Acceptor Strengths of Some Group IV Lewis Acids by Electron Paramagnetic Resonance Studies of Their Complexes with Aliphatic Nitroxides

Allan H. Cohen, Brian M Hoffman*

*Corresponding author for this work

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

Molecular complexes have been formed between two aliphatic nitroxides, di-tert-butyl nitroxide and 2,2,6,6-tetramethylpiperidine-N-oxyl, and group IV Lewis acids. Analysis of the epr spectra shows that in all cases 1:1 complexes are formed. The π-electron spin density of a nitroxide complex can be analyzed from its epr spectrum and changes in the nitroxide 14N hfs upon complexation are a measure of the acceptor strength of the Lewis acid. For the acids studied here the order of acceptor strength is TiCl4 > SnCl4 > SnBr4 > SiF4 ≳ Sn(t-Bu)2Cr(CO)5 ≈ SiCl4 ≳ GeCl4 ≈ Ti(OPh)4. In some cases epr spectra show the nitroxide and its complex to be in equilibrium and thermodynamic constants for complex formation are obtained.

Original languageEnglish (US)
Pages (from-to)1484-1491
Number of pages8
JournalInorganic chemistry
Volume13
Issue number6
DOIs
StatePublished - Jun 1 1974

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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