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Synthesis, Crystal Structures, and DNA Cleavage Activities of Manganese(II) Complexes: A Good Example of the Synergy between Metal Ions Prompting DNA Cleavage
Author(s) -
Zhu LiNa,
Gao HuanRui,
Wang HaiXian,
Xu MingYuan,
Li XiaoZeng
Publication year - 2014
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201400044
Subject(s) - chemistry , cleavage (geology) , dna , crystallography , stereochemistry , manganese , metal , intramolecular force , circular dichroism , metal ions in aqueous solution , crystal structure , phenanthroline , biochemistry , geotechnical engineering , organic chemistry , fracture (geology) , engineering
The potential synergy between metal centers makes multinuclear metal complexes promising candidates for artificial nucleases. However, few multinuclear mimics have shown higher DNA cleavage efficiencies than their mononuclear analogues. By using 1,8‐naphthalene dicarboxylic acid (1,8‐H 2 ndc) and 1,10‐phenanthroline (phen) ligands, one mononuclear complex [Mn(1,8‐ndc)(phen) 2 (H 2 O)] · CH 3 OH · 2H 2 O ( 1 ), two dinuclear complexes [Mn(1,8‐Hndc)(phen) 2 ] 2 · 2ClO 4 · 4H 2 O ( 2 ) and [Mn(1,8‐ndc)(phen)(H 2 O) 2 ] 2 · CH 3 OH · H 2 O ( 3 ), and one hexanuclear complex [Mn(1,8‐ndc)(phen)(H 2 O) 2 ] 6 · 11H 2 O ( 4 ) were synthesized and structurally characterized by single‐crystal X‐ray analysis. Complexes 2 – 4 have closed‐ring structures bridged by 1,8‐ndc ligands that adopt a peculiar μ 2 ‐η 1 :η 1 bridging mode, which has never been reported before. Circular dichroism and fluorescence studies show that the four complexes interacted with calf thymus DNA through the intercalative binding mode, and the binding ability order is 2 > 1 > 3 > 4 . All of the complexes can efficiently promote the oxidative cleavage of plasmid pBR 322 DNA in the presence of H 2 O 2 with an efficiency order 3 > 4 > 2 > 1 . The higher DNA cleavage abilities of the multinuclear complexes than the mononuclear one, combined with the fact that 3 with the shortest intramolecular Mn ··· Mn distance and the strongest magnetic coupling between Mn II ions shows the highest DNA cleavage efficiency, confirm the great effect of the synergy between metal centers on the DNA cleavage efficiency of complexes. The four complexes also show strong concentration‐dependent cytotoxicity to human breast cancer cells.