Small Difference in Cation Stability in Controlling the Formation of Hydrocarbon Salt or Covalent Hydrocarbon

The reaction of sterically comparable cations, 3-(p-methylphenyl)- and 3-phenyl-1,2-dicyclopropylcyclopropenylium ions with highly stable Kuhn’s anion (C67H39−) gives a hydrocarbon salt and a covalent hydrocarbon, respectively, suggesting that a slight difference in cation stability differentiates the formation of either product.