4th EucheMs chemistry congress

tuesday, 28-Aug 2012
s787
chem. Listy 106, s587–s1425 (2012)
organic Chemistry, Polymers – ii
Polymer chemistry – i
o - 2 2 3
SuLfonAtion of PoLyButAdiene And
ButAdiene-Styrene CoPoLyMerS AS verSAtiLe
route for the ProduCtion of
PoLyeLeCtroLyteS And ionoMerS with
enhAnCed therMAL StABiLity And
ControLLed MorPhoLoGy
A. GrASSi 1 , A. BuonerBA 1 , v. SPerAnzA 2
1 University of Salerno, Chemistry and Biology, Salerno, Italy
2 University of Salerno, Chemical Engineering, Salerno, Italy
Sulfonated ionomers find applications ranging from ion
exchange membranes for fuel cells to superacid catalysts,
surfactants, compatibilizers and sensors. Typical examples are
sulfonated polystyrene, polybenzimidazole and polyphenylene
oxide in which the sulfonic acid groups are randomly introduced
onto the aromatic rings of the polymer chains. The selective
functionalization of polymer segments in block copolymers is
more challenging but of interest for the production of phase
separated materials containing polar domains homogeneously
dispersed in hard polymer matrices.
In this presentation we describe a two steps process which
allows the fast and selective sulfonation of olefinic carbon-carbon
double bonds of polybutadiene and polystyrene-b-polybutadieneb-polystyrene
triblock copolymers (SBS), without producing
crosslinking of the polymer chains and functionalization of aryl
groups. High level of sulfonation and ion exchange capacities
(IEC) were thus obtained. Sulfonation of semicrystalline
multiblock syndiotactic polystyrene-co-cis-1,4-polybutadiene
(sPSB) [1] led tosPSB-SA in which the polybutadiene segments are
completely sulfonated and the crystallinity of the syndiotactic
polystyrene domains is preserved. A thin film by spin-coating of
sPSB-SA (12 mol% of -SO H) showed at AFM analysis a phase
3
separated morphology, consisting of conductive regions of few
tens of nanometers embedded in a non conductive matrix of
syndiotactic polystyrene. The thermal stability of sPSB-SAs was
investigated by DSC and TGA-FTIR analysis. sPSB-SA samples
debated in water/chloroform solvent mixture produced micelles
of 200-300 nm highlighted by TEM analysis. The selective
staining with Pb(II) revealed the core-shell nature of the micelles,
exhibiting -SO H groups on the surface.
3
references:
1. a) Cuomo, C.; Serra, M. C.; Gonzalez Maupoey, M.;
Grassi, A.; Macromolecules, 2007, 40, 7089.
b) Buonerba, A.; Cuomo, C.; Speranza, V.; Grassi, A.;
Macromolecules, 2010, 43, 367.
Keywords: sulfonation; polyanion; Nanostructures; Block
copolymers;
Polymer chemistry – i
4 th EucheMs chemistry congress
o - 2 2 4
AMPhiPhiLiC CAtioniC CArBoSiLAne-PeG
dendriMerS: SyntheSiS And APPLiCAtionS in
Gene therAPy
J. SAnChez-nieveS 1 , P. frAnSen 2 , d. PuLido 3 ,
r. Lorente 4 , M. A. Munoz-fernández 4 , M. royo 3 ,
f. ALBeriCio 5 , r. GóMez 1 , f. J. de LA MAtA 1
1 Universidad de Alcalá, Inorganic Chemistry, Alcalá de
Henares (Madrid), Spain
2 Barcelona Science Park, Institute for Research in Biomedicine,
Barcelona, Spain
3 Barcelona Science Park, Combinatorial Chemistry Unit,
Barcelona, Spain
4 Hospital General Universitario Gregorio Maranón,
Laboratorio de Inmunología Molecular, Madrid, Spain
5 University of Barcelona, Organic Chemistry, Barcelona, Spain
The interest on treating diseases by gene therapy has clearly
bloomed as consequence of the increase knowledge on disease
molecular pathways and human genome. This method requires
guiding functional genetic material (plasmids, nucleic acids,
oligonucleotides) to the target cells. [1] Macromolecules, polymers
and nanosystems, which can be rationally designed, have been
employed as synthetic gene vectors. These vectors have to interact
with the nucleic acids, usually forming electrostatic complexes
compacting them and preventing their degradation. Thus, different
systems functionalized with cationic groups have been employed
for this objective. In the particular case of dendritic
macromolecules, their properties such as well defined size and
structure, flexibility, monodispersity and multivalency molecular
surface have attracted attention for biomedical applications. [2]
Carbosilane dendrimers present a hydrophobic framework.
The introduction of ammonium groups at the periphery turn them
water soluble and have been successfully tested as gene transfer
agents. [3] However, the major drawback of cationic dendrimers is
their intrinsic toxicity. An adequate procedure to overcome this
problem has been PEGylation of these systems, increasing also
the solubility of the macromolecule. [4]
We described here the synthesis of cationic amphiphilic
carbosilane-PEG dendrimers with ammonium groups via click
chemistry coupling of carbosilane (generation 1 to 3) and
PEG-based dendrons functionalized at the periphery with NHBoc
groups. The cationic heterodendrimers thus obtained have been
evaluated in gene therapy against HIV in Peripheral Blood
Mononuclear Cells, and their results compared with a carbosilane
homodendrimer.
references:
1. Verma, I. M.; Somia, N. Nature 1997, 389, 239.
2. Astruc, D.; Boisselier, E.; Ornelas, C. Chem. Rev. 2010,
110, 1857.
3. Bermejo, J. F.; Ortega, P.; Chonco, L.; Eritja, R.;
Samaniego, R.; Mullner, M.; de Jesús, E.; de la Mata, F. J.;
Flores, J. C.; Gómez, R.; Munoz-Fernández, A. Chem.
Eur. J. 2007, 13, 483.
4. Sousa-Herves, A.; Riguera, R.; Fernández-Megia, E.
New J. Chem. 2012, 36, 205.
Keywords: Dendrimers; Antiviral agents; Amphiphiles;
Cations;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc