Issue 17, 2007

Dramatic size effects and evidence of structural isomers in the reactions of rhodium clusters, Rhn±, with nitrous oxide

Abstract

The reactions of gas phase rhodium clusters, Rhn± (n < 30), with nitrous oxide, N2O, have been investigated under single collision conditions by Fourier transform ion cyclotron resonance mass spectrometry. The only significant reaction observed is the sequential generation of oxides. Absolute rate constants for the reactions of all clusters have been determined and, in the case of the cationic clusters especially, they exhibit large fluctuations as a function of cluster size with local minima observed for n = 5, 19, 28. Striking similarities are observed with the variation in rate constants for these clusters in reactions with small hydrocarbons (C. Adlhart and E. Uggerud, J. Chem. Phys., 2005, 123, 214709). Corresponding size effects are also observed but are less marked in the reactions of the anionic clusters. The reactions of several clusters exhibit marked deviations from simple pseudo-first-order kinetics suggesting the presence of multiple isomeric forms: Rh11+, Rh12+ and Rh8 exhibit characteristic biexponential decays which are interpreted in terms of the existence of different structural forms of the cluster which have markedly different reactivity. By contrast, Rh6+, Rh7+and Rh8+ show rates which apparently increase with time, probably due to collisional activation. Thermalisation of the clusters prior to reaction by exposure to pulses of argon results in changes to the kinetics of these anomalous systems which can be explained in terms of collision induced isomerisation.

Graphical abstract: Dramatic size effects and evidence of structural isomers in the reactions of rhodium clusters, Rhn±, with nitrous oxide

Article information

Article type
Paper
Submitted
14 Dec 2006
Accepted
23 Jan 2007
First published
16 Feb 2007

Phys. Chem. Chem. Phys., 2007,9, 2130-2136

Dramatic size effects and evidence of structural isomers in the reactions of rhodium clusters, Rhn±, with nitrous oxide

D. Harding, M. S. Ford, T. R. Walsh and S. R. Mackenzie, Phys. Chem. Chem. Phys., 2007, 9, 2130 DOI: 10.1039/B618299B

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements