A QUANTUM-CHEMICAL INVESTIGATION ON 3-(4H-1,2,4-TRIAZOL-4-YL)-1H-1,2,4-TRIAZOLE

The molecular conformations and electronic properties of the 3-(4H-1,2 ,4-triazol-4-yl)-1H-1,2,4-triazole molecule containing various reactio n centers were investigated by the semiempirical methods MNDO, AM1 and PM3. The most stable conformation of the molecule was determined to b e the planar conformation. The total energies, heats of formation, dip ole moments, rotational barriers, geometric parameters, ionization pot entials, full atomic charges, energies of frontier molecular orbitals (E-HOMO and E-LUMO) and their electron densities were calculated and d iscussed. In order to determine the protonation sites of the 3,4'-bitr iazole system, the molecular electrostatic potential (MESP) of the mol ecule has also been calculated. The conformations and electronic prope rties of mono- and di-protonated species were also performed by AM1 an d PM3 treatments. The proton affinities for the different nitrogens of the molecule were calculated using AM1 and PM3, and possible protonat ion sites were determined. The complex forming ability of the bitriazo le molecule with metal cations was also discussed. The geometry and el ectronic properties of the complex formed by Mg2+ ions were investigat ed using PM3.