A density functional investigation on the structures, electronic, spectral and fluxional properties of VB20- cluster

By using a joint experimental and first principle calculation, in 2017, Li's group reported a tubular molecular rotor, TaB20-, which possesses a Ta-centred eighteen-membered drum with a slight distortion and two bridging B atoms atop the drum. Moreover, the tubular B-2-Ta@B-18(-) presents a new type of internal rotation, the rotation with barrier of Lambda E = 1.13 kcal/mol possesses nine equivalent positions with the rotation angle of 40 degrees in each step [Chem. Commun. 53, 1587 (2017)]. Then, an interesting question arises: whether the other same group atoms dopant can form the similar frameworks? And if it is, whether the B2 unit can rotate relative to drum motif? In present work, with inspirations from research of tubular molecular rotor TaB20-, we present herein the possibility of the novel structures of VB20- cluster by using Crystal structure Analysis by Particle Swarm Optimization (CALYPSO) searching method and first-principle theory calculations. The results indicated that VB20- cluster is composed of a V-centered eighteen-membered drum with a B-2 unit on the top of drum. Based on the lowest energy structure of VB20- cluster, electronic properties are analyzed by calculating the molecular orbitals, charge transfer, Wiberg bond order and electron localization function. In addition, the infrared spectra, Raman spectra and photoelectron spectra are predicted and used to identify the structures from experiments. At last, based on detailed bonding analyses, the fluxional properties are analyzed systematically. We hope that knowledge obtained from this study can be helpful for future theoretical and experimental synthesis of novel vanadium-boride nanomaterials. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study investigates the possible novel structures of VB20- cluster inspired by the tubular molecular rotor TaB20-, and explores its electronic properties through experiments and calculations to identify structures and analyze bonding.