Linked Life Data

17199152

Source:http://linkedlifedata.com/resource/pubmed/id/17199152

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2007-1-2
pubmed:abstractText
The (13)C CPMAS spectrum is presented for the polymorph of oxybuprocaine hydrochloride which is stable at room temperature, i.e. Mod. II degrees . It shows crystallographic splittings arising from the fact that there are two molecules, with substantially different conformations, in the asymmetric unit. An INADEQUATE two-dimensional experiment was used to link signals for the same independent molecule. The chemical shifts are discussed in relation to the crystal structure. Of the four ethyl groups attached to NH(+) nitrogens, one gives rise to unusually low chemical shifts, very different from those of the other three ethyl groups. This is attributed empirically to gamma-gauche conformational effects, as is confirmed by shielding computations. These considerations allow (13)C signals to be assigned to specific carbons in the two crystallographically inequivalent molecules in the crystal structure. Indeed, information about the conformations is inherent in the NMR spectrum, which thus provides data of crystallographic significance. A (13)C/(1)H HETCOR experiment enabled resolution to be obtained in the (1)H dimension and allowed (1)H and (13)C signals for the same independent molecule to be linked.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1463-9076
pubmed:author
pubmed:issnType
Print
pubmed:day
21
pubmed:volume
9
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
360-8
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
NMR crystallography of oxybuprocaine hydrochloride, Modification II degrees.
pubmed:affiliation
Department of Chemistry, University of Durham, South Road, Durham, UK DH1 3LE. r.k.harris@durham.ac.uk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't