Linked Life Data

20873860

Source:http://linkedlifedata.com/resource/pubmed/id/20873860

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
41
pubmed:dateCreated
2010-10-14
pubmed:abstractText
When refining structures using gas electron diffraction (GED) data, assumptions are often made in order to reduce the number of required geometrical parameters. Where these relate to light, peripheral atoms there is little effect on the refined heavy-atom structure, which is well defined by the GED data. However, this is not the case when heavier atoms are involved. We have determined the gas-phase structure of perfluoro(methylcyclohexane), C(6)F(11)CF(3), using three different refinement methods and have shown that our new method, which makes use of both MP2 and molecular mechanics (MM) calculations to restrain the peripheral-atom geometry, gives a realistic structure without the need for damaging constraints. Only the conformer with the CF(3) group in an equatorial position was considered, as ab initio calculations showed this to be 25 kJ mol(-1) lower in energy than the axial conformer. Refinements combining both high-level and low-level calculations to give constraints were superior both to those based only on molecular mechanics and to those in which assumptions about the geometry were imposed.
pubmed:language
eng
pubmed:journal
pubmed:status
PubMed-not-MEDLINE
pubmed:month
Oct
pubmed:issn
1520-5215
pubmed:author
pubmed:issnType
Electronic
pubmed:day
21
pubmed:volume
114
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11022-6
pubmed:year
2010
pubmed:articleTitle
Low symmetry in molecules with heavy peripheral atoms. The gas-phase structure of perfluoro(methylcyclohexane), C6F11CF3.
pubmed:affiliation
School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JJ, UK.
pubmed:publicationType
Journal Article