Noninnocent behavior of PCP and PCN pincer ligands of late metal complexes

Elena Poverenov, David Milstein

Research output: Chapter in Book/Report/Conference proceedingChapter

39 Citations (Scopus)


Pincer complexes are generally viewed as stable compounds in which the pincer ligand framework remains unchanged during stoichiometric and catalytic reactions. However, there are now several cases in which the pincer ligand itself undergoes transformations that result in extraordinary reactivity of the metal complex and formation of unusual species. In the current chapter, we review our work on noninnocent reactivity modes of various PCP and PCN-type pincer ligands of Rh, Ir, Ru, Os, Pd, and Pt. Participation of the arene ring in the reactivity of PCP type complexes has led to formation of unprecedented quinonoid complexes, including complexes in which the pincer ligand adopts structures of quinone methides, thio-quinone methides, xylylenes, methylene arenium, and oxo-arenium compounds. In addition, pincer systems can collapse and be regenerated under redox conditions, and reduction can lead to a ring-localized radical anion complex. The generation of C-H agostic arene PCP complexes has led to new insights regarding the C-H bond activation process, and the effect of CO ligands on it.

Original languageEnglish
Title of host publicationOrganometallic Pincer Chemistry
PublisherSpringer Verlag
Number of pages28
ISBN (Print)9783642310805
Publication statusPublished - 2013

Publication series

NameTopics in Organometallic Chemistry
ISSN (Print)1436-6002


  • Pincer ligands
  • agnostic pincer complex
  • late transition metals
  • methylene arenium complex
  • phenoxonium complex
  • quinone methide complex
  • reactive intermediates
  • thioquinone methide complex
  • xylylene complex

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry
  • Inorganic Chemistry

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