Structure and reactivity of the zero-valent ruthenium complex Ru(1,2-bis(diphenylphosphino)ethane)(CO)3 and the dicationic ruthenium dimer [Ru2(1,2-bis(diphenylphosphino)ethane)2(CO) 6]2+

Steven J. Skoog, Amy L. Jorgenson, John P. Campbell, Michelle L. Douskey, Eric Munson, Wayne L. Gladfelter

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

The structure of Ru(dppe)(CO)3 was characterized by single crystal X-ray diffraction [monoclinic crystal system, space group P21/n, a=12.2353(2) Å, b=16.0803(3) Å, c=14.2451(3) Å, β=111.109(1)°, V=2614.62(9) Å3, Z=4] and found to be intermediate between trigonal bipyramidal and square pyramidal. One electron oxidation of Ru(dppe)(CO)3 using [(η5-C5H5)2Fe][PF6] produced [Ru2(dppe)2(CO)6][PF6]2. The dicationic complex was fully characterized by solution spectroscopic methods and by single crystal X-ray diffraction [trigonal crystal system, space group P3121, a=20.566(2) Å, c=13.871(2) Å, V=5080.7(8) Å3, Z=3] and found to have a dimeric structure with two octahedral units sharing a common apex via a Ru(I)-Ru(I) single bond. One octahedral unit is rotated approximately 45° relative to the other, and the chelating phosphine ligand occupies sites cis and trans to the Ru(I)-Ru(I) bond. All of the carbonyl ligands were found to be terminal. The dimer was fluxional in solution and line-shape analysis of the 31P{1H} and 13C{1H} variable-temperature NMR spectra was used to investigate the exchange mechanism and evaluate the rate constants. The mechanism involved an intramolecular, two-site exchange involving pairwise bridging carbonyls and had activation parameters of 11.8±0.15 kcal mol-1 and -6.7±0.6 eu for ΔH and ΔS respectively. The dimer exhibited similar thermal and photochemical reactivity patterns; disproportionation occurred in CH3CN and halogen atom abstraction occurred in halogenated solvents.

Original languageEnglish (US)
Pages (from-to)13-28
Number of pages16
JournalJournal of Organometallic Chemistry
Volume557
Issue number1
DOIs
StatePublished - Apr 20 1998

Bibliographical note

Funding Information:
We thank Ken Caulton for helpful conversations. The research was supported by a grant from the National Science Foundation (CHE-9223433)

Keywords

  • Carbonyl
  • Crystal structure
  • Dynamic NMR
  • Metal-centered radicals
  • Photochemistry
  • Ruthenium

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