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41Author    Tetramethylammoniumfluorid Bildung, Wasserstoffbrückenbindung Struktur, Dieter Stäben, Dietrich MootzRequires cookie*
 Title    Die kristallinen Hydrate  
 Abstract    The melting diagram of the system M e4N F -H 20 in the region 50-100 mol% H zO has been investigated for the first time, using D T A , D SC and tem perature-dependent X-ray powder diffraction. Four crystalline hydrates M e4N F\*H 20 were found, with x = 1 ,2 .3 3 ,4 and 5, which decom pose irreversibly above ca. 160 °C and m elt incongruently at 36 °C, congruently at 46 °C and again incongruently at 10 °C, respectively. The crystal structure o f each hydrate, except the already known one of the tetrahydrate, has b een determ ined with M oK a diffractom eter data. The monohydrate is rhombohedral with space group R3m and Z = 6 formula units per unit cell (hexagonal axes), the 2.33-hydrate m onoclinic with P2j/n and Z = 12, and the pen-tahydrate tetragonal with 142 m and Z = 2. The hydrogen-bonded H 20/F ~ structure is an iso­ lated centrosymmetric [F2(H 20) 2]2_ four-m em bered ring in the m onohydrate, a rather open three-dim ensional network in the 2.33-hydrate and a corrugated dense layer o f fused five-mem bered rings in the pentahydrate. 
  Reference    Z. Naturforsch. 48b, 1057—57 (1993); eingegangen am 5. April 1993 
  Published    1993 
  Keywords    Tetramethylamm onium Fluoride, Fluoride Hydrates, M elting Diagram, Crystal Structure, Hydrogen Bonding 
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 TEI-XML for    default:Reihe_B/48/ZNB-1993-48b-1057.pdf 
 Identifier    ZNB-1993-48b-1057 
 Volume    48 
42Author    Michael Born, Dietrich Mootz, Sigrid SchaefgenRequires cookie*
 Title    Tautomere Wasserschichten. Bildung und Struktur tiefschmelzender Trihydrate von Triethylamin und 4-Methylpyridin [1] Tautomeric Water Layers. Formation and Structure of Low-Melting Trihydrates of Triethylamine and 4-Methylpyridine [1]  
 Abstract    Low-melting trihydrates of triethylamine (E t3N) and 4-methylpyridine (4-M ePy) have been confirmed and detected by phase analysis and the crystal structures determined. Both are monoclinic with space group P 2!/c and Z = 4 formula units per unit cell. The lattice parameters are a = 13.606, b = 6.291, c = 12.412 A , and ß = 99.47° at -1 0 0 °C for Et3N -3 H 20 , and a = 9.982, b = 6.877, c = 12.958 Ä , and ß = 103.50° at -9 0 °C for 4-M eP y-3 H20 . The water m olecules in the two structures are hydrogen-bonded in condensed four-, five-, and six-membered rings with 1:2:1 ratio, thus forming characteristic layers parallel (1 0 0) of identical topology and tautomeric to each other. The amine m olecules are linked to both sides of the layers by O -H — N bonds from different O atoms. 
  Reference    (Z. Naturforsch. 50b, 101—105 [1995]; eingegangen am 11. August 1994) 
  Published    1995 
  Keywords    Am ine Hydrates, Crystal Structure, Hydrates, Hydrogen Bonding, M elting Diagram, Water Layers 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-0101.pdf 
 Identifier    ZNB-1995-50b-0101 
 Volume    50 
43Author    Saalfrank, JochenN. Achtrab, Stephan Reck, Frank HampelRequires cookie*
 Title    Synthese und Aggregatbildung eines 5-Hydroxy-2,5-dihydropyrrols. Enantiomerenreine, eindimensionale Stränge durch Wasserstoff- brückenbindungen und chiroselektive Selbstorganisation [1]  
 Abstract    Synthesis and A ggregation o f a 5-H ydroxy-2,5-dihydropyrrole. E nantiom erically Pure, O ne-dim ensional Strands via Hydrogen Bonds and Chiroselective S eif O rganization [ 1 ] R olf W. Reaction of dimethyl 1,3-acetonedicarboxylate 8 with oxalylchloride 2 and magnesium chlo­ ride as catalyst yielded 2,3-dioxo-2,3-dihydrofuran 9, which is in equilibrium with tautomer 10 (9:10 = 1:2). Addition of thionyl chloride to a mixture of 9/10 afforded 3-chloro-2(5H)-furanone 11. The structure of 11 was unequivocally established by X-ray diffraction, which indirectly pro­ ved the structure of 10 as well. Ring opening of 11 by nucleophilic attack with benzylamine 14 in C2-position and subsequent recyclization led to racemic 3-chloro-5-hydroxy-2-oxo-2,5-di-hydropyrrole 15. According to a single crystal X-ray analysis, 15 aggregates via stereospecific self selection through hydrogen bonds to give chiroselectively the one-dimensional strands 1 1(S)-15] and I [(R)-1SI 
  Reference    Z. Naturforsch. 54b, 179—186 (1999); eingegangen am 28. September 1998 
  Published    1999 
  Keywords    2(5H)-Furanones, Hydrogen-Bonding, Chiral Recognition, One-Dimensional Strand, Crystal Structure 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0179.pdf 
 Identifier    ZNB-1999-54b-0179 
 Volume    54 
44Author    Biing-Chiau Tzeng, Johann Zank, Annette Schier, Hubert SchmidbaurRequires cookie*
 Title    The Structural Chemistry of GoId(I) Quinoline-2-thiolate and Iodide Complexes of Polytertiary Phosphines  
 Abstract    Treatment of (chloro)gold(I) complexes of di-and tetra-tertiary phosphines with equivalent quantities of sodium quinoline-2-thiolate in methanol / dichloromethane affords the correspond­ ing (phosphine)gold(I) quinoline-2-thiolates in high yields. The di-and tetranuclear complexes, respectively, of a,u>bis(diphenylphosphino)-propane (1), -butane (2) and -pentane (3) and of tris(2-diphenylphosphino-ethyl)phosphine (4) have been obtained as crystalline solids, and the structures of 2 and 4 have been determined by single crystal X-ray diffraction studies. Un­ expectedly, the molecules of 2 are loosely aggregated into strings via weak intermolecular gold-sulfur, not via Au-Au interactions. Compound 4 is a monomeric tetranuclear cluster in the solid state with two intramolecular gold-gold bonds. Bis(2-diphenylphosphino-ethyl)-phenylphosphine (PPP) forms trinuclear complexes with gold(I) chloride, bromide and iodide (5a -c). The iodide complex features a chain structure through intermolecular Au -Au contacts between the two terminal P-Au-I units. The closest contacts between the chains are determined by Au-I and I -I interactions of the central P-Au-I unit. 
  Reference    Z. Naturforsch. 54b, 825—831 (1999); received April 19 1999 
  Published    1999 
  Keywords    Gold(I) Complexes, Thiolate Complexes, Aurophilicity, Hydrogen Bonding, Polytertiary Phos-phine Complexes 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0825.pdf 
 Identifier    ZNB-1999-54b-0825 
 Volume    54 
45Author    D. Blaschette, PeterG. JonesRequires cookie*
 Title    Polysulfonylamine, CXVII [1]  
 Abstract    Wasserstoffbrücken in kristallinen Onium-dimesylamiden: Sechs systematisch variierte s££.-Ammonium-dimesylamide mit sechs verschiedenen null-, ein-oder zweidimensionalen Wasserstoffbrückenmustern Polysulfonylamines, C X V II [1] H ydrogen B onding in Crystalline O n iu m Dimesylamides: Six Systematically Varied sec. -A m m onium Dimesylamides Exhibiting Six D ifferent Zero-, One-, or Two-Dimensional Hydrogen B onding Patterns O liver Moers, Karna W ijaya, D agm ar Henschel, A rm a n In order to examine packing preferences and hydrogen bond patterns in secondary ammo­ nium salts, low-temperature X-ray analyses were conducted for six compounds of general formula R^N H ^M eSO ^hN ", where R 2NH2 = Me2NH2 (1, triclinic, space group P I), 
  Reference    Z. Naturforsch. 54b, 1420—1430 (1999); eingegangen am 13. Juli 1999 
  Published    1999 
  Keywords    Di(methanesulfonyl)amide, Secondary Ammonium Cation, Crystal Structure, Hydrogen Bonding, Crystal Engineering 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-1420.pdf 
 Identifier    ZNB-1999-54b-1420 
 Volume    54 
46Author    Dagmar Henschel, Oliver Moers, Karna Wijaya, Blaschette Arm, PeterG. JonesRequires cookie*
 Title    Wasserstoffbrücken in kristallinen Onium-dimesylamiden: Drei prim. -Ammonium-dimesylamide mit zwei-oder dreidimensionalen Wasserstoffbrückenmustern Polysulfonylamines, CXVIII [1] Hydrogen Bonding in Crystalline Onium Dimesylamides: Three prim. -Ammonium Dimesylamides Exhibiting Two-or Three-Dimensional Hydrogen Bond Patterns  
 Abstract    In order to study hydrogen bonding patterns in primary ammonium salts and the hydrogen bond acceptor potential of the dimesylamide anion, low-temperature X-ray structures have been determ ined for the 1:1 salts R N H ^M eSC ^^N -, where R = Et (1, monoclinic, space 
  Reference    Z. Naturforsch. 54b, 1431—1440 (1999); eingegangen am 13. Juli 1999 
  Published    1999 
  Keywords    Di(methanesulfonyl)amide, Primary Ammonium Cation, Crystal Structure, Hydrogen Bonding, Ionic Self-Clathrate 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-1431.pdf 
 Identifier    ZNB-1999-54b-1431 
 Volume    54 
47Author    K. Am, Wijaya, Oliver Moers, A. Rm, Blaschette, PeterG. JonesRequires cookie*
 Title    Wasserstoffbrücken in kristallinen Onium-dimesylamiden: Ein antidromes Achtringmuster als robustes supramolekulares Synthon - Drei prototypische Strukturen Polysulfonylamines, CXIX [1, 2] Hydrogen Bonding in Crystalline Onium Dimesylamides: An Antidromic Eight-M embered Ring Pattern as a Robust Supramolecular Synthon - Three Prototypical Structures  
 Abstract    Syntheses and low-temperature X-ray structures are reported for three ionic solids of gen­ eral formula BH +(M eS 0 2)2N_, where B H + is 3,4,6,7,8,9-hexahydro-2//-pyrimido[l,2-tf]pyri-midinium (1, monoclinic, space group P 2 1/c), N,N'-diphenylformamidinium (2, monoclinic, P2xlc), or 2-phenylaminopyridinium (3, triclinic, P I, two independent formula units). As a common feature, the onium cations in question exhibit a difunctional hydrogen-bond donor sequence H -N -C (s p 2) -N -H geometrically complementary to an O -S -N fragment of the anion. Consequently, the three crystal packings consist of discrete cation-anion pairs (for­ mula units) assembled by an N -H --N and an N -H ---0 hydrogen bond. In both independ­ ent ion pairs of 3, the N -H ---N bond originates from the pyridinium centre and the N-H-O bond from the amino group. The eight-membered ring [graph set N2 = R2(8), antidromic] that results in all these prototypical structures has potential as a new and robust supramolecular synthon. In each case, short C-H-O contacts with H -O < 260pm and C-H-O ^ 140° are present; in 2, two Car-H ---0 hydrogen bonds are assisted by a C(formyl)-H -O contact and a n -n interaction to create a centrosymmetric formula unit dimer. 
  Reference    Z. Naturforsch. 54b, 1441—1449 (1999); eingegangen am 13. Juli 1999 
  Published    1999 
  Keywords    Di(methanesulfonyl)amide, Onium Cation, Crystal Structure, Hydrogen Bonding, Molecular Recognition, Supramolecular Synthon 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-1441.pdf 
 Identifier    ZNB-1999-54b-1441 
 Volume    54 
48Author    Wanda Wagner, Maria Zaborowska, Wlodzimierz Puzyna, David ShugarRequires cookie*
 Title    Studies on Purine-Pyrimidine Hydrogen Bonded Base Pairing by Means of Absorption and Emission Spectroscopy  
 Abstract    Procedures are described for measurement of association constants between potentially com­ plementary purine and pyrimidine bases by hydrogen bonding in non-aqueous medium by means of absorption and emission spectroscopy. The methods require that one of the two constituents be fluorescent and exhibit a long wavelength absorption band not, or only partially, overlapped by the second constituent. The foregoing has been applied to measurements of the association constants, and other parameters, of hydrogen-bonded complexes of 2-aminopurine with 1-substituted uracil, thymine and barbital in chloroform solution, both in the ground and excited states. It was estab­ lished that the 1:1 hydrogen-bonded base pairs 2-aminopurine : 1-cyclohexyluracil and 2-amino­ purine: 1-octylthymine maintain the ground-state equilibrium during the life time of the excited state, whereas for the corresponding pair 2-aminopurine: 1-methylbarbital this equilibrium is per­ turbed on excitation. The influence of N-alkylation of the 2-aminopurine residue on base-pairing with the pyrimidines has also been examined. The results are compared with those obtained by other methods. The specific advantages of the procedures employed, and their possible applications to studies on the behaviour of fluorescent residues in polynucleotides, are discussed. 
  Reference    (Z. Naturforsch. 29c, 672 [1974]; received August 1 1974) 
  Published    1974 
  Keywords    Purines and Pyrimidines, Hydrogen Bonding, Base-pairing, Excited States, Fluorescence 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0672.pdf 
 Identifier    ZNC-1974-29c-0672 
 Volume    29