Struct. Chem. 31, 25-35 (2020)

DOI: 10.1007/s11224-019-01451-5

Theoretical studies of perimidine and its derivatives: structures, energies, and spectra

Theoretical calculations at the B3LYP/6-311++G(d,p) level plus GIAO calculations for NMR absolute shieldings have been carried out for the parent perimidine and several of its derivatives. These include its anion and cation and the acid-base equilibria and other examples of annular tautomerism, such as the 2-hydroxy (and their radical cations), 2-thiol, 2-amino, and 2-alkyl perimidines, and the functional tautomers, such as the benzologues of perimidone. The protonation of 2-aminoperimidines (cyclic guanidines) and the properties of perimidine carbene (dimerization and addition to carbon dioxide), biperimidine, dihydroperimidine, and spiro bidihydroperimidine were also studied.