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1987 (1)
1Author    W. S. Sheldrick, P. BellRequires cookie*
 Title    Interaction of Metal Ions with 7-Deaza-8-aza-and 8-Aza-purines Preparation and X-Ray Structural Analysis of Copper(II) Complexes  
 Abstract    The reaction of 8-aza-and 7-deaza-8-aza-purines with Cu :+ cations in acid solution has been studied. At a pH value of 2, the 8-azaadenine complex [Cu(H 2 0) 4 (AAdH) 2 ](N0 3) 2 (1), which displays Cu-N9 coordination, may be isolated from solution. The reaction of CuCl 2 with 8-aza-hypoxanthine in concentrated HCl solution leads to ring opening at C 2 of the azapurine with subsequent formation of dichlorobis[(5-amino-4-carboxamide)[l — 3]triazole] copper(II) dihydrate 2, in which the triazole ligands display a chelating function, coordinating the metal via N7 and 06. The results for 1 and 2 suggest that copper coordination of the azapurine base is not a prerequisite for opening of the pyrimidine ring. Respectively N9-and N8-coordinated complexes [CUC13(A11H3)]" 3 and [CuCl 2 (H 2 0)(MAllH)] n (4) of allopurinol (A11H 2) and 9-methylallopurinol (MA11H) may be prepared by the reaction of CuCl 2 with the respective bases in HCl solution. In contrast, with the analogous l-methyl-4-aminopyrazolo[3,4-d]pyrimidine MAPP, only the salt (MAPPH)4(CU2C18) (5) could be isolated under similar conditions, indicating that N8 is less attractive as a binding site in this 7-deaza-8-azaadenine derivative. The structures of 1—5 have been established by X-ray structural analysis. A distorted octahedral [4+2]geometry is found for the copper atoms in 1 and 2. Chlorine bridged polymeric chain structures are adopted by the complexes 3 and 4. An intermediate coordination geometry between trigonal bipyramidal and square-pyrami-dal is observed for the metal atoms in 3, a distorted square-pyramidal geometry in 4. 
  Reference    Z. Naturforsch. 42b, 195—202 (1987); received August 18/October 17 1986 
  Published    1987 
  Keywords    8-Azapurines, Allopurinol, Copper(II) Complexes, X-Ray 
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 TEI-XML for    default:Reihe_B/42/ZNB-1987-42b-0195.pdf 
 Identifier    ZNB-1987-42b-0195 
 Volume    42