Inst. Chemie

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IR-spektroskopische Charakterisierung von organisch-funktionalisierten Monolagen und Immobilisierung von Peptiden auf Silizium Oberflächen

Borowski, Anne (2018)

Das Interesse an der Entwicklung und Forschung von Biosensoren hat sich in den letzten Jahren stetig gesteigert. Die Verwendung von optischen, auf SOI (silicon-on-isulator) basierenden Sensoren, bietet die Möglichkeit Protein-Ligand-Wechselwirkungen auf ihre thermodynamischen und kinetischen Eigenschaften zu untersuchen. Das Konzept von selbstassemblierten Monoschichten (SAMs) mit definierten o...

The inverse perovskite BaLiF3: single-crystal neutron diffraction and analyses of potential ion pathways

Wiedemann, Dennis ; Meutzner, Falk ; Fabelo, Oscar ; Ganschow, Steffen (2018)

Doped barium lithium trifluoride has attracted attention as component for scintillators, luminescent materials and electrodes. With lithium and fluoride, it contains two possibly mobile species, which may account for its ionic conductivity. In this study, neutron diffraction on oxide-containing BaLiF3 single-crystals is performed at up to 636.2°C. Unfortunately, ion-migration pathways could not...

At the Gates: The Tantalum-Rich Phase Hf3Ta2O11 and its Commensurately Modulated Structure

Wiedemann, Dennis ; Lüdtke, Tobias ; Palatinus, Lukáš ; Willinger, Elena ; Willinger, Marc G. ; Mühlbauer, Martin J. ; Lerch, Martin (2018)

Generic mixtures in the system (Zr,Hf)O2–(Nb,Ta)2O5 are employed as tunable gate materials for field-effect transistors. Whereas production processes and target compositions are well-defined, resulting crystal structures are vastly unexplored. In this study, we summarize the sparse reported findings and present the new phase Hf3Ta2O11 as synthesized via a sol–gel route. Its commensurately modul...

Studies on Herbicide Binding in Photosystem II Membrane Fragments from Spinach

Fromme, R. ; Renger, G. (1990)

The mechanism of atrazine binding and its modification by Chelex-100-induced Ca2+ depletion and proteolytic degradation by trypsin, was analyzed in PS II membrane fragments from spinach. It was found: 1) Chelex-100 treatment leads in a comparatively slow process (t1/2 = 5 - 10 min) to Ca2+ re moval from a site that is characterized by a high affinity as reflected by KD values of the order of 10...

The Flash Pattern of Photosynthetic Oxygen Evolution after Treatment with Low Concentrations of Hydroxylamine as a Function of the Previous S1/S0-Ratio Further Evidence that NH2OH Reduces the Water Oxidizing Complex in the Dark

Messinger, J. ; Pauly, S. ; Witt, H. T. (1991)

Flash induced oxygen evolution patterns of isolated PS II complexes from the cyanobacterium Synechococcus were measured with a Joliot-type electrode. By suitable preflash and dark adaptation procedures, samples were prepared in the state S1 (100%), as well as enriched in S0 (60% S0, 40% S,). After treatment with low concentrations of NH2OH (≤ 100 μм), the two flash patterns were identical. This...

Effect of Tentoxin on the Activation and on the Catalytic Reaction of Reconstituted H+-ATPase from Chloroplasts

Fromme, Petra ; Dahse, Ingo ; Gräber, Peter (1992)

The proton-translocating ATPase from chloroplasts, CF0F1, was isolated, purified and reconstituted into asolectin liposomes. The effect of the energy transfer inhibitor, tentoxin, on different functions of the enzyme was investigated. Tentoxin does not inhibit the nucleotide release during energization by a pH /ΔΨ jump, i.e. the activation of the enzyme is not influenced. ATP synthesis driven b...

1-[4-{1,1′,1″,1‴,1′′′′-(1,3-Cyclopentadien-1,2,3,4,5-pentayl)pentakis}]-(4,1-phenylen)-alkanone und -benzoesäure pentaalkylester und deren Natrium- und Thallium(I)-Komplexe

Schumann, Herbert ; Kucht, Homa ; Kucht, Andreas (1992)

Pentaphenylcyclopentadiene (1) reacts with acyl chlorides RC(O)Cl (R = CH3, C3H7, C5H11, C7H15) with formation of the corresponding [(cyclopentadiene pentayl)pentakis] (1,4-phenylene) alkanones C5H(C6H4C(O)R-4)5 (2a, 2c, 2d and 2e). 2 a reacts with KOCl in water/dioxane to yield C5Cl(C6H4C(O)OH-4)5 (3), which after reaction with C2H5OH and C5H11OH gives the pentaesters C5Cl(C6H4C(O)OR-4)5 (4b a...

Photosystem II: Thermodynamics and Kinetics of Electron Transport from QA- to QB(QB- ) and Deleterious Effects of Copper(II)

Renger, G. ; Gleiter, H. M. ; Haag, E. ; Reifarth, F. (1993)

Studies on thermodynamics and kinetics of electron transfer from QA- to QB(QB-) were performed by monitoring laser flash induced changes of the relative fluorescence emission as a function of temperature (220 K < T < 310 K) in isolated thylakoids and PS II membrane fragments. In addition, effects of bivalent metal ions on PS II were investigated by measuring conventional fluorescence induction ...

X-Ray Structural Analysis and Vibrational Spectra of Sodium Cysteine-S-sulfonate, +H3NCH(COO-)CH2S2O3Na • 3/2H2O [1]

Steudel, Ralf ; Albertsen, Angela ; Kustos, Monika ; Pickardt, Joachim (1993)

The title compound crystallizes orthorhombically (space group C 2221) with a = 797.0, b = 870.3 and c = 2739.0 pm. The anions are zwitterions which are heavily involved in intra- and intermolecular NH •••O and OH•••O hydrogen bonding. The two types of sodium cations are coordinated by six oxygen atoms each of which belongs to either SO3 groups (Na 2) or water molecules and SO3 groups (Na1). A s...

The Bishydridobis(tetrazol-1-yl)borate Anion, [H2B(CHN4)2]-: Synthesis and Structure of the First Tetrazolylborate

Janiak, Christoph ; Esser, Lothar (1993)

Potassium bishydridobis(tetrazol-1-yl)borate (1) has been synthesized from KBH4 and tetrazole and characterized spectroscopically. Its crystal structure has been determined. 1 crystallizes in the monoclinic space group P21/n with a = 537.8(2), b = 1703.5(9), c = 919.6(3) pm, β = 106.12(3)° and V = 809.4(6)· 106 pm3.

Metallkomplexe mit 1,4,7-Trithiacyclononan: Kristallstrukturen von [CdI2 · C6H12S3]2 und [Hg(C6H12S3)2](HgI3)2

Pickardt, Joachim ; Shen, Jing (1993)

Crystals of the complexes [CdI2 · C6H12S3]2 (1) and [Hg(C6H12S3)2](HgI3)2 (2) were obtained by diffusion of 1,4,7-trithiacyclononane (9 S 3) in ethanol into aqueous solutions of cadmium iodide and mercuric iodide/potassium iodide, resp. Both compounds crystallize monoclinically,1: space group P21/n, Z = 4, a = 1207.1(5), b = 909.9(2), c = 1240.3(7) pm, β = 92.59(9)°; 2: P21/c, Z = 2, a = 804.7(...

Kristallstruktur des „supramolekularen“ Silber(I)thiocyanat-Cyclam-Komplexes [Ag(SCN)·(C10H24N4)1/2]

Pickardt, Joachim ; Shen, Jing (1994)

Colourless crystals of the 1,4,8,11-tetraazacyclotetradecane (cyclam) silver(I) thiocyanate complex [Ag(SCN) · (C10H24N4)1/2] were obtained by diffusion of a solution of cyclam in ethanol into an aqueous solution of K[Ag(SCN)2], The crystals are tetragonal, space group P42/n, Z = 8, a = b - 1256.0(4), c = 1185.5(9) pm. The SCN groups act as μ3 ligands, the S atoms of two SCN groups bridge two n...

Kristallstruktur des „supramolekularen“ Quecksilber(II)chlorid-thiocyanat- Hexamethylentetramin-Addukts Hg(SCN)2 · 2HgCl2 · 2C6H12N4

Pickardt, Joachim ; Gong, Gill-Taik ; Röleke, Dietmar (1994)

Crystals of the adduct Hg(SCN)2 · 2HgCl2·2C6H12N4 were obtained from an aqueous solution containing 0.1 mol/l hexamethylenetetramine and 0.05 mol/l potassium thiocyanate and mercury(II) chloride. The compound crystallizes monoclinically; space group P21/n, a = 767.3(4), b = 1854.7(7), c = 872.5(7) pm, and β = 101.48(5)°. The structure consists of a net­work of chains -Cl-Hg-Cl-Hg- and -(Cl-Hg-)...

Kristallstruktur zweier Zinkthiocyanat-Hexamethylentetramin-Addukte, Zn(SCN)2 · (C6H12N4)2 und {Zn(SCN)2 · C6H12N4 · 2H2O}n, mit unterschiedlich koordinierten Zinkionen

Pickardt, Joachim ; Gong, Gill-Taik ; Wischnack, Sabine ; Steinkopff, Christina (1994)

Crystals of the adducts Zn(SCN)2 · (C6H12N4)2 (1), and {Zn(SCN)2 · C6H12N4 · 2H2O}n (2) were obtained by crystallization from aqueous solutions containing hexamethylenetetrami­ne, potassium thiocyanate and zinc nitrate or zinc sulfate, resp., under identical conditions, as two totally different products. 1 crystallizes orthorhombically, space group P nmm, Z = 2, a = 622.4(5), b = 1152.3(7), c =...

Kristallstrukturen der [2.2.2]Cryptate [Cd(cryptand 222)][CdCl4] und [Hg(cryptand 222)][Hg2Cl6] mit achtfach koordinierten Metallionen

Pickardt, Joachim ; Kühn, Britta (1994)

Reactions of [2.2.2]cryptand, 4,7,13,16,21,24-Hexaoxa-1,10-diazabicyclo-[8.8.8]hexacosane, (“cryptand 222”) with cadmium chloride and mercuric chloride yielded crystals of [Cd(cryptand 222)][CdCl4] (1) and [Hg(cryptand 222)][Hg2Cl6] (2). 1 crystallizes tetragonally, space group P42/n, Z = 4, a = 1239.8(2), c = 1801.2(8) pm; 2 is monoclinic, space group P2/n, Z = 2, a = 1060.3(3), b = 955.2(2), ...

Mößbauer-Untersuchung ferrimagnetischer Spinelle des Systems CdϰNi1-ϰFe2O4

Riedel, E. ; Prick, D. ; Wolska, E. (1994)

Room temperature Mößbauer spectra of ferrimagnetic spinels in the system Cdϰ2+Fe1-ϰ3+[Ni1-ϰ2+Fe1-ϰ3+]O4 have been interpreted using the polyhedron model which is based on six different environments at the A-site for the B-site Fe3+-ions. To each environment belongs one sextet with a characteristic magnetic splitting. An additional sextet is due to Fe3+-ions at the A-site.

Binuclear Manganese(III) Complexes as Electron Donors in D1/D2/Cytochrome b559 Preparations Isolated from Spinach Photosystem II Membrane Fragments

Allakhverdiev, S. I. ; Karacan, M. S. ; Somer, G. ; Karacan, N. ; Khan, E. M. ; Rane, S. Y. ; Padhye, S. ; Klimov, V. V. ; Renger, G. (1994)

The capability of different manganese complexes to act as PS II electron donors in D1/D2/ cytochrome b 559 complexes has been analyzed by measuring actinic light-induced absorption changes at 680 nm (650 nm) and 340 nm, reflecting the photoaccumulation of Pheophytin- (Pheo-) and the reduction of NADP+ respectively. The data obtained reveal: a) the donor capacity of synthetic binuclear Mn(III)2 ...

Mössbauer Studies of Nickel-Iron Hydrotalcites

Pegelow, U. ; Winterer, M. ; Mosel, B. D. ; Schmalz, M. ; Schöllhorn, R. (1994)

Hydrotalcite-like Fe-Ni-hydroxides [Ni2/3IIFe1/3III(OH)2](CO3)1/6(H2O)y , [Ni3/4IIFe1/4III(OH)2]-(CO3)1/8(H2O)y and [Ni3/4II/IIIFe1/4III(OH)2](CO3)0.14(H20)y as well as the ternary oxide NaNi2/3Fe1/3O2 have been studied by 57Fe-Mössbauer spectroscopy. All samples contain Fe3+ in a high spin state. The quadrupole interaction is smaller if a magnetic splitting is present, which may indicate a non...

Kristallstrukturen der „supramolekularen“ 1,4-Diazabicyclo[2.2.2]octan- Quecksilber(II)-Komplexe [Hg(dabco)I2] und [Hg(dabco)(SCN)2]

Pickardt, Joachim ; Shen, Jing ; Gong, Gill-Taik (1995)

Reactions of 1,4-diazabicyclo[2.2.2]octane (“dabco”) with K2[HgI4] or Hg(SCN)2 yield crystals of [Hg(dabco)I2] (1) and [Hg(dabco)(SCN)2] (2). 1 crystallizes monoclinically, space group P21/a. Z = 4, a = 1211.6(5), b = 682.3(6), c = 1430.4(3) pm, β = 98.90(5)°; 2 is orthorhombic, space group Pmmn, Z = 2, a - 740.5(3), b = 609.1(4), c = 1220.0(8) pm. In 1 HgI2 groups are connected by bridging dab...

Kristallstrukturen zweier Kupfer(II)-Cyclam-Komplexe: [{CuCl(C10N4H24)}2][CdCl4] und [Cu(C10N4H24)][CdCl3(H2O)2]Cl

Pickardt, Joachim ; Hoffmeister, Isabella (1995)

Crystals of both complexes were obtained by evaporation of the ethanol solvent. The crystals of [{CuCl(C10N4H24)}2][CdCl4] are tetragonal, space group I4̄2d, Z = 4, a = b = 1784.1(11), c = 1101.1(8) pm. Each copper atom is bonded to one cyclam ligand and two chlorine atoms which are acting as bridging ligands and connect the copper atoms to chains of distorted octahedra. Distorted tetrahedra of...