Phosphorus-selenium heterocycles from the tetraphospholane (PhP)₄CH₂

Two new heterocyclic and one acyclic species were prepared by reduction/deselenation of the five-membered heterocycle PhP(Se)CH2PhP(Se)Se-2 (containing a PCPSe2 ring sequence). Deselenation with Me3SiCN led to the four-membered heterocycle PhP(Se)CH2PPh(Se)Se (containing a PCPSe ring sequence), whereas reaction with Bu3P afforded the five-membered heterocycle PhP(Se)CH2PhP(Se)SePPh (ring sequence PCPSeP) and reduction with K metal afforded the dipotassiurn salt of methylene-bis(diselenophenylphosphinic) acid [K-2(PhPSe2)(2)CH2]. The new compounds were characterised by a combination of NMR, MS and FT IR spectroscopic techniques; their structures were confirmed by single crystal X-ray analyses. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).