PNNL

Abstract

The structure, energy, and magnetic properties of titanacyclobutadiene are compared with cyclobutadiene, silacyclobutadiene, benzene, and silabenzene to determine the nature of the aromaticity using Hartree–Fock and density functional theory. According to isodesmic and homodesmotic reaction energies, titanacyclobutadiene has a significant stability attributed to resonance delocalization. Nucleus-independent chemical shift indicates that a diatropic ring current dominates the p space of the molecule and indicates titanacyclobutadiene to be aromatic. Titanacyclobutadiene is also compared with titanatetrahedrane and found to be the more stable of the two.