title: Bio-relevant cobalt(II) complexes with compartmental polyquinoline ligand: synthesis, crystal structures and biological activities.
abstract: Three new Co(II) complexes, [Co4(L)2(μ3-CrO4)2](ClO4)2·2CH3CN (1), [Co2(L)(μ2-na)(H2O)](ClO4)2 (2) and [Co2(L)(μ2-ba)](ClO4)2·0.5CH3CN (3) (Hna=nicotinic acid, Hba=benzoic acid, HL=N,N,N',N'-tetrakis (2-quinolylmethyl)-1,3-diaminopropan-2-ol), have been synthesized and characterized by various physicochemical techniques. The Co(II) centers are connected by endogenous alkoxy bridge from L(-) and various extrinsic auxiliary linkers, some of which display coordination number asymmetry (5, 6-coordinated for 1 and 2; 5, 5-coordinated for 3). It is worth mentioning that complex 1 contains two rare reported μ3-η(1), η(1), η(1)-CrO4(2-) moieties. Susceptibility data of three complexes indicated intramolecular antiferromagnetic coupling of high-spin Co(II) atoms with exchange integral values (J) -14.94 cm(-1), -11.26 cm(-1) and -13.66 cm(-1) for 1, 2 and 3, respectively. Interaction of compounds with calf thymus DNA (CT-DNA) have been investigated by absorption spectral titration, ethidium bromide (EB) displacement assay and viscosity measurement, which revealed that compounds bound to CT-DNA with a moderate intercalative mode, accompanied the affinities order: 1>2≈3. Three complexes exhibit oxidative cleavage of pBR322 plasmid DNA including a reliance on H2O2 as the activator. Compound 1 demonstrates an increased DNA cleavage activity as compared with 2 and 3, which could degrade super coiled DNA (SC DNA) into nicked coiled DNA (NC DNA) in lower concentration (5 μM). Moreover, all compounds could quench the intrinsic fluorescence of bovine serum albumin (BSA) in a static quenching process. Complex 1 also shows higher anticancer activity than cisplatin with lower IC50 value of incubation for both 24 h and 48 h.
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, People's Republic of China; Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Tianjin 300071, People's Republic of China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), People's Republic of China.
authors.forename: Jun-Ling
authors.initials: JL
authors.lastname: Li
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, People's Republic of China; Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Tianjin 300071, People's Republic of China; Key Laboratory of Advanced Energy Materials Chemistry (MOE), Tianjin 300071, People's Republic of China.
authors.forename: Lin
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, People's Republic of China; Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Tianjin 300071, People's Republic of China; Key Laboratory of Advanced Energy Materials Chemistry (MOE), Tianjin 300071, People's Republic of China.
authors.forename: Bi-Wei
authors.initials: BW
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, People's Republic of China; Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Tianjin 300071, People's Republic of China; Key Laboratory of Advanced Energy Materials Chemistry (MOE), Tianjin 300071, People's Republic of China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), People's Republic of China. Electronic address: tiant@nankai.edu.cn.
authors.forename: Jin-Lei
authors.initials: JL
authors.lastname: Tian
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, People's Republic of China; Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Tianjin 300071, People's Republic of China.
authors.forename: Wen
authors.initials: W
authors.lastname: Gu
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, People's Republic of China; Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Tianjin 300071, People's Republic of China; Key Laboratory of Advanced Energy Materials Chemistry (MOE), Tianjin 300071, People's Republic of China. Electronic address: liuxin64@nankai.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Nankai University, Tianjin 300071, People's Republic of China; Tianjin Key Laboratory of Metal and Molecule Based Material Chemistry, Tianjin 300071, People's Republic of China.
authors.forename: Shi-Ping
authors.initials: SP
authors.lastname: Yan
mesh_terms: D000818:Animals; D002417:Cattle; D003035:Cobalt / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D004354:Drug Screening Assays, Antitumor; D006367:HeLa Cells; D006801:Humans; D008024:Ligands; D008280:Magnetics; D011108:Polymers / Q000737:chemistry; D011485:Protein Binding; D011804:Quinolines / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D014783:Viscosity
chemical_list: D008024:Ligands; D011108:Polymers; D011804:Quinolines; D012710:Serum Albumin, Bovine; D003035:Cobalt; D004247:DNA
keywords: Co(II) complexes; Crystal structures; DNA cleavage; Protein binding; ‘end-off’ type ligand