Synthesis, Crystal Structure and DNA Binding of a Chiral New Cu(II) Complex with (1R, 2R)-1,2-Hexanediamine

Abstract

The compound 1, (R,R)-N,N’-bis(benzaldehyde)-1,2-cyclohexanediamine schiff base was synthesized and characterized by 1H-NMR spectra, MS spectra and IR spectra. And the coordination reaction of 1 with nitrate of Cu (II) was studied. The reaction of 1 with CuII salt [Cu(NO3)2.2H2O] generates a new compound 2. The compound 2 was determined by IR spectra, elemental analysis and single-crystal X-ray diffraction. Crystal data for 2: space group P2(1)2(1)2(1) , with a= 9.632(12)Å, b = 9.706(12)Å, c = 22.04(3)Å, α=90.00 º,β=90.00 º , γ=90.00 º, Flack=0.02(3), Z=4, V= 2061(4) Å 3, Dc=1.457 mg.m-3, µ=1.109mm-1, F(000)=956. There are 6 coordination sites around Cu2+ of 2, which are respectively occupied by two oxygen atoms (all from two H2O) and four nitrogen atoms all from two cyclohexanediamine molecule. The Cu atom and four chelating nitrogen atoms are coplanar. There exist intra-molecular H-bond and intermolecular H-bond. The DNA binding behaviors of 2 has been examined by viscosity measurements, fluorescent spectroscopy, absorption spectra and cyclic voltammetric techniques. Results suggest that the compound 2 binds to DNA with a non-classical intercalative mode and static interaction mode. The observed efficient nuclease activity of the compound 2 is interesting and may have further influences in the chemistry of DNA binders.