Linked Life Data

19037860

Source:http://linkedlifedata.com/resource/pubmed/id/19037860

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
2009-4-30
pubmed:abstractText
A quantum chemical model is introduced to predict the H-bond donor strength of monofunctional organic compounds from their ground-state electronic properties. The model covers -OH, -NH, and -CH as H-bond donor sites and was calibrated with experimental values for the Abraham H-bond donor strength parameter A using the ab initio and density functional theory levels HF/6-31G** and B3LYP/6-31G**. Starting with the Morokuma analysis of hydrogen bonding, the electrostatic (ES), polarizability (PL), and charge transfer (CT) components were quantified employing local molecular parameters. With hydrogen net atomic charges calculated from both natural population analysis and the ES potential scheme, the ES term turned out to provide only marginal contributions to the Abraham parameter A, except for weak hydrogen bonds associated with acidic -CH sites. Accordingly, A is governed by PL and CT contributions. The PL component was characterized through a new measure of the local molecular hardness at hydrogen, eta(H), which in turn was quantified through empirically defined site-specific effective donor and acceptor energies, EE(occ) and EE(vac). The latter parameter was also used to address the CT contribution to A. With an initial training set of 77 compounds, HF/6-31G** yielded a squared correlation coefficient, r(2), of 0.91. Essentially identical statistics were achieved for a separate test set of 429 compounds and for the recalibrated model when using all 506 compounds. B3LYP/6-31G** yielded slightly inferior statistics. The discussion includes subset statistics for compounds containing -OH, -NH, and active -CH sites and a nonlinear model extension with slightly improved statistics (r(2) = 0.92).
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1096-987X
pubmed:author
pubmed:copyrightInfo
(c) 2008 Wiley Periodicals, Inc.
pubmed:issnType
Electronic
pubmed:day
15
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1454-64
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Modeling the H bond donor strength of -OH, -NH, and -CH sites by local molecular parameters.
pubmed:affiliation
UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't