The electronic effect on the selectivity of covalent or ionic bond formation was examined for the reaction of Kuhn's anion 1-(C67H39-; tris (7H-dibenzo [cglfluorenylidenemethyl) methide ion) and l-aryl-2, 3-dicyclopropylcyclopropenylium ions. The carbocation stability was progressively changed by varying the substituent on the phenyl ring, while the steric effect was kept essentially unchanged. The cations having the p-chlorophenyl (2a+), phenyl ( ...
