Toward a New Type of Multifunctional Metal-Organic Systems Based on Nucleobase Analogues: First Results Derived From The Use of Aliphatic α,ω-Dicarboxylates

Five new transition metal complexes, containing the purine-mimetic ligands 7-amine-1,2,4-triazolo[1,5-a]pyrimidine (7atp) and 4,5-dihydro-5-oxo-1,2,4-triazolo[1,5-c]pyrimidine (5HtpO), and also malonate (mal(2-)) and succinate (suc(2-)) as secondary ligands are reported. Their formula are [Mn-2(mu-7atp)(2)(mu-mal)(2)(H2O)(2)] (1), [Zn-2(mu-7atp)(2)(mu-mal)(2)(H2O)(2)] (2), [Cu-2(5HtpO)(2)(mal)(2)(H(2)mal)(2)(mu-H2O)(2)] (3), [Cu-2(mu-5tpO)(2)(mu-Hsuc)(2)(H2O)(2)] (4), and [Cd-2(mu-5tpO)(2)(mu(4)-suc)(H2O)(2)](n) (5). Single-crystal X-ray analysis show that compounds 1-4 feature all dinuclear units with different topologies while compound 5 exhibits a 3D-network with small-diameter pores. The variety of coordination modes displayed by both triazolopyrimidine derivatives together with the bridging capability of the aliphatic alpha,omega-dicarboxylates used lead to compounds with interesting structural features and physical properties. The Cu(II) malonate dimer 3 exhibits weak ferromagnetic interactions (J = +1.5 cm(-1)) while a weak and a moderately strong antiferromagnetism are displayed, respectively, in the Mn(II) (J = 2.1 cm(-1)) and Cu(II) succinate dimer 4 (J = -109.7 cm(-1)). On the other hand, solid-state photoluminescent emission is observed for the Zn(II) compound with a Stokes shift of 73 nm.