4th EucheMs chemistry congress

Poster Session 1
s1032
chem. Listy 106, s587–s1425 (2012)
Poster session 1 - organic chemistry
P - 0 3 4 1
ContinuouS MetAtheSiS under
Liquid-Liquid ConditionS uSinG A diCAtioniC
ru-ALKyLidene in MonoLith-SuPPorted ioniC
LiquidS
B. Autenrieth 1 , w. frey 2 , M. r. BuChMeiSer 1
1 Stuttgart University, Institute of Polymer Chemistry, Stuttgart,
Germany
2 Stuttgart University, Institute of Organic Chemistry, Stuttgart,
Germany
Supported ionic liquid phase (SILP) catalysis has proven
valid for various reactions7 [1] . There, the catalyst is immobilized
within a thin layer of an ionic liquid, which is coating a highly
porous support material. We have developed a catalytic system
for continuous metathesis-reactions, based on porous ROMPderived
polymeric monoliths, whose structures can be varied
precisely with high reproducibility [2] . Following, the monoliths`
surface was functionalized by grafting an ammonium-based
monomer. Hereupon thin layers of the ionic liquid [BDMIM + BF4- ] were immobilized which contained the novel dicationic
Ru-alkylidene complex [Ru(DMF) (IMesH )(=CH-2-(2-PrO)-
3 2
-C H )] 6 4 2+ (BF4- ) ]. Beside the primary objective to gain
2
catalyst-free products, our concept enables continuous product
formation using two liquid phases, i.e. one supported and a second
continuous one, simply by cycling reactants through a monolithic
support containing a suitable catalyst dissolved in an ionic liquid.
Our catalytic system has proven valid for several biphasic (l-l),
continuous metathesis reactions at a multitude of different flow
rates and temperatures. For instance, the ring-closing-metathesis
(RCM) of neat 1,7-octadiene as well as the RCM of N,N-diallyl
trifluoroacetamide and diethyl diallyl malonate where heptane
served as non-polar mobile phase, have been investigated in
detail. Furthermore, the system was applied to the self-metathesis
of methyl oleate. High turnover numbers and an exceptionally low
catalyst leaching (≤ 0.1% with respect to the initial amount of
catalyst present in the IL phase) were observed. The fact, that a
biphasic liquid/liquid system is used definitely widens the range
of potentially accessible substrates. Moreover, the facile recycling
of the monolithic support by flushing with, e.g., methanol,
represents an additional advantage [3] .
references:
1. P. Wasserscheid, W. Keim, Angew. Chem. 2000, 112, 3926;
A. Riisager, R. Fehrmann, M. Haumann, P. Wasserscheid,
Topics Catal. 2006, 40, 91.
2. E. B. Anderson, M. R. Buchmeiser, ChemCatChem. 2012,
4, 30-44.
3. B. Autenrieth, W. Frey, M. R. Buchmeiser, submitted 2012.
Keywords: Metathesis; Ruthenium; Immobilization;
Mesoporous materials; Ionic liquids;
4 th EucheMs chemistry congress
P - 0 3 4 2
ShAPe-PerSiStent LineAr, KinKed,
And CyCLiC oLiGo(PhenyLene-ethynyLene-
-ButAdiynyLene)S: SeLf-ASSeMBLed
MonoLAyerS
A. ideLSon 1 , S. S. JeSter 1 , d. SChMitz 1 ,
f. eBerhAGen 1 , S. hÖGer 1
1 Rheinische Friedrich-Wilhelms-Universität Bonn, Kekulé-
Institut für Organische Chemie und Biochemie, Bonn,
Germany
Self-assembled monolayers (SAMs) of rigid oligomers,
particularly phenylene-ethynylene-butadiynylenes at the
HOPG/TCB interface, are studied by scanning tunneling
microscopy (STM) with submolecular resolution. Substitution of
the terminating acetylene functions of the linear oligomers with
polar 3-cyanopropyl dimethyl silyl groups leads to a 2D phase
separation and defined rod-rod interactions, which determine the
packing distances between the rigid rods. The results stimulated
the connection of rigid rods via septiarylene clamp units. They
covalently link two rigid rod units and define the intramolecular
rod-rod distance that matches the alkoxy substituent chain lengths.
The systems can be described as half-ring structures of two rigid
rods that are connected via a rotatable joint unit. These
acetylene-terminated half-ring structures are also oligomerized
under Cu and Pd catalysis to yield defined acyclic and cyclic
oligomers. Detailed STM studies decode the molecular origin of
the surface patterning of such systems. The dodecyloxy side
chains are adsorbed along the HOPG main axes and, together with
the alkoxy backbone angle, determine the adsorption direction of
the adlayers.
references:
1. S.-S. Jester, A. Idelson, D. Schmitz, F. Eberhagen, S. Höger,
Langmuir 2011, 27, 8205.
2. S.-S. Jester, N. Shabelina, S. M. Le Blanc, S. Höger,
Angew. Chem. Int. Ed. 2010, 49, 6101.
Keywords: self-assembled monolayers; scanning tunneling
microscopy; shape-persistent molecules; solid/liquid interface;
freely rotating chains;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc