N9,N9′-polymethylene-bisadenine complexes with d10 metal ions

The reaction of N-9,N-9'-(tri or tetramethylene)-bisadenines (Ade(2)C(x); x = 3 or 4) in HCl 2 M at 50 degrees C with MCl2 center dot 2H(2)O [M = Zn(II), Cd(II)] yields outer sphere compounds like the Previously described [(H-Ade)(2)C-3][ZnCl4] center dot H2O (3) and [(H-Ade)(2)C-3](2)[Cd2Cl8(H2O)(2)] center dot 4H(2)O (4) for Ade(2)C(3) and the new {[(H-Ade)(2)C-4][Cd2Cl6(H2O)(2)]center dot 2H(2)O}(n), (5) for Ade(2)C(4). On the other hand, only in case of Zn(II) complexes by changing [HCl] to 0.1 M, the inner sphere compounds [H-(Ade)(2)C-3(ZnCl3)] (6) and [H-(Ade)(2)C-4(ZnCl3)]center dot 1.5H(2)O (7) are obtained. X-ray diffraction study of compound 6, which represents the first inner sphere complex with a N-9,N-9'-bisadenine, shows a zwitterionic form with one adenine ring protonated at N(1) while the other ring is coordinated via N(7) to a ZnCl3 moiety as in other alkyl-adenine derivatives. In addition, with Ade(2)C(4), is also possible to obtain another inner sphere complex: [(H-Ade)(2)C-4(ZnCl3)(2)]center dot 3H(2)O (8). (c) 2006 Elsevier Ltd. All rights reserved.