Reactions and stereochemistry of thiolato and sulfenato cobalt (III) complexes Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/g158bm289

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • This thesis describes a study of the synthesis, stereochemistry, and reactivity of cobalt(III) cysteinato (CyS) and related thiolato complexes. The preparation of [Co(en)₂CyS]⁺ resulted in a product solution containing a mixture of diastereomers in the ratio 2.3:1 (Δ:A). The isomers were separated by ion exchange chromatography, and their absolute configurations were assigned on the basis of their CD spectra and relative stabilities. Interconversion of the two isomers was shown to occur under the proper conditions. Oxidation of A-[Co(en)₂CyS]⁺ by H₂O₂ led to a 2.9:1 (S:R) mixture of AS- and AR- [Co(en)₂CyS]⁺, the S and R indicating configuration at sulfur. Both of these sulfenato isomers underwent further oxidation by H₂O₂ to form the same product, A-[Co(en)₂(CySO₂)]⁺. The S and R sulfenato isomers were stable in solution if kept in the dark, but exposure to room light caused a rapid interconversion of the isomers, which led in 1-3 hr to an equilibrium 76:24 (AS:AR) mixture. A slower decomposition reaction also occurred upon exposure to light. Similar behavior toward H₂O₂ and light was observed in the Δ system. The synthesis of the analogous penicillaminato complexes produced a ca. 2:1 mixture of A-[ Co(en)₂PenS]⁺. Both isomers underwent oxidation by H₂O₂ to form sulfenato and sulfinato complexes. The complexes [ Co(CyS)₃]³⁻ and [Co(PenS)₂]⁻ also reacted readily with H₂O₂, producing sulfenato and sulfinato complexes. The bis(cysteinato) complex previously formulated in the literature as [ Co(CyS)₂(H₂O)₂]⁻ did not react with H₂O₂. Based on this and other observations, a new trinuclear structure was proposed in which six sulfur ligands form bridges between three cobalt(III) ions. The kinetics of oxidation by H₂O₂ were measured for several of the thiolato and sulfenato complexes. The resulting rate constants were analyzed in terms of the steric and electronic characteristics of the various isomeric species. Other reactions briefly examined include oxidation of [ Co(en)₂CyS]⁺ and [ Co(en)₂(CySO)]⁺ by Br₂, and reaction of [ Co(en)₂(CySO)]⁺ with hydroxylamine-O-sulfonic acid.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 24-bit Color) using ScandAll PRO 1.8.1 on a Fi-6670 in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-09-11T17:22:15Z (GMT) No. of bitstreams: 1 HertingDanielL1980.pdf: 1234542 bytes, checksum: ba4551658f7b311cef2e75f63e1c6bc3 (MD5)
  • description.provenance : Made available in DSpace on 2013-09-12T17:45:48Z (GMT). No. of bitstreams: 1 HertingDanielL1980.pdf: 1234542 bytes, checksum: ba4551658f7b311cef2e75f63e1c6bc3 (MD5) Previous issue date: 1979-08-31
  • description.provenance : Submitted by Katy Davis (kdscannerosu@gmail.com) on 2013-09-11T16:46:50Z No. of bitstreams: 1 HertingDanielL1980.pdf: 1234542 bytes, checksum: ba4551658f7b311cef2e75f63e1c6bc3 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2013-09-12T17:45:48Z (GMT) No. of bitstreams: 1 HertingDanielL1980.pdf: 1234542 bytes, checksum: ba4551658f7b311cef2e75f63e1c6bc3 (MD5)

Relationships

In Administrative Set:
Last modified: 08/10/2017

Downloadable Content

Download PDF
Citations:

EndNote | Zotero | Mendeley

Items