One-dimensional copper(II) coordination polymers bridged both by μ-trans-oxamidates and phenyldicarboxylates: Synthesis, crystal structure and DNA binding studies

Two new one-dimensional copper(II) polymers with formulae of [Cu2(H2O)2(dmapox)(ipa)2]n (1) and [Cu2(H2O)2(dmapox)(tpa)2]n (2), where dmapox, ipa and tpa stand for the dianion of N,N′-bis[3-(dimethylamino)propyl]oxamide, isophthalic acid and terephthalic acid respectively, have been synthesized and characterized by elemental analysis, conductivity measurement, IR and electronic spectral studies. The crystal structures of the two complexes have been determined by X-ray single-crystal diffraction. The structures of 1 and 2 consist of one-dimensional copper(II) coordination polymeric chain constructed both by the bis-tridentate trans-dmapox and bis-monodentate phenyldicarboxylate bridging ligands. In the two complexes, the environment around the copper(II) atoms can be described as distorted square–pyramid and the Cu···Cu separations through μ-trans-dmapox and phenyldicarboxylato bridging ligands are 5.245(5) Å and 8.212(3) Å for 1, 5.237(8) Å and 11.171(1) Å for 2, respectively. The binding properties of the two copper(II) polymers with herring sperm DNA (HS-DNA) have been investigated by using absorption and emission spectral and electrochemical techniques and viscometry. The results show that the two copper(II) complexes interact with the HS-DNA in the mode of intercalation with the intrinsic binding constants of 1.22(±0.2) × 104 M−1 and 1.45(±0.3) × 104 M−1 for 1 and 2, respectively.