Interplay between solvent and counteranion stabilization of highly unsaturated rhodium(III) complexes

Facile unsaturation-induced dearomatization

Mark Gandelman, Leonid Konstantinovski, Haim Rozenberg, David Milstein

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Abstraction of the chloride ligand from the PCN-based chloromethylrhodium complex 2 by AgX (X = BF4 -, CF3SO3 -) or a direct C-C cleavage reaction of the PCN ligand 1 with [(coe)2Rh(solv)n]+X- (coe = cyclooctene) lead to the formation of the coordinatively unsaturated rhodium(III) complexes 3. Compound 3a (X = BF4 -) exhibits a unique medium effect; the metal center is stabilized by reversible coordination of the bulky counteranion or solvent as a function of temperature. Reaction of [(PCN)Rh(CH3)(CI)] with AgBArf in diethyl ether leads to an apparent rhodium(III) 14-electron complex 4, which is stabilized by reversible, weak coordination of a solvent molecule. This complex coordinates donors as weak as diethyl ether and dichloromethane. Upon substitution of the BF4 - ion in [(PCN)Rh(CH3)]BF4 by the noncoordinating BArf - ion in a noncoordinating medium, the resulting highly unsaturated intermediate undergoes a 1,2-metal-to-carbon methyl shift, followed by β-hydrogen elimination, leading to the Rh-stabilized methylene arenium complex 5. This process represents a unique mild, dearomatization of the aromatic system induced by unsaturation.

Original languageEnglish
Pages (from-to)2595-2602
Number of pages8
JournalChemistry - A European Journal
Volume9
Issue number11
DOIs
Publication statusPublished - Jun 6 2003

Fingerprint

Pregnenolone Carbonitrile
Rhodium
Ethers
Stabilization
Ligands
Dichloromethane
Ions
Metals
Ether
Substitution reactions
Hydrogen
Molecules
Carbon
Electrons
Methylene Chloride
Chlorides
Temperature

Keywords

  • Dearomatization
  • N,P ligands
  • Rhodium
  • Tridentate ligands
  • Unsaturated complexes

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Interplay between solvent and counteranion stabilization of highly unsaturated rhodium(III) complexes : Facile unsaturation-induced dearomatization. / Gandelman, Mark; Konstantinovski, Leonid; Rozenberg, Haim; Milstein, David.

In: Chemistry - A European Journal, Vol. 9, No. 11, 06.06.2003, p. 2595-2602.

Research output: Contribution to journalArticle

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