Insertion reactions of phenyl isocyanate into hafnium nitrogen bonds: Synthesis and reactivity of hafnium complexes bearing substituted pyrrolyl ligands

Kun Chun Hsieh, Wen Yi Lee, Chun Liang Lai, Ching Han Hu, Hon Man Lee, Jui Hsien Huang, Shie Ming Peng, Gene Hsing Lee

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

A bis(diethylamido)hafnium compound [C4(CH2NMe 2)-2]2Hf(NEt2)2 (1) has been prepared in 79% yield by reacting Hf(NEt2)4 with 2 equiv. of [C4H(CH2NMe2)-2] in heptane via deamination. Reacting compound 1 with 2 equiv. of phenyl isocyanate at room temperature in diethyl ether results in the PhNCO being inserted seletively into hafnium-NEt2 bonds to generate [C4(CH2NMe2)-2]2Hf[PhNC (NEt2)O]2 (2) in 56% yield. Similarly, while reacting 1 with 2 equiv. of phenyl isocyanate for a week in toluene produces a mixture of 2 and [C4(CH2NMe 2)-2]Hf[PhNC(NEt2)O]3 (3). For comparison, reacting Hf(NEt2)4 with 4 equiv. of PhNCO in a toluene solution at room temperature results in the PhNCO inserted into Hf-N bonds, and forms a tetrakis-ureato hafnium compound Hf[PhNC(NEt2)O]4 (4) in 88% yield. A theoretical calculation found that the unpaired electrons of the ureato fragments of 2 are resonance delocalized between the C-O, C-NPh, and C-NEt2 bonds, which are all partially doubly bonded.

Original languageEnglish (US)
Pages (from-to)3362-3369
Number of pages8
JournalJournal of Organometallic Chemistry
Volume689
Issue number21
DOIs
StatePublished - Oct 15 2004

Keywords

  • Insertion hafnium
  • Phenyl isocyanate
  • Pyrrolyl

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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