Bonding, aromaticity, and planar tetracoordinated carbon in Si2CH2 and Ge2CH2

  • Stefan Vogt-Geisse
  • Judy I-Chia Wu
  • Paul v. R. Schleyer
  • Henry F. SchaeferIII
Original Paper

DOI: 10.1007/s00894-015-2736-8

Cite this article as:
Vogt-Geisse, S., Wu, J.IC., Schleyer, P..R. et al. J Mol Model (2015) 21: 217. doi:10.1007/s00894-015-2736-8

Abstract

Natural bond orbital (NBO) analyses and dissected nucleus-independent chemical shifts (NICSπzz) were computed to evaluate the bonding (bond type, electron occupation, hybridization) and aromatic character of the three lowest-lying Si2CH2 (1-Si, 2-Si, 3-Si) and Ge2CH2 (1-Ge, 2-Ge, 3-Ge) isomers. While their carbon C3H2 analogs favor classical alkene, allene, and alkyne type bonding, these Si and Ge derivatives are more polarizable and can favor “highly electron delocalized”? and “non-classical”? structures. The lowest energy Si 2CH2 and Ge 2CH2 isomers, 1-Si and 1-Ge, exhibit two sets of 3–center 2–electron (3c-2e) bonding; a π-3c-2e bond involving the heavy atoms (C–Si–Si and C–Ge–Ge), and a σ-3c-2e bond (Si–H–Si, Ge–H–Ge). Both 3-Si and 3-Ge exhibit π and σ-3c-2e bonding involving a planar tetracoordinated carbon (ptC) center. Despite their highly electron delocalized nature, all of the Si2CH2 and Ge2CH2 isomers considered display only modest two π electron aromatic character (NICS(0)πzz=--6.2 to –8.9 ppm, computed at the heavy atom ring center) compared to the cyclic-C 3H2 (–13.3 ppm).

Graphical Abstract

The three lowest Si2CH2 and Ge2CH2 isomers.

Keywords

Main group chemistry Planar tetracoordinated carbon Natural bond orbital 3–center 2–electron bond Nuclear-independent chemical shift Aromaticity Electrostatic potential 

Supplementary material

894_2015_2736_MOESM1_ESM.pdf (9.1 mb)
(PDF 9.08 MB)

Copyright information

© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  • Stefan Vogt-Geisse
    • 1
    • 2
  • Judy I-Chia Wu
    • 2
    • 3
  • Paul v. R. Schleyer
    • 2
  • Henry F. SchaeferIII
    • 2
  1. 1.Facultad de QuímicaPontifícia Universidad Católica de ChileSantiagoChile
  2. 2.Center for Computational Quantum ChemistryUniversity of GeorgiaAthensUSA
  3. 3.Department of ChemistryUniversity of HoustonHoustonUSA

Personalised recommendations