Ab initio mo study of P-Si π systems: Structures and energies

Masae Takahashi, Kenkichi Sakamoto

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The origin of the relative stability of isomers of 1,2-diphosphinodisilene and related compounds is discussed. The geometries of 18 isomers of (H2X)HE=EH(XH2), (H2X)HE=EH(XH2)2+, and HX=EH-HE=XH (E = C, Si; X = P, N) have been optimized at the MP2/6-311++G(d, p) level of theory. Since nitrogen and phosphorus have lone-pair electrons, six electrons can delocalize in four orbitals of (H2X)HE=EH(XH2) (6e/4o), while four electrons can delocalize in four orbitals of (H2X)HE=EH(XH2)2+ and HX=EH-HE=XH (4e/4o). To examine the interaction that governs the structure and relative stability of their cis and trans (or cisoid and transoid) isomers, the π-σ* delocalization energies and isodesmic reaction energies of the compounds were calculated. It is concluded that the π-σ* delocalization affects the bending structure of disilene derivatives, and phosphorus substituents prefer 2e/4o and 4e/4o systems.

Original languageEnglish
Pages (from-to)1721-1724
Number of pages4
JournalPhosphorus, Sulfur and Silicon and Related Elements
Issue number6-7
Publication statusPublished - 2002 Jan 1
Externally publishedYes


  • Ab initio MO calculation
  • Disilene
  • Isodesmic reaction
  • Phosphorus
  • π-σ* delocalization

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Inorganic Chemistry


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