Linked Life Data

19916604

Source:http://linkedlifedata.com/resource/pubmed/id/19916604

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2009-11-17
pubmed:abstractText
The infrared (IR) spectrum of protonated azulene (AzuH(+), C(10)H(9)(+)) has been measured in the fingerprint range (600-1800 cm(-1)) by means of IR multiple photon dissociation (IRMPD) spectroscopy in a Fourier transform ion cyclotron resonance mass spectrometer equipped with an electrospray ionization source using a free electron laser. The potential energy surface of AzuH(+) has been characterized at the B3LYP/6-311G(**) level in order to determine the global and local minima and the corresponding transition states for interconversion. The energies of the local and global minima, the dissociation energies for the lowest-energy fragmentation pathways, and the proton affinity have been evaluated at the CBS-QB3 level. Comparison with calculated linear IR absorption spectra supports the assignment of the IRMPD spectrum to C4-protonated AzuH(+), the most stable of the six distinguishable C-protonated AzuH(+) isomers. Comparison between Azu and C4-AzuH(+) reveals the effects of protonation on the geometry, vibrational properties, and the charge distribution of these fundamental aromatic molecules. Calculations at the MP2 level indicate that this technique is not suitable to predict reliable IR spectra for this type of carbocations even for relatively large basis sets. The IRMPD spectrum of protonated azulene is compared to that of isomeric protonated naphthalene and to an astronomical spectrum of the unidentified IR emission bands.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1089-7690
pubmed:author
pubmed:issnType
Electronic
pubmed:day
14
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
184307
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Infrared spectra of protonated polycyclic aromatic hydrocarbon molecules: azulene.
pubmed:affiliation
Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstrasse 36, Berlin D-10623, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't