Reversible cyclometalation of silyl ligands. First X-ray structure of an iridium(I) silyl that is not stabilized by chelation

Michael Aizenberg, David Milstein

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Abstract

The iridasilacycle fac-(PMe3)3Ir(o-C6H4SiMe 2)(H) (1) results from the ortho metalation of the transient (PMe3)3Ir(SiMe2Ph) (7), generated from Ir(PMe3)4Cl and PhMe2SiLi at ambient temperature. Complex 1 can also be obtained from fac-(PMe3)3Ir(CH3)(H)(SiMe2Ph) (6), which, when heated, reductively eliminates methane. 1 and its analog fac-(PMe3)3Ir(o-C6-H4SiPh 2)(H) (2), react with hydrogen at 80 °C to yield the dihydridosilyliridium(III) complexes fac-(PMe3)3Ir(SiR2Ph)(H)2 (3, R = Me; 4, R = Ph). The reaction of 1 with deuterium demonstrates that initial opening of the iridasilacycle takes place, followed by D-D oxidative addition to 7. The reaction of 1 with CO allows us to trap the iridium(I) species and provides a synthetic route to Ir(PMe3)2(CO)2(SiMe2Ph) (5). Complex 5 was identified by spectroscopy and by X-ray crystallography and was synthesized independently from 3 and CO. The chemistry presented shows that metalation of silyl ligands can be a facile reversible process that takes place under mild conditions. It also indicates that iridasilacycles can be used as a masked form of electron-rich Ir(I) silyl complexes, which are not readily accessible species.

Original languageEnglish
Pages (from-to)3317-3322
Number of pages6
JournalOrganometallics
Volume15
Issue number15
Publication statusPublished - Jul 23 1996

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ASJC Scopus subject areas

  • Inorganic Chemistry
  • Organic Chemistry

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