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Item Open Access Ein 1λ5, 3λ5, 5λ3-Triphosphabenzol-Derivat(1986) Fluck, Ekkehard; Becker, Gerd; Neumüller, Bernhard; Knebl, Robert; Heckmann, Gernot; Riffel, HeinzDie erste Ringverbindung mit (PC)3-Gerüst, die Titelverbindung 3, wurde wie unten skizziert hergestellt. Die 13C-NMR-Daten deuten auf einen hohen Ylid-Charakter der Gruppierung C4-P5-C6 hin.Item Open Access A 1λ5,3λ5,5λ3-triphosphabenzene derivative(1986) Fluck, Ekkehard; Becker, Gerd; Neumüller, Bernhard; Knebl, Robert; Heckmann, Gernot; Riffel, HeinzThe first ring compound containing the (P=C)3 skeleton, the title compound 3, was prepared as shown below. 13C-NMR data indicate a highly ylidic character of the C4-P5-C6 grouping.Item Open Access 1,2- and 1,3-diphosphetanes from alkylidenephosphines(1983) Becker, Gerd; Becker, Winfried; Uhl, Gudrun; Uhl, Werner; Wessely, Hans-JürgenAlkyl- or arylbis(trimethylsilyl)phosphines as well as tris(trimethylsilyl)phosphine and the corresponding arsines react with acyl chlorides to give [1-(trimethylsiloxy)alkylidene]phosphines 1 and -arsines 2; most of their 2,2-dimethylpropylidene derivatives are thermally stable at room temperature. With the same class of phosphines as starting compounds and carbon disulfide [bis(trimethylsilylsulfano)methylidene]phosphines 3 are formed, whereas [(dialkylamino)methylidene]-4 and [diarylmethylidene]phosphines 5 or the corresponding arsines 6 and 7 can be obtained from acyl amides or ketones.Item Open Access 1,3,5-Tris(dialkylamino)benzenes : model compounds for the electrophilic substitution and oxidation of aromatic compounds(1989) Effenberger, FranzAnionic σ complexes have been known and extensively studied as intermediates of nucleophilic aromatic substitution since the beginning of the century. In a paper that still makes fascinating reading, Meisenheimer describes the formation and isolation of anionic σ complexes by reaction of picryl ethers with potassium alkoxides. Structural proof is derived from the fact that identical σ complexes are obtained from methyl 2,4,6-trinitrophenyl ether with potassium ethoxide, and from ethyl 2,4,6-trinitrophenyl ether with potassium methoxide. Cationic σ complexes (Wheland intermediates), on the other hand, had been characterized or isolated only in a few cases: despite the ubiquitous implication of electrophilic aromatic substitution in synthesis. Such cationic u complexes were expected to be stabilized best by three amino substituents, in meta positions relative to each other! in analogy to the stabilization of anionic u complexes by three meta-oriented nitro groups.Item Open Access 1,3,5-Tris(dimethylamino)benzol mit Iod und 1,3,5-Tricyanobenzol : eine ungewöhnliche Dimerisierung und ein "normaler" Donor/Akzeptor-Komplex(1988) Keller, Heimo J.; Niebl, Roland; Renner, Gerd; Ruhr, Dorothea von der; Schweitzer, DieterWir sind auf der Suche nach "organischen" Ferromagneten. Als Zielsubstanz haben wir kristallisierte Radikal-Ionen mit bahnentarteten Grundzuständen ausgewählt. Molekulare Festkörper aus planaren organischen Radikalionen zeigen ein breites Spektrum teilweise recht interessanter physikalischer Eigenschaften, die durch kollektives Elektronenverhalten zu erklären sind. In den letzten Jahren wurde vor allem das elektrische Verhalten dieser Substanzen untersucht. Dies führte zur Entdeckung einer Vielzahl "organischer Metalle", von denen einige bei tiefer Temperatur auch supraleitend werden.Item Open Access 1,8-dipyrenylnaphthalenes : syntheses, molecular structure, and spectroscopic properties(1984) Wahl, Peter; Krieger, Claus; Schweitzer, Dieter; Staab, Heinz A.Syntheses of the 1,8-dipyrenylnaphthalenes 1-3 are reported. The stereoisomers 1 and 2 were separated; their structural assignment is based on 1H NMR, on the optical activity of 2, and on X-ray structure analyses of 1 and 2. Kinetic parameters for the isomerisation 2 = 1 were determined by optical rotation measurements. - Emission spectra of 1 - 3 are discussed in comparison to monopyrenyl compounds 4 and 8. For 1 and 3 typical 'excimer-like' fluorescence is observed. The difference between 1 and 2 clearly demonstrates the dependence of excimer interactions between the pyrene units on the mutual orientation of the π-systems involved. - On the basis of X-ray analyses the molecular structures of 1- 3 are discussed with emphasis on π···π-interactions between the pyrene units.Item Open Access 1.2-Thiazetidin-1-oxide aus Enoläthern mit N-Sulfinyl-sulfonamiden (Enoläther ; 4)(1966) Effenberger, Franz; Gleiter, RolfEnoläther reagieren mit N-Sulfinyl-sulfonamiden (4) schon bei 0° unter Cycloaddition zu N-substituierten 3-Alkoxy-1.2-thiazetidin-1-oxiden (7). Die Spaltung der Thiazetidine 7 mit Grignard-Verbindungen liefert β-Alkoxy-β-sulfonylamino-sulfoxide (8), die mit 2.4-Dinitrophenylhydrazin die Osazone 12 bilden.Item Open Access 10 Gb/s monolithic integrated MSM-photodiode AlGaAs/GaAs-HEMT optoelectronic receiver(1991) Hurm, Volker; Rosenzweig, Josef; Ludwig, Manfred; Benz, Willi; Osorio, Ricardo; Berroth, Manfred; Hülsmann, Axel; Kaufel, Gudrun; Köhler, Klaus; Raynor, Brian; Schneider, JoachimA photoreceiver based on a metal-semiconductor-metal (MSM) photodiode and AlGaAs/GaAs HEMTs is presented. The photoreceiver was fabricated using a 0.5-μm recessed-gate process for double delta-doped quantum-well HEMTs. The following mean values for the enhancement and depletion HEMT parameters, respectively, have been obtained: threshold voltages of 0.1 and -0.5 V, transconductances of 500 and 390 mS/mm, source resistances of 0.7 and 0.6 Ω-mm, and transit frequencies of 35 and 30 GHz. This process includes photodiodes. A deep wet etch was used to deposit the photodiodes on an undoped GaAs buffer layer.Item Open Access 10 Gbit/s monolithic integrated optoelectronic receiver using an MSM photodiode and AlGaAs/GaAs HEMTs(1991) Hurm, Volker; Rosenzweig, Josef; Ludwig, Manfred; Axmann, Albert; Benz, Willi; Berroth, Manfred; Osorio, Ricardo; Hülsmann, Axel; Kaufel, Gudrun; Köhler, Klaus; Raynor, Brian; Schneider, JoachimA 10 Gbit/s monolithic integrated optoelectronic receiver has been fabricated with a metal-semiconductor-metal (MSM) photodiode and enhancement/depletion 0.5 μm recessed-gate AlGaAs/GaAs HEMTs. A -3 dB bandwidth of 11.3 GHz has been achieved.Item Open Access A 10 V transfer standard based on low-noise solid-state Zener voltage reference ADR1000(2024) Bülau, André; Walter, Daniela; Zimmermann, AndréVoltage standards are widely used to transfer volts from Josephson voltage standards (JVSs) at national metrology institutes (NMIs) into calibration labs to maintain the volts and to transfer them to test equipment at production lines. Therefore, commercial voltage standards based on Zener diodes are used. Analog Devices Inc. (San Jose, CA, USA), namely, Eric Modica, introduced the ADR1000KHZ, a successor to the legendary LTZ1000, at the Metrology Meeting 2021. The first production samples were already available prior to this event. In this article, this new temperature-stabilized Zener diode is compared to several others as per datasheet specifications. Motivated by the superior parameters, a 10 V transfer standard prototype for laboratory use with commercial off-the-shelf components such as resistor networks and chopper amplifiers was built. How much effort it takes to reach the given parameters was investigated. This paper describes how the reference was set up to operate it at its zero-temperature coefficient (z.t.c.) temperature and to lower the requirements for the oven stability. Furthermore, it is shown how the overall temperature coefficient (t.c.) of the circuit was reduced. For the buffered Zener voltage, a t.c. of almost zero, and with amplification to 10 V, a t.c. of <0.01 µV/V/K was achieved in a temperature span of 15 to 31 °C. For the buffered Zener voltage, a noise of ~584 nVp-p and for the 10 V output, ~805 nVp-p were obtained. Finally, 850 days of drift data were taken by comparing the transfer standard prototype to two Fluke 7000 voltage standards according to the method described in NBS Technical Note 430. The drift specification was, however, not met.Item Open Access The 10th International Conference on Life Cycle Management 2021 : Stuttgart, Germany, September 05-08, 2021(2021) Fischer, Matthias; Barkmeyer, Mercedes; Albrecht, Stefan; Braune, Anna; Leistner, Philip; Seifert, Rainer; Kreissig, JohannesItem Open Access 11.6 Gbps 1:4 demultiplexer using double pulse doped quantum well GaAs/AlGaAs transistors(1991) Lang, Manfred; Nowotny, Ulrich; Berroth, ManfredAn ultrahigh speed 4 bit demultiplexer circuit has been developed and fabricated using a recessed gate process for enhancement and depletion transistors with 0.3 mu m gate length. First results show a data rate of 11.6 Gbit/s and a power consumption of 165 mW at 0.85 V supply voltage, including four 50 Omega buffers.Item Open Access 13C nuclear magnetic relaxation studies at 62 MHz(1971) Jaeckle, H.; Haeberlen, Ulrich; Schweitzer, DieterAn apparatus suitable to measure 13C relaxation times T1 and T2 in liquids at 62 MHz is described. The required field of 58 kG is generated by a superconducting magnet. Results of T1 measurements on a variety of liquids, including benzene, derivatives of benzene, saturated rings, CS2, and others are reported. They are discussed in terms of dipole-dipole interactions, spin-rotation interactions and anisotropic chemical shifts, the latter of which turn out to play only a minor role. Intramolecular dipole-dipole interactions are found to provide by far the most important spin-lattice relaxation mechanism, whenever protons are bound directly to the carbons under investigation, even when the samples contain dissolved oxygen.Item Open Access 14 GHz bandwidth MSM photodiode AlGaAs/GaAs HEMT monolithic integrated optoelectronic receiver(1993) Hurm, Volker; Ludwig, Manfred; Rosenzweig, Josef; Benz, Willi; Berroth, Manfred; Bosch, Roland; Bronner, Wolfgang; Hülsmann, Axel; Köhler, Klaus; Raynor, Brian; Schneider, JoachimA monolithic optoelectronic receiver consisting of an MSM photodiode and a two-stage amplifer has been fabricated using an enhancement/depletion 0.3 μm recessed-gate AlGaAs/GaAs HEMT process. The band-width of 14.3 GHz implies suitability for transmission rates of up 20 Gbit/s. The transimpendance is 670 Ω (into 50 Ω) and the projected sensitivity is 16.4 dBm (BER = 10 -9).Item Open Access 15 Gbit/s integrated laser diode driver using 0.3 μm gate length quantum well transistors(1992) Wang, Zhigong; Berroth, Manfred; Nowotny, Ulrich; Gotzeina, Werner; Hofmann, Peter; Hülsmann, Axel; Kaufel, Gudrun; Köhler, Klaus; Raynor, Brian; Schneider, JoachimAn integrated laser diode driver was realised using enhancement/depletion 0.3 μm recessed-gate AlGaAs/GaAs quantum well transistors. Fully-open eye diagrams were observed at bit rates up to 10 Gbit/s with 50 Ω loads. The maximum DC and modulation current were 25 and 45 mA, respectively. The power consumption is less than 450 mW.Item Open Access 16 x 16 bit parallel multiplier based on 6 K gate array with 0.3 μm AlGaAs/GaAs quantum well transistors(1992) Thiede, Andreas; Berroth, Manfred; Hurm, Volker; Nowotny, Ulrich; Seibel, Jörg; Gotzeina, W.; Sedler, Martin; Raynor, Brian; Köhler, Klaus; Hofmann, Peter; Hülsmann, Axel; Kaufel, Gudrun; Schneider, JoachimThe design and performance of a 16x16 bit parallel multiplier based on a 6 K gate array will be presented. This LSI semicustom IC demonstrates the high potential of the authors' AlGaAs/GaAs quantum well FETs with a gate length of 0.3 μm. The best multiplication time measured was 7.2 ns.Item Open Access 18 Gbit/s monolithically integrated 2:1 multiplexer and laser driving using 0.3 μm gate length quantum well HEMTs(1992) Wang, Zhigong; Nowotny, Ulrich; Berroth, Manfred; Bronner, Wolfgang; Hofmann, Peter; Hülsmann, Axel; Köhler, Klaus; Raynor, Brian; Schneider, JoachimA monolithically integrated 2:1 multiplexer and laser diode driver was developed, using AlGaAs quantum well HEMTs of 0.3 μm gate length. The DC and modulation current is 25 and 45 mA, respectively. Open eye diagrams were measured at bit rates up to 18 Gbit/s with pseudorandom data streams.Item Open Access An 18-34-GHz dynamic frequency divider based on 0.2-μm AlGaAs/GaAs/AlGaAs quantum-well transistors(1993) Thiede, Andreas; Berroth, Manfred; Nowotny, Ulrich; Seibel, Jörg; Bosch, Roland; Köhler, Klaus; Raynor, Brian; Schneider, JoachimThe design and performance of a dynamic frequency divider was presented. This digital IC demonstrates the ability of the authors' AlGaAs/GaAs/AlGaAs quantum-well FETs with gate lengths of 0.2 μm. Stable operation was achieved in the frequency range from 18 GHz up to 34 GHz with a power consumption of 250 mW. To the authors' knowledge, this is the best result ever reported for HEMT circuits, and is similar to the frequency limit achieved by use of AlGaAs/GaAs HBTs.Item Open Access 2′/3′ regioselectivity of enzyme‐free copying of RNA detected by NMR(2020) Motsch, Sebastian; Pfeffer, Daniel; Richert, ClemensThe RNA‐templated extension of oligoribonucleotides by nucleotides produces either a 3′,5′ or a 2′,5′‐phosphodiester. Nature controls the regioselectivity during RNA chain growth with polymerases, but enzyme‐free versions of genetic copying have modest specificity. Thus far, enzymatic degradation of products, combined with chromatography or electrophoresis, has been the preferred mode of detecting 2′,5′‐diesters produced in enzyme‐free reactions. This approach hinges on the substrate specificity of nucleases, and is not suitable for in situ monitoring. Here we report how 1H NMR spectroscopy can be used to detect the extension of self‐templating RNA hairpins and that this reveals the regioisomeric nature of the newly formed phosphodiesters. We studied several modes of activating nucleotides, including imidazolides, a pyridinium phosphate, an active ester, and in situ activation with carbodiimide and organocatalyst. Conversion into the desired extension product ranged from 20 to 90 %, depending on the leaving group. Integration of the resonances of H1′ protons of riboses and H5 protons of pyrimidines gave regioselectivities ranging from 40:60 to 85:15 (3′,5′ to 2′,5′ diester), but no simple correlation between 3′,5′ selectivity and yield. Our results show how monitoring with a high‐resolution technique sheds a new light on a process that may have played an important role during the emergence of life.Item Open Access 2(1H)-Pyridon als Austrittsgruppe bei Acylierungsreaktionen - Anwendungen in der Peptidchemie(1985) Effenberger, Franz; Brodt, WernerAlkyl-2-pyridylcarbonate 3 bzw. Gemische aus 3 und den isomeren N-(Alkoxycarbonyl)-2-pyridonen 3 eignen sich zur Einführung von Urethan-Schutzgruppen in Aminosäuren. Aus den N-geschützten Aminosäuren 7-10 lassen sich mit 2(1H)-Pyridon (1a) mittels der Carbodiimid-Methode 2-Pyridyl-Aktivester 11 synthetisieren, die in guten Ausbeuten mit Aminosäure-Estern 12 unter Abspaltung von 1a zu Peptiden 13 hoher optischer Reinheit kuppeln.