Phase-Transfer Activation of Transition Metal Catalysts

Robert Tuba, Zhenxing Xi, Hassan S. Bazzi, John A. Gladysz

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

With metal-based catalysts, it is quite common that a ligand (L) must first dissociate from a catalyst precursor (L′nM£L) to activate the catalyst. The resulting coordinatively unsaturated active species (L′nM) can either back react with the ligand in a k-1 step, or combine with the substrate in a k2 step. When dissociation is not rate determining and k-1[L] is greater than or comparable to k2[substrate], this slows the rate of reaction. By introducing a phase label onto the ligand L and providing a suitable orthogonal liquid or solid phase, dramatic rate accelerations can be achieved. This phenomenon is termed "phase-transfer activation". In this Concept, some historical antecedents are reviewed, followed by successful applications involving fluorous/organic and aqueous/organic liquid/liquid biphasic catalysis, and liquid/solid biphasic catalysis. Variants that include a chemical trap for the phase-labeled ligands are also described.

Original languageEnglish
Pages (from-to)15894-15906
Number of pages13
JournalChemistry - A European Journal
Volume21
Issue number45
DOIs
Publication statusPublished - 1 Nov 2015

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Keywords

  • biphasic catalysis
  • fluorous solvents
  • olefin metathesis
  • phase transfer
  • polymerization

ASJC Scopus subject areas

  • Chemistry(all)

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