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Title: Investigation of the hydrated 7-hydroxy-4-methylcoumarin dimer by combined IR/UV spectroscopy

Abstract

The first molecular beam investigations on a coumarin dimer and clusters of a coumarin dimer with water both in the neutral (S{sub 0}) and cationic (D{sub 0}) electronic ground state are performed. The structure and structural changes due to ionization of the isolated 7-hydroxy-4-methylcoumarin dimer (7H4MC){sub 2} as well as its mono- and dihydrate (7H4MC){sub 2}(H{sub 2}O){sub 1-2} are analyzed by applying combined IR/UV spectroscopy compared with density functional theory calculations. In case of the neutral dimer of 7H4MC a doubly hydrogen-bonded structure is formed. This doubly hydrogen-bonded arrangement opens to a singly hydrogen-bonded structure in the ion presenting a rearrangement reaction within an isolated dimer. By attaching one or two water molecules to the neutral 7H4MC dimer water is inserted into the hydrogen bonds. In contrast to the non-hydrated species this general binding motif with water in a bridging function does not change via ionization but especially for the dihydrate the spatial arrangement of the two 7H4MC units changes strengthening the interaction between the aromatic chromophores. The presented analyses illustrate the strong dependence of binding motifs as a function of successive hydration and charge including a rearrangement reaction.

Authors:
;
Publication Date:
OSTI Identifier:
22415378
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 141; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COUMARIN; DENSITY FUNCTIONAL METHOD; DIMERS; GROUND STATES; HYDRATES; HYDRATION; HYDROGEN; INTERACTIONS; IONIZATION; MOLECULAR BEAMS; MOLECULES; SPECTROSCOPY; WATER

Citation Formats

Stamm, A., Schwing, K., and Gerhards, M., E-mail: gerhards@chemie.uni-kl.de. Investigation of the hydrated 7-hydroxy-4-methylcoumarin dimer by combined IR/UV spectroscopy. United States: N. p., 2014. Web. doi:10.1063/1.4900893.
Stamm, A., Schwing, K., & Gerhards, M., E-mail: gerhards@chemie.uni-kl.de. Investigation of the hydrated 7-hydroxy-4-methylcoumarin dimer by combined IR/UV spectroscopy. United States. https://doi.org/10.1063/1.4900893
Stamm, A., Schwing, K., and Gerhards, M., E-mail: gerhards@chemie.uni-kl.de. 2014. "Investigation of the hydrated 7-hydroxy-4-methylcoumarin dimer by combined IR/UV spectroscopy". United States. https://doi.org/10.1063/1.4900893.
@article{osti_22415378,
title = {Investigation of the hydrated 7-hydroxy-4-methylcoumarin dimer by combined IR/UV spectroscopy},
author = {Stamm, A. and Schwing, K. and Gerhards, M., E-mail: gerhards@chemie.uni-kl.de},
abstractNote = {The first molecular beam investigations on a coumarin dimer and clusters of a coumarin dimer with water both in the neutral (S{sub 0}) and cationic (D{sub 0}) electronic ground state are performed. The structure and structural changes due to ionization of the isolated 7-hydroxy-4-methylcoumarin dimer (7H4MC){sub 2} as well as its mono- and dihydrate (7H4MC){sub 2}(H{sub 2}O){sub 1-2} are analyzed by applying combined IR/UV spectroscopy compared with density functional theory calculations. In case of the neutral dimer of 7H4MC a doubly hydrogen-bonded structure is formed. This doubly hydrogen-bonded arrangement opens to a singly hydrogen-bonded structure in the ion presenting a rearrangement reaction within an isolated dimer. By attaching one or two water molecules to the neutral 7H4MC dimer water is inserted into the hydrogen bonds. In contrast to the non-hydrated species this general binding motif with water in a bridging function does not change via ionization but especially for the dihydrate the spatial arrangement of the two 7H4MC units changes strengthening the interaction between the aromatic chromophores. The presented analyses illustrate the strong dependence of binding motifs as a function of successive hydration and charge including a rearrangement reaction.},
doi = {10.1063/1.4900893},
url = {https://www.osti.gov/biblio/22415378}, journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 19,
volume = 141,
place = {United States},
year = {Fri Nov 21 00:00:00 EST 2014},
month = {Fri Nov 21 00:00:00 EST 2014}
}