Two isomers of a bis(diphenylphosphino)phosphinine, and the synthesis and reactivity of Ru arene/Cp* phosphinophosphinine complexes

Abstract

Two isomers of a bis(diphenylphosphino)phosphinine have been synthesised, and the Ru coordination chemistry of a 2-phosphinophosphinine extended to include reactions of H2O across a PC double bond.

Reactivity Studies of Phosphinines: The Selenation of Diphenyl-Phosphine Substituents and Formation of a Chelating Bis(Phosphinine) Palladium(II) Complex

“…Single crystal X-ray diffraction revealed the anticipated molecular structure (Figure 3). The phosphinine ring was planar with C-C bond lengths similar to those observed in other aromatic phosphinine rings [18,19,36] and benzene. The P-C bond lengths in the ring (1.7516(17) and 1.7282(18) Å) were shorter than the P-C bond length to the PPh 2 substituent (1.8235(17) Å).…”

“…The characterisation of 8 was performed by mass spectrometry (accurate mass determined for [M + H] + ) and by single crystal X-ray diffraction. The molecular structure (Figure 2) revealed disorder in the central phosphinine ring over an inversion centre situated in the middle of the molecule, as was seen in the structure of 5 [36], which prevented a detailed assessment of the bond lengths and angles in the ring. The P=Se bond lengths were determined to be 2.1097(5) Å.…”

“…Other related examples are cationic and supported by a β-diketiminate framework [56,57]. The phosphinines 4 [58], 5 [36] and 6 [18] all featured additional P donors, either another phosphinine ring (4) or PPh 2 moieties. They were synthesised by the reaction of diazaphosphinine (3) with alkynes in two sequential steps due to the slower reaction of the intermediate azaphosphinines with alkynes.…”

“…Phosphinophosphinines are useful ligands for transition metal complexes [5,9] and form four-membered chelates that can be extended into five-membered chelates through oxidation of the phosphine with sulfur, which has been well-studied [10], or oxygen, selenium and organic azides [36], which are almost unknown. For example, phosphinines bearing two ortho-P(S)Ph 2 groups were cleanly synthesised from analogous diphenylphosphinesubstituted phosphinines by a reaction with elemental sulfur [37,38].…”

A ruthenium cis-dihydride with 2-phosphinophosphinine ligands catalyses the acceptorless dehydrogenation of benzyl alcohol

“…46 Previous work in our group has demonstrated that Ru catalysts based on the bidentate chelating phosphinophosphinine ligand 2-PPh 2 -3-Me-6-SiMe 3 -PC 5 H 2 (PP′) catalysed the room temperature transfer hydrogenation of acetophenone and the H-borrowing upgrading of alcohol fuels. 46,51 Ruthenium hydrides are implicated in many catalytic reactions, yet the first Ru complex comprising of both a hydride and phosphinine ligand has only been described recently by us. 52 Herein, we describe the first ruthenium phosphinine dihydride complex and compare its catalytic activity to that of classical diphosphine-supported complexes for AD reactions.…”