Spin-orbit effects on the ring current strengths of the substituted cyclophosphazene: c-P₃N₃X₆(X=H, F, Cl, Br, I, At, Ts)

This work reports the magnetic index of aromaticity of cyclophosphazene ((Formula presented.) -P (Formula presented.) N (Formula presented.) H (Formula presented.)) and their halogenated cyclic derivatives: (Formula presented.) -P (Formula presented.) N (Formula presented.) F (Formula presented.), (Formula presented.) -P (Formula presented.) N (Formula presented.) Cl (Formula presented.), (Formula presented.) -P (Formula presented.) N (Formula presented.) Br (Formula presented.), (Formula presented.) -P (Formula presented.) N (Formula presented.) I (Formula presented.), (Formula presented.) -P (Formula presented.) N (Formula presented.) At (Formula presented.) and (Formula presented.) -P (Formula presented.) N (Formula presented.) Ts (Formula presented.). This index, also known as ring-current strength, is calculated by numerical integration of the magnetically-induced current density vector field which is generated by a perturbing external magnetic field. Due to the presence of heavy (Formula presented.) atoms in (Formula presented.) -P (Formula presented.) N (Formula presented.) X (Formula presented.), important relativistic were expected. Accordingly, all-electron density functional theory (DFT) calculations were carried out using the four-component Dirac-Coulomb (DC) Hamiltonian, including scalar and spin-orbit relativistic effects. The values were also compared with the corresponding spin-free (scalar relativistic) ones.