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ID 37974
file
creator
Boyarkin, Oleg V.
Kusaka, Ryoji
Rizzo, Thomas R.
NDC
Chemistry
abstract
We report UV photodissociation (UVPD) and IR-UV double-resonance spectra of dibenzo-18-crown-6 (DB18C6) complexes with alkali metal ions (Li+, Na+, K+, Rb+, and Cs+) in a cold, 22-pole ion trap. All the complexes show a number of vibronically resolved UV bands in the 36000-38000 cm-1 region. The Li+ and Na+ complexes each exhibit two stable conformations in the cold ion trap (as verified by IR-UV double-resonance), whereas the K+, Rb+, and Cs+ complexes exist in a single conformation. We analyze the structure of the conformers with the aid of density functional theory (DFT) calculations. In the Li+ and Na+ complexes, DB18C6 distorts the ether ring to fit the cavity size to the small diameter of Li+ and Na+. In the complexes with K+, Rb+, and Cs+, DB18C6 adopts a boat-type (C2v) open conformation. The K+ ion is captured in the cavity of the open conformer thanks to the optimum matching between the cavity size and the ion diameter. The Rb+ and Cs+ ions sit on top of the ether ring, because they are too large to enter the cavity of the open conformer. According to time-dependent DFT calculations, complexes that are highly distorted to hold metal ions open the ether ring upon S1-S0 excitation, and this is confirmed by extensive low-frequency progressions in the UVPD spectra.
description
This is a preprint of an article published by American Chemical Society in Journal of the American Chemical Society, 2011, available online: http://pubs.acs.org/doi/abs/10.1021/ja2046205.
This work is supported by Grant-in-Aids (Grant No. 21350016) for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan and the Swiss National Science foundation through grant 200020_130579.
journal title
Journal of the American Chemical Society
volume
Volume 133
issue
Issue 31
start page
12256
end page
12263
date of issued
2011-08-10
publisher
American Chemical Society
issn
0002-7863
publisher doi
pubmed id
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Copyright (c) 2011 American Chemical Society
relation is version of URL
http://dx.doi.org/10.1021/ja2046205
department
Graduate School of Science