One electron C-C bond or Weak Interaction? New paper in PCCP
The compound spiro-dibenzocycloheptatriene (figure 1) made headlines a year ago by claiming that the ipso carbon atoms across the molecule were bound together by a single electron σ bond. This is truly a seductive idea: that somewhere…
The compound spiro-dibenzocycloheptatriene (figure 1) made headlines a year ago by claiming that the ipso carbon atoms across the molecule were bound together by a single electron σ bond. This is truly a seductive idea: that somewhere out there, in the shadows of open-shell aromatics, carbon atoms might form a single-electron σ-bond — a unicorn of bonding, indeed. Since bold claims require bold scrutiny, we went ahead and dissected the electronic structure of the radical molecule in question with all the tools at our disposal; We also analyzed that of the neutral complex from where it was derived and also the double cation to analyze the consequences of removing the alleged electron holding such an unusual interaction, for if this C-C bond truly exists, it should alter the interaction energy between the fragments in a way consistent with a real σ bond.
