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ID 45812
file
creator
Nakatsuma, Maki
Kida, Motoki
NDC
Chemistry
abstract
We measure UV photodissociation (UVPD) spectra of benzo-12-crown-4 (B12C4) complexes with alkali metal ions, M+·B12C4 (M = Li, Na, K, Rb, and Cs), in the 36300−37600 cm−1 region. Thanks to the cooling of ions to ∼10 K, all the M+·B12C4 complexes show sharp vibronic bands in this region. For UV−UV hole-burning (HB) spectroscopy, we first check if our experimental system works well by observing UV−UV HB spectra of the K+ complex with benzo-18-crown-6 (B18C6), K+·B18C6. In the UV−UV HB spectra of the K+·B18C6 complex, gain signals are also observed; these are due to vibrationally hot K+·B18C6 complex produced by the UV excitation of cold K+·B18C6 complex. Then we apply UV−UV HB spectroscopy to the M+·B12C4 complexes, and only one conformer is found for each complex except for the Li+ complex, which has two conformers. The vibronic structure around the origin band of the UVPD spectra is quite similar for all the complexes, indicating close resemblance of the complex structure. The most stable structures calculated for the M+·B12C4 (M = Li, Na, K, Rb, and Cs) complexes also have a similar conformation among them, which coincides with the UVPD results. In these conformers the metal ions are too big to be included in the B12C4 cavity, even for the Li+ ion. In solution, it was reported that 12-crown-4 (12C4) shows the preference of Na+ ion among alkali metal ions. From the similarity of the structure for the M+·B12C4 complexes, it is suggested that the solvation of free metal ions, not of the M+·12C4 complexes, may lead to the selectivity of Na+ ion for 12C4 in solution.
description
This work was partly supported by JSPS KAKENHI Grant Number 16H04098.
journal title
Journal of Physical Chemistry A
volume
Volume 120
issue
Issue 32
start page
6394
end page
6401
date of issued
2016-07-26
publisher
American Chemical Society
issn
1089-5639
1520-5215
publisher doi
pubmed id
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
publisher
rights
Copyright (c) 2016 American Chemical Society
This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
department
Graduate School of Science