
Doctoral Committee Chair(s)
Rauchfuss, Thomas B.
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
  • Covellite, $\rm Cu\sp{I}\sb2(S\sb2)Cu\sp{II}S$ (T$\sb{\rm c}$ = 1.66 K) and $\rm YBa\sb2Cu\sp{II}\sb2Cu\sp{III}O\sb{7-x}\ (T\sb{c}$ = 92 K) are similar in that both are superconductors containing layered structures and mixed valent copper centers. Our studies on YBa$\sb2$Cu$\sb3$O$\sb{\rm 7-x}$ focused on $\sp{17}$O-labelling of samples of $\rm YBa\sb2 Cu\sb3 O\sb{7-x}$ and the $\sp{17}$O NMR studies of these samples. The $\sp{17}$O-labelling process was carried out using a specially designed glass apparatus. Powder X-ray diffraction and magnetic susceptibility measurements showed that our samples were highly pure. $\sp{17}$O NMR spectroscopy showed that we were able to prepare samples which have uniform and non-uniform distribution of $\sp{17}$O atoms.
  • Our work on covellite began with studies of its synthesis at low temperatures. This work led to the discovery of a low temperature route to metal sulfides. We initially prepared covellite by the reaction of a suspension of copper metal and elemental sulfur in refluxing pyridine. When the same reaction was conducted at room temperature we obtained amorphous CuS and (Cu(S$\sb5$)$\sb2$(pyridine)) $\sb4$. (Cu(S$\sb5)\sb2$(pyridine)) $\sb4$ was shown to be a molecular intermediate in the formation of covellite from its elements. Subsequently it was found that the reaction between copper and sulfur is particularly rapid in N-methylimidazole, affording (Cu(S$\sb5$)$\sb2$(N-MeIm)) $\sb4$ in 50% yield.
  • Other first row transition metals which react with S$\sb8$ in N-methylimidazole at room temperature include manganese, iron and nickel. The product in all of these cases is (M(N-MeIm)$\sb6$) S$\sb8$ (M = Mn, Fe, Ni). (M(N-MeIm)$\sb6$) S$\sb8$ provides the first evidence for S$\sb8\sp{2-}$ anion, the product of the 2 e$\sp-$ reduction of S$\sb8$.
  • Zinc metal reacts with S$\sb8$ in N-methylimidazole at 90$\sp\circ$C to form (ZnS(N-MeIm)) $\sb{\rm n}$ when Zn: S = 1: 1 and ZnS$\sb6$(N-MeIm)$\sb2$ when Zn: S = 1: 6. The two compounds are interconvertible via addition of elemental sulfur or zinc.
Type of Resource
text
Permalink
http://hdl.handle.net/2142/21567
Copyright and License Information
Copyright 1991 Ramli, Emannuel

Owning Collections

Graduate Dissertations and Theses at Illinois PRIMARY
Graduate Theses and Dissertations at Illinois
Dissertations and Theses - Chemistry