Binding Studies of Asymmetric Pentacoordinate Copper(II) Complexes Containing Phenanthroline and Ethane-1,2-diamine Ligands with Calf-Thymus DNA
✍ Scribed by Farukh Arjmand; Mala Chauhan
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- German
- Weight
- 163 KB
- Volume
- 88
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
New chiral complexes of the composition [MLL′], where HL=1,2‐bis(1__H__‐benzimidazol‐2‐yl)ethane‐1,2‐diol=H~2~bimedol, M=Co^II^, Ni^II^, Cu^II^, and L′=1,10‐phenanthroline (phen) or ethane‐1,2‐diamine (en), were synthesized and characterized. The ligand L exhibited a coordination mode involving the O‐atom of only one OH group, the other one being directed away from the metal center. The complexes [Cu(Hbimedol)(en)]Cl (1), [Cu(Hbimedol)(phen)]Cl (2), [Co(Hbimedol)(phen)]Cl (3), [Ni(Hbimedol)(en)]Cl (4), and [Ni(Hbimedol)(phen)]Cl (5) were ionic in nature and stable at room temperature. The donor sets involved in coordination with the metal ions were the O‐atom of one OH group and two N‐atoms of the two benzimidazole moieties, besides the two N‐atoms of phen or en (Fig. 1.). The proposed five‐coordinate geometry of 1–5 was established by analysis of spectroscopic data; the ball‐and‐stick models supported the proposed structures of 1–5 since they showed apparently no strain on any bond and angle. The interaction of complexes 1 and 2 with calf‐thymus DNA were carried out by UV/VIS titration, circular dichroism, electrochemical methods, and viscometry. The intrinsic binding constant K~b~ of 1 and 2 was determined as 1.57⋅10^4^ and 1.51⋅10^4^ M^−1^, respectively, suggesting that both complexes bind strongly to calf‐thymus DNA.