### Abstract

The aromaticity of phospholes, P_{n} (CH)_{4-n}PH with n = 0-4, becomes larger as the number of dicoordinate atoms (n) in the ring increases. This is due to the decreasing pyramidality of the tricoordinate phosphorus. The aromaticity is shown by various criteria, e.g., the nucleus-independent chemical shifts (NICS), and the separated π contribution NICS(π), as well as the Bird aromaticity (BI) and the bond-shortening (BDSHRT) indexes. The change of the aromaticity is correlated with the bond angle sum (the degree of planarity) about the tricoordinate phosphorus (e.g., correlation coefficient = 0.968 with NICS). The aromaticities of the planar P_{n}(CH)4-ffPH phospholes (first-order saddle points for n = 0-3, minimum for n = 4) (NICS values between -15.4 and -17.4 ppm) all are similar. The same is true for the NICS (-12.3 to -15.9) aromaticity of the phospholyl anions (P_{n}(CH)_{4-n}P-), n = 0-4, which are close to those of the planar phospholes. According to NICS, BI and BDSHRT planar phospholes are more aromatic than pyrrol or thiophene. Isodesmic reaction energies do not correlate with the bond angle sum, since the energy cost of the increasing planarization of the tricoordinate phosphorus consumes the stabilization achieved by aromaticity.

Original language | English |
---|---|

Pages (from-to) | 4413-4420 |

Number of pages | 8 |

Journal | Inorganic Chemistry |

Volume | 37 |

Issue number | 17 |

Publication status | Published - 1998 |

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### ASJC Scopus subject areas

- Inorganic Chemistry

### Cite this

*Inorganic Chemistry*,

*37*(17), 4413-4420.

**The Aromaticity of Polyphosphaphospholes Decreases with the Pyramidality of the Tricoordinate Phosphorus.** / Dransfeld, Alk; Nyulászi, L.; Von Schleyer, Paul Ragué.

Research output: Contribution to journal › Article

*Inorganic Chemistry*, vol. 37, no. 17, pp. 4413-4420.

}

TY - JOUR

T1 - The Aromaticity of Polyphosphaphospholes Decreases with the Pyramidality of the Tricoordinate Phosphorus

AU - Dransfeld, Alk

AU - Nyulászi, L.

AU - Von Schleyer, Paul Ragué

PY - 1998

Y1 - 1998

N2 - The aromaticity of phospholes, Pn (CH)4-nPH with n = 0-4, becomes larger as the number of dicoordinate atoms (n) in the ring increases. This is due to the decreasing pyramidality of the tricoordinate phosphorus. The aromaticity is shown by various criteria, e.g., the nucleus-independent chemical shifts (NICS), and the separated π contribution NICS(π), as well as the Bird aromaticity (BI) and the bond-shortening (BDSHRT) indexes. The change of the aromaticity is correlated with the bond angle sum (the degree of planarity) about the tricoordinate phosphorus (e.g., correlation coefficient = 0.968 with NICS). The aromaticities of the planar Pn(CH)4-ffPH phospholes (first-order saddle points for n = 0-3, minimum for n = 4) (NICS values between -15.4 and -17.4 ppm) all are similar. The same is true for the NICS (-12.3 to -15.9) aromaticity of the phospholyl anions (Pn(CH)4-nP-), n = 0-4, which are close to those of the planar phospholes. According to NICS, BI and BDSHRT planar phospholes are more aromatic than pyrrol or thiophene. Isodesmic reaction energies do not correlate with the bond angle sum, since the energy cost of the increasing planarization of the tricoordinate phosphorus consumes the stabilization achieved by aromaticity.

AB - The aromaticity of phospholes, Pn (CH)4-nPH with n = 0-4, becomes larger as the number of dicoordinate atoms (n) in the ring increases. This is due to the decreasing pyramidality of the tricoordinate phosphorus. The aromaticity is shown by various criteria, e.g., the nucleus-independent chemical shifts (NICS), and the separated π contribution NICS(π), as well as the Bird aromaticity (BI) and the bond-shortening (BDSHRT) indexes. The change of the aromaticity is correlated with the bond angle sum (the degree of planarity) about the tricoordinate phosphorus (e.g., correlation coefficient = 0.968 with NICS). The aromaticities of the planar Pn(CH)4-ffPH phospholes (first-order saddle points for n = 0-3, minimum for n = 4) (NICS values between -15.4 and -17.4 ppm) all are similar. The same is true for the NICS (-12.3 to -15.9) aromaticity of the phospholyl anions (Pn(CH)4-nP-), n = 0-4, which are close to those of the planar phospholes. According to NICS, BI and BDSHRT planar phospholes are more aromatic than pyrrol or thiophene. Isodesmic reaction energies do not correlate with the bond angle sum, since the energy cost of the increasing planarization of the tricoordinate phosphorus consumes the stabilization achieved by aromaticity.

UR - http://www.scopus.com/inward/record.url?scp=0542373374&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0542373374&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0542373374

VL - 37

SP - 4413

EP - 4420

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 17

ER -