One-dimensional copper(II) polymer with bridging μ-trans-oxamidate and thiocyanate ligands: Synthesis, crystal structure and DNA binding studies

A new one-dimensional copper(II) polymer, [Cu-4(dmapox)(2)(SCN)(4)(CH3CH2OH)(2)](n) center dot 2nCH(3)CH(2)OH, where dmapox is the dianion of N,N'-bis[3-(dimethylamino)propyl]oxamide, was synthesized and characterized by elemental analysis, conductivity measurement, IR and electronic spectral studies. The crystal structure of the copper(II) complex has been determined by X-ray single-crystal diffraction. The complex crystallizes in triclinic, space group P (1) over bar and exhibits infinite one-dimensional copper(II) polymeric chain bridged both by the bis-tridentate mu-trans-dmapox and mu-1,3-thiocyanate ligands. The environment around the copper(II) atom can be described as distorted square-pyramid. The Cu center dot center dot center dot Cu separations through mu-trans-oxamidate and thiocyanate bridges are 5.245(5) angstrom (Cu1-Cu1(i))(i = -x+1, -y, -z+1), 5.262(4) angstrom (Cu2-Cu2(ii))(ii = -x, -y, -z+1) and 6.022(3) angstrom (Cu1-Cu2), respectively. The interaction of the copper(II) complex with herring sperm DNA (HS-DNA) has been investigated by using absorption and emission spectral and electrochemical techniques and viscometry. The results reveal that the copper(II) complex interacts with the DNA in the mode of groove binding with the intrinsic binding constant of 2.38 x 10(5) M (1). (C) 2008 Elsevier B.V. All rights reserved.