Novel mononuclear zinc complexes with 2,2 '-dimethyl-4,4 '-bithiazole: Synthesis, crystal structure and DNA-binding studies

作者：Lighvan Zohreh Mehri; Abedi Anita^*; Bordar Maryam

来源：Polyhedron, 2012, 42(1): 153-160.

DOI：10.1016/j.poly.2012.05.006

• Zinc complexes
• Crystal structure
• DNA interaction
• Fluorimetry
• CD spectroscopy

Two neutral mononuclear zinc complexes with 2,2'-dimethyl-4,4'-bithiazole (dm4bt), [Zn(dm4bt)Br-2] (1) and [Zn(dm4bt)I-2] (2) were synthesized and characterized by elemental analysis, IR, UV-Vis and NMR spectroscopy and their structures were studied by single-crystal diffraction. These complexes have a bidentate nitrogenous ligand with two halide anions attached to a zinc metal in a distorted tetrahedral geometry. The interaction ability of the two complexes with native calf thymus DNA (CT-DNA) has been monitored as a function of the metal complex-DNA molar ratio by UV-Vis absorption spectrophotometry, fluorescence spectroscopy, circular dichroism (CD) and thermal denaturation studies. The intrinsic binding constants K-b of complexes 1 and 2, with CT-DNA obtained from UV-Vis absorption studies were 3.47 +/- 0.02 x 10(4) M-1 and 3.19 +/- 0.02 x 10(4) M-1, respectively. Both complexes exhibit luminescent properties in the absence and presence of CT-DNA and the fluorescence study ascertain the interaction of 1 and 2 with CT-DNA. Moreover the addition of the complexes to CT-DNA (1:2) led to an increase of the melting temperature of DNA up to around 2.7 degrees C. Further fluorimetric studies were performed using methylene blue (MB) as a fluorescence probe, indicating low intercalative interaction of the complexes with CT-DNA. The CD study also points to groove binding mode in the complexes rather than intercalation mode.

• 出版日期2012-7-25