Preparation of a dicationic, p-cymene ruthenium(II) dimer, [(p-cymene)Ru(µ-Cl)(P{OCH₂}₃CEt)]₂²⁺: structure, characterization and reactivity

Abstract

Reaction of (p-cymene)RuCl₂(P{OCH₂}₃CEt) (P{OCH₂}₃CEt = 4-ethyl-2,6,7-trioxa-1-phosphabicyclo[2.2.2]octane) with silver tetrakis[(3,5-trifluoromethyl)phenyl]borate (Ag[BArF′]) in the presence of acetonitrile produces the monomeric, cationic, acetonitrile ruthenium(II) compound, [(p-cymene)RuCl(P{OCH₂}₃CEt)(NCMe)][BArF′] (1), in near quantitative yields (97%). Chloroform solutions of 1 cause precipitation of the binuclear, dicationic ruthenium(II) dimer complex, [(p-cymene)Ru(µ-Cl(P{OCH₂}₃CEt)]₂[BArF′]₂ (2), with bridging chloride ligands (73%). Complex 2 can be readily converted back to 1 by treatment with acetonitrile. Complexes 1 and 2 were characterized by ¹H, ¹³C{¹H}, ³¹P{¹H}, ¹⁹F{¹H} nuclear magnetic resonance spectroscopy and infrared spectroscopy. Complex 2 was also characterized by single crystal X-ray crystallography, which revealed a rhomboid Ru₂Cl₂ core. The two ruthenium ions in 2 are displaced at 3.668 Å, which precludes Ru–Ru bonding. To our knowledge, this is the first cymene ruthenium(II) dimeric complex with bridging halide ligands supported by a monodentate phosphite ligand.

Graphical Abstract

Keywords:

• Cymene ruthenium
• ruthenium dimer
• acetonitrile adduct
• single crystal X-ray crystal structure
• binuclear
• nuclear magnetic resonance spectroscopy

Acknowledgements

The work was supported or partially supported by the American Chemical Society Petroleum Research Fund (PRF# 53848-UNI3) and Georgia Southern SEED Grants.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported or partially supported by the American Chemical Society Petroleum Research Fund (PRF# 53848-UNI3) and Georgia Southern SEED Grants.