Posts Tagged ‘Cyclopentadienyl anion’

The π-π stacking of aromatic rings: what is their closest parallel approach?

Thursday, April 13th, 2017
No Gravatar

Layer stacking in structures such as graphite is well-studied. The separation between the π-π planes is ~3.35Å, which is close to twice the estimated van der Waals (vdW) radius of carbon (1.7Å). But how much closer could such layers get, given that many other types of relatively weak interaction such as hydrogen bonding can contract the vdW distance sum by up to ~0.8Å or even more? This question was prompted by the separation calculated for the ion-pair cyclopropenium cyclopentadienide (~2.6-2.8Å).

(more…)

Cyclopropenium cyclopentadienide: a strangely neutral ion-pair?

Sunday, April 9th, 2017
No Gravatar

Both the cyclopropenium cation and the cyclopentadienide anion are well-known 4n+2-type aromatic ions, but could the two together form an ion-pair?

(more…)