Characterization of the Effects of Ligands on Bonding and σ-Aromaticity of Small Pt Nanoclusters.

Nanoclusters, particularly gold nanoclusters, have attracted the attention of researchers due to their potential applications in the medicine and energy fields. Other noble-metal nanoclusters, including Pt, have also been studied, but in lesser detail. Pt is known for its excellent catalytic properties and is a promising candidate for applications in catalysis and biomedicine.

Ion Mobility Spectrometry Characterization of the Intermediate Hydrogen-Containing Gold Cluster Au(PPh)H.

We employ ion mobility spectrometry and density functional theory to determine the structure of Au(PPh)H (PPh = triphenylphosphine), which was recently identified by high mass resolution mass spectrometry. Experimental ion-neutral collision cross sections represent the momentum transfer between the ionic clusters and gas molecules averaged over the relative thermal velocities of the colliding pair, thereby providing structural insights. Theoretical calculations indicate the geometry of Au(PPh)H is similar to Au(PPh), with three hydrogen atoms bridging two gold atoms and two hydrogen atoms forming single Au-H bonds.

ESI-MS Identification of the Cationic Phosphine-Ligated Gold Clusters Au: Insight into the Gold-Ligand Ratio and Abundance of Larger Clusters.

Triphenylphosphine (PPh)-ligated gold nanoclusters are valuable for a number of potential applications due to their relative ease of synthesis and usefulness in forming advanced cluster architectures. While previous studies have reported cationic PPh-ligated gold clusters with core sizes of Au, Au, and Au, there has not been definitive identification by mass spectrometry of many larger clusters in the Au range. Herein, we survey a polydisperse solution of cationic PPh-ligated gold clusters using high-mass-resolution (/Δ = 60,000) electrospray ionization mass spectrometry (ESI-MS).

Role of sterics in phosphine-ligated gold clusters.

This study examined the solution-phase exchange reactions of triphenylphosphine (PPh3) ligands on Au8L72+ (L = PPh3) gold clusters with three different tolyl ligands using electrospray ionization mass spectrometry to provide insight into how steric differences in the phosphines influence the extent of ligand exchange and the stability of the resulting mixed-phosphine clusters. The size distributions of tolyl-exchanged gold clusters were found to depend on the position of the methyl group in the tri(tolyl)phosphine ligands (-ortho, -meta, and -para). Due to different sterics, the tri(m-tolyl)phosphine (TMTP) and tri(p-tolyl)phosphine (TPTP) ligands exchanged efficiently onto the Au8L72+ (L = PPh3) clusters while the tri(o-tolyl)phosphine ligands did not exchange.

The binding energy and bonding in dialane.

The binding energy of dialane, Al2H6, has been measured using mass spectrometric techniques to be 33 +/- 5 kcal/mol. This represents the first measurement of the thermochemical properties of dialane, which has only recently been observed in low-temperature matricies. High-level quantum mechanical calculations give a binding energy in agreement with the measured value.

The origin of sticking between a hydroperoxy radical and a water surface.

An understanding of how gas-phase radicals in the earth's atmosphere become incorporated with liquid-phase cloud droplets is a vital part of understanding the chemical budgeting of these highly reactive species. Recent studies have suggested that hydroperoxy radicals (HO2) have an affinity for binding to a water surface. The calculations presented here are used to extricate the components of the attractive contribution of the intermolecular interactions that are responsible for the unusually strong binding between the hydroperoxy radical and a water surface.