4th EucheMs chemistry congress

thursday, 30-Aug 2012
s802
chem. Listy 106, s587–s1425 (2012)
organic Chemistry, Polymers – ii
frontiers and Advances of organic Chemistry – i
o - 4 9 0
nitroAroMAtiC exPLoSiveS SenSinG uSinG
non PorouS, nAno-orGAnized fLuoreSCent
oLiGoPhenyLeneethynyLene fiLMS: how
doeS it worK?
e. PASquinet 1 , t. CAron 1 , P. MontMeAt 1 ,
A. vAn der Lee 2 , r. PAnSu 3 , v. roueSSAC 2 ,
M. BouhAdid 1 , f. Serein-SPirAu 4 ,
J. P. Lere-Porte 4
1 CEA LE RIPAULT, Department of Explosives, Monts, France
2 IEM, Institut Européen des Membranes, Montpellier, France
3 ENS CACHAN, PPSM, Cachan, France
4 Institut Charles Gerhardt, ENSCM, Montpellier, France
The use of explosives in terrorist attacks has created a strong
demand for explosives vapor sensors that would be suitable for
suspicious luggage checking and forensic analysis. Fluorescence
quenching of phenyleneethynylene compounds by nitroaromatic
explosives is now a well-established method for sensing purposes.
A great deal of attention has been focusing on the design of
polymer structures incorporating sufficient porosity to allow
diffusion of the nitroaromatic molecules in the film. However,
some efficient non polymeric phenyleneethynylene derivatives
have been reported. For these compounds, a rationale explaining
their ability to detect nitroaromatic vapors is clearly lacking.
The crystal structures of films of two similar
phenyleneethynylene compounds displaying different behaviors
were investigated. The first, Di8, bearing diimine moieties, is very
sensitive to nitroaromatics but the second, unsubstituted
compound shows poor responses. First it was shown that both
non-porous films exhibited a high degree of crystallization and a
preferred orientation, and that the crystal structure was identical
in films or single crystals. Analysis of the very specific molecular
arrangement within the crystals revealed that the fluorescent
conjugated pi-structure of the non-responsive compound is highly
tilted from the surface so that it can hardly be accessed by
nitroaromatic vapors. On the contrary, the pi-structure of the
efficient compound Di8 is readily available since it is almost
parallel to the surface. This arrangement was also observed in
films of another related product that also exhibited excellent
sensing performances, thus consolidating the hypothesis.
Moreover, exciton migration within the films of Di8 was
clearly observed through time-resolved fluorescence experiments.
This explains how most of the fluorescence of these non-porous
films can be quenched even at very low concentrations of
nitroaromatic species.
Therefore, for the first time, structural data are provided on
organic thin films to better understand the structure/sensing ability
relationships for non porous phenyleneetynylene compounds.
Keywords: sensors; fluorescence; thin films; nanostructures;
supramolecular chemistry;
4 th EucheMs chemistry congress
frontiers and Advances of organic Chemistry – i
o - 4 9 1
redox-neutrAL Bio-CASCAde to AMineS froM
PriM-ALCohoLS
J. SAttLer 1 , M. fuChS 1 , K. tAuBer 1 , f. G. Mutti 1 ,
K. fABer 1 , J. Pfeffer 2 , t. hAAS 2 , w. KroutiL 1
1 Karl-Franzens-Universität Graz, Institute of organic and
bioorg. Chemistry, Graz, Austria
2 Evonik Industries AG, Creavis Technologies, Marl, Germany
While to transform primary alcohols to amines has been
vividly investigated for metal catalysts applying the so called
“borrowing hydrogen” methodology, [1–3] no such process has been
reported for primary alcohols employing biocatalytic methods.
A biocatalytic cascade was thus designed: In the first step
an alcohol dehydrogenase (ADH) [4, 5] catalyzed the oxidation of
the alcohol consuming NAD + leading to the formation of the
aldehyde and NADH.
In the second sequential simultaneous step, an
ω-transaminase (ω-TA) is doing the amination reaction
transferring the amine group from L-alanine to the aldehyde
creating pyruvate, which is recycled by an NADH-dependent
alanine dehydrogenase (AlaDH) using an ammonium salt as the
nitrogen source regenerating the cofactor as well as the amine
donor.
Acknowledgement: The research leading to these results has
received funding from the European Union’s Seventh
Framework Programme FP7/2007-2013 under grant agreement
no 245144 (AmBioCas) and Evonik.
references:
1. D. Pingen, C. Müller, D. Vogt, Angew. Chem. Int. Ed.
2010, 49, 8130.
2. S. Imm, S. Bähn, L. Neubert, H. Neumann, M. Beller,
Angew. Chem. Int. Ed. 2010, 49, 8126.
3. C. Gunanathan, D. Milstein, Angew. Chem. Int. Ed. 2008,
47, 8661.
4. T. Orbegozo, J. G. d. Vries, W. Kroutil, Eur. J. Org. Chem.
2010, 3445.
5. C. V. Voss, C. C. Gruber, K. Faber, T. Knaus, P.
Macheroux, W. Kroutil, J. Am. Chem. Soc. 2008, 130,
13969.
Keywords: amination; primary alcohols; biocatalysis; Nylon;
cascade reaction;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc