Synthesis, structure, magnetism and nuclease activity of tetranuclear copper(II) phosphonates contatining ancillary 2,2'-bipyridine or 1,10-phenanthroline ligands
The reaction of cyclohexylphosphonic acid (C{sub 6}H{sub 11}PO{sub 3}H{sub 2}), anhydrous CuCl{sub 2} and 2,2{prime}-bipyridine (bpy) in the presence of triethylamine followed by a metathesis reaction with KNO{sub 3} afforded [Cu{sub 4}({micro}-Cl){sub 2}({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(bpy){sub 4}](NO{sub 3}){sub 2} (1). In an analogous reaction involving Cu(OAc){sub 2} {center_dot} H{sub 2}O, the complex [Cu{sub 4}({micro}-CH{sub 3}COO){sub 2}({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(2,2-bpy){sub 4}](CH{sub 3}COO){sub 2} (2) has been isolated. The three-component reaction involving Cu(NO{sub 3}){sub 2} {center_dot} 3H{sub 2}O, cyclohexylphosphonic acid and 2,2{prime}-bipyridine in the presence of triethylamine afforded the tetranuclear assembly [Cu{sub 4}({micro}-OH)({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(2,2{prime}-bpy){sub 4} (H{sub 2}O){sub 2}](NO{sub 3}){sub 3} (3). Replacing 2,2{prime}-bipyridine with 1,10-phenanthroline (phen) in the above reaction resulted in [Cu{sub 4}({micro}-OH)({micro}{sub 3}-C{sub 6}H{sub 11}PO{sub 3}){sub 2}(phen){sub 4}(H{sub 2}O){sub 2}](NO{sub 3}){sub 3} (4). In all the copper(II) phosphonates (1-4) the two phosphonate ions bridge the four copper(II) ions in a capping coordination action. Each phosphonate ion bridges four copper(II) ions in a {micro}{sub 4}, coordination mode or 4.211 of the Harris notation. Variable-temperature magnetic studies on 1-4 reveal that all four complexes exhibit moderately strong intramolecular antiferromagnetic coupling. The DNA cleavage activity of complexes 1-4 is also described. Compounds 1 and 3 were able to completely convert the supercoiled pBR322 DNA form I to nick form II without any co-oxidant. In contrast, 50% conversion occurred with 2 and 40% with 4. In the presence of magnesium monoperoxyphthalate all four compounds achieved rapid conversion of form I to form II.
- Research Organization:
- Ames Lab., Ames, IA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC02-07CH11358
- OSTI ID:
- 973370
- Report Number(s):
- IS-J 7385; TRN: US201006%%347
- Journal Information:
- Dalton Transactions, Journal Name: Dalton Transactions
- Country of Publication:
- United States
- Language:
- English
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