Identifying structural building blocks in CuO 6 clusters: CuO 2 complexes vs CuO 3 ozonides

Evolution of the atomic and electronic structures of CuO clusters: a comprehensive study using the DFT approach

One of the most fundamental aspects of cluster science is to understand the structural evolution at the atomic scale. In this connection, here we report a comprehensive study of the atomic and electronic structures of (CuO)n clusters for n = 1 to 12 using DFT-based formalisms. Both the plane wave-based pseudo-potential approach and LCAO-MO-based method have been employed to obtain the ground state geometries of neutral, cation and anion copper oxide clusters. The results reveal that neutral copper oxide clusters favor a planar ring structure up to heptamer and from octamer onwards they adopt a three-dimensional motif with (CuO)9 and (CuO)12 forming a barrel-shaped layered structure. Detailed electronic structure analysis reveals that the transition of the atomic structure from 2D to 3D is guided by the energy balance of the Cu-O (d-p) and Cu-Cu (d-d) bonds. The removal of one electron from the cluster (cation) results in slightly stretched bonds while the addition of one electron (anion) showed compression in the overall geometries. The thermodynamic and electronic stability of these clusters has been analyzed by estimating their binding energy, ionization energy and electron affinity as a function of size. Remarkably, among these clusters, the octamer (CuO)8 and dodecamer (CuO)12 show higher binding energy and electron affinity (∼6.5 eV) with lower ionization energy (5.5-6.0 eV). This unique feature of the octamer and dodecamer indicates that they are very promising candidates for both oxidizing and reducing agents in different important chemical reactions.

Structural and bonding properties of Cu3O3- and Cu3O4- clusters: anion photoelectron spectroscopy and density functional calculations

The structural and electronic properties of Cu3O3- and Cu3O4- were investigated using mass-selected anion photoelectron spectroscopy in combination with density functional theoretical calculations. The vertical detachment energies of Cu3O3- and Cu3O4- were measured to be 3.48 ± 0.08 and 3.54 ± 0.08 eV, respectively. Their geometrical structures were determined by comparison of the theoretical calculations with the experimental results. The most stable structure of Cu3O3- can be characterized as a C3v symmetric six-membered ring structure with alternating Cu-O bonds, in which the plane of the three O atoms is slightly above that of the three Cu atoms. The most stable structure of Cu3O4- can be viewed as a Cs symmetric seven-membered ring with a peroxo unit. The bond order and molecular orbital analyses indicate that the Cu-Cu interactions in Cu3O3- and Cu3O4- are weak. The calculated NICS(0) and NICS(1) values of Cu3O3- are -25.0 ppm and -19.2 ppm, respectively, and those of Cu3O4- are -18.6 ppm and -10.5 ppm, respectively, indicating that they both are significantly aromatic.

Density functional calculation of the structure and electronic properties of Cu(n)O(n) (n = 1-8) clusters

Ab initio simulations and calculations were used to study the structures and stabilities of copper oxide clusters, Cu(n)O(n) (n = 1-8). The lowest energy structures of neutral and charged copper oxide clusters were determined using primarily the B3LYP/LANL2DZ model chemistry. For n ≥ 4, the clusters are nonplanar. Selected electronic properties including atomization energies, ionization energies, electron affinities, and Bader charges were calculated and examined as a function of n.

A theoretical study of small copper oxide clusters: Cu2Ox (x=1–4)

Density functional theory (DFT) calculations are performed to study Cu2Ox (x = 1 - 4) clusters in their neutral, anionic and cationic states. The ground state structures are obtained and found to exhibit linear or near linear structures, which are different from the two- or three-dimensional ones suggested by the previous theoretical calculations. The calculated electron affinities of the clusters are in good agreement with the experimental ones. The low-lying excited states for the clusters are calculated using time-dependent DFT and used to assign the features in the photoelectron spectra. Our results compare well with the available experimental data.