Quantum chemical analysis of para-substitution effects on the electronic structure of phenylnitrenium ions in the gas phase and aqueous solution

The effects of para substitution on the electronic properties of phenylnitrenium ions in the gas phase and aqueous solution were investigated via quantum chemical computations. Linear free energy relationships between phenylnitrenium ion S-T gaps and three model substituents for para-substitution effects were also examined. Experimental results revealed trends in singlet-triplet splittings, singlet aromatic stretching frequencies and singlet C-N+ bond lengths, which are associated with linear free energy relationships.