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Infrared Multiple Photon Dissociation (IRMPD) Spectroscopy of the Proton-Bound Dimer of 1-Methylcytosine in the Gas Phase

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Author
Abstract

The vibrational spectrum of a hemiprotonated pair of the nucleobase cytosine has been recorded in the 300-1810 cm(-1) domain using action spectroscopy on electrosprayed positive ions with a free-electron laser. The singly charged gaseous cation has the same structure as that reported from crystallography, inferred from a strong absorption seen at 1761 cm(-1), identified as the carbonyl stretch of the protonated ring mixed with in-plane bending of the bridging H+ based on a 29 cm(-1) shift to lower frequency when all five of the exchangeable hydrogens are replaced by deuterium. IRMPD expels the neutral from the proton-bound dimer, leaving behind a protonated monomer. Whereas the bridging H+ in the dimer ion lies between the nitrogens of the two rings, IRMPD of the protonated monomer ion resulting from the dimer shows its H+ preferably situated on the carbonyl oxygen, indicating that the proton moves from one basic atom to another when the dimer ion dissociates.

Year of Publication
2010
Journal
Journal of Physical Chemistry Letters
Volume
1
Number
19
Number of Pages
2891-2897
Date Published
Oct
Type of Article
Article
ISBN Number
1948-7185
Accession Number
ISI:000282727700026
URL
PId
504472fd6fd023a49d01431fec5b8290
Alternate Journal
J. Phys. Chem. Lett.
Journal Article
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