Exceptionally facile CO addition to a saturated ruthenium complex

Christine Bibal; Yegor D Smurnyy; Maren Pink; Kenneth G Caulton

doi:10.1021/ja051296h

Exceptionally facile CO addition to a saturated ruthenium complex

J Am Chem Soc. 2005 Jun 29;127(25):8944-5. doi: 10.1021/ja051296h.

Authors

Christine Bibal¹, Yegor D Smurnyy, Maren Pink, Kenneth G Caulton

Affiliation

¹ Department of Chemistry and Molecular Structure Center, Indiana University, Bloomington, Indiana 47405, USA.

PMID: 15969559
DOI: 10.1021/ja051296h

Abstract

Synthesis and characterization of Cp*Ru[eta3-HC(PPh2NPh)2], 1, reveals it to have a "piano stool" structure with the ligand bound to Ru(II) via two N and the unique, sp3 hybridized carbon. While the analogous (cymene) Ru[eta3-HC(PPh2NPh)2]+ does not react with CO, under the same conditions, 1 adds one CO rapidly (25 degrees C, 1 atm CO). Characterization, including an X-ray structure determination, shows that CO has displaced one chelate ligand nitrogen, which then hangs off the molecule, free of Ru. DFT calculations reveal a possible mechanism via a remarkably low energy (+9.3 kcal/mol) intermediate, pendant N, but with one phenyl on phosphorus stabilizing Ru via donation from a C(ipso)=C(ortho) bond. DFT calculations show that the electronic energy change for binding CO is over 20 kcal/mol less favorable for cymene than for C5Me5- as ligand; the reactivity difference is thus thermodynamic in origin.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Carbon Monoxide / chemistry*
Crystallography, X-Ray
Models, Molecular
Molecular Conformation
Organometallic Compounds / chemical synthesis*
Organometallic Compounds / chemistry
Ruthenium / chemistry*
Ruthenium Compounds / chemical synthesis*
Ruthenium Compounds / chemistry

Substances

Organometallic Compounds
Ruthenium Compounds
Carbon Monoxide
Ruthenium