Pentagon Stability: Cyclic Delocalization of Lone Pairs through σ Conjugation and Design of Polycyclophosphanes
The orbital-phase theory was applied to propose pentagon stability in a well-defined manner. Cyclic delocalization of the lone pair electrons on the five-membered ring atoms through the vicinal σ bonds was shown to be favored by the orbital-phase properties. The pentagon stability was found to be ou...
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Published in | Inorganic chemistry Vol. 41; no. 7; pp. 1876 - 1882 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
08.04.2002
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Online Access | Get full text |
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Summary: | The orbital-phase theory was applied to propose pentagon stability in a well-defined manner. Cyclic delocalization of the lone pair electrons on the five-membered ring atoms through the vicinal σ bonds was shown to be favored by the orbital-phase properties. The pentagon stability was found to be outstanding in saturated phosphorus five-membered rings in the puckered conformation, and was substantiated by the negative strain energy of cyclopentaphosphane, P5H5 (3). The relative increments of the remarkable increase in the strain energies of protonation on the different atoms in the most stable conformers supported the significance of the cyclic delocalization of the lone pairs. Pentagon stability led to the design of three novel polycyclic phosphanes, P12H4 (18), P13H3 (19), and P14H2 (20), with low strain energies due to many puckered pentagon units in them. The low stability of the dodecahedron P20 (22) was suggested by the high strain energy due to its planar pentagon units. The pentagon stability is less significant in the saturated nitrogen ring molecules due to the greater energy gap between the n and σ* orbitals. |
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Bibliography: | istex:62E0D995E858C1C4737B568E4F23905B907ABAEE ark:/67375/TPS-FG72S931-L ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0020-1669 1520-510X |
DOI: | 10.1021/ic0107835 |