Issue 29, 2007

Activation of the C–I and C–OH bonds of 2-iodoethanol by gas phase silver cluster cations yields subvalent silver-iodide and -hydroxide cluster cations

Abstract

The gas phase ion–molecule reactions of silver cluster cations (Agn+) and silver hydride cluster cations (AgmH+) with 2-iodoethanol have been examined using multistage mass spectrometry experiments in a quadrupole ion trap mass spectrometer. These clusters exhibit size selective reactivity: Ag2H+, Ag3+, and Ag4H+ undergo sequential ligand addition only, while Ag5+ and Ag6H+ also promote both C–I and C–OH bond activation of 2-iodoethanol. Collision induced dissociation (CID) of Ag5HIO+, the product of C–I and C–OH bond activation by Ag5+, yielded Ag4OH+, Ag4I+ and Ag3+, consistent with a structure containing AgI and AgOH moieties. Ag6H+ promotes both C–I and C–OH bond activation of 2-iodoethanol to yield the metathesis product Ag6I+ as well as Ag6H2IO+. The metathesis product Ag6I+ also promotes C–I and C–OH bond activation.

DFT calculations were carried out to gain insights into the reaction of Ag5+ with ICH2CH2OH by calculating possible structures and their energies for the following species: (i) initial adducts of Ag5+ and ICH2CH2OH, (ii) the subsequent Ag5HIO+ product, (iii) CID products of Ag5HIO+. Potential adducts were probed by allowing ICH2CH2OH to bind in different ways (monodentate through I, monodentate through OH, bidentate) at different sites for two isomers of Ag5+: the global minimum “bowtie” structure, 1, and the higher energy trigonal bipyramidal isomer, 2. The following structural trends emerged: (i) ICH2CH2OH binds in a monodentate fashion to the silver core with little distortion, (ii) ICH2CH2OH binds to 1 in a bidentate fashion with some distortion to the silver core, and (iii) ICH2CH2OH binds to 2 and results in a significant distortion or rearrangement of the silver core. The DFT calculated minimum energy structure of Ag5HIO+ consists of an OH ligated to the face of a distorted trigonal bipyramid with I located at a vertex, while those for both Ag4X+ (X = OH, I) involve AgX bound to a Ag3+ core. The calculations also predict the following: (i) the ion–molecule reaction of Ag5+ and ICH2CH2OH to yield Ag5HIO+ is exothermic by 34.3 kcal mol−1, consistent with the fact that this reaction readily occurs under the near thermal experimental conditions, (ii) the lowest energy products for fragmentation of Ag5HIO+ arise from loss of AgI, consistent with this being the major pathway in the CID experiments.

Graphical abstract: Activation of the C–I and C–OH bonds of 2-iodoethanol by gas phase silver cluster cations yields subvalent silver-iodide and -hydroxide cluster cations

Supplementary files

Article information

Article type
Paper
Submitted
04 Jan 2007
Accepted
30 Apr 2007
First published
17 May 2007

Dalton Trans., 2007, 3149-3157

Activation of the C–I and C–OH bonds of 2-iodoethanol by gas phase silver cluster cations yields subvalent silver-iodide and -hydroxide cluster cations

G. N. Khairallah and R. A. J. O'Hair, Dalton Trans., 2007, 3149 DOI: 10.1039/B700132K

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