Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India.
Dalton Trans. 2011 Feb 14;40(6):1233-42. doi: 10.1039/c0dt00223b. Epub 2010 Dec 24.
Cobalt(II) complexes of terpyridine bases Co(L)₂₂ (1-3), where L is 4'-phenyl-2,2':6',2''-terpyridine (ph-tpy in 1), 4'-(9-anthracenyl)-2,2':6',2''-terpyridine (an-tpy in 2) and 4'-(1- pyrenyl)-2,2':6',2''-terpyridine (py-tpy in 3), are prepared and their photo-induced DNA and protein cleavage activity and photocytotoxic property in HeLa cells studied. The 1 : 2 electrolytic and three-electron paramagnetic complexes show a visible band near 550 nm in DMF-Tris-HCl buffer. The complexes 1-3 show emission spectral bands at 355, 421 and 454 nm, respectively, when excited at 287, 368 and 335 nm. The quantum yield values for 1-3 in DMF-H₂O (2 : 1 v/v) are 0.025, 0.060 and 0.28, respectively. The complexes are redox active in DMF-0.1 M TBAP. The Co(III)-Co(II) and Co(II)-Co(I) couples appear as quasi-reversible cyclic voltammetric responses near 0.2 and -0.7 V vs. SCE, respectively. Complexes 2 and 3 are avid binders to calf thymus DNA giving K(b) value of ∼10⁶ M⁻¹. The complexes show chemical nuclease activity. Complexes 2 and 3 exhibit oxidative cleavage of pUC19 DNA in UV-A and visible light. The DNA photocleavage reaction of 3 at 365 nm shows formation of singlet oxygen and hydroxyl radical species, while only hydroxyl radical formation is evidenced in visible light. Complexes 2 and 3 show non-specific photo-induced bovine serum albumin protein cleavage activity at 365 nm. The an-tpy and py-tpy complexes exhibit significant photocytotoxicity in HeLa cervical cancer cells on exposure to visible light giving IC₅₀ values of 24.2 and 7.6 μM, respectively. Live cell imaging study shows accumulation of the complexes in the cytosol of HeLa cancer cells.
钴（II）配合物的三吡啶碱基[Co（L）₂]（ClO₄）₂（1-3），其中 L 是 4'-苯基-2,2':6',2''-三吡啶（ph-tpy 在 1 中），4'-(9-蒽基）-2,2':6',2''-三吡啶（an-tpy 在 2 中）和 4'-(1- 并苯)-2,2':6',2''-三吡啶（py-tpy 在 3 中），被制备并且其在 HeLa 细胞中的光诱导 DNA 和蛋白质切割活性和光细胞毒性性质被研究。1:2 电和三电子顺磁共振配合物在 DMF-Tris-HCl 缓冲液中显示出近 550nm 的可见带。配合物 1-3 在 287、368 和 335nm 激发时分别显示出 355、421 和 454nm 的发射光谱带。在 DMF-H₂O（2:1 v/v）中，1-3 的量子产率值分别为 0.025、0.060 和 0.28。配合物在 DMF-0.1M TBAP 中是氧化还原活性的。Co（III）-Co（II）和 Co（II）-Co（I）偶合作为准可逆循环伏安响应出现在近 0.2 和-0.7V vs.SCE，分别。配合物 2 和 3 是小牛胸腺 DNA 的强烈结合物，给出∼10⁶M⁻¹的 K(b)值。配合物表现出化学核酸酶活性。配合物 2 和 3 在 UV-A 和可见光下表现出 pUC19 DNA 的氧化切割。在 365nm 下，3 的 DNA 光裂解反应显示出单线态氧和羟基自由基的形成，而只有在可见光下才证明了羟基自由基的形成。配合物 2 和 3 在 365nm 下表现出非特异性光诱导牛血清白蛋白蛋白切割活性。an-tpy 和 py-tpy 配合物在可见光照射下对 HeLa 宫颈癌细胞具有显著的光细胞毒性，IC₅₀ 值分别为 24.2 和 7.6μM。活细胞成像研究表明，配合物在 HeLa 癌细胞的细胞质中积累。
