Metal-ligand synergistic effects in the complex Ni(η2-TEMPO) 2: Synthesis, structures, and reactivity

Derek Isrow, Nathan J. Deyonker, Anjaneyulu Koppaka, Perry J. Pellechia, Charles Edwin Webster, Burjor Captain

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

In the current investigation, reactions of the "bow-tie" Ni(η2-TEMPO)2 complex with an assortment of donor ligands have been characterized experimentally and computationally. While the Ni(η2-TEMPO)2 complex has trans-disposed TEMPO ligands, proton transfer from the C-H bond of alkyne substrates (phenylacetylene, acetylene, trimethylsilyl acetylene, and 1,4-diethynylbenzene) produce cis-disposed ligands of the form Ni(η2-TEMPO) (κ1-TEMPOH)(κ1-R). In the case of 1,4-diethynylbenzene, a two-stage reaction occurs. The initial product Ni(η2-TEMPO)(κ1-TEMPOH)[κ1- CC(C6H4)CCH] is formed first but can react further with another equivalent of Ni(η2-TEMPO)2 to form the bridged complex Ni(η2-TEMPO)(κ1-TEMPOH) [κ11-CC(C6H4)CC] Ni(η2-TEMPO)(κ1-TEMPOH). The corresponding reaction with acetylene, which could conceivably also yield a bridging complex, does not occur. Via density functional theory (DFT), addition mechanisms are proposed in order to rationalize thermodynamic and kinetic selectivity. Computations have also been used to probe the relative thermodynamic stabilities of the cis and trans addition products and are in accord with experimental results. Based upon the computational results and the geometry of the experimentally observed product, a trans-cis isomerization must occur.

Original languageEnglish (US)
Pages (from-to)13882-13893
Number of pages12
JournalInorganic Chemistry
Volume52
Issue number24
DOIs
StatePublished - Dec 16 2013

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Fingerprint Dive into the research topics of 'Metal-ligand synergistic effects in the complex Ni(η<sup>2</sup>-TEMPO) <sub>2</sub>: Synthesis, structures, and reactivity'. Together they form a unique fingerprint.

  • Cite this