Metal-silicon bonding energetics in organo-Group 4 and organo-f-element complexes. Implications for bonding and reactivity

Wayne A. King, Tobin J. Marks

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)


Metal-silicon bond disruption enthalpies have been measured for a series of U, Zr, and Sm metallocene complexes: Cp3USi(TMS)3, Cp2Zr(Cl)Si(TMS)3, Cp2Zr(Me)Si(TMS)3, Cp2Zr(TMS)Si(TMS)3, Cp2Zr(TMS)OtBu, Cp′2SmSiH(TMS)2 (Cp = η5-C5H5, Cp′ = η5-Me5C5, TMS = trimethylsilyl). Data were obtained by anaerobic batch-titration solution calorimetry in toluene. Derived metal-ligand bond enthalpies D(LnM-R) in kcal mol-1 are: D[Cp3USi(TMS)3] = 37(3), D[Cp2(Cl)ZrSi(TMS)3]=57(3), D[Cp2(Me)ZrSi(TMS)3]=56(5), D[Cp2(Si(TMS)3)ZrMe] = 66(5), D[Cp2(OtBu)Zr-TMS] = 60(5), D[Cp2(TMS)ZrSi(TMS)3] = 42(11), D[Cp2(Si(TMS)3)Zr-TMS] = 45(7), D[Cp′2SmSiH(TMS)2] = 43(5). These results show that metal-silicon bond disruption enthalpies involving these electron-deficient metals are substantially smaller than those of the corresponding metal hydride and hydrocarbyl bonds. These data in combination with previously measured metal-ligand bond enthalpies allow thermodynamic analyses of a variety of stoichiometric and catalytic transformations involving metal silyl functionalities. The latter include potential pathways for dehydrogenative silane polymerization, dehydrogenative silane-hydrocarbon coupling, olefin hydrosilylation, and dehydrogenative silane-amine coupling. It is not uncommon for there to be multiple pathways which effect the same catalytic transformation and which contain no steps having major enthalpic impediments.

Original languageEnglish
Pages (from-to)343-354
Number of pages12
JournalInorganica Chimica Acta
Issue number1-2
Publication statusPublished - Feb 1995


  • Block f-element complexes
  • Bond enthalpies
  • Group 4 transition element complexes
  • Organyl complexes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Fingerprint Dive into the research topics of 'Metal-silicon bonding energetics in organo-Group 4 and organo-f-element complexes. Implications for bonding and reactivity'. Together they form a unique fingerprint.

Cite this