@misc{ThielZehbeRoeseretal.2013, author = {Thiel, Kerstin and Zehbe, Rolf and Roeser, Jer{\^o}m{\´e} and Strauch, Peter and Enthaler, Stephan and Thomas, Arne}, title = {A polymer analogous reaction for the formation of imidazolium and NHC based porous polymer networks}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95118}, pages = {1848 -- 1856}, year = {2013}, abstract = {A polymer analogous reaction was carried out to generate a porous polymeric network with N-heterocyclic carbenes (NHC) in the polymer backbone. Using a stepwise approach, first a polyimine network is formed by polymerization of the tetrafunctional amine tetrakis(4-aminophenyl)methane. This polyimine network is converted in the second step into polyimidazolium chloride and finally to a polyNHC network. Furthermore a porous Cu(II)-coordinated polyNHC network can be generated. Supercritical drying generates polymer networks with high permanent surface areas and porosities which can be applied for different catalytic reactions. The catalytic properties were demonstrated for example in the activation of CO2 or in the deoxygenation of sulfoxides to the corresponding sulfides.}, language = {en} } @misc{InalKoelschSellrieetal.2013, author = {Inal, Sahika and K{\"o}lsch, Jonas D. and Sellrie, Frank and Schenk, J{\"o}rg A. and Wischerhoff, Erik and Laschewsky, Andr{\´e} and Neher, Dieter}, title = {A water soluble fluorescent polymer as a dual colour sensor for temperature and a specific protein}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95336}, pages = {6373 -- 6381}, year = {2013}, abstract = {We present two thermoresponsive water soluble copolymers prepared via free radical statistical copolymerization of N-isopropylacrylamide (NIPAm) and of oligo(ethylene glycol) methacrylates (OEGMAs), respectively, with a solvatochromic 7-(diethylamino)-3-carboxy-coumarin (DEAC)- functionalized monomer. In aqueous solutions, the NIPAm-based copolymer exhibits characteristic changes in its fluorescence profile in response to a change in solution temperature as well as to the presence of a specific protein, namely an anti-DEAC antibody. This polymer emits only weakly at low temperatures, but exhibits a marked fluorescence enhancement accompanied by a change in its emission colour when heated above its cloud point. Such drastic changes in the fluorescence and absorbance spectra are observed also upon injection of the anti-DEAC antibody, attributed to the specific binding of the antibody to DEAC moieties. Importantly, protein binding occurs exclusively when the polymer is in the well hydrated state below the cloud point, enabling a temperature control on the molecular recognition event. On the other hand, heating of the polymer-antibody complexes releases a fraction of the bound antibody. In the presence of the DEAC-functionalized monomer in this mixture, the released antibody competitively binds to the monomer and the antibody-free chains of the polymer undergo a more effective collapse and inter-aggregation. In contrast, the emission properties of the OEGMA-based analogous copolymer are rather insensitive to the thermally induced phase transition or to antibody binding. These opposite behaviours underline the need for a carefully tailored molecular design of responsive polymers aimed at specific applications, such as biosensing.}, language = {en} } @misc{LiBabuTurneretal.2013, author = {Li, Hongguang and Babu, Sukumaran Santhosh and Turner, Sarah T. and Neher, Dieter and Hollamby, Martin J. and Seki, Tomohiro and Yagai, Shiki and Deguchi, Yonekazu and M{\"o}hwald, Helmuth and Nakanishi, Takashi}, title = {Alkylated-C60 based soft materials}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95358}, pages = {1943 -- 1951}, year = {2013}, abstract = {Derivatization of fullerene (C60) with branched aliphatic chains softens C60-based materials and enables the formation of thermotropic liquid crystals and room temperature nonvolatile liquids. This work demonstrates that by carefully tuning parameters such as type, number and substituent position of the branched chains, liquid crystalline C60 materials with mesophase temperatures suited for photovoltaic cell fabrication and room temperature nonvolatile liquid fullerenes with tunable viscosity can be obtained. In particular, compound 1, with branched chains, exhibits a smectic liquid crystalline phase extending from 84 °C to room temperature. Analysis of bulk heterojunction (BHJ) organic solar cells with a ca. 100 nm active layer of compound 1 and poly(3-hexylthiophene) (P3HT) as an electron acceptor and an electron donor, respectively, reveals an improved performance (power conversion efficiency, PCE: 1.6 ± 0.1\%) in comparison with another compound, 10 (PCE: 0.5 ± 0.1\%). The latter, in contrast to 1, carries linear aliphatic chains and thus forms a highly ordered solid lamellar phase at room temperature. The solar cell performance of 1 blended with P3HT approaches that of PCBM/P3HT for the same active layer thickness. This indicates that C60 derivatives bearing branched tails are a promising class of electron acceptors in soft (flexible) photovoltaic devices.}, language = {en} } @misc{McQuadeO'BrienDoerretal.2013, author = {McQuade, D. Tyler and O'Brien, Alexander G. and D{\"o}rr, Markus and Rajaratnam, Rajathees and Eisold, Ursula and Monnanda, Bopanna and Nobuta, Tomoya and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Meggers, Eric and Seeberger, Peter H.}, title = {Continuous synthesis of pyridocarbazoles and initial photophysical and bioprobe characterization}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95214}, pages = {4067 -- 4070}, year = {2013}, abstract = {Pyridocarbazoles when ligated to transition metals yield high affinity kinase inhibitors. While batch photocyclizations enable the synthesis of these heterocycles, the non-oxidative Mallory reaction only provides modest yields and difficult to purify mixtures. We demonstrate here that a flow-based Mallory cyclization provides superior results and enables observation of a clear isobestic point. The flow method allowed us to rapidly synthesize ten pyridocarbazoles and for the first time to document their interesting photophysical attributes. Preliminary characterization reveals that these molecules might be a new class of fluorescent bioprobe.}, language = {en} } @misc{SchmidtHauke2013, author = {Schmidt, Bernd and Hauke, Sylvia}, title = {Cross metathesis of allyl alcohols}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95037}, pages = {4194 -- 4206}, year = {2013}, abstract = {Under standard conditions the cross metathesis of allyl alcohols and methyl acrylate is accompanied by the formation of ketones, resulting from uncontrolled and undesired double bond isomerization. By conducting the CM in the presence of phenol, the catalyst loading and the reaction time required for quantiative conversion can be reduced, and isomerization can be suppressed. On the other hand, consecutive isomerization can be deliberately promoted by evaporating excess methyl acrylate after completing cross metathesis and by adding a base or silane as chemical triggers.}, language = {en} } @misc{JungingerKuebelSchacheretal.2013, author = {Junginger, Mathias and K{\"u}bel, Christian and Schacher, Felix H. and M{\"u}ller, Axel H. E. and Taubert, Andreas}, title = {Crystal structure and chemical composition of biomimetic calcium phosphate nanofibers}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95176}, pages = {11301 -- 11308}, year = {2013}, abstract = {Calcium phosphate nanofibers with a diameter of only a few nanometers and a cotton-ball-like aggregate morphology have been reported several times in the literature. Although fiber formation seems reproducible in a variety of conditions, the crystal structure and chemical composition of the fibers have been elusive. Using scanning transmission electron microscopy, low dose electron (nano)diffraction, energy-dispersive X-ray spectroscopy, and energy-filtered transmission electron microscopy, we have assigned crystal structures and chemical compositions to the fibers. Moreover, we demonstrate that the mineralization process yields true polymer/calcium phosphate hybrid materials where the block copolymer template is closely associated with the calcium phosphate.}, language = {en} } @misc{EichSchmaelzlinLoehmannsroeben2013, author = {Eich, Susanne and Schm{\"a}lzlin, Elmar and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Distributed fiber optical sensing of oxygen with optical time domain reflectometry}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1085}, issn = {1866-8372}, doi = {10.25932/publishup-47665}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-476659}, pages = {16}, year = {2013}, abstract = {In many biological and environmental applications spatially resolved sensing of molecular oxygen is desirable. A powerful tool for distributed measurements is optical time domain reflectometry (OTDR) which is often used in the field of telecommunications. We combine this technique with a novel optical oxygen sensor dye, triangular-[4] phenylene (TP), immobilized in a polymer matrix. The TP luminescence decay time is 86 ns. The short decay time of the sensor dye is suitable to achieve a spatial resolution of some meters. In this paper we present the development and characterization of a reflectometer in the UV range of the electromagnetic spectrum as well as optical oxygen sensing with different fiber arrangements.}, language = {en} } @misc{MondalBhuniaBaburinetal.2013, author = {Mondal, Suvendu Sekhar and Bhunia, Asamanjoy and Baburin, Igor A. and J{\"a}ger, Christian and Kelling, Alexandra and Schilde, Uwe and Seifert, Gotthard and Janiak, Christoph and Holdt, Hans-J{\"u}rgen}, title = {Gate effects in a hexagonal zinc-imidazolate-4-amide-5-imidate framework with flexible methoxy substituents and CO2 selectivity}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94341}, pages = {7599 -- 7601}, year = {2013}, abstract = {A new imidazolate-4-amide-5-imidate based MOF, IFP-7, is generated, having flexible methoxy groups, which act as molecular gates for guest molecules. This allows highly selective CO2 sorption over N2 and CH4 gases.}, language = {en} } @misc{TheteRojasNeumeyeretal.2013, author = {Thete, Aniket and Rojas, Oscar and Neumeyer, David and Koetz, Joachim and Dujardin, Erik}, title = {Ionic liquid-assisted morphosynthesis of gold nanorods using polyethyleneimine-capped seeds}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95196}, pages = {14294 -- 14298}, year = {2013}, abstract = {Seed-mediated gold nanorods with tunable lengths are prepared using new polyethyleneimine-capped gold nanoparticles synthesized in ionic liquid. The effect of polyethyleneimine and ionic liquid during nanorod growth is investigated and shows a marked effect on their final aspect ratio.}, language = {en} } @misc{MenSiebenbuergerQiuetal.2013, author = {Men, Yongjun and Siebenb{\"u}rger, Miriam and Qiu, Xunlin and Antonietti, Markus and Yuan, Jiayin}, title = {Low fractions of ionic liquid or poly(ionic liquid) can activate polysaccharide biomass into shaped, flexible and fire-retardant porous carbons}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-95250}, pages = {11887 -- 11887}, year = {2013}, abstract = {Sugar-based molecules and polysaccharide biomass can be turned into porous functional carbonaceous products at comparably low temperatures of 400 °C under a nitrogen atmosphere in the presence of an ionic liquid (IL) or a poly(ionic liquid) (PIL). The IL and PIL act as "activation agents" with own structural contribution, and effectively promote the conversion and pore generation in the biomaterials even at a rather low doping ratio (7 wt\%). In addition, this "induced carbonization" and pore forming phenomenon enables the preservation of the biotemplate shape to the highest extent and was employed to fabricate shaped porous carbonaceous materials from carbohydrate-based biotemplates, exemplified here with cellulose filter membranes, coffee filter paper and natural cotton. These carbonized hybrids exhibit comparably good mechanical properties, such as bendability of membranes or shape recovery of foams. Moreover, the nitrogen atoms incorporated in the final products from the IL/PIL precursors further improve the oxidation stability in the fire-retardant tests.}, language = {en} }