On the redox properties of cyclotetraphosphines. A novel dication rearrangement

Contributions to the chemistry of phosphorus. 218. Monocyclic and polycyclic phosphines

“…122 The electrochemical oxidation of the cyclotetraphosphanes (PR)4 (R = NPr'2, N(SiMe3)2, Bu*) occurs in two steps. 123 In the first step, a stable, violet-colored radical cation (PR)4,+ is formed; this reaction is reversible. On further oxidation of the amino-substituted compounds, the corresponding dications (PNR2)42+ are formed which, in contrast to the stable S42+ ion,124 undergo rapid rearrangement to the diaminophosphenium cations iP(NR2)2+ and white phosphorus.…”

Structure of 6.pi.-electron four-membered rings containing second-row atoms

“…Geometric Parameters for C2, PiRgP'i Molecules For the molecule of interest in the present study, the tetraphosphetane dication P4H42+ with 6w electrons, available data are scarce. Scháfer et al41 have performed an experimental and theoretical MNDO study on the dication. They report that the dication, generated via cyclic voltammetry, is unstable and rapid rearrangements occur at a low temperature of-100 ®C.…”

Structural Changes Upon Oxidation of (PtBu2)2 and 1,4‐(CH2)2(PtBu)4: Transannular P–P Interactions in Cations of the 1,4‐C2P4 Ring

“…Dications of the type [(PR) 4 ] 2+ are isoelectronic with the well‐known, square‐planar [S 4 ] 2+ dication . Investigations of the formation of such species by both electrochemical and chemical oxidation (using AlCl 3 in CH 2 Cl 2 ) showed that amino substituents stabilize the corresponding cation radicals [(PR) 4 ] +• (R = N i Pr 2 , N(SiMe 3 ) 2 ), which were identified by electron paramagnetic resonance (EPR) spectra recorded at –78°C [a]. Very recently, Wang et al have isolated and structurally characterized a salt of the cation radical [(PR) 4 ] +• (R = N i Pr 2 [b].…”

“…Investigations of the formation of such species by both electrochemical and chemical oxidation (using AlCl 3 in CH 2 Cl 2 ) showed that amino substituents stabilize the corresponding cation radicals [(PR) 4 ] +• (R = N i Pr 2 , N(SiMe 3 ) 2 ), which were identified by electron paramagnetic resonance (EPR) spectra recorded at –78°C [a]. Very recently, Wang et al have isolated and structurally characterized a salt of the cation radical [(PR) 4 ] +• (R = N i Pr 2 [b]. Upon warming to room temperature, these cyclic cation radicals undergo ring degradation to give the corresponding diamagnetic phosphenium cations [PR 2 ] + ; a similar, but more rapid, decomposition is observed for the dications [(PR) 4 ] 2+ (R = N i Pr 2 , N(SiMe 3 ) 2 ) [a].…”

“…Very recently, Wang et al have isolated and structurally characterized a salt of the cation radical [(PR) 4 ] +• (R = N i Pr 2 [b]. Upon warming to room temperature, these cyclic cation radicals undergo ring degradation to give the corresponding diamagnetic phosphenium cations [PR 2 ] + ; a similar, but more rapid, decomposition is observed for the dications [(PR) 4 ] 2+ (R = N i Pr 2 , N(SiMe 3 ) 2 ) [a].…”