221129-49-3Relevant articles and documents
From 2-phosphino-2H-phosphirene to 1-phosphino-1H-phosphirene, lλ5,2λ3-diphosphete, and 1,2-dihydro-1λ3,2λ3-diphosphete: An experimental and theoretical study
Sanchez, Muriel,Réau, Régis,Marsden, Colin J.,Regitz, Manfred,Bertrand, Guy
, p. 274 - 279 (1999)
The [bis(diisopropylamino)phosphino](trimethylsilyl)carbene 4 reacts cleanly with tert-butylphosphaalkyne 2 to give 2-phosphino-2H-phosphirene 5, which was spectroscopically characterized. Heterocycle 5 is thermally unstable and quantitatively rearranges after 3 h at room temperature into the 1λ5,2λ3-diphosphete 3. Irradiation of 5 at room temperature (λ=254 nm) with a Rayonnet photochemical reactor produces 1-phosphino-1H-phosphirene 6 (10 %), 1,2-dihydrodiphosphete 7 (3 %), and diphosphete 3 (87 %). Irradiation of 3 with a high pressure mercury lamp at λ = 254 nm affords the dihydrodiphosphete 7, which was isolated in 69 % yield. Calculations carried out on heterocycles 3 and 5-7 emphasize the crucial effect the amino substituents have on the stability of λ5-phosphacyclobutadiene derivatives, and show that the intrinsic difference in the thermodynamic stability between 1H and 2H- phosphirenes is rather small (68 kJ mol-1).
