Preparation, Structural Analysis, and Reactivity Studies of Phosphenium Dications
Tay, Madelyn Qin Yi
Date of Issue2015-11-06
School of Physical and Mathematical Sciences
This work expands on the recent synthesis and reactivity of the two-coordinate P(III)-containing dication [((Ph3P)2C)P(NiPr2)]2+ (3a2+). Two additional dications of general formula [((RPh2P)2C)P(NR′2)]2+ (3b2+, R = 1/2 (CH2)3, R′ = iPr; 3c2+, R = Ph, R′ = Cy) have been prepared. Solution and solid-state 31P NMR isotropic shifts for this dication class were observed around 360 ppm. Except for [3a][SbF6]2, the 31P CP/MAS NMR spectra reveal a high degree of structural disorder around the dicationic site in the solid state. Surprisingly, the synthesis of dication 3a2+ was only possible in the presence of AlCl4–, SbF6–, and substituted tetraarylborates, while the use of ClO4–, OTf–, BF4–, PF6–, and BPh4– resulted in complex product mixtures. Single-crystal X-ray analysis of dications 3a2+ and 3c2+ suggested a 4π allyl-like structure for the central CPN fragment, and this has been supported through detailed theoretical investigations. Initial reactivity studies between dications 3a2+/3c2+ and PMe3 show an equilibrium between the free dication and the target adduct. Furthermore, 3a2+ has been shown to be capable of O–H bond activation using water and methanol and polymerizes THF when it is dissolved in this solvent
© 2015 American Chemical Society. This is the author created version of a work that has been peer reviewed and accepted for publication by Organometallics, American Chemical Society. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [http://dx.doi.org/10.1021/acs.organomet.5b00763].