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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - CONF A1 - Peplinski, Burkhard A1 - Schultze, Dietrich A1 - Schierhorn, Eike A1 - Schulz, Gert ED - Cernik, R. T1 - Improved X-ray powder diffraction data for the disordered n-Cu6Sn5 alloy phase T2 - 4th European Powder Diffraction Conference CY - Chester, England, UK DA - 1995-07-10 PY - 1996 SN - 0-87849-744-7 SN - 0255-5476 SP - 577 EP - 582 PB - Trans Tech Publ. CY - Zuerich-Uetikon AN - OPUS4-12599 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 - 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 - Sonnenschein, Helmut A1 - Hennrich, Gunther A1 - Resch-Genger, Ute A1 - Schulz, Burkhard T1 - Fluorescence and UV/Vis spectroscopic behaviour of novel biindolizines N2 - Indolizines, known as a useful class of fluorophores, were bridged yielding biindolizines. We intended to obtain long wavelength absorbing and emitting fluorescent systems suitable for fluorescence labeling of biomolecules. The influence of the different kinds of coupling on the absorption and fluorescence behaviour of the resulting biidolizines was studied. The new fluorophore systems were characterized spectroscopically by their absorption and emission maxima and their quantum yields. KW - Dimerisation KW - Bridged indolizines KW - Extended pi-systems KW - Fluorophores KW - UV/Vis KW - Fluorescence spectroscopy PY - 2000 DO - https://doi.org/10.1016/S0143-7208(00)00032-2 SN - 0143-7208 SN - 1873-3743 VL - 46 SP - 23 EP - 27 PB - Elsevier Science CY - Kidlington AN - OPUS4-2113 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thünemann, Andreas A1 - Kurth, D.G. A1 - Beinhoff, M. A1 - Bienert, Ralf A1 - Schulz, Burkhard T1 - V-Shaped Crystalline Structures of Di-n-alkyl Esters of Phosphoric Acid N2 - We prepared crystals of di-n-alkyl esters of phosphoric acid with chain lengths of n = 10, 12, 14, 16, and 18. These were characterized by single-crystal X-ray analysis and differential scanning calorimetry (DSC). It was found that the alkyl chains are in an extended all-trans conformation and aligned close to perpendicular, forming V-shaped molecules. This is in strong contrast to the typical arrangement of the alkyl chains of phospholipids where the two alkyl chains are arranged parallel in the same direction (e.g., tuning fork configuration in bilayers). Additionally, it was found that the arrangement of the V-shaped molecules of the di-n-alkyl esters in neighboring stacks of the lamellar crystals is antiparallel for short chain lengths (n = 10 and 12) and parallel for the longer (n = 14 and 16). DSC reveals that the melting of the crystals increases systematically with increasing chain lengths from 48 to 82 C. The contribution of each methylene group to the melting enthalpy (70-133 kJ/mol) is independent of the chain length (3.9 kJ per mol CH2). PY - 2006 DO - https://doi.org/10.1021/la0603572 SN - 0743-7463 SN - 1520-5827 VL - 22 IS - 13 SP - 5856 EP - 5861 PB - American Chemical Society CY - Washington, DC AN - OPUS4-12446 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 -