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

Abstract

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-a]pyrimidine (5HtpO), and also malonate (mal2–) and succinate (suc2–) as secondary ligands are reported. Their formula are [Mn2(μ-7atp)2(μ-mal)2(H2O)2] (1), [Zn2(μ-7atp)2(μ-mal)2(H2O)2] (2), [Cu2(5HtpO)2(mal)2(H2mal)2(μ-H2O)2] (3), [Cu2(μ-5tpO)2(μ-Hsuc)2(H2O)2] (4), and [Cd2(μ-5tpO)2(μ4-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 α,ω-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.