Pentaphosphole: An Aromatic Ring with a Planar σ3-Phosphorus

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Abstract

Correlated ab initio calculations show that pentaphosphole (P5H) is a planar five-membered heterocycle at all levels of theory investigated here. The HP out of plane bending potential, however, is rather shallow. All the PP bond lengths are nearly equal, indicating significant aromatic character. The Bird index is 77, a value that is among the largest for the five membered heterocycles. The average of the double bond characters is 59.6% that is smaller than the 67% for benzene. The stabilization as measured by an isodesmic reaction is comparable to the value for thiophene. In spite of the aromatic stabilization the inherent instability of the P=P-P=P linkage indicates that the ring is rather unstable. Several dimeric products (P10H2) were found, however, which were more stable than two P5H molecules by 28-35 kcal/mol. Since in case of P5R there is no possibility for kinetic stabilization by bulky substituents, it is questionable that the compound can be synthesized.

Original languageEnglish
Pages (from-to)4690-4693
Number of pages4
JournalInorganic Chemistry
Volume35
Issue number16
Publication statusPublished - 1996

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Phosphorus
phosphorus
Stabilization
stabilization
rings
Thiophenes
birds
Birds
Bond length
Benzene
thiophenes
linkages
benzene
Molecules
Kinetics
kinetics
products
molecules

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

Pentaphosphole : An Aromatic Ring with a Planar σ3-Phosphorus. / Nyulászi, L.

In: Inorganic Chemistry, Vol. 35, No. 16, 1996, p. 4690-4693.

Research output: Contribution to journalArticle

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