Isolation of the Diphenylphosphorus Radical

Abstract

ation by splitting offaldeh5de even when, as in the case of the formaldehyde compound, the b. p. of the hemiacetal ( 3~) is higher than that of the acctal (2a). With amines, hydrazines, and thiols, the corresponding types ofmixed acetal are formed, viz. (4)-(7), e . g . from (Zo): RO-RN-CH-NR'?(4) R =-CH,, R I N = pipertdine, b p. 61-62 "CjIO mni RO-RN-CHI N R -NRI ( 5 ) R=-CH,, h.p. 46"C/t2mni RO-RN-CHz SR' (6) R = CH?, R'= C4H9, b.p. 74 'C/IOnim o r from (3151 RO-RN -C H R S R (7) K CH,, R' -C T H~, b.p. 101 'C/23 iniii The acetals can be split by acyl chloridcs, just as Bu/inw and Haitke [3] found for aminals, e.g.: + Ph-CO CI + Ph -CO-NR-OR -1-RO CO -CI i RO-CO-NR-OR ( 2 a) --f RO RN C H z -C I Received, M a y Ihth, 1963 [Z 5081339 IE] German version: Angew. Chem. 75, 640 (1963).

Coupling reactions of diorganophosphides with organic halides. Evidence for a one-electron path

“…However, that for (C6H5)2P• is 2.009. 26 Since hydrocarbon radicals have g values close to that of the free electron in the absence of strongly electron-withdrawing groups,27 Ag > 0. Further, the hyperfine interaction, Á3iP, is anticipated to be greater than zero.…”

The Flash Photolysis of Tetraphenyldiphosphine, Triphenylphosphine, and Diphenylphosphine in Alcohols

“…Some direct evidence of the existence of the radical has been obtained from an e.s.r. study of a combined effect of heat and light on tetraphenyldiphosphine and diphenylphosphine (4). More recently a better resolved e.s.r.…”

Phosphorus radicals and radical ions

“…37 Although single-crystal was not isolated, the structure of the radical 3 was determined by the EPR experiments and theoretical calculations. The solution EPR spectra of 3 show a fourline pattern due to the hyperfine coupling of two non-equivalent 31 P nuclei. The radical is soluble in hexane and has an intense green color (UV/Vis: λ max 668 nm).…”

“…However, due to the short lifetime, the direct characterization of these paramagnetic species is difficult. The EPR signal of the proposed Ph 2 P • radical intermediate was first recorded in 1963 at 77 K. 31 A few years later, Ph 2 P • was fully characterized by solid-state EPR measurements, and the radical (Ph 2 P • ) was generated by UV photolysis of a single crystal of high purity triphenylphosphine. 32 Later, Ph 2 P • and the related radicals were characterized using a spin trapping agent such as nitrosodurene, nitrosobenzene, etc.…”