Positional and compositional disorder in a ruthenium(II) piano-stool complex

Abstract

In (η⁶-p-cymene)(difluorophosphinato-κO){2-[(1H-pyrazol-1-yl)methyl-κN²]pyridine-κN}ruthenium(II) 0.85-hexafluorophosphate 0.15-tetrafluoroborate, [Ru(PO₂F₂)(C₁₀H₁₄)(C₉H₉N₃)](PF₆)0.85(BF₄)0.15, (I), the [PO₂F₂]⁻ ligand exhibits positional disorder due to one F atom and one O atom sharing the same two positions related by a mirror reflection across the O-P-F plane. The correct composition of this coordinated anion was successfully determined to be [PO₂F₂]⁻ by refining the complex with various tetrahedral anions in which terminal atoms have similar atomic form factors. The noncoordinated counter-ion is compositionally disordered between [PF₆]⁻ and [BF₄]⁻. The difficulty in determining the correct composition of this anion illustrates the importance of a crystallographer remaining impartial and open to encountering unexpected moieties in the process of elucidating a structure.

Efficient Solvent-Free Hydrogenation of Levulinic Acid to γ-Valerolactone by Pyrazolylphosphite and Pyrazolylphosphinite Ruthenium(II) Complexes

“…The crystal structures obtained for 1a and 1b , as shown in Figures and , confirmed the successful abstraction of one chloride from the ruthenium center that allowed the coordination of the pyrazole nitrogen atom to the ruthenium metal. As expected, these complexes assumed a piano-stool structure about the ruthenium center with the aromatic ring of the p -cymene showing η 6 -bonded to the ruthenium . The seven-membered heterocyclic rings formed as a result of the bonding of the nitrogen atom to the ruthenium center are nonplanar as expected for nonaromatic rings.…”

“…As expected, these complexes assumed a piano-stool structure about the ruthenium center with the aromatic ring of the p-cymene showing η 6 -bonded to the ruthenium. 35 The seven-membered heterocyclic rings formed as a result of the bonding of the nitrogen atom to the ruthenium center are nonplanar as expected for nonaromatic rings. Selected bond distances and angles of 1a and 1b are represented as captions under each molecular structure.…”

Novel pyrazolylphosphite– and pyrazolylphosphinite–ruthenium(ii) complexes as catalysts for hydrogenation of acetophenone

“…The Ru-Cl and Ru-P bond lengths observed for the complexes are similar to those observed for other related ruthenium complexes reported in the literature. [22][23][24][25][26][27] Hydrogenation using 2-propanol…”