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'Crown Ether' in keywords Facet   Publication Year 1998  [X]
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1Author    Antje Albert, Dietrich MootzRequires cookie*
 Title    8-Krone-6 und kleine Carbonsäuren. Bildung und Struktur binärer Addukte mit Ameisen-und Essigsäure sowie ternärer mit Essigsäure und Wasser 18-Crown-6 and Small Carboxylic Acids. Formation and Structure of Binary Adducts with Formic and Acetic Acid, as well as Ternary Ones with Acetic Acid and Water  
 Abstract    The melting diagrams of the binary systems 18-crown-6/formic acid and 18-crown-6/acetic acid have been set up and the crystal structures of the adducts 18C6 • 2 HCOOH (1, space group P 2 !/c with Z = 2 formula units per unit cell) and 18C6 • 2 CH 3COOH (2, C2/m, Z = 2) determined. Furthermore three ternary phases, 18C6 • CH3COOH • H20 (3, P2!/c, Z = 4) and dimorphic 18C6 • 2 C H 3COOH • 4 H 20 (high temperature form 4, P2,/n, Z = 2; low temperature form 5, P2|/n, Z = 2) have been characterized in the same way. In each structure the crown ether molecule has the (pseudo) D3d conformation common for many of its complexes. Various aspects of the intermolecular hydrogen bonding are described. 
  Reference    Z. Naturforsch. 53b, 242—248 (1998); eingegangen am 29. Oktober 1997 
  Published    1998 
  Keywords    Acetic Acid, Crown Ether, Formic Acid, Hydrate, Melting Diagram 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-0242.pdf 
 Identifier    ZNB-1998-53b-0242 
 Volume    53 
2Author    Dirk Steinbom, Olaf Gravenhorst, Henrik Junicke, FrankW. HeinemannRequires cookie*
 Title    Synthese und Charakterisierung von kronenetherstabilisierten Platin(IV)- Komplexen mit Aminosäureliganden Synthesis and Characterization of Amino Acid Complexes of Platinum(IV) Stabilized by Crown Ethers  
 Abstract    Crown ether complexed pentachloro(aqua)platinic acid, (H30)[PtCl5(H20)]-2(18-cr-6) • 6H20 (1) reacts with glycine, L-alanine, and DL-2-aminobutyric acid to give ds-[PtCl4(0-glyH)(H20)](1 8 -cr-6)H 20 (4a)1 and ds-[PtCl4(0-amacH)(H2O)](18-cr-6) (amacH = alaH 4b, abuH 4c), respectively, as well as (amacH2)2[PtCl6]-2(18-cr-6) (amacH = glyH 5a, alaH 5b, abuH 5c). The crown ether complexed hexachloroplatinic acid, (H30) 2[PtCl6]-2(18-cr-6) (2), reacts with glycine to afford (glyH2)[PtCl4(yV,0-gly)]-2(18-cr-6)1.25H20 (6). The structures of 4b and 6 were determined by X-ray diffraction. The alanine ligand in 4b is a zwitterion that is coordinated to platinum by one oxygen atom of the carboxylate group only. The other oxygen atom is engaged in a strong hydrogen bond to the ds-coordinated aqua ligand. The glycinato ligand in 6 is /V,(9-coordinated at platinum forming an anion [PtCl4(/V,0-gly)]_ . The other oxygen atom of the carboxylate group is involved in a strong hydrogen bridge to the cation (glyH2)+. In both complexes hydrogen bridges are formed between the -N+H3 and -NH2 groups of the amino acid ligands and the oxygen atoms of the crown ether molecules. 1 Abbreviations: amacH = amino acid, glyH = glycine, alaH = L-alanine, abuH = DL-2-amino-butyric acid. 
  Reference    Z. Naturforsch. 53b, 581—586 (1998); eingegangen am 16. Januar 1998 
  Published    1998 
  Keywords    Platinum(IV) Complexes, Crown Ethers, Amino Acids, Crystal Structure 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-0581.pdf 
 Identifier    ZNB-1998-53b-0581 
 Volume    53