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Lead(ii) soaps : Crystal structures, polymorphism, and solid and liquid mesophases

Martinez, Francisco LU ; Ramos Riesco, M.; Rodríguez-Cheda, José A.; Redondo Yélamos, M. Isabel; Garrido, L; Fernández-Martínez, A.; García-Barriocanal, J.; da Silva, Iván; Durán-Olivencia, M. and Poulain, A. (2017) In Physical Chemistry Chemical Physics 19(26). p.17009-17018
Abstract

The long-chain members of the lead(ii) alkanoate series or soaps, from octanoate to octadecanoate, have been thoroughly characterized by means of XRD, PDF analysis, DSC, FTIR, ssNMR and other techniques, in all their phases and mesophases. The crystal structures at room temperature of all of the members of the series are now solved, showing the existence of two polymorphic forms in the room temperature crystal phase, different to short and long-chain members. Only nonanoate and decanoate present both forms, and this polymorphism is proven to be monotropic. At higher temperature, these compounds present a solid mesophase, defined as rotator, a liquid crystal phase and a liquid phase, all of which have a similar local arrangement. Since... (More)

The long-chain members of the lead(ii) alkanoate series or soaps, from octanoate to octadecanoate, have been thoroughly characterized by means of XRD, PDF analysis, DSC, FTIR, ssNMR and other techniques, in all their phases and mesophases. The crystal structures at room temperature of all of the members of the series are now solved, showing the existence of two polymorphic forms in the room temperature crystal phase, different to short and long-chain members. Only nonanoate and decanoate present both forms, and this polymorphism is proven to be monotropic. At higher temperature, these compounds present a solid mesophase, defined as rotator, a liquid crystal phase and a liquid phase, all of which have a similar local arrangement. Since some lead(ii) soaps appear as degradation compounds in oil paintings, the solved crystal structures of lead(ii) soaps can now be used as fingerprints for their detection using X-ray diffraction. Pair distribution function analysis on these compounds is very similar in the same phases and mesophases for the different members, showing the same short range order. This observation suggests that this technique could also be used in the detection of these compounds in disordered phases or in the initial stages of formation in paintings.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Chemistry Chemical Physics
volume
19
issue
26
pages
10 pages
publisher
The Royal Society of Chemistry
external identifiers
  • scopus:85024489535
  • wos:000405422900007
ISSN
1463-9076
DOI
10.1039/c7cp02351k
language
English
LU publication?
yes
id
472fa32f-1929-4f3c-b342-e16fa817200c
date added to LUP
2017-07-31 13:44:29
date last changed
2017-09-18 11:40:34
@article{472fa32f-1929-4f3c-b342-e16fa817200c,
  abstract     = {<p>The long-chain members of the lead(ii) alkanoate series or soaps, from octanoate to octadecanoate, have been thoroughly characterized by means of XRD, PDF analysis, DSC, FTIR, ssNMR and other techniques, in all their phases and mesophases. The crystal structures at room temperature of all of the members of the series are now solved, showing the existence of two polymorphic forms in the room temperature crystal phase, different to short and long-chain members. Only nonanoate and decanoate present both forms, and this polymorphism is proven to be monotropic. At higher temperature, these compounds present a solid mesophase, defined as rotator, a liquid crystal phase and a liquid phase, all of which have a similar local arrangement. Since some lead(ii) soaps appear as degradation compounds in oil paintings, the solved crystal structures of lead(ii) soaps can now be used as fingerprints for their detection using X-ray diffraction. Pair distribution function analysis on these compounds is very similar in the same phases and mesophases for the different members, showing the same short range order. This observation suggests that this technique could also be used in the detection of these compounds in disordered phases or in the initial stages of formation in paintings.</p>},
  author       = {Martinez, Francisco and Ramos Riesco, M. and Rodríguez-Cheda, José A. and Redondo Yélamos, M. Isabel and Garrido, L and Fernández-Martínez, A. and García-Barriocanal, J. and da Silva, Iván and Durán-Olivencia, M. and Poulain, A.},
  issn         = {1463-9076},
  language     = {eng},
  number       = {26},
  pages        = {17009--17018},
  publisher    = {The Royal Society of Chemistry},
  series       = {Physical Chemistry Chemical Physics},
  title        = {Lead(ii) soaps : Crystal structures, polymorphism, and solid and liquid mesophases},
  url          = {http://dx.doi.org/10.1039/c7cp02351k},
  volume       = {19},
  year         = {2017},
}