Colossal Stability of Gas‐Phase Trianions: Super‐Pnictogens

Exploring the properties of new super-chalcogens based on multiple electron counting rules: a combined DFT and ab initio study on [M(B2C4X6)2]2- dianion clusters

The theoretical exploration of the super-chalcogen properties of multi-charged sandwich structures whose geometry simultaneously satisfyies the octet rule and Hückel's 4n+2 rule is reported here via a case study of dianion clusters [M(B2C4X6)2]2- (M = Be, Mg or Ca; X = H, F or Cl). The properties of these dianion clusters [M(B2C4X6)2]2- are close to or even superior to those of traditional clusters based on separate electron-counting rules, i.e., the octet rule and Hückel's 4n+2 rule. At the theoretical level of combined ab initio and DFT methods, these clusters, including halogen-substituents (F, Cl) are super-chalcogens due to their high first vertical electron detachment energy (FVDE), of which the largest value is 1.64 eV. This may be attributed to the strong ability of halogen-substituents (F, Cl) to attract an extra electron, according to an analysis of the distribution of the extra electron, and the spin density and the contribution of HOMO orbitals, leading to a larger spatial extent of the extra electron on both the ring skeleton and halogen ligands, which will lower the electronic kinetic energy according to fundamental quantum mechanics.

Super-electrophiles of tri- and tetra-anions stabilized by selected terminal groups and their role in binding noble gas atoms

Stabilization of multiply-charged atomic clusters in the gas phase has been a topic of great interest not only because of their potential applications as weakly-coordinating anions, but also for their ability to promote unusual reactions and serve as building blocks of materials. Recent experiments have shown that, after removing one terminal ligand from the closo-dodecacyano-borate, B12(CN)122-, the cluster can strongly bind an argon atom at room temperature. Bearing this in mind, here, we have developed more than a dozen highly stable tri- and tetra-anions using density functional theory (DFT) calculations with hybrid functional (B3LYP) and semi-empirical dispersion corrections. The interactions between the clusters and noble gas atoms, including Ne, Ar and Kr, are studied. The resulting super-electrophilic sites embedded in these charged clusters can bind noble gas atoms with binding energies up to 0.7 eV. This study enriches the database of highly-charged clusters and provides a viable design rule for super-electrophiles that can strongly bind noble gas atoms.

On the Role of Alkali-Metal-Like Superatom Al12 P in Reduction and Conversion of Carbon Dioxide

Developing efficient catalysts for the conversion of CO₂ into fuels and value-added chemicals is of great significance to relieve the growing energy crisis and global warming. With the assistance of DFT calculations, it was found that, different from Al₁₂ X (X=Be, Al, and C), the alkali-metal-like superatom Al₁₂ P prefers to combine with CO₂ via a bidentate double oxygen coordination, yielding a stable Al₁₂ P(η² -O₂ C) complex containing an activated radical anion of CO₂ (i.e., CO₂ ^.- ). Thereby, this compound could not only participate in the subsequent cycloaddition reaction with propylene oxide but also initiate the radical reaction with hydrogen gas to form high-value chemicals, revealing that Al₁₂ P can play an important role in catalyzing these conversion reactions. Considering that Al₁₂ P has been produced in laboratory and is capable of absorbing visible light to drive the activation and transformation of CO₂ , it is anticipated that this work could guide the discovery of additional superatom catalysts for CO₂ transformation and open up a new research field of superatom catalysis.

Record-high stability and compactness of multiply-charged clusters aided by selected terminal groups

Multiply-charged clusters with compact sizes that are stable in the gas phase are important due to their potential applications as weakly-coordinating ions and building blocks of bulk materials.