Structural Evolution and Chemical Bonding of Diniobium Boride Clusters Nb₂B_x^–/0 (x = 1–6): Hexagonal‐Bipyramidal Nb₂B₆^–/0 Species

Abstract

Theoretical calculations are performed to probe the geometric and electronic properties of diniobium boride clusters, Nb 2 B x -/0 (x = 1-6). Generalized Koopmans' theorem is utilized to predict vertical detachment energies (VDEs) and to simulate the photoelectron spectra (PES). Density functional theory (DFT) calculations are carried out at the BP86 level to hunt for the most stable structures of the abovementioned species. A fascinating structural evolution is observed in Nb 2 B x -(x = 1- [a] 942 in which the Nb-Nb bond length is 2.217 Å and the Nb-B distances are 2.081 Å. Its corresponding triplet state (C 2v , 3 A 1 ) (Figure 1b) is computed to be 0.15 eV higher at the BP86 level. The results of CCSD(T) single-point calculations are in line with the aforementioned DFT results, making the C 2v ( 1 A 1 ) state 0.19 eV more stable than the triplet C 2v ( 3 A 1 ) state. The neutral Nb 2 B ground state (Figure 1c) is found to be a doublet C 2v ( 2 A 1 ) struc-Eur. J. Inorg. Chem. 2018, 940-950 www.eurjic.org

Two‐layer molecular rotors: A zinc dimer rotating over planar hypercoordinate motifs

“…To facilitate their experimental confirmation, the simulated infrared spectrums of MB 8 Zn 2 (M = Be, Ru, Os) and photoelectron spectrums of MB 7 Zn 2 − (M = Be, Ru, Os) clusters were displayed at left and right of Figure 6 at the BP86/def2‐TZVP level, respectively. Note that the BP86 functional presents a good performance on couples of metal‐doped boron clusters studied by both theoretical calculations and photoelectron spectrums 27,60–64 . The high‐symmetry C 2 v BeB 8 Zn 2 exhibits major IR active peaks at 571 and 599 cm −1 (Figure 6A), and major IR active peaks of RuB 8 Zn 2 and OsB 8 Zn 2 are similar, being 145, 365 cm −1 (Figure 6B) and 144, 357 cm −1 (Figure 6C), respectively.…”

Structural transformations in boron clusters induced by metal doping

“…50,51 Similar arrangement is found in the neutral and anionic state of B 4 V 2 , 52 B 4 ScTi, 53 and B 4 Nb 2 . 54 Interestingly, the B–B opening is even larger in 4-6 (B 4 Mo, B 4 Ta, and B 4 Ta 2 ), 55–57 forming a circular arc around the TM. This arrangement is particularly interesting since, as will be shown later, 4-6 is the precursor of the boron wheels.…”

“…50,52 Similar structural pattern is also followed in B 5 ScTi, 53 B 5 Ta 2 − , 56 B 5 Nb 2 and B 5 Nb 2 − ( 5-5 ). 54 These clusters can be seen as an equatorial B belt around the metallic dimer, and the increase in the number of B atoms would result in the wheel-type clusters. 56 For B 5 Fe and B 5 Zr, the structure can be thought of as 4-5 with a transition metal replacing one of the axial atoms.…”

“…The same can be said for B 6 Nb 2 − , B 6 Ta 2 − B 6 Nb 2 , B 6 Ta 2 , and B 6 Ni 2 . 54,80 However, the GM of B 6 Ni resembles the pentagon capped with Ni ( 6-4 ). 64 On the other hand, if B 6 is doped with C, 63 P, 81 or As, 82 it maintains the shape of the deformed hexagonal cluster with the heteroatom bonding with two B atoms, like in B 6 Si − ( 6-5 ).…”

Theoretical Study on the Structures and Stabilities of CunZn3O3 (n = 1–4) Clusters: Sequential Doping of Zn3O3 Cluster with Cu Atoms

“…We have constantly strived to explore the novel chemical bonding of gas-phase clusters and to gain further insights into the active sites of complicated catalyst surfaces and the reaction mechanisms of catalytic processes [23][24][25][26]. As mentioned above, the sintering and aggregation of the supported Cu nano-particles are among the deactivation reasons for Cubased catalyst [2]; whereas small-sized supported Cu clusters possess high activity in some reactions [14].…”