N-H and N-C bond formation with an N2-derived dihafnium μ-nitrido complex

Scott P. Semproni, Paul J. Chirik

Research output: Contribution to journalArticle

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Abstract

Exposure of the base-free isocyanato dihafnocene μ-nitrido complex prepared from CO-induced N2 cleavage to a dihydrogen atmosphere resulted in rapid 1,2-addition across the hafnium-nitrogen bond followed by insertion of the terminal isocyanate ligand into the putative hafnium hydride ligand and formed a bridging formamide ligand. Terminal alkynes and sterically hindered allenes underwent preferential addition of a C-H bond across the hafnium nitride fragment and resulted in isolation of the μ-imido acetylide and allenyl dihafnocene complexes, respectively. Reducing the steric profile of the allene enabled N-C rather than N-H bond-forming chemistry arising from cycloaddition of the π system. In the presence of additional allene, the resulting azahafnacyclobutanes underwent exchange, establishing the reversibility of the N-C bond forming reaction. Ketones with enolizable hydrogens, amines, and guanidines underwent rapid deprotonation upon addition to the isocyanato dihafnocene μ-nitrido complex and offer a route to N-H bond formation, as well as allowing isolation of a rare example of a parent amido compound. The preference of the dihafnium nitrido system for N-H over N-C bond formation was explored by treatment with styrene oxide, which afforded exclusively the E2 elimination product rather than the expected 1,2-amino alkoxide complex.

Original languageEnglish (US)
Pages (from-to)3727-3737
Number of pages11
JournalOrganometallics
Volume33
Issue number14
DOIs
StatePublished - Jul 28 2014

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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