C-F bond activation by transient phosphenium dications.

C-F bond cleavage by transient phosphorus(III)-based dications [RP(C(PPh3)2)](2+) (4a(2+), R = Ph; 4b(2+), R = 4-F-Ph) is reported. These dications were generated by reaction of the corresponding monocationic precursors with excess Na[BAr4(Cl)]. Evidence for the existence of transient dicationic species was obtained by trapping the dication 4a(2+) with PMe3. According to theoretical analysis, the low-lying lowest unoccupied molecular orbitals of these species were responsible for the observed activation of C-F bonds.

Dihaloborenium cations stabilized by a four-membered N-heterocyclic carbene: electron deficiency compensation by asymmetric structural changes.

The synthesis, characterization and X-ray analysis of dichloro- and dibromo-borenium cations stabilized by a 4-membered carbene are reported. The ligand's structural changes, atypical for similar systems, were caused by coordination to electron deficient fragments and its CN2P ring strain.

Oxidative addition of water and methanol to a dicationic trivalent phosphorus centre.

Our recently synthesised phosphorus dication is observed to activate water (and methanol) under reactions conditions atypical for other systems containing a non-metal centre. This particular activation described as oxidative addition is quite rare and has been reserved exclusively for a couple of metal-based compounds.