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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2009-4-17
pubmed:abstractText
Anionic group II metal nitrate clusters of the formula [M(2)(NO(3))(5)](-), where M(2) = Mg(2), MgCa, Ca(2), and Sr(2), are investigated by infrared multiple photon dissociation (IRMPD) spectroscopy to obtain vibrational spectra in the mid-IR region. The IR spectra are dominated by the symmetric and the antisymmetric nitrate stretches, with the latter split into high and low-frequency components due to the distortion of nitrate anion symmetry by interactions with the cation. Density functional theory (DFT) is used to predict geometries and vibrational spectra for comparison to the experimental spectra. Calculations yield two stable isomers: the first one contains two terminal nitrate anions on each cation and a single bridging nitrate ("mono-bridging"), while the second structure features a single terminal nitrate on each cation with three bridging nitrate ligands ("tri-bridging"). The tri-bridging isomer is calculated to be lower in energy than the mono-bridging one for all species. Theoretical spectra of the tri-bridging structure provide a better qualitative match to the experimental infrared spectra of [Mg(2)(NO(3))(5)](-) and [MgCa(NO(3))(5)](-). However, the profile of the low-frequency nu(3) band for the Mg(2) complex suggests a third possible isomer not predicted by theory. The IRMPD spectra of the Ca(2) and Sr(2) complexes are better reconciled by a weighted summation of the spectra of both isomers suggesting that a mixture of structures is present.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
May
pubmed:issn
1879-1123
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
772-82
pubmed:year
2009
pubmed:articleTitle
IRMPD spectroscopy of anionic group II metal nitrate cluster ions.
pubmed:affiliation
Department of Chemistry, Wichita State University, Wichita, Kansas 67260-0051, USA.
pubmed:publicationType
Journal Article