A new Schiff base ligand N-(2-hydroxylacetophenone)-3-oxapentane-1,5-diamine (HL) and its Ni complex, [Ni 2 (L) 2 (NO 3 ) 2 ], have been synthesized and characterized by physicochemical and spectroscopic methods. The X-ray crystal structure of [Ni 2 (L) 2 (NO 3 ) 2 ] shows it to be a dinuclear 2:2 complex, in which each Ni(II) atom is in a distorted octahedral geometry. The two Ni(II) atoms are dibridged by two phenoxo ligands, forming a Ni 2 O 2 parallelogram-type moiety. The interactions between free HL and the complex with calf thymus DNA have been investigated, and the binding constant and linear Stern-Volmer quenching constant suggest that the two compounds bind to DNA via the intercalation mode. The binding affinity of the complex was higher than that of HL. Antioxidant assays in vitro showed that the Ni(II) complex possesses significant antioxidant activity.

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Bis(N-allylbenzimidazol-2-ylmethyl)benzylamine (babb) and two of its complexes, [Cu(babb)(pic) 2 ]ÁH 2 O (1) and [Co(babb) 2 ](pic) 2 (2) (pic = picrate), have been synthesized and characterized by physico-chemical and spectroscopic methods. Single crystal X-ray diffraction revealed that the two complexes have similar distorted octahedral structures, but the degree of distortion and the coordinated atoms are different. The DNA-binding properties of the free ligand and its two complexes have been investigated by electronic absorption, fluorescence, and viscosity measurements. The results suggest that all three compounds bind to DNA via an intercalative binding mode, and their binding affinity for DNA follows the order 2 [ 1 [ ligand. Additionally, both complexes exhibited potential antioxidant properties in in vitro studies, and complex 1 was the more effective.

A new copper(II) complex with formulae of [Cu(buobb)2](pic)2, where buobb stands for the ligand of 1,3-bis(1- butylbenzimidazol-2-yl)-2-oxopropane and pic represents 2,4,6-trinitrophenol, has been synthesized and characterized by elemental analyses, molar conductivity, IR, UV-Vis spectra measurements, and cyclic voltammetry. The crystal structure of the copper(II) complex has been determined by X-ray single-crystal diffraction. The coordination environment around each copper(II) atom can be described as a distorted octahedral geometry. The π-π stacking interactions link the copper(II) complex into a 1D infinite network. The interactions of the ligand and the copper(II) complex with calf thymus DNA (CT-DNA) are investigated by using electronic absorption titration, ethidium bromide-DNA displacement experiments, and viscosity measurements. Additionally, the copper(II) complex's antioxidant properties have been investigated in vitro.

Tris(N-methylbenzimidazol-2-ylmethyl)amine (Mentb) and its two complexes, [Mn(Mentb)(DMF)-(H 2 O)](pic) 2 1 and [Zn(Mentb)(pic)](pic) 2 (pic = picrate), have been synthesized and characterized by physico-chemical and spectroscopic methods. Single crystal X-ray diffraction revealed that the two complexes have different structures. In complex 1, the coordination sphere around Mn(II) is distorted octahedral, whereas in complex 2 the coordination sphere around Zn(II) is distorted trigonal bipyramidal. The DNA-binding properties of the free ligand and its two complexes have been investigated by electronic absorption, fluorescence, and viscosity measurements. The results suggest that the ligand and its two complexes bind to DNA via an intercalation binding mode, and their binding affinity for DNA follows the order 1 [ 2 [ ligand.