Geometrical Structures of Gas Phase Chromium Oxide Cluster Anions Studied by Ion Mobility Mass Spectrometry

Abstract

Structural assignments of gas phase chromium oxide cluster anions, CrO (m = 1-7), have been achieved by comparison between experimental collision cross sections measured by ion mobility mass spectrometry and theoretical collision cross sections of optimized structures by quantum chemical calculations. In the mass spectrum, significant magic behavior between the numbers m and n was not observed for CrO, while wide ranges of compositions were observed around CrO to (CrO) as reported previously. The (CrO) (m = 3-7) ions were assigned to have monocyclic-ring structures for m = 3-5 and bicyclic rings for m = 6 and 7. In addition, gradual structural change from these cyclic structures of (CrO) to three-dimensional structures of CrO was found for m = 4-7. The energy levels of molecular orbitals of a calculated monocyclic structure of CrO were also found to be consistent with previous results of photoelectron spectroscopy, although those of the bicyclic isomer exhibited a different behavior. Moreover, the observation of abundant ions generated by collision induced dissociations at the inlet of the ion drift cell indicates that the larger sized (CrO) (m > 5) series were unstable and easily dissociated to smaller ions.

Compositions and Isomer Separation of Palladium Oxide Cluster Cations Studied by Ion Mobility Mass Spectrometry

“…Although it is difficult to determine detailed structural parameters of each cluster ion solely from the CCS measurement, IMMS is easily applicable for various-sized cluster ions in combination with quantum chemical calculations. Recently, by using a home-built IMMS apparatus, we investigated the geometrical structures of oxide cluster ions of the first-row transition metals such as Ti, 21 V, 22 Cr, 23 Fe, 24 Co, 25 Ni, 26 Cu, 27 and Zn. 28 Isomers and structural transitions were effectively observed in those reports.…”

Collision cross sections of negative cluster ions of phosphoric acid in N2 determined by drift tube ion mobility and their use in travelling wave ion mobility

“…13,14,15 Cluster ions are readily produced using direct infusion of salt solutions with an electrospray ion source and are routinely used for calibration of mass analyzers. 16,17,18,19,20 A number of ionic clusters derived from alkali halides salts, 21,22,23 ionic liquids 24,25,26,27 and transition metal oxides 28,29,30,31,32,33 have been studied by drift tube ion mobility mainly and differential mobility analysis-time-of-flight mass spectrometry. Since a first study in 2014, 34 we have started studying negative phosphoric acid cluster ions in view of investigating their potential as reference for the calibration of the TWIMS.…”

Stable Compositions and Structures of Copper Oxide Cluster Cations CunOm+ (n = 2–8) Studied by Ion Mobility Mass Spectrometry

“…Recently, we studied the structures of metal oxide cluster ions of first-row transition metals, such as, Zn, Co, Fe, Ni, Ti, V, and Cr, by IMMS. Transitions from two-dimensional (2D) to three-dimensional (3D) structures were commonly observed in the cluster ions of oxides of the metals of the latter half of this row. − In the present study, the structures of copper oxide cluster cations, Cu n O m + , have been studied by IMMS.…”