Linked Life Data

19199614

Source:http://linkedlifedata.com/resource/pubmed/id/19199614

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
12
pubmed:dateCreated
2009-3-30
pubmed:abstractText
Adamantyl-end-capped polyynes with chains of 4, 6, 8, 10, 12, 16, and 20 sp-hybridized carbons (C4-C20) have been synthesized and their IR and Raman spectra obtained. On the basis of violations of the mutual-exclusion principle between IR and Raman spectroscopy, spectral evidence demonstrates that these molecules possess a noncentrosymmetric molecular structure in both the solid and solution states. This premise is supported by X-ray crystallographic analysis of C12, which shows a bent, noncentrosymmetric structure in the solid state. Density functional theory (DFT) calculations for adamantyl-end-capped polyynes, in comparison with those for hydrogen-end-capped polyynes, show that the observed violation of mutual exclusion is independent of the end group of the polyyne chain (i.e., adamantyl versus H). The origin of these experimental spectroscopic observations is ascribed to the existence of dynamic contributions to molecular nonlinearity resulting from low-frequency skeletal bending vibrations of the chains and/or the existence of low-energy bent conformations of the polyyne chains, as DFT-optimized structures seem to suggest.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
1520-5126
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4239-44
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Evidence for solution-state nonlinearity of sp-carbon chains based on IR and Raman spectroscopy: violation of mutual exclusion.
pubmed:affiliation
Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica G. Natta Piazza Leonardo da Vinci 32, 20133 Milano, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't