Theoretical Prediction of a Stable Xenon Bis(diazaborolyl) Complex: A Donor-Acceptor Complex

Complexes with bulky ligand-supported low-valent elements are very well-known in chemistry. However, because of their little reactivity, such complexes are unknown so far for noble gas (Ng) atoms. Here, the viability of a xenon complex with the ligand diazaborolyl ((L = HCN(dipp))₂B) in the form of HCN(dipp)₂B-Xe-B(HCN(dipp))₂ (1) is assessed through quantum chemical calculations. Complex 1 is thermochemically stable at room temperature against dissociation, 1 → Xe + 2L. Although the dissociation process that leads to the formation of ligand dimer [(HCN(dipp))₂B]₂ and Xe, 1 → Xe + L₂, is exergonic in nature, the scrutiny of the corresponding mechanism through B-Xe-B bending reveals that this process eventually leads to the formation of free Xe and two (HCN(dipp))₂BH units with one isopropyl group in dipp being converted into an isopropenyl group. This process involves a significant potential energy barrier to occur. 1 can be described as a donor-acceptor complex between ligand and Xe, L⇄Xe⇆L, where Xe is in zero oxidation state. Despite being a donor-acceptor complex, the electrostatic interaction in the B-Xe-B bond plays a crucial role in the stabilization of the complex.