Structure, Dynamic Behavior, and Catalytic Activity of a Novel Ruthenium Cyclopentadienyl Complex with a Tridentate P<i>,</i>P<i>,</i>O Ligand

Reaction of 1,2-bis(bis(<i>o</i>-methoxyphenyl)phosphino)ethane (<i>o</i>-MeO-dppe) with [RuClCp(PPh<sub>3</sub>)<sub>2</sub>] (<b>1</b>) at 135 °C results in the formation of (η<sup>5</sup>-cyclopentadienyl)[1-(bis(<i>o</i>-methoxyphenyl)phosphino-κ<i>P</i>)-2-((<i>o</i>-methoxyphenyl)(<i>o</i>-phenolato-κ<i>O</i>)phosphino-κ<i>P</i>)ethane]ruthenium(II) ([RuCp(tappe)]; <b>3</b>), which constitutes the first example of a ruthenium cyclopentadienyl complex with a tridentate P,P,O ligand. The X-ray structure of <b>3</b> has been determined to elucidate its solid-state structure, which shows evidence for a CH/π interaction. An NMR study corroborates this finding, and temperature-dependent <sup>31</sup>P and <sup>1</sup>H NMR spectra reveal the dynamic behavior of <b>3</b> in solution. Complex <b>3</b> shows catalytic activity in the isomerization of allylic alcohols to carbonyl compounds.