38317
2014
2014
eng
1481
1488
8
10
10
article
Royal Society of Chemistry
Cambridge
1
--
--
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Polyelectrolyte multilayers with perfluorinated phthalocyanine selectively entrapped inside the perfluorinated nanocompartments
A novel perfluorinated magnesium phthalocyanine (MgPcF64) was synthesized and employed to probe nanodomains in hydrophobically modified, amphiphilic cationic polyelectrolytes bearing alkyl and/or fluoroalkyl side chains. MgPcF64 was found to be solubilized exclusively in the aqueous solutions of the fluorocarbon modified polycations, occupying the perfluorinated nanocompartments provided, while analogous polyelectrolytes with alkyl side chains forming hydrocarbon nanocompartments could not host the MgPcF64 dye. Multilayer films were fabricated by means of the layer-by-layer (LbL) deposition method using sodium poly(styrene sulfonate) as a polyanion. Linear multilayer growth was confirmed by UV-Vis spectroscopy and spectroscopic ellipsometry. Atomic force microscopy studies indicated that the micellar conformation of the polycations is preserved in the multilayer films. Fluorescence spectroscopy measurements confirmed that MgPcF64 stays embedded inside the fluorocarbon domains after the deposition process. This facile way of selectively incorporating water-insoluble, photoactive molecules into the structure of polyelectrolyte multilayers may be utilized for nanoengineering of ultrathin film-based optoelectronic devices.
Soft matter
10.1039/c2sm26938d
24653994
1744-683X
1744-6848
wos:2014
WOS:000332461800005
Kopec, M (reprint author), Jagiellonian Univ, Fac Chem, PL-30060 Krakow, Poland., zapotocz@chemia.uj.edu.pl; nowakows@chemia.uj.edu.pl
Polish Ministry of Science and Higher Education [IdP2011 000561];
Foundation for Polish Science, Team Programme; EU European Regional
Development Fund (PolyMed) [TEAM/2008-2/6]; European Regional
Development Fund [POIG.02.01.00-12-023/08]; Deutsche
Forschungsgemeinschaft DFG [LA 611/6-2]
Maciej Kopec
Lukasz Lapok
André Laschewsky
Szczepan Zapotoczny
Maria Nowakowska
Institut für Chemie
Referiert
38313
2014
2014
eng
12981
12988
8
25
4
article
Royal Society of Chemistry
Cambridge
1
--
--
--
Improvement of wood material properties via in situ polymerization of styrene into tosylated cell walls
As an engineering material derived from renewable resources, wood possesses excellent mechanical properties in view of its light weight but also has some disadvantages such as low dimensional stability upon moisture changes and low durability against biological attack. Polymerization of hydrophobic monomers in the cell wall is one of the potential approaches to improve the dimensional stability of wood. A major challenge is to insert hydrophobic monomers into the hydrophilic environment of the cell walls, without increasing the bulk density of the material due to lumen filling. Here, we report on an innovative and simple method to insert styrene monomers into tosylated cell walls (i.e. -OH groups from natural wood polymers are reacted with tosyl chloride) and carry out free radical polymerization under relatively mild conditions, generating low wood weight gains. In-depth SEM and confocal Raman microscopy analysis are applied to reveal the distribution of the polystyrene in the cell walls and the lumen. The embedding of polystyrene in wood results in reduced water uptake by the wood cell walls, a significant increase in dimensional stability, as well as slightly improved mechanical properties measured by nanoindentation.
RSC Advances
10.1039/c4ra00741g
2046-2069
wos:2014
WOS:000332485000043
Burgert, I (reprint author), ETH, Inst Bldg Mat, Zurich, Switzerland., iburgert@ethz.ch
Max Planck Society, Germany; Bundesamt fur Umwelt (BAFU); Lignum,
Switzerland; SNF [NRP66]
Mahmut Ali Ermeydan
Etienne Cabane
Notburga Gierlinger
Joachim Koetz
Ingo Burgert
Institut für Chemie
Referiert
38311
2014
2014
eng
320
327
8
3
67
article
CSIRO
Clayton
1
--
--
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Intermediates in the formation and thermolysis of peroxides from oxidations with singlet oxygen
Herein we describe the recent mechanistic understandings of the singlet oxygen ene reaction to give hydroperoxides and the [4+2] cycloaddition affording endoperoxides. Both experimental findings and theoretical work conclude in the formation of intermediates structurally similar to perepoxides during the ene reaction. Such intermediates mainly control the regio- and stereoselectivities of this reaction class. For the [4+2] cycloaddition, both a synchronous concerted reaction (benzene, naphthalenes) and a stepwise reaction with a non-symmetric zwitterionic intermediate (larger acenes) have been found. The thermolysis of endoperoxides derived from acenes proceeds stepwise for anthracenes, but in a concerted manner for less stable adducts such as naphthalene.
Australian journal of chemistry
10.1071/CH13423
0004-9425
1445-0038
wos:2014
WOS:000332709400001
Linker, T (reprint author), Univ Potsdam, Dept Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany., linker@uni-potsdam.de
Werner Fudickar
Torsten Linker
Institut für Chemie
Referiert
38309
2014
2014
eng
6118
6128
11
13
16
article
Royal Society of Chemistry
Cambridge
1
--
--
--
Diffusion of finite-size particles in two-dimensional channels with random wall configurations
Diffusion of chemicals or tracer molecules through complex systems containing irregularly shaped channels is important in many applications. Most theoretical studies based on the famed Fick-Jacobs equation focus on the idealised case of infinitely small particles and reflecting boundaries. In this study we use numerical simulations to consider the transport of finite-size particles through asymmetrical two-dimensional channels. Additionally, we examine transient binding of the molecules to the channel walls by applying sticky boundary conditions. We consider an ensemble of particles diffusing in independent channels, which are characterised by common structural parameters. We compare our results for the long-time effective diffusion coefficient with a recent theoretical formula obtained by Dagdug and Pineda
Physical chemistry, chemical physics : a journal of European Chemical Societies
10.1039/c3cp55160a
24556939
1463-9076
1463-9084
wos:2014
WOS:000332474700029
Metzler, R (reprint author), Univ Potsdam, Inst Phys & Astron, D-14476 Potsdam, Germany., rmetzler@uni-potsdam.de
German Federal Ministry for Education and Research; Academy of Finland
within the FiDiPro scheme
Maximilian Bauer
Aljaz Godec
Ralf Metzler
Institut für Chemie
Referiert
38308
2014
2014
eng
6060
6067
8
13
16
article
Royal Society of Chemistry
Cambridge
1
--
--
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Photophysical evaluation of a new functional terbium complex in FRET-based time-resolved homogenous fluoroassays
A new functional luminescent lanthanide complex (LLC) has been synthesized with terbium as a central lanthanide ion and biotin as a functional moiety. Unlike in typical lanthanide complexes assembled via carboxylic moieties, in the presented complex, four phosphate groups are chelating the central lanthanide ion. This special chemical assembly enhances the complex stability in phosphate buffers conventionally used in biochemistry. The complex synthesis strategy and photophysical properties are described as well as the performance in time-resolved Forster Resonance Energy Transfer (FRET) assays. In those assays, this biotin-LLC transferred energy either to acceptor organic dyes (Cy5 or AF680) labelled on streptavidin or to quantum dots (QD655 or QD705) surfacefunctionalised with streptavidins. The permanent spatial donor-acceptor proximity is assured through strong and stable biotin-streptavidin binding. The energy transfer is evidenced from the quenching observed in donor emission and from a decrease in donor luminescence decay, both associated with simultaneous increase in acceptor intensity and in the decay time. The dye-based assays are realised in TRIS and in PBS, whereas QD-based systems are studied in borate buffer. The delayed emission analysis allows for quantifying the recognition process and for auto-fluorescence-free detection, which is particularly relevant for application in bioanalysis. In accordance with Forster theory, Forsterradii (R0) were found to be around 60 angstrom for organic dyes and around 105 angstrom for QDs. The FRET efficiency (Z) reached 80% and 25% for dye and QD acceptors, respectively. Physical donor-acceptor distances (r) have been determined in the range 45-60 angstrom for organic dye acceptors, while for acceptor QDs between 120 angstrom and 145 angstrom. This newly synthesised biotin-LLC extends the class of highly sensitive analytical tools to be applied in the bioanalytical methods such as time-resolved fluoroimmunoassays (TR-FIA), luminescent imaging and biosensing.
Physical chemistry, chemical physics : a journal of European Chemical Societies
10.1039/c3cp54883j
24556813
1463-9076
1463-9084
wos:2014
WOS:000332474700022
Cywinski, PJ (reprint author), Univ Potsdam, Inst Chem, Dept Phys Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany., piotr.cywinski@iap.fraunhofer.de
Marie Curie European Reintegration Grant QUANTUM<INF>DOT</INF>IMPRINT [PERG05-GA2009-247825]; FP7 Collaborative Project NANOGNOS-TICS [HEALTH-F5-2009-242264]
Piotr J. Cywinski
Katia Nchimi Nono
Loic J. Charbonniere
Tommy Hammann
Hans-Gerd Löhmannsröben
Institut für Chemie
Referiert
38288
2014
2014
eng
5441
5443
3
41
50
article
Royal Society of Chemistry
Cambridge
1
--
--
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A supramolecular Co(II)(14)- metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent
The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)(2.) 6H(2)O under solvothermal conditions in DMF, a MOF, IFP-8 and a hydrogen-bonded network consisting of tetradecanuclear Co(II)(14)-metal organic cube (1) are achieved. 1 shows the bcu net with 14 cobalt atoms.
Chemical communications
10.1039/c3cc49698h
24710036
1359-7345
1364-548X
wos:2014
WOS:000335333700005
Holdt, HJ (reprint author), Univ Potsdam, Inst Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany., holdt@uni-potsdam.de
Priority Program 1362 of the German Research Foundation on
"Metal-Organic Frameworks"
Suvendu Sekhar Mondal
Asamanjoy Bhunia
Alexandra Kelling
Uwe Schilde
Christoph Janiak
Hans-Jürgen Holdt
Institut für Chemie
Referiert
38286
2014
2014
eng
3536
3540
5
20
10
article
Royal Society of Chemistry
Cambridge
1
--
--
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Decoupling of ionic conductivity from structural dynamics in polymerized ionic liquids
Charge transport and structural dynamics in low molecular weight and polymerized 1-vinyl-3-pentylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquids (ILs) are investigated by a combination of broadband dielectric spectroscopy, dynamic mechanical spectroscopy and differential scanning calorimetry. While the dc conductivity and fluidity exhibit practically identical temperature dependence for the non-polymerized IL, a significant decoupling of ionic conduction from structural dynamics is observed for the polymerized IL. In addition, the dc conductivity of the polymerized IL exceeds that of its molecular counterpart by four orders of magnitude at their respective calorimetric glass transition temperatures. This is attributed to the unusually high mobility of the anions especially at lower temperatures when the structural dynamics is significantly slowed down. A simple physical explanation of the possible origin of the remarkable decoupling of ionic conductivity from structural dynamics is proposed.
Soft matter
10.1039/c3sm53202j
24718358
1744-683X
1744-6848
wos:2014
WOS:000335927400002
Sangoro, JR (reprint author), Univ Tennessee, Dept Chem & Biomol Engn, Knoxville, TN 37996 USA., jsangoro@utk.edu
Deutsche Forschungsgemeinschaft under the DFG SPP 1191 Priority Program
on Ionic Liquids; NSF Chemistry program [CHE-1213444]; University of
Potsdam for mass spectrometric investigation; Fraunhofer Institute for
Applied Polymer Research Potsdam-Golm
Joshia R. Sangoro
C. Iacob
A. L. Agapov
Yangyang Wang
Stefan Berdzinski
Hans Rexhausen
Veronika Strehmel
C. Friedrich
A. P. Sokolov
F. Kremer
Institut für Chemie
Referiert
38285
2014
2014
eng
3196
3203
8
21
2
article
Royal Society of Chemistry
Cambridge
1
--
--
--
A multilayered sulfonated polyaniline network with entrapped pyrroloquinoline quinone-dependent glucose dehydrogenase: tunable direct bioelectrocatalysis
A feasible approach to construct multilayer films of sulfonated polyanilines - PMSA1 and PABMSA1 containing different ratios of aniline, 2-methoxyaniline-5-sulfonic acid (MAS) and 3-aminobenzoic acid (AB), with the entrapped redox enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) on Au and ITO electrode surfaces, is described. The formation of layers has been followed and confirmed by electrochemical impedance spectroscopy (EIS), which demonstrates that the multilayer assembly can be achieved in a progressive and uniform manner. The gold and ITO electrodes subsequently modified with PMSA1:PQQ-GDH and PABMSA1 films are studied by cyclic voltammetry (CV) and UV-Vis spectroscopy which show a significant direct bioelectrocatalytical response to the oxidation of the substrate glucose without any additional mediator. This response correlates linearly with the number of deposited layers. Furthermore, the constructed polymer/enzyme multilayer system exhibits a rather good long-term stability, since the catalytic current response is maintained for more than 60% of the initial value even after two weeks of storage. This verifies that a productive interaction of the enzyme embedded in the film of substituted polyaniline can be used as a basis for the construction of bioelectronic units, which are useful as indicators for processes liberating glucose and allowing optical and electrochemical transduction.
Journal of materials chemistry : B, Materials for biology and medicine
10.1039/c4tb00336e
2050-750X
2050-7518
wos:2014
WOS:000336072400004
Sarauli, D (reprint author), Tech Univ Appl Sci Wildau, Inst Appl Life Sci, Hochschulring 1, D-15745 Wildau, Germany., david.sarauli@th-wildau.de; flisdat@th-wildau.de
BMBF, Germany [02IS2201I]
David Sarauli
Chenggang Xu
Birgit Dietzel
Burkhard Schulz
Fred Lisdat
Institut für Chemie
Referiert
38281
2014
2014
eng
3313
3321
9
6
16
article
Royal Society of Chemistry
Cambridge
1
--
--
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Fully biodegradable modification of wood for improvement of dimensional stability and water absorption properties by poly(epsilon-caprolactone) grafting into the cell walls
Materials derived from renewable resources are highly desirable in view of more sustainable manufacturing. Among the available natural materials, wood is one of the key candidates, because of its excellent mechanical properties. However, wood and wood-based materials in engineering applications suffer from various restraints, such as dimensional instability upon humidity changes. Several wood modification treatments increase water repellence, but the insertion of hydrophobic polymers can result in a composite material which cannot be considered as renewable anymore. In this study, we report on the grafting of the fully biodegradable poly(epsilon-caprolactone) (PCL) inside the wood cell walls by Sn(Oct)(2) catalysed ring-opening polymerization (ROP). The presence of polyester chains within the wood cell wall structure is monitored by confocal Raman imaging and spectroscopy as well as scanning electron microscopy. Physical tests reveal that the modified wood is more hydrophobic due to the bulking of the cell wall structure with the polyester chains, which results in a novel fully biodegradable wood material with improved dimensional stability.
Green chemistry : an international journal and green chemistry resource
10.1039/c4gc00194j
1463-9262
1463-9270
wos:2014
WOS:000336836100047
Ermeydan, MA (reprint author), Swiss Fed Inst Technol, Inst Bldg Mat, Zurich, Switzerland., iburgert@ethz.ch
Bundesamt fur Umwelt (BAFU); Lignum, Switzerland; Max Planck Society,
Germany; SNF [NRP66]
Mahmut Ali Ermeydan
Etienne Cabane
Philipp Hass
Joachim Koetz
Ingo Burgert
Institut für Chemie
Referiert
38277
2014
2014
eng
3626
3635
10
23
2
article
Royal Society of Chemistry
Cambridge
1
--
--
--
Multivalent grafting of hyperbranched oligo- and polyglycerols shielding rough membranes to mediate hemocompatibility
Hemocompatible materials are needed for internal and extracorporeal biomedical applications, which should be realizable by reducing protein and thrombocyte adhesion to such materials. Polyethers have been demonstrated to be highly efficient in this respect on smooth surfaces. Here, we investigate the grafting of oligo- and polyglycerols to rough poly(ether imide) membranes as a polymer relevant to biomedical applications and show the reduction of protein and thrombocyte adhesion as well as thrombocyte activation. It could be demonstrated that, by performing surface grafting with oligo-and polyglycerols of relatively high polydispersity (>1.5) and several reactive groups for surface anchoring, full surface shielding can be reached, which leads to reduced protein adsorption of albumin and fibrinogen. In addition, adherent thrombocytes were not activated. This could be clearly shown by immunostaining adherent proteins and analyzing the thrombocyte covered area. The presented work provides an important strategy for the development of application relevant hemocompatible 3D structured materials.
Journal of materials chemistry : B, Materials for biology and medicine
10.1039/c4tb00184b
2050-750X
2050-7518
wos:2014
WOS:000336851600008
Neffe, AT (reprint author), Helmholtz Zentrum Geesthacht, Inst Biomat Sci, Kantstr 55, D-14513 Teltow, Germany., axel.neffe@hzg.de; andreas.lendlein@hzg.de
Federal Ministry of Education and Research (BMBF) [1315696]
Axel T. Neffe
Maik von Rüsten-Lange
Steffen Braune
Karola Lützow
Toralf Roch
Klaus Richau
Anne Krüger
Tobias Becherer
Andreas F. Thünemann
Friedrich Jung
Rainer Haag
Andreas Lendlein
Institut für Chemie
Referiert