Anionic d8 alkyl hydrides - Selective formation and reactivity of anionic cisPtII methyl hydride

Elena Poverenov, Mark A. Iron, Mark Gandelman, Yehoshoa Ben-David, David Milsteins

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Abstract

The pincer-type complexes [(PCN)PtR] [R = H, 2; Me, 4; PCN = C 6H4[CH2P(tBu)2](CH2) 2N(CH3)2} react with MeLi or Et 3BHNa, to give anionic cis-Pt(Me).H complexes [(PCN*)Pt(H)(Me) J-Li+(Me irons to P; PCN* denotes the PCN ligand in which the amine arm is not coordinated) and [(PCN*)Pt(Me)(H)]-Na+ (H trans to P). Only the isomer in which the incoming nucleophile is situated trans to the phosphane ligand is formed. These first d8 anionic alkyl hydride complexes were fully characterized spectroscopically, The hemilabile PCN ligand allows for reversible de-coordination of the amine arm, thereby providing a desirable balance of stability vs. reactivity. Theoretical calculations on model systems indicate a concerted mechanism in which the nucleophilic attack and the amine dissociation occur concurrently. The (unobserved) methane reductive elimination from the stable anionic methyl hydride complex [(PCN*)Pt(Me)(H)]-Li+ (3) is thermodynamically and kinetically unfavorable, as indicated by DFT. This complex reacts with electrophiles, such, as water and methyl iodide, to yield exclusively methane and the corresponding organometallic product (either 2 or 4). This reactivity was also further examined by DFT.

Original languageEnglish
Pages (from-to)1991-1999
Number of pages9
JournalEuropean Journal of Inorganic Chemistry
Issue number13
DOIs
Publication statusPublished - May 1 2010

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Keywords

  • Alkyl hydride
  • Anionic complexes
  • Density functional calculations
  • Pincer ligand
  • Platinum

ASJC Scopus subject areas

  • Inorganic Chemistry

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