Thermodynamic, kinetic, and computational study of heavier chalcogen (S, Se, and Te) terminal multiple bonds to molybdenum, carbon, and phosphorus

James E. McDonough, Arjun Mendiratta, John J. Curley, George C. Fortman, Serena Fantasia, Christopher C. Cummins, Elena V. Rybak-Akimova, Steven P. Nolan, Carl D. Hoff

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

Enthalpies of chalcogen atom transfer to Mo(N[t-Bu]Ar)3, where Ar = 3,5-C6H3Me2, and to IPr (defined as bis-(2,6-isopropylphenyl)imidazol-2-ylidene) have been measured by solution calorimetry leading to bond energy estimates (kcal/mol) for EMo(N[t-Bu]Ar) 3 (E = S, 115; Se, 87; Te, 64) and EIPr (E = S, 102; Se, 77; Te, 53). The enthalpy of S-atom transfer to PMo(N[t-Bu]Ar)3 generating SPMo(N[t-Bu]Ar)3 has been measured, yielding a value of only 78 kcal/mol. The kinetics of combination of Mo(N[t-Bu]Ar)3 with SMo(N[t-Bu]Ar)3 yielding (μ-S)[Mo(N[t-Bu]Ar)3] 2 have been studied, and yield activation parameters ΔH‡ = 4.7 ± 1 kcal/mol and ΔS‡ = -33 ± 5 eu. Equilibrium studies for the same reaction yielded thermochemicai parameters ΔH° = -18.6 ± 3.2 kcal/mol and ΔS° = -56.2 ± 10.5 eu. The large negative entropy of formation of (μ-S)[Mo(N[t-Bu]Ar)3] 2 is interpreted in terms of the crowded molecular structure of this complex as revealed by X-ray crystallography. The crystal structure of Te-atom transfer agent TePCy3 is also reported. Quantum chemical calculations were used to make bond energy predictions as well as to probe terminal chalcogen bonding in terms of an energy partitioning analysis.

Original languageEnglish (US)
Pages (from-to)2133-2141
Number of pages9
JournalInorganic Chemistry
Volume47
Issue number6
DOIs
StatePublished - Mar 17 2008

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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    McDonough, J. E., Mendiratta, A., Curley, J. J., Fortman, G. C., Fantasia, S., Cummins, C. C., Rybak-Akimova, E. V., Nolan, S. P., & Hoff, C. D. (2008). Thermodynamic, kinetic, and computational study of heavier chalcogen (S, Se, and Te) terminal multiple bonds to molybdenum, carbon, and phosphorus. Inorganic Chemistry, 47(6), 2133-2141. https://doi.org/10.1021/ic701611p