ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P60. Mixed-ligand M(II) Complexes with Malonate and Adenine
I. García-Santos a , A. Castiñeiras a , J.M. González-Pérez b , J. Niclós-Gutiérrez b
a
Inorganic Chemistry, University of Santiago de Compostela, Faculty of Pharmacy, E-15782, Santiago de
Compostela, Spain
e-mail: qiisags@usc.es
c
Inorganic Chemistry, University of Granada, Faculty of Pharmacy, E-18071, Granada, Spain
Adenine (Hade) can bind to metals in cationic (H2ade+), neutral (Hade) or anionic (ade-) forms. The malonate
ligand (mal) can display both terminal (monodentate and chelating bidentate) and bridging coordination. Thus
adenine and malonate have versatile coordinating behaviours leading from mono- to poly-nuclear species, with
diverse nuclearity and dimensionality. By reaction of mal and Hade with different M(II) salts we have obtained
compounds with a wide coordinating variety, depending on the metal: [Ni(mal)(Hade)(H2O)]2•2H2O (1),
[Co(Hade)2(H2O)4][Co(mal)2(H2O)2].4H2O (2), [Cu(mal)(Hade)(H2O)]n, (3) (H2ade)2[Cu(Memal)2(H2O)](4)
and [Zn(mal)(Hade) (H2O)]2 2H2O (5). In 1 (Figure) each metal atom is six-coordinated and
both mal and Hade act as bridging ligands, thus contributing to the binuclear structure. Noteworthy Hade acts as
a µ-N3, N9(H(N7))- bridge. This complex can be used like a core to its controlled-expansion, for example by
addition of two ML chelates, after the dissociation of both Hade to remain as µ -N3, N7, N9-ade- bridges. The
degree of protonation and possibilities of different tautomeric forms in Hade and additional water molecules
present in the complexes favour the formation of many intra- and inter-molecular H-bonding interactions and a
strong three-dimensional network is formed. In 2 and 3 there are π, π-stacking interactions that further reinforce
their crystals.
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