TY - JOUR A1 - Rudert, R. A1 - Schulz, Burkhard A1 - Reck, Günter A1 - Vollhardt, D. A1 - Kriwanek, J. T1 - (Carboxymethyl)dimethylundecylammonium bromide N2 - The title compound, C₁₅H₃₂NO₂⁺.Br⁻, crystallizes to form layers with interdigitating hydrocarbon chains stabilized by Br⁻۰۰۰H—O hydrogen bonds and Br⁻۰۰۰N⁺ contacts. KW - (Carboxymethyl)dimethylundecylammonium bromide KW - Crystal structure PY - 1995 DO - https://doi.org/10.1107/s0108270194011443 SN - 0108-2701 VL - 51 SP - 768 EP - 770 PB - Wiley-Blackwell CY - Oxford AN - OPUS4-56998 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Freyer, D. A1 - Reck, Günter A1 - Bremer, M. A1 - Voigt, W. T1 - Thermal behaviour and crystal structure of sodium-containing hemihydrates of calcium sulfate N2 - A metastable sodium-containing hemihydrate ((6-x)CaSO₄∙xNa₂SO₄∙3H₂O, 0≤x≤1) limited by the pentasalt composition Na₂SO₄∙5CaSO₄∙3H₂O occurs as an intermediate solid phase in the systems Na₂SO₄-CaSO₄-H₂O, NaCl-Na₂SO₄-CaSO₄-H₂O, and NaCl-CaSO₄-H₂O. X-Ray structure determination of a crystal with pentasalt composition results in a super-structure of the pure hemihydrate (CaSO₄∙0.5H₂O), in which one Ca²⁺ion is statistically replaced by two Na⁺ ions. One Na⁺ cation is situated in a Ca²⁺ position in only one of the three chains of CaSO₄ forming an axis of nearly three fold symmetry along the c-axis. The second Na⁺ is located in the water channel neighbouring to the first Na⁺. The hydrate crystallized in a monoclinic space group C121 (No. 5) with a=24.1781(11), b=13.805(2), c=12.7074(12) Å, β=90.089(12)°. The dehydration temperature of the hydrates depends on their Na⁺ ion content. A high Na⁺ content (in water channels) blocks the water escape strongly, and the dehydration temperature increases. Thermal behaviour is also effected by the crystal sizes. The thermograms of small crystals as opposed to large ones show a exothermic effect adjoining the endothermic dehydration. This may be indicative for a change in the dehydration mechanism upon crystal size. KW - Bassanite KW - Crystal structure KW - Sodium pentasalt KW - Calcium sulfate hemihydrate KW - Thermal analysis PY - 1999 DO - https://doi.org/10.1007/pl00010180 SN - 1434-4475 SN - 0026-9247 VL - 130 SP - 1179 EP - 1193 PB - Springer CY - Wien AN - OPUS4-61831 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vossmeyer, T. A1 - Reck, Günter A1 - Katsikas, L. A1 - Haupt, E. T. K. A1 - Schulz, Burkhard A1 - Weller, H. T1 - A "double-diamond superlattice" built up of Cd17S4(SCH2CH20H)26 clusters N2 - A simple preparation of Cd17S4(SCH2CH2OH)26 clusters in aqueous solution leads to the formation of colorless blocky crystals. X-ray structure determinations revealed a superlattice framework built up of covalently linked clusters. This superlattice is best described as two enlarged and interlaced diamond or zinc blende lattices. Because both the superlattice and the clusters display the same structural features, the crystal structure resembles the self-similarities known from fractal geometry. The optical spectrum of the cluster solution displays a sharp transition around 290 nanometers with a large Absorption coefficient (~84,000 per molar per centimeter). KW - superlattice KW - cluster KW - X-ray structure determination PY - 1995 DO - https://doi.org/10.1126/science.267.5203.1476 SN - 0036-8075 SN - 1095-9203 VL - 267 IS - 5203 SP - 1476 EP - 1479 PB - AAAS, American Association for the Advancement of Science CY - Washington, DC AN - OPUS4-44409 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Orgzall, I. A1 - Schulz, B. A1 - Dietzel, B. T1 - Two polymorphic forms of 2,5-bis(4-methoxycarbonylphenyl)-1,3,4-oxadiazole N2 - In the title compound, C13H14BN3O, the aziridine ring is an almost equilateral triangle, the C—C distance being slightly shorter than the C—N distances, probably because of the dative B—N bond. The five-membered ring, composed of two C atoms and N, B and O atoms, is fused with the aziridine ring to form a six-membered ring with a chair conformation. PY - 2003 DO - https://doi.org/10.1107/S0108270103022698 SN - 0108-2701 SN - 1600-5759 VL - 59 SP - o634 EP - o635 PB - Blackwell Publ. CY - Oxford AN - OPUS4-2694 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Becker, Roland T1 - Phenanthroline complexes of zinc and calcium carbamates N2 - Bis(N,N-di-n-butyl­di­thio­carbamato-?2S,S')(1,10-phenanthroline-?2N,N')­zinc(II) ethanol hemisolvate, [Zn(C9H18NS2)2(C12H8N2)]·0.5C2H6O, (I), and bis(N,N-di-n-hexyldithiocarbamato-?2S,S')­bis(1,10-phenanthroline-?2N,N')calcium(II), [Ca(C13H26NS2)2(C12H8N2)2], (II), are mixed-ligand com­plexes. In the first compound, the Zn atom has a distorted octahedral coordination, while in the second compound, the Ca atom is eight-coordinate, with four S and four N atoms forming a highly distorted cube. KW - X-ray structure analyses KW - Metal-organic complexes KW - Antioxidant properties PY - 2004 DO - https://doi.org/10.1107/S0108270104001441 SN - 0108-2701 SN - 1600-5759 VL - 60 SP - m134 EP - m136 PB - Blackwell Publ. CY - Oxford AN - OPUS4-3110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraus, Werner A1 - Stephan, H. A1 - Röllich, A. A1 - Matejka, Z. A1 - Reck, Günter T1 - K6H2[TiW11CoO40].13H2O, with a monotitanoundecatungstocobaltate(II) anion N2 - Hexapotassium dihydrogen monotitanoundeca­tungsto­cobalt­ate(II) trideca­hydrate, K6H2[TiW11CoO40]·13H2O, crystallizes from aqueous solution in the cubic space group P 3m. The structure was refined as an inversion twin. The [TiW11CoO40]8- anion has a Keggin structure with one W-atom site occupied by titanium and a central tetra­hedral CoO4 group. PY - 2005 DO - https://doi.org/10.1107/S1600536805005180 SN - 1600-5368 VL - 61 IS - 3 SP - i35 EP - i37 PB - Munksgaard CY - Copenhagen AN - OPUS4-7043 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hennig, C. A1 - Reich, T. A1 - Kraus, Werner A1 - Reck, Günter A1 - Prokert, F. A1 - Schell, N. T1 - Combining EXAFS and X-ray powder diffraction to solve structures containing heavy atoms N2 - Determination of structures using x-ray powder diffraction is complicated if the reflection intensities are mainly influenced by the scattering from heavy atoms and the atomic coordinates of light atoms remain uncertain. A method like EXAFS, which is sensitive to short range order, gives reliable atomic distances in the surroundings of heavy atoms with a precision of ±0.02 Å. The probability for obtaining the complete structure from x-ray powder diffraction increases if one includes parameters derived from EXAFS measurements as restraints during the procedure of structure solving. We demonstrate the potential of combining EXAFS and x-ray powder diffraction by solving the structure UO2[H2AsO4]2H2O. The procedure starts with the determination of space group and cell parameters from XRD powder data. In a second step the absolute values of the structure factor |F| are separated by iterating a decomposition formula. The heavy atom positions are determined by direct methods. In the third step atomic distances of coordination polyhedra are estimated using EXAFS. Subsequently, the complete coordination geometries around the heavy atoms including reliable distances are used as restraints in the structure solving and refinement procedure. PY - 2005 DO - https://doi.org/10.1238/Physica.Topical.115a00352 SN - 0031-8949 SN - 1402-4896 SN - 0281-1847 VL - T115 SP - 352 EP - 355 PB - IoP Publ. CY - Bristol AN - OPUS4-7378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reck, Günter T1 - Uric Acid Monohydrate a Nev Urinary Calculus Phase T2 - Tag der Chemie, Freie Universität Berlin CY - Berlin, Germany DA - 2005-06-08 PY - 2005 AN - OPUS4-7473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reck, Günter T1 - X-ray Structure Determination from Powder Diffraction Data by PowderCell T2 - Tag der Chemie, Freie Universität Berlin CY - Berlin, Germany DA - 2005-06-08 PY - 2005 AN - OPUS4-7474 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schiller, E. A1 - Kraus, Werner A1 - Reck, Günter A1 - Spies, H. A1 - Pietzsch, H.-J. T1 - [2-Carboxy-2,2',2''-nitrilotris(ethanethiolato)-kappa4N,S,S',S''](triphenyl-phosphine-kappaP)rhenium(III) acetone solvate N2 - The title compound, [Re(C7H12NO2S3)(C18H15P)]·C3H6O, crystallizes from a solution in chloro­form–acetone–cyclo­­hexane with enantiomers disordered equally over each mol­ecular site. Hydrogen bonds between the carbox­yl groups form dimers in the crystal structure. PY - 2005 DO - https://doi.org/10.1107/S1600536805018660 SN - 1600-5368 VL - 61 IS - 7 SP - m1373 EP - m1375 PB - Munksgaard CY - Copenhagen AN - OPUS4-7613 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schubert, G. A1 - Reck, Günter A1 - Jancke, Harald A1 - Kraus, Werner A1 - Patzelt, C. T1 - Uric acid monohydrate - a new urinary calculus phase N2 - In our laboratory more than 100,000 urinary calculi have been analysed since 1972. Amongst this huge sample, 15 specimens originating from a total of eight patients were observed showing similar characteristics but escaping unambiguous identification with any of the substances that have been described so far in urinary concrements. Therefore, the unknown substance was submitted to a more extended analytical regimen. Structural analysis by x-ray crystallography turned out to be most successful, identifying the unknown material as uric acid monohydrate. Uric acid monohydrate crystallizes in the monocline space group P21/c. Within the crystal, uric acid and water molecules form continuous layers by hydrogen bonds. This is in contrast to uric acid in its water free and its dihydrate forms, which both crystallize by forming 3-dimensional networks To the best of our knowledge , the existence of a monohydrate form of uric acid has not been reported so far. Accordingly, this is the first report on uric acid monohydrate as a urinary stone component. The frequency of only 0.015% in our survey indicates that uric acid monohydrate is rarely the main component in concrements, in contrast to uric acid and uric acid dihydrate with frequencies of 10% and 6%, respectively. The infrared spectrum of uric acid monohydrate is very similar to that of the other crystal forms of uric acid. Because of this similarity and its low frequency, uric acid monohydrate may have been overlooked as a component of urinary concrements. X-ray diffraction allows for better differentiation in routine stone analysis. All samples of uric acid monohydrate were found by solid state NMR spectroscopy to be highly contaminated by amorphous material. This material consisted of long aliphatic chains reminiscent of lipids and fatty acids, respectively. Concrements consisting of other forms of uric acid or urate lacked this amorphous component. Therefore, a role of this aliphatic material has to be taken into consideration when discussing the conditions that may favour the rare formation of concrements from uric acid monohydrate. As for as the metabolic situation of the affected patients is concerned, no common peculiarities became evident by a retrospective survey. KW - Uric acid monohydrate KW - Urinary calculus KW - Crystal structure KW - Solid state NMR KW - X-ray diffraction KW - Infrared spectroscopy PY - 2005 DO - https://doi.org/10.1007/s00240-005-0467-5 SN - 0300-5623 SN - 1434-0879 VL - 33 IS - 3 SP - 231 EP - 238 PB - Springer CY - Berlin AN - OPUS4-7676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brehme, R. A1 - Gründemann, E. A1 - Schneider, M. A1 - Radeglia, Reiner A1 - Reck, Günter A1 - Schulz, Burkhard T1 - Aza-enamines X - Formylation of Pyrazole-4-carbaldehyde Hydrazones at the Hydrazonoazomethine C-Atom N2 - 1,3-Disubstituted 1H-pyrazole-4-carbaldehyde-N,N-di­methylhydrazones 1 reacted with the Vilsmeier-Haackreagent, corresponding to the aza-enamine concept, in an electrophilicsubstitution reaction at the azomethine C-atom yielding the 1,4,5-triaza-pentadieniumsalts 2. These were hydrolysed to give2-hydrazono-2-(1H-pyrazole-4-yl)ethanals 3. The electrophilic attack did not takeplace at the vinylogous position 5' of the pyrazoles. KW - Aza-enamines KW - Hydrazones KW - Heterocycles KW - Formylation KW - Alpha-oxoethanals PY - 2003 DO - https://doi.org/10.1055/s-2003-40527 SN - 0039-7881 SN - 1437-210X IS - 10 SP - 1615 EP - 1619 PB - Thieme [u.a.] CY - Stuttgart AN - OPUS4-2617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brehme, R. A1 - Reck, Günter A1 - Schulz, Burkhard A1 - Radeglia, Reiner T1 - Synthesis and Reactions of (1E,2Z)-2-N,N-Dialkylhydrazono-2-phenylethanal N,N-Dimethylhydrazones N2 - (1E,2Z)-2-N,N-Dialkylhydrazono-2-phenylethanal N,N-dimethylhydrazones 3a-e weresynthesised by the reaction of 1,4,5-triazapentadienium salts 2 with N,N-dimethylhydrazine. The compounds 3a and 3d didnot react with tosyl isocyanate in an electrophilic substitutionreaction at the azomethine C-1 as aza-enamines, but they reactedat room temperature in benzene in a 1,4-dipolar cycloaddition toyield 1,3,5-triazinan-2,4-diones 5a and 5d, whereas at 70 °Coctahydroimidazoimidazol-2,5-dione 6a wasformed via criss-cross addition reaction. With dimethyl sulfatein DMF, 3a was transformed into the trimethylhydrazoniumsalts 7a and 8a,isolated as co-crystallised perchlorates (molar ratio 1:1). KW - Aza-enamines KW - Heterocycles KW - Hydrazonium salts KW - 1,4-dipolar cycloaddition KW - Criss-cross addition reaction PY - 2003 DO - https://doi.org/10.1055/s-2003-40528 SN - 0039-7881 SN - 1437-210X IS - 10 SP - 1620 EP - 1625 PB - Thieme [u.a.] CY - Stuttgart AN - OPUS4-2618 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Becker, Roland T1 - (N,N-Diiso­butyl­di­thio­carbamoyl­sulfinato)­zinc(II) N2 - Zinc di­alkyl di­thio­carbamoyl­sulfinates have been proposed as intermediates in the antioxidant action of the respective zinc di­alkyl di­thio­carbamate additives in hydro­carbon-based plastics and lubricants. As a model compound, zinc diiso­butyl di­thio­carbamoyl­sulfinate, [Zn(C9H18NO2S2)2], has been prepared and its crystal structure determined. PY - 2003 DO - https://doi.org/10.1107/S160053680301314X SN - 1600-5368 VL - 59 IS - 7 SP - m489 EP - m490 PB - Munksgaard CY - Copenhagen AN - OPUS4-2577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Orgzall, I. A1 - Schulz, B. T1 - 2,5-Di-p-tolyl-1,3,4-oxa­diazo­le N2 - The mol­ecule of the title compound, C16H14N2O, consists of two equivalent parts related by a twofold axis of the space group. The O atom occupies a special position on this twofold axis. PY - 2003 DO - https://doi.org/10.1107/S1600536803014867 SN - 1600-5368 VL - 59 IS - 8 SP - o1135 EP - o1136 PB - Munksgaard CY - Copenhagen AN - OPUS4-2609 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kraus, Werner A1 - Stephan, H. A1 - Reck, Günter T1 - Käfigstrukturen für den Einschluss von Pertechnetat und Perrhenat PY - 2004 SN - 0930-486X VL - 21 SP - 70 PB - Oldenbourg CY - München AN - OPUS4-3489 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aree, T. A1 - Reck, Günter A1 - Schulz, Burkhard T1 - Crystal Structures of ß-Cyclodextrin Complexes with Formic Acid and Acetic Acid N2 - ß-Cyclodextrin (ߖCD)-formic acid (1) and ß-CD–acetic acid (2) inclusion complexes crystallizeas ß-CD...0.3HCOOH...7.7H2O and ß-CD...0.4CH3COOH...7.7H2O in themonoclinic space group P21 with comparable unit cell constants. Anisotropic refinement of atomic parameters against X-ray diffractiondata with Fo 2 > 2 (Fo 2) (986/8563 and 991/8358) converged at R-factors of 0.051 and 0.054 for 1 and 2,respectively. In both complexes, the ß-CD molecularconformation, hydration pattern and crystal packing are similar,but the inclusion geometries of the guest molecules are different.The ß-CD macrocycles adopt a ``round'' conformationstabilized by intramolecular, interglucose O3(n)...O2(n + 1)hydrogen bonds and their O6–H groups are systematically hydratedby water molecules. In the asymmetric unit, each complex contains one ß-CD, 0.3 formic acid (or 0.4 acetic acid), and 7.7 water moleculesthat are distributed over 9 positions. Water sites located in the ß-CD cavity hydrogen bond to the guest molecule. In thecrystal lattice, ß-CD molecules are packed in a typical ``herringbone'' fashion. In 1, the formic acid (occupancy 0.3) is entirely included in the ß-CD cavity such that its C atom is shifted from the O4-plane center to the ß-CD O6-side by 2.90 Å and C=O, C–-O bonds point to this side. In 2, the acetic acid (occupancy 0.4) is completely embedded in the ß-CD cavity, in which the carboxylic C atom is displaced from the O4-plane centerto the ß-CD O6-side by 0.87 Å; the C=O bond directsto the ß-CD O6-side and makes an angle of 15°to the ß-CD molecular axis. Furthermore, bothdimethyl-ß-CD-acetic acid and ß-CD-acetic acidcomplexes form a cage structure, showing that the small guestsenclosed entirely in the cavity either in ß-CD or indimethyl--CD do not affect the packing of the host macrocycles. KW - Acetic acid KW - Crystal structures KW - Beta-cyclodextrin KW - Formic acid KW - Hydrogen bond KW - Inclusion complex KW - X-ray analysis PY - 2003 DO - https://doi.org/10.1023/B:JIPH.0000003923.92981.0f SN - 1388-3127 SN - 0923-0750 SN - 1573-1111 VL - 47 IS - 1-2 SP - 39 EP - 45 PB - Kluwer Academics Publishers CY - Dordrecht AN - OPUS4-3707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Stephan, H. A1 - Gloe, K. A1 - Kraus, Werner A1 - Spies, H. A1 - Johannsen, B. A1 - Wichmann, K. A1 - Reck, Günter A1 - Chand, D. K. A1 - Bharadwaj, P. K. A1 - Müller, U. A1 - Müller, W. M. A1 - Vögtle, F. ED - Moyer, B. A. T1 - Binding and extraction of pertechnetate and perrhenate by azacages T2 - Symposium Fundamentals and Applications of Anion Separations ; American Chemical Society national meeting CY - Chicago, IL, USA DA - 2001-08-25 PY - 2004 SN - 0-306-47911-7 SP - 151 EP - 168 PB - Kluwer Acad./Plenum Publ. CY - New York, NY AN - OPUS4-3667 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reck, Günter T1 - Growth and domain structure of PZN.PT crystals T2 - 2nd French-German Crystal Growth Meeting CY - Nancy, France DA - 2003-03-10 PY - 2003 AN - OPUS4-3752 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reck, Günter T1 - Uric Acid Monohydrate - a New Urinary Calculus Phase T2 - Jahrestagung der Deutschen Gesellschaft für Kristallographie (DGK) CY - Berlin, Germany DA - 2003-03-10 PY - 2003 AN - OPUS4-4887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bertram, R. A1 - Reck, Günter A1 - Alex, V. A1 - Uecker, R. T1 - Growth and domain structure of PZN-PT crystals T2 - 2nd French-German Crystal Growth Meeting (FGCGM - 2003) CY - Nancy, France DA - 2003-03-10 PY - 2003 AN - OPUS4-2129 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Becker, Roland T1 - Bis­[N-n-butyl-N-(3,5-di-tert-butyl-2-hydroxy­benzyl)­di­thio­carbamato-Kappa²S,S']zinc(II) N2 - Both zinc di­thio­carbamates and sterically hindered phenols are known to exhibit antioxidant activity. As part of an investigation on the effect of both moieties being combined in one mol­ecule, the title compound, [Zn(C17H26NOS2)2], has been prepared and its crystal structure determined. PY - 2003 DO - https://doi.org/10.1107/S1600536803007372 SN - 1600-5368 VL - 59 IS - 5 SP - m234 EP - m235 PB - Munksgaard CY - Copenhagen AN - OPUS4-2464 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Franco, O. A1 - Reck, Günter A1 - Orgzall, I. A1 - Schulz, Burkhard A1 - Schulz, B. T1 - Characterization of a new non-centrosymmetric polymorph of diphenyl-1,3,4-oxadiazole N2 - Diphenyl-1,3,4-oxadiazole (DPO) crystallization experiments from solutions clearly reveal the polymorphism of the substance. Besides the formerly known centrosymmetric monoclinic structure with space group P21/c (DPO I) a new monoclinic structure with the non-centrosymmetric space group Cc is found (DPO II): a=2.4134(4) nm, b=2.4099(3) nm, c=1.2879(2) nm,?=110.048(3)°, and V=7.0363(17) nm3. The asymmetric unit contains six independent molecules in a complex packing motif. A re-determination of the crystal structure of DPO I at room temperature gives lattice parameters a=0.51885(6) nm, b=1.8078(2) nm, c=1.21435(14) nm, ?=93.193(3)°, and V=1.1373(2) nm3. X-ray measurements at 363 K show a significant increase of the unit cell volume by 1.6%. Differences between both structures concerning morphology and characteristic Raman bands are outlined in detail. DSC investigations show an irreversible transition from DPO I to DPO II at 97 °C. DPO II does not show any transition in the temperature range up to the melting point at 141 °C. The non-centrosymmetric DPO II structure shows triboluminescence. KW - Diphenyl-1,3,4-oxadiazole KW - X-ray structure KW - Polymorphism KW - Non-centrosymmetric structure PY - 2003 DO - https://doi.org/10.1016/S0022-2860(02)00569-0 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 649 SP - 219 EP - 230 PB - Elsevier CY - Amsterdam AN - OPUS4-2465 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hennig, C. A1 - Reck, Günter A1 - Reich, T. A1 - Roßberg, A. A1 - Kraus, Werner A1 - Sieler, J. T1 - EXAFS and XRD investigations of zeunerite and meta-zeunerite N2 - In this paper EXAFS was used to determine bond lengths in the structures of zeunerite and meta-zeunerite. The atomic distances between heavy and light scatterers observed using EXAFS in meta-zeunerite deviate approximately 0.1 Å from literature data of single-crystal X-ray diffraction measurements. Because this difference is significant higher than the error limits of EXAFS measurements, the complete crystal structure of meta-zeunerite, Cu[UO2AsO4]2·8 H2O, is revised by X-ray structure analysis. The bond length determinations by EXAFS and the revised XRD data agree within the experimental error limits. In this study EXAFS spectroscopy has proven to be an useful tool for determining precise local bond lengths in the environment of heavy atoms. Moreover, the crystal structure of zeunerite, Cu[UO2AsO4]2·12 H2O, hitherto not been described in the literature, was investigated. Reflex broadening effects and intergrowth relationship between zeunerite and meta-zeunerite show that meta-zeunerite grows in nature due to dehydration of zeunerite. The structural transition from zeunerite to meta-zeunerite is connected with a change in the uranyl arsenate layer arrangement and the crystal water content. PY - 2003 DO - https://doi.org/10.1524/zkri.218.1.37.20776 SN - 0044-2968 VL - 218 IS - 1 SP - 37 EP - 45 PB - Oldenbourg CY - München AN - OPUS4-2291 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bertram, R. A1 - Reck, Günter A1 - Uecker, R. T1 - Growth and correlation between composition and structure of (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 crystals near the morphotropic phase boundary N2 - The correlation between composition and structure of unpoled relaxor ferroelectric (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO3 (PZN-PT) solid solutions around the morphotropic phase boundary was studied by Rietveld refinement of X-ray powder diffraction patterns of crystals with x=0.06–0.13 grown by a solution technique. It was found that PZN-PT exists with the rhombohedral structure only below x=0.06. The rhombohedral R3 m phase coexists with the tetragonal P4 mm phase between x=0.08 and 0.11 and above x=0.11 PZN-PT is purely tetragonal. In addition a metastable monoclinic phase (Pm) forms during cooling after crystal growth in the composition range x=0.06–0.11. The volume fraction of this monoclinic phase is a maximum in the most interesting composition range, i.e. x=0.08–0.09. The amount of monoclinic phase is enhanced further by mechanical treatment as the pulverization of the crystals for X-ray powder diffraction analysis which induces a tetragonal-to-monoclinic phase transition. KW - A1. Crystal structure KW - A1. Solid solutions KW - A1. X-ray diffraction KW - A2. Growth from high temperature solutions KW - B1. Perovskites KW - B2. Piezoelectric materials PY - 2003 DO - https://doi.org/10.1016/S0022-0248(03)00972-2 SN - 0022-0248 SN - 1873-5002 VL - 253 SP - 212 EP - 220 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-2538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Roland A1 - Reck, Günter A1 - Radeglia, Reiner A1 - Springer, A. A1 - Schulz, Burkhard T1 - Designed self-assembly of a bimolecular calix[4]resorcinarene capsule held together by hydrogen bonds N2 - The X-ray crystallographic study of the macrocyclic tetrakis-N[N-2-hydroxyethyl-piperazino]calix[4]resorcinarene·3CH3CH2OH·H2O (3) reveals a self-assembled dimeric capsule-like complex held together by an array of intermolecular hydrogen bonds. Pairs of concave molecules associate directly in bowl-to-bowl fashion and enclose an accessible supramolecular cavity of Å3 hosting one water and three ethanol molecules. The supramolecular arrangement displays alternating layers of facing bowls and interlocking lower rim aliphatic moieties. The helical conformation of the 2-hydroxyethyl piperazinomethyl moieties displays chirality of a bimolecular capsule frozen in the solid state. 3 crystallises in the triclinic space group P-1 with two symmetry independent molecules in the asymmetric unit. Two enantiomeric capsules form a racemic pair in the unit cell. KW - Hydrogen bonded molecular capsule KW - Conformational chirality KW - Calix[4]resorcinarenes KW - Crystal structure PY - 2006 DO - https://doi.org/10.1016/j.molstruc.2005.08.027 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 784 IS - 1-3 SP - 157 EP - 161 PB - Elsevier CY - Amsterdam AN - OPUS4-12241 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Becker, Roland A1 - Walther, G. T1 - Crystal structures of two polymorphic forms of bis-(zinc-dibutyldithiopercarbamate) PY - 1995 SN - 0044-2968 VL - 210 SP - 769 EP - 774 PB - Oldenbourg CY - München AN - OPUS4-14852 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Reck, Günter A1 - Kraus, Werner A1 - Orgzall, I. A1 - Schulz, B. T1 - Structure determination of two asymmetrically substituted oxadiazoles from powder diffraction data N2 - The crystal structures of the 1,3,4 oxadiazole compounds N,N-dimethyl-N-[4-(1,3,4-oxadiazol-2-yl)phenyl]amine (1) and 2-methyl-5-phenyl-1,3,4-oxadiazole (2) have been determined. In case of 1 no adequate crystals were available; therefore the structure was solved at room temperature from X-ray powder diffraction data using the method of simulated annealing. This solution is compared to a second one obtained by applying the molecular replacement method. Subsequent Rietveld refinements combined with the so called two stage method based on the data collected to 1.6 Å resolution yielded an Rwp value of 7.27% for 1. Compound 1 crystallizes in the orthorhombic space group P212121 with lattice parameters of a = 7.599(4) Å, b = 6.004(2) Å, c = 21.736(3) Å. The crystal structure of 2 was solved by means of single crystal structure analysis (monoclinic space group P21/c, a = 8.010(3) Å, b = 10.783(4) Å, c = 19.234(7) Å, β = 90.794(9)°). KW - Crystal structure KW - Oxadiazoles KW - Powder diffraction X-ray investigations KW - Structure determination PY - 2008 DO - https://doi.org/10.1002/crat.200711053 SN - 0023-4753 SN - 1521-4079 SN - 0232-1300 VL - 43 IS - 1 SP - 99 EP - 107 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-16582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Franco, O. A1 - Reck, Günter A1 - Orgzall, I. A1 - Schulz, B. T1 - Structure and high pressure behaviour of organic crystals based on aromatically substituted 1,3,4-oxadiazoles KW - C. High pressure KW - D. Equations-of-state KW - D. Crystal structure PY - 2002 SN - 0022-3697 VL - 63 SP - 1805 EP - 1813 PB - Pergamon Press CY - New York, NY AN - OPUS4-1555 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dushenko, G. A1 - Mikhailov, I. A1 - Reck, Günter A1 - Schulz, Burkhard A1 - Zschunke, Adolf A1 - Kharabaev, N. A1 - Minkin, V. T1 - Structure and Tautomerism of Cyclopentadiene Derivatives - IX. Synthesis and Structure of Substituted N-Cyclopentadienyl Amidinium Ylides N2 - A procedure has been developed for the synthesis of N-cyclopentadienyl amidinium ylides of the general formula C5(CO2Me)4[ArNC(Ar')NHAr]. According to the X-ray diffraction data, 1H and 13C NMR spectroscopy, and MNDO quantum-chemical calculations, the title compounds have a zwitterionic structure with the positive charge localized over the amidine NÄCÄN triad, and the negative charge, over the cyclopentadiene fragment. The configuration of the amidine moiety is stabilized by additional interaction of the NH hydrogen atom with the negatively charged cyclopentadiene ring (-bonding). The ylides are chiral due to atropoisomerism arising from a high energy barrier (G 298 >25 kcal/mol) to rotation of the Ar' substituent about the ordinary CÄC bond in the amidinium fragment. PY - 2002 DO - https://doi.org/10.1023/A:1020897411534 SN - 1070-4280 SN - 1608-3393 VL - 38 IS - 7 SP - 982 EP - 994 PB - MAIK Nauka/Interperiodica Publ. CY - Moscow AN - OPUS4-1556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Dähne, Siegfried A1 - Kirstein, S. A1 - v. Berlepsch, H. A1 - Böttcher, C. A1 - Burger, C. A1 - Ouart, A. T1 - Chiral J-aggregates formed by achiral cyanine dyes PY - 2000 UR - http://www3.interscience.wiley.com/cgi-bin/abstract/74500665/ABSTRACT DO - https://doi.org/10.1002/1439-7641(20001103)1:3<146::AID-CPHC146>3.0.CO;2-Y SN - 1439-4235 SN - 1439-7641 VL - 1 IS - 3 SP - 146 EP - 150 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shen, Z. A1 - Röhr, Holger A1 - Rurack, Knut A1 - Uno, H. A1 - Spieles, Monika A1 - Schulz, Burkhard A1 - Reck, Günter A1 - Ono, N. T1 - Boron-Diindomethene (BDI) Dyes and Their Tetrahydrobicyclo Precursors - en Route to a New Class of Highly Emissive Fluorophores for the Red Spectral Range N2 - The X-ray crystallographic, optical spectroscopic, and electrochemical properties of a newly synthesized class of boron-diindomethene (BDI) dyes and their tetrahydrobicyclo precursors (bc-BDP) are presented. The BDI chromophore was designed to show intensive absorption and strong fluorescence in an applicationary advantageous spectral range. Its modular architecture permits fusion of a second subunit, for example, a receptor moiety to the dye's core to yield directly linked yet perpendicularly prearranged composite systems. The synthesis was developed to allow facile tuning of the chromophore platform and to thus adjust its redox properties. X-ray analysis revealed a pronounced planarity of the chromophore in the case of the BDIs, which led to a remarkable close packing in the crystal of the simplest derivative. On the other hand, deviation from planarity was found for the diester-substituted bc-BDP benzocrown that exhibits a butterfly-like conformation in the crystal. Both families of dyes show charge- or electron-transfer-type fluorescence-quenching characteristics in polar solvents when equipped with a strong donor in the meso-position of the core. These processes can be utilized for signaling purposes if an appropriate receptor is introduced. Further modification of the chromophore can invoke such a guest-responsive intramolecular quenching process, also for receptor groups of low electron density, for example, benzocrowns. In addition to the design of various prototype molecules, a promising fluoroionophore for Na+ was obtained that absorbs and emits in the 650 nm region and shows a strong fluorescence enhancement upon analyte binding. Furthermore, investigation of the remarkable solvatokinetic fluorescence properties of the butterfly-like bc-BDP derivatives suggested that a second intrinsic nonradiative deactivation channel can play a role in the photophysics of boron-dipyrromethene dyes. KW - Charge KW - Transfer KW - Dyes/pigments KW - Electron transfer KW - Fluorescence KW - Farbstoffe KW - Chemosensoren KW - NIR-Bereich KW - Photophysik KW - Röntgenstrukturanalyse PY - 2004 DO - https://doi.org/10.1002/chem.200400173 SN - 0947-6539 SN - 1521-3765 VL - 10 SP - 4853 EP - 4871 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-4125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kovalchuck, Anton V. A1 - Bricks, Julia A1 - Reck, Günter A1 - Rurack, Knut A1 - Schulz, Burkhard A1 - Szumna, A. A1 - Weißhoff, Hardy T1 - A charge transfer-type fluorescent molecular sensor that "lights up" in the visible upon hydrogen bond-assisted complexation of anions PY - 2004 DO - https://doi.org/10.1039/b405207b SN - 0022-4936 SN - 0009-241x SN - 1359-7345 SN - 1364-548x SP - 1946 EP - 1947 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-4123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Bricks, J. L. A1 - Reck, Günter A1 - Schulz, Burkhard A1 - Spieles, Monika T1 - Cation coordination of bisamidopyridine-derived receptors as investigated in the solid-state and in solution N2 - A bisamidopyridine-type receptor, N,N'-bis(6-methyl-2-pyridyl)pyridine-2,6-dicarboxamide (1), and its CoIII complex were prepared and their X-ray structures were compared to those of N,N'-diphenylpyridine-2,6-dicarboxamide (2) and CoIII(2)2. Introduction of the two additional coordinative groups resulted in second-order interactions between the central ion and the nitrogen atoms of the terminal pyridine moieties in the crystalline state. Solution studies in acetonitrile revealed the importance of these interactions for the ligand's metal ion recognition ability. Whereas 2 only binds to PbII and CuII, 1 yields complexes with a majority of the heavy and transition metal ions studied, CoII, NiII, CuII, ZnII, FeIII, FeII, HgII, and PbII, respectively. The cation binding properties in solution were investigated by absorption spectroscopy and in the case of 1-MII/III, the formation of two spectroscopically distinguishable types of complexes was found. Protonation experiments and theoretical considerations helped to gain further insight into possible modes of coordination in solution. KW - Pyridine carboxamides KW - Ion recognition KW - Crystal structure KW - N-coordination PY - 2003 DO - https://doi.org/10.1080/1061027031000078239 SN - 1061-0278 SN - 1029-0478 VL - 15 IS - 3 SP - 189 EP - 197 PB - Gordon and Breach Science Publ. CY - New York, NY AN - OPUS4-2106 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Radeglia, Reiner A1 - Reck, Günter A1 - Schulz, Burkhard A1 - Resch-Genger, Ute A1 - Bricks, J. A1 - Sonnenschein, H. T1 - Reaction of a N-anthrylcarbonylthiourea derivative with Cu2+ or H+ - unusual rearrangement to a highly fluorescent S-(9-anthryl)-isothiouronium salt N2 - For the fluorescent ligand 1-(9-anthrylcarbonyl)-3,3-tetramethylenethiourea with Cu(ClO4)2 or strong acids an unusual rearrangement reaction occurred yielding a highly emissive S-(9-anthryl)isothiouronium salt. This rearrangement product was characterised by NMR spectroscopy and X-ray analysis as well as absorption and fluorescence spectroscopy. Additionally, the chemical and complexation behaviour of the N-anthrylcarbonylthiourea derivative is compared to that of its naphthyl and phenyl analogues. PY - 2000 DO - https://doi.org/10.1039/b000138o SN - 1472-779X IS - 6 SP - 1209 EP - 1214 PB - Royal Society of Chemistry CY - Cambridge AN - OPUS4-857 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reck, Günter A1 - Schulz, Burkhard A1 - Bricks, J. A1 - Li, Yanqin A1 - Resch-Genger, Ute T1 - Monoalkylated 4'-aryl-substituted terpyridines N2 - 1-Methyl-2-[4-phenyl-6-(pyridinium-2-yl)­pyridin-2-yl]­pyridinium diperchlorate, C22H19N32+·2ClO4-, (I), and 2-[4-(methoxy­phenyl)-2,2'-bipyridin-6-yl]-1-methyl­pyridinium iodide, C23H20N3O+·I-, (II), both crystallize in the monoclinic space group P21/c. In contrast with the monocharged mol­ecule of (II), the doubly charged mol­ecule of (I) contains an additional protonated pyridine ring. One of the two perchlorate counter-anions of (I) interacts with the cation of (I) via an N—HO hydrogen bond. In (II), two mol­ecules related by a centre of symmetry are connected by weak ?–? interactions, forming dimers in the crystal structure. KW - X-ray structure analysis KW - Fluorescent sensors KW - Molecular conformation KW - Intermolecular interactions PY - 2004 DO - https://doi.org/10.1107/S010827010400825X SN - 0108-2701 SN - 1600-5759 VL - 60 SP - o402 EP - o404 PB - Blackwell Publ. CY - Oxford AN - OPUS4-3563 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Schulz, Burkhard A1 - Reck, Günter A1 - Resch-Genger, Ute A1 - Bricks, J. A1 - Maus, M. T1 - Substituted 1,5-Diphenyl-3-benzothiazol-2-yl-Delta2-pyrazolines - Synthesis, X-ray Structure, Photophysics, and Cation Complexation Properties N2 - The spectroscopic properties of 1-phenyl-3-benzothiazol-2-yl-5-(4-R-phenyl)-2-pyrazolines are strongly dependent on both the electronic nature of the substituent R and solvent polarity. As revealed by spectroscopic studies as a function of solvent polarity as well as temperature, for electron-rich amino donor substituents in polar solvents, deactivation of the strongly emissive charge transfer (CT) state of the basic 1-phenyl-3-benzothiazol-2-yl-2-pyrazoline chromophore has to compete with a fast intramolecular electron transfer (ET) quenching reaction. In the case of the dimethylamino derivative (R = DMA), the rate constant of ET in acetonitrile was determined to ket = 3 × 1010 s-1. This ET process can be utilized for metal ion sensing by introducing nitrogen containing aza crown ether receptor units to the 4-position of the 5-phenyl group. The spectroscopically determined ET rates of the 5-(N-alkyl)anilino substituents, a DMA, a tetrathia- (AT415C5), and a tetraoxa-monoaza-15-crown-5 (A15C5) group, correlate with electrochemical data and increase in the order AT415C5 < A15C5 < DMA. The metal ion sensing abilities of the two crowned derivatives are presented, and the different signaling mechanisms include binding to the crown ether in the 4-R-position, chelate formation in the 3-benzothiazol-2-yl-2-pyrazoline moiety, and electrophotochemical detection. Furthermore, the rigid "pseudo spiro" geometry of the molecules, which holds the three substituents of the central 2-pyrazoline ring in a fixed prearrangement, was confirmed by X-ray structure analysis. KW - Farbstoff KW - Fluoreszenz KW - Kationen KW - Photophysik PY - 2000 DO - https://doi.org/10.1021/jp993404q SN - 1089-5639 SN - 1520-5215 VL - 104 IS - 26 SP - 6171 EP - 6188 PB - Soc. CY - Washington, DC AN - OPUS4-841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rurack, Knut A1 - Bricks, J. L. A1 - Reck, Günter A1 - Radeglia, Reiner A1 - Resch-Genger, Ute T1 - Chalcone-analogue dyes emitting in the near-infrared (NIR) - influence of donor-acceptor substitution and cation complexation on their spectroscopic properties and X-ray structure N2 - The photophysical properties of several newly synthesized 1-benzothiazole-3-(4-donor)-phenyl-substituted prop-2-en-1-ones (substituted chalcones) are studied as a function of solvent polarity, temperature, and metal ion by employing steady-state and time-resolved spectroscopy. To investigate the effect of bulkiness and donor strength of the anilino moiety on the spectroscopic properties of these dyes, the spectroscopic behavior of the 4-N-dimethylamino (DMA), the 4-N-tetraoxa-monoaza-15-crown-5 (A15C5), and the 4-N-tetrathia-monoaza-15-crown-5 (AT415C5) derivatives as well as the 3-julolidino (Jul) analogue is compared. Absorption and fluorescence measurements reveal that the strength of the intramolecular charge transfer (ICT) process increases on the order of AT415C5 < A15C5 ~ DMA < Jul. The slight but significant differences between the two crowned dyes are well-supported by the results of the X-ray structure analysis, where oxa aza and thia aza crowns show essentially different geometries. For both fluoroionophores, this variation of heteroatom substitution pattern of the receptor induces specific cation selectivities. The spectroscopic effects accompanying complexation and the different binding sites are studied by steady-state and time-resolved optical spectroscopy as well as NMR spectroscopy. Whereas the probe carrying a tetraoxa monoaza 15-crown-5 receptor shows cation-induced fluorescence enhancement in the presence of alkali and alkaline-earth metal ions, its tetrathia analogue binds selectively to HgII, AgI, and CuII in acetonitrile. Moreover, an increase in fluorescence is observed for the latter probe even upon coordination to the widely known fluorescence quencher HgII. Besides receptor complexation, chelate formation in the benzothiazole-carbonyl acceptor part of these intrinsic fluorescent probes is possible, leading to a chromoionophoric signaling behavior in the near-infrared (NIR). PY - 2000 DO - https://doi.org/10.1021/jp994269k SN - 1089-5639 SN - 1520-5215 VL - 104 IS - 14 SP - 3087 EP - 3109 PB - Soc. CY - Washington, DC AN - OPUS4-2088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - López, J.P. A1 - Kraus, Werner A1 - Reck, Günter A1 - Thünemann, Andreas A1 - Kurth, D.G. T1 - Alternating perpendicular 1-D channels in the supramolecular structure of the copper(II) complex [Cu(pyterpy)2](PF6)2 . CH3OH . 0.5 CH2Cl2 (pyterpy = 4'-(4'''-pyridyl)-2,2':6',2''-terpyridine) KW - 4´-(4´´´-pyridyl)-2,2´:6´2´´-terpyridine KW - Copper complexes KW - Crystal structure KW - Supramolecular chemistry KW - Pi-pi stacking PY - 2005 SN - 1387-7003 VL - 8 SP - 281 EP - 284 PB - Elsevier CY - Amsterdam AN - OPUS4-6301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - López, J.P. A1 - Kraus, Werner A1 - Reck, Günter A1 - Thünemann, Andreas A1 - Kurth, D.G. T1 - Synthesis, structure and reactivity of the homoleptic iron(II) complex of the novel 4'-(4'''-pyridyl-N-oxide)-2,2':6',2''-terpyridine ligand N2 - The new ligand 4´-(4´´´-pyridyl-N-oxide)-2,2´:6´,2´´-terpyridine (pyNoxterpy) and its homoleptic iron(II) complex have been synthesised, and structural and spectroscopic studies have been carried out. The obtained results have been compared with the reported data for the parent ligand 4´-(4´´´-pyridyl)-2,2´:6´,2´´-terpyridine (pyterpy) and its homoleptic iron(II) complex. Significant differences between the spectral and electrochemical properties of the metal complexes have been found, derived from the changes in the electronic properties of the coordinated ligands. KW - Terpyridine KW - Pyridine N-oxide KW - Iron complexes KW - Crystal structure PY - 2005 SN - 0020-1693 SN - 1873-3255 VL - 358 IS - 12 SP - 3384 EP - 3390 PB - Elsevier Sequoia CY - Lausanne AN - OPUS4-10908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Orgzall, I. A1 - Dietzel, B. A1 - Schulz, Burkhard A1 - Reck, Günter A1 - Schulz, B. T1 - Structural studies on trifluoromethyl substituted 2,5-diphenyl-1,3,4-oxadiazoles N2 - Three new compounds have been synthesized based on the molecular motif 2-[2,6-bis(trifluoromethyl)phenyl]-5-phenyl-1,3,4-oxadiazole, with subsequent CF3-substitution in the ortho-positions of the phenylene ring. The crystal structures of the compounds have been determined by single crystal X-ray diffraction. All compounds have a monoclinic structure. The solid state structure of the compounds is influenced by the electronic properties of the fluorine atoms, leading to the occurrence of C–H...F, and C–F...ϖ interactions, partly replacing ϖ–ϖ interactions usually observed in the crystal structures of 2,5-diphenyl-1,3,4-oxadiazole derivatives. Other significant interactions than those involving fluorine appear only in rare cases. The strong impact of the fluorine atoms on the intra- and intermolecular interactions, and the molecular conformation lead to novel inputs for the understanding of molecular recognition, supramolecular assembly, and crystal packing of fluorine containing compounds. KW - Crystal structure KW - 1,3,4-oxadiazole KW - Molecular conformation KW - Weak interactions PY - 2007 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 832 IS - 1-3 SP - 124 EP - 131 PB - Elsevier CY - Amsterdam AN - OPUS4-14644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tuchalski, G. A1 - Emmerling, Franziska A1 - Gröger, K. A1 - Hänsicke, A. A1 - Nagel, T. A1 - Reck, Günter T1 - X-ray investigations of nebivolol and its isomers N2 - The molecular and crystal structures of the hydrochlorides of d-nebivolol, dl-nebivolol, and seven nebivolol isomers have been determined by X-ray structure analysis. The absolute configuration of all the compounds could be determined unambiguously using anomal dispersion effects. Two compounds, dl-nebivolol (NEB-1d,l) and the (S,R,S,R) nebivolol isomer (NEB-6), crystallize as racemic mixtures in the centrosymmetric space group P-1. d-Nebivolol and six nebivolol isomers crystallize in space group P212121. The d- and l-nebivolol molecules in NEB-1d and NEB-1d,l adopt a conformation which is significantly different compared with that of all nebivolol isomers. With the exception of dl-nebivolol (NEB-1d,l) numerous intermolecular hydrogen bonds connect the molecules forming molecular layers. KW - X-ray crystal structure KW - Nebivolol PY - 2006 DO - https://doi.org/10.1016/j.molstruc.2006.03.086 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 800 IS - 1-3 SP - 28 EP - 44 PB - Elsevier CY - Amsterdam AN - OPUS4-13800 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Meißner, T. A1 - Bergmann, R. A1 - Oswald, J. A1 - Rode, K. A1 - Stephan, H. A1 - Richter, W. A1 - Zänker, H. A1 - Kraus, Werner A1 - Emmerling, Franziska A1 - Reck, Günter T1 - Chitosan-encapsulated Keggin anion [Ti2W10PO40]7-.Synthesis, characterization and cellular uptake studies N2 - The Keggin type polyoxotungstate [Ti2W10PO40]7- forms stable associates with the biopolymer chitosan in the nanometer size range. The cluster compound crystallizes from aqueous solution as K4H3[Ti2W10PO40] · 15H2O having a tetragonal structure. Both, the cluster compound and the chitosan/[Ti2W10PO40] associates show a high hydrolytic stability at pH 7.4. The associates formed between the cluster anion [Ti2W10PO40]7- with the polyaminosaccharide chitosan have been characterized by photon correlation spectroscopy, scanning electron microscopy, filtration, centrifugation and zeta potential measurements. The size of the associates formed is in the range of ca. 5×101 to 5×102 nm. These particles have a defined stoichiometry with 5–6 cluster anions bound per molecule chitosan. The isoelectric point determined by zeta potential measurements was found for a cluster anion to chitosan molar ratio of 5.5, indicating the charge neutralization between protonated chitosan and [Ti2W10PO40]7- anions. Cellular uptake studies with [Ti2W10PO40]7- using tumor cell lines FaDu (human squamous carcinoma) and HT-29 (human adenocarcinoma) showed that the tungsten amount inside the cells is remarkably enhanced in the presence of chitosan. KW - Cluster compound KW - Keggin structure KW - Bipolymer KW - Chitosan PY - 2006 DO - https://doi.org/10.1007/s11243-006-0035-z SN - 0340-4285 SN - 1572-901X VL - 31 IS - 5 SP - 603 EP - 610 PB - Springer CY - Dordrecht AN - OPUS4-12568 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Orgzall, I. A1 - Reck, Günter A1 - Schulz, Burkhard A1 - Stockhause, S. A1 - Schulz, B. T1 - Structures of substituted di-aryl-1,3,4-oxadiazole derivatives: 2,5-bis(pyridyl)- and 2,5-bis(aminophenyl)-substitution N2 - Crystal structures of four different di-aryl-1,3,4-oxadiazole compounds (aryl = 2-pyridyl-, 3-pyridyl-, 2-aminophenyl-, 3-aminophenyl-) are determined. Crystallization of di(2-pyridyl)-1,3,4-oxadiazole yielded monoclinic and triclinic polymorphs. The structures are characterized by the occurrence of π–π interactions. Additionally, in case of the aminophenyl compounds intra- as well as intermolecular hydrogen bonds are found that influence the packing motif as well. Since these molecules are often used as ligands in metal–organic complexes similarities and differences of the molecular conformation between the molecules in the pure crystals and that of the ligands in the complexes are discussed. KW - Crystal structure KW - 1,3,4-Oxadiazole KW - Molecular conformation KW - Hydrogen bonds PY - 2006 DO - https://doi.org/10.1016/j.molstruc.2006.03.076 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 800 IS - 1-3 SP - 74 EP - 84 PB - Elsevier CY - Amsterdam AN - OPUS4-13799 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Bricks, J. L. A1 - Resch-Genger, Ute A1 - Kraus, Werner A1 - Schulz, Burkhard A1 - Li, Yanqin A1 - Reck, Günter T1 - Influence of the donor substituent and acceptor alkylation on the structure-analytical properties of mono- and bifunctional biphenyl-type fluorescent reporters N2 - A systematic structural investigation of R-phenyl-substituted 2,2':6',2"-terpyridines, a family of mono- and bifunctional charge transfer (CT)-operated fluorescent reporters for protons and metal ions, is presented. These molecules are equipped with non-binding and analyte coordinating donor substituents R (R = CF3, H, OMe, OH, DMA, A15C5 equaling monoaza-15-crown-5) of various donor strength and display CT-controlled spectroscopic properties and communication of analyte–receptor interactions. The crystal structures of the neutral fluorescent probes are compared to the structures of their terpyridine-alkylated or -protonated counterparts that represent model systems for acceptor protonation or cation coordination. The aim is here a better understanding of the complexation-induced structural and spectroscopic changes and the identification of common packing motifs of bpb-R thereby taking into account the importance of terpyridine building blocks for the construction of supramolecular systems and coordination arrays revealing π–π interactions. KW - Biphenyl KW - Terpyridine KW - Crystal structure KW - Fluorescent probe KW - Charge transfer KW - Bifunctional PY - 2008 DO - https://doi.org/10.1016/j.molstruc.2007.03.025 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 874 IS - 1-3 SP - 14 EP - 27 PB - Elsevier CY - Amsterdam AN - OPUS4-17087 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emmerling, Franziska A1 - Becker, Roland A1 - Reck, Günter T1 - Mixed crystal of bis(µ2-N,N-di-n-butyldithiocarbamato-S,S,S')-bis(N,N-di-n-butyldithiocarbamato-S,S')-di-zinc(II) and bis(µ2-N,N-di-n-butyldithiopercarbamato-S,O,O')-bis(N,N-di-n-butyldithiocarbamato-S,S')-di-zinc(II) N2 - The title compounds Zn2[S2CN(n-C4H9)2]4 1 and Zn2[(S(SO)CN(n-C4H9)2)(S2CN(n-C4H9)2)]2 3 build mixed crystals in the ratio 0.42: 0.58. Each compound forms dimers, in which the monomer moieties are related via a two-fold axis, coinciding with that of the monoclinic space group C2/c. The lattice parameters are a = 23.581(9), b = 17.112(5), c = 16.372(9) Å, and β = 128.33(3)°. KW - Crystal structure KW - Zinc KW - Dithiocarbamate KW - Dithiopercarbamate PY - 2007 DO - https://doi.org/10.1002/crat.200710956 SN - 0023-4753 SN - 1521-4079 SN - 0232-1300 VL - 42 IS - 10 SP - 1018 EP - 1023 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-17843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoffmann, Katrin A1 - Dietzel, B. A1 - Schulz, B. A1 - Reck, Günter A1 - Hoffmann, Angelika A1 - Orgzall, I. A1 - Resch-Genger, Ute A1 - Emmerling, Franziska T1 - Combined structural and fluorescence studies of methyl-substituted 2,5-diphenyl-1,3,4-oxadiazoles - relation between electronic properties and packing motifs N2 - Prerequisite for the rational design of functional organic materials with tailor-made electronic properties is the knowledge of the structure–property relationship for the specific class of molecules under consideration. This encouraged us to systematically study the influence of the molecular structure and substitution pattern of aromatically substituted 1,3,4-oxadiazoles on the electronic properties and packing motifs of these molecules and on the interplay of these factors. For this purpose, seven diphenyl-oxadiazoles equipped with methyl substituents in the ortho- and meta-position(s) were synthesized and characterized. Absorption and fluorescence spectra in solution served here as tools to monitor substitution-induced changes in the electronic properties of the individual molecules whereas X-ray and optical measurements in the solid state provided information on the interplay of electronic and packing effects. In solution, the spectral position of the absorption maximum, the size of Stokes shift, and the fluorescence quantum yield are considerably affected by ortho-substitution in three or four ortho-positions. This results in blue shifted absorption bands, increased Stokes shifts, and reduced fluorescence quantum yields whereas the spectral position and vibrational structure of the emission bands remain more or less unaffected. In the crystalline state, however, the spectral position and shape of the emission bands display a strong dependence on the molecular structure and/or packing motifs that seem to control the amount of dye–dye-interactions. These observations reveal the limited value of commonly reported absorption and fluorescence measurements in solution for a straightforward comparison of spectroscopic results with single X-ray crystallography. This underlines the importance of solid state spectroscopic studies for a better understanding of the interplay of electronic effects and molecular order. KW - Diphenyl-oxadiazoles KW - X-ray structure KW - Packing motif KW - Optical properties KW - Fluorescence quantum yield PY - 2011 DO - https://doi.org/10.1016/j.molstruc.2010.11.071 SN - 0022-2860 SN - 1872-8014 SN - 0377-046X VL - 988 IS - 1-3 SP - 35 EP - 46 PB - Elsevier CY - Amsterdam AN - OPUS4-23253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -