Solvent induced quadrupole polarization of the molecules of diazo and diazocarbonyl compounds: Quantum-chemical investigation

Equilibrium structural parameters, atomic charges, and quadrupole moments of the molecules of 2,4,6-tris(diazo)cyclohexane-1,3,5-trione, 3,6-bis(diazo)cyclohexane-1,2,4,5-tetraone and its anion, isomeric 3,6-bis(diazonium)cyclohexanediondioles and 4,4′-bis(diazonium)-1,1′-biphenyl in a vacuum and in dichloromethane were calculated by the quantum chemical method PBE0/cc-pVTZ using the polarizable continuum model (PCM).The p-quinoid dication is more favorable than o-quinoid dication by 20 kcal mol-1 in a vacuum and by 13 kcal mol⁻¹ in dichloromethane.The norm of the quadrupole moment of the centrosymmetric molecules in a polarizable medium increases while that of the dications decreases. The quadrupole polarization of molecules and molecular ions by the solvent does not change their symmetry point group.