title: Association of structural modifications with bioactivity in three new copper(II) complexes of Schiff base ligands derived from 5-chlorosalicylaldehyde and amino acids.
abstract: Three novel structurally associated copper(II) complexes [Cu(II)(SalCl-Gly)(H2O)2] (1), [Cu(II)(SalCl-Ala)(H2O)] (2) and [Cu(II)(SalCl-Gly)(bipy)]·0.5H2O (3) (SalCl-Gly=5-chloro-2-hydroxybenzylidene-glycine, SalCl-Ala=5-chloro-2-hydroxybenzylidene-alanine, bipy=2,2'-bipyridine) have been synthesized and characterized by X-ray crystallography, elemental analysis, IR and fluorescence spectroscopy. Single-crystal diffraction reveals that complex 1 is an infinite 1D zigzag chain in which SalCl-Gly serves as both a chelating and a bridging ligand, while complexes 2 and 3 are mononuclear. Cu(II) ions in complexes 1-3 exhibit distorted quasi-hexacoordinated octahedral, tetracoordinated square planar, and pentacoordinated square pyramid geometry, respectively. Their interactions with calf thymus DNA (CT-DNA) have been investigated by viscosity measurements and fluorescence spectroscopy. The apparent binding constant (Kapp) values for 1-3 are 1.02×10(5), 0.98×10(5) and 1.57×10(5)M(-1), respectively. All complexes displayed efficient oxidative cleavage of supercoiled DNA in the presence of H2O2. Complex 2, whose ligand can be regarded as a methyl-modification of SalCl-Gly of 1, showed a reduced DNA cleavage activity and a little-changed DNA-binding ability compared with 1. While attaching a 2,2'-bipyridine group to 1, the resulting complex 3 was conferred an enhanced intercalation into DNA. Moreover, cytotoxicity studies of three complexes against HepG-2 (human liver hepatocellular carcinoma) and NCI-H460 (human large-cell lung carcinoma) cells indicated that, thereto, complex 3 possessed the highest inhibition on viability of tested cells.
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Ang
authors.initials: A
authors.lastname: Li
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Ya-Hong
authors.initials: YH
authors.lastname: Liu
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Ling-Zhi
authors.initials: LZ
authors.lastname: Yuan
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Zhong-Ying
authors.initials: ZY
authors.lastname: Ma
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Chun-Lai
authors.initials: CL
authors.lastname: Zhao
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Cheng-Zhi
authors.initials: CZ
authors.lastname: Xie
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China.
authors.forename: Wei-Guo
authors.initials: WG
authors.lastname: Bao
authors.affiliation: Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), School of Pharmacy, Tianjin Medical University, Tianjin 300070, PR China. Electronic address: xujingyuan@tmu.edu.cn.
authors.forename: Jing-Yuan
authors.initials: JY
authors.lastname: Xu
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004247:DNA / Q000737:chemistry; D056945:Hep G2 Cells; D006801:Humans; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000633:toxicity; D012545:Schiff Bases / Q000737:chemistry*
chemical_list: C527448:5-chloro-salicylaldehyde; D000447:Aldehydes; D000596:Amino Acids; D009942:Organometallic Compounds; D012545:Schiff Bases; D003300:Copper; D004247:DNA; C427203:calf thymus DNA
keywords: Amino acid; Copper complex; Cytotoxic activity; DNA binding; Schiff base