Unexpected Stability of Al ₄ H ₆ : A Borane Analog?

Abstract

Whereas boron has many hydrides, aluminum has been thought to exhibit relatively few. A combined anion photoelectron and density functional theory computational study of the Al4H-6 anion and its corresponding neutral, Al4H6, showed that Al4H6 can be understood in terms of the Wade-Mingos rules for electron counting, suggesting that it may be a borane analog. The data support an Al4H6 structure with a distorted tetrahedral aluminum atom framework, four terminal Al-H bonds, and two sets of counter-positioned Al-H-Al bridging bonds. The large gap between the highest occupied and the lowest unoccupied molecular orbitals found for Al4H6, together with its exceptionally high heat of combustion, further suggests that Al4H6 may be an important energetic material if it can be prepared in bulk.

Stable Valence Anions of Nucleic Acid Bases and DNA Strand Breaks Induced by Low Energy Electrons

“…Both electrospray and matrix isolated laser desorption ionization produce anions, but they are not usually parent anions. Typically, in negative ion mode, the biomolecules made with these sources have lost one or more hydrogen atoms, while in positive ion [38]. Reprinted with permission from AAAS.)…”

“…The pulsed arc discharge source ( Figure 21-12 [38]) also operates by pulsed vaporization of refractory materials. In this source, a pulsed discharge strikes a sample rod producing a plasma while a pulsed valve behind the discharge region admits a high pressure burst of helium gas.…”

Quantum Monte Carlo studies of covalent and metallic clusters: Accuracy of density functional approximations

“…Clusters have naturally been the subject of numerous experimental and theoretical studies in recent years. [2][3][4][5][6][7][8] There are many potential technological applications of nanoclusters. Several metallic clusters have been shown to be very active catalysts 9,10 due to their high surface-area-to-volume ratios and unusual surface structures.…”

Al 13 H − : Hydrogen atom site selectivity and the shell model

“…3 Even more recently, we explored the bonding and structure of a wide variety of aluminum hydride clusters, Al m H n , by utilizing a combination of negative ion photoelectron spectroscopy to study their anions, Al m H n − , and density functional theory calculations to characterize both their anions and their neutrals. 4,5 The neutral counterparts of several of these anions were found to exhibit significant stability, as evidenced by their large highest occupied molecular orbitallowest unoccupied molecular orbital ͑HOMO-LUMO͒ gaps. Their geometric structures were found to obey the predictions of the Wade-Mingos electron-counting rules, in agreement with calculations that also replicated key photoelectron-derived values.…”