Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (3): 423-430.doi: 10.3866/PKU.WHXB201312251


Structures and Properties of BX[(CH2)n]3 and BX(CH2)[CH(CH2)nCH] (X=N, P) with the [n.n.n]propellane Configuration

LI Jin-Xia, ZHANG Cong-Jie   

  1. Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, P. R. China
  • Received:2013-09-26 Revised:2013-12-23 Published:2014-02-27
  • Contact: ZHANG Cong-Jie
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21373133).


We have designed a family of novel molecules BX[(CH2)n]3 and BX(CH2)[CH(CH2)nCH] (X=N, P) with the [n.n.n]propellane configuration (n=1-6). The structures, stabilities, chemical bonds, and electronic spectra of these structures were investigated using density functional theory (DFT). The calculated results indicate that all of these compounds are situated at minima on the potential energy surfaces. The energy gaps between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of BN[(CH2)n]3 and BP[(CH2)n]3 (n=1-6) were in the range of 5.24-7.07 eV and 5.47-7.33 eV, respectively, and the energy gap of BX[CH2]3 is close to that of C5H6. In addition, the energy gaps of BN(CH2) [CH(CH2)nCH] and BP(CH2) [CH(CH2)nCH] (n=1-6) are around 6.80 eV. To compare the relative stabilities of these compounds, we investigated the second-order differences of energies. The results indicate that BN[(CH2)3]3, BP[(CH2)4]3, and BX(CH2)[CH(CH2)2CH] (X=N, P) are more stable than the other structures. Moreover, based on the bond lengths, Wiberg bond indices, and charges of the two"inverted"atoms, it can be concluded that the bridgehead B and N(P) atoms in BN[(CH2)n]3 (n=2, 6) and BP[(CH2)2]3 do not form chemical bonds, while the two bridgehead atoms in the other compounds studied formed chemical bonds. Additionally, topological analysis of the electron density using the theory of atoms-in-molecules shows that the inverted N―B bonds in BN[(CH2)n]3 (n=3-5) are ionic bonds whereas the B―P bonds in BP[(CH2)n]3 (n=3-6) have covalent character. The vertical transition energies of BN[(CH2)n]3, BP[(CH2)n]3, BN(CH2) [CH(CH2)nCH], and BP(CH2) [CH(CH2)nCH] (n=1-6) range from 191.1 to 284.8 nm, 191.8 to 270.1 nm, 190.5 to 199.7 nm, and 209.0 to 221.3 nm, respectively.

Key words: [n.n.n]propellane, BX[(CH2)n]3, BX(CH2)[CH(CH2)nCH], Stability, Chemical bond, Electronic spectrum


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