Cadmium Complexes with Nucleobases and Related Ligands

2 Cadmium Complexes with Nucleobases and Related Ligands [Pg.147]

A number of structures of cadmium complexes have been described for purine-like bases such as adenine (Hade) and 2,6-diaminopurine (Hdap), either in neutral, cationic or anionic forms. [Pg.147]

Neutral adenine has been reported in two polymeric compounds. The compound [Cd(p2-ox)(H(N7)ade)(H20)]-H20 n [7] consists of ID zig-zag chains in which [Pg.147]

Carballo, Castineiras, Domrnguez-Martm, Garcia-Santos, and Niclos-Gutierrez [Pg.148]

Cd(H(N7)ade)(H20) units are linked by H2-oxo bridges with tetradentate oxalate ligands. Curiously, Hade coordinates through the less basic heterocyclic donor atom, giving rise to the Cd-N3 bond (2.282 A), which is assisted by an (aqua) O-H—N9 H-bond (2.766 A, 147.7°). Thus, the tautomer H(N7)ade seems to be favored due to the involvement of the N7-H bond in the crystal packing. The compound [Cd(p3-S04)(p2-N7,N9-H(Nl)ade)] [8] craitains the tautomer H(Nl)ade, a situation consistent with the bidentate role of adenine and its basicity order (N9 N1 N7 N3 N6). The Cd-N9 bond (2.239 A) does not cooperate with an interligand H-bonding interaction, whereas the Cd-N7 bond (2.204 A) is reinforced by a N6-H -0(sulfate) interaction (2.940 A, 164.7°). In these polymers the cadmium ion adopts a six-coordination mode. [Pg.148]

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