General Approach to Direct Measurement of the Hydration State of Coordination Complexes in the Gas Phase: Variable Temperature Mass Spectrometry.

The formation of ternary aqua complexes of metal-based diagnostics and therapeutics is closely correlated to their in vivo efficacy but approaches to quantify the presence of coordinated water ligands are limited. We introduce a general and high-throughput method for characterizing the hydration state of para- and diamagnetic coordination complexes in the gas phase based on variable-temperature ion trap tandem mass spectrometry. Ternary aqua complexes are directly observed in the mass spectrum and quantified as a function of ion trap temperature.

The Interplay Between Hydrogen Bonding and Coulombic Forces in Determining the Structure of Sulfuric Acid-Amine Clusters.

Acid-base cluster chemistry drives atmospheric new particle formation (NPF), but the details of the growth mechanisms are difficult to experimentally probe. Clusters of ammonia, alkylamines, and sulfuric acid, species fundamental to NPF, are probed by infrared spectroscopy. These spectra show that substitution of amines for ammonia, which is linked to accelerated growth, induces profound structural rearrangement in clusters with initial compositions (NH) (HSO) (1 ≤ n ≤ 3).