Probing the structural and electronic properties of zirconium doped boron clusters: Zr distorted B12 ligand framework

Abstract

As an extension of boron based materials, transition-metal doped boron clusters deserve interest in controlling size-dependent structural and electronic properties. Herein, using the Crystal structure AnaLYsis by Particle Swarm Optimization (CALYPSO) method and density functional theory (DFT) calculations, we have performed a global search for the lowest-energy structures of ZrB^Q_n (Q = 0, −1) clusters with n = 10–20. The results show that the ground-state structures of the obtained clusters feature a distinctive structural evolution pattern, from half-sandwich bowl to distorted drum-like and then to Zr-centered distorted tubular motifs. For the sake of validating the current ground-state structures, photoelectron spectra are predicted from time-dependent DFT calculations. More interestingly, the neutral and anionic ZrB₁₂ clusters are found to possess enhanced stability in the size regime studied here. The stability of the closed shell half-sandwich ZrB₁₂ cluster is analyzed by intrinsic bond orbital (IBO) and Adaptive Natural Density Partitioning (AdNDP) methods, which indicates that the stability mechanism is caused by the dopant Zr atom breaking the boron bowl's triangle B₃ unit to form a quasi-linear B₃ unit in B₁₂ and strengthen both the interaction of the B–B σ-bonds and the Zr–B π-bonds.