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Article Citation - WoS: 75Citation - Scopus: 80Unique Ligand-Based Oxidative Dna Cleavage by Zinc(ii) Complexes of Hpyramol and Hpyrimol(Wiley-v C H verlag Gmbh, 2007) Maheswari, Palanisamy Uma; Barends, Sharief; Oezalp-Yaman, Seniz; de Hoog, Paul; Casellas, Helene; Teat, Simon J.; Reedijk, JanThe zinc(II) complexes reported here have been synthesised from the ligand 4-methyl-2-N-(2-pyridylmethyl)aminophenol (Hpyramol) with chloride or acetate counterions. All the five complexes have been structurally characterised, and the crystal structures reveal that the ligand Hpyramol gradually undergoes an oxidative dehydrogenation to form the ligand 4-methyl-2-N-(2-pyridylmethylene)aminophenol (Hpyrimol), upon coordination to Zn-II. All the five complexes cleave the phi X174 phage DNA oxidatively and the complexes with fully dehydrogenated pyrimol ligands were found to be more efficient than the complexes with non-dehydrogenated Hpyramol ligands. The DNA cleavage is suggested to be ligand-based, whereas the pure ligands alone do not cleave DNA. The DNA cleavage is strongly suggested to be oxidative, possibly due to the involvement of a non-diffusible phenoxyl radical mechanism. ne enzymatic religation experiments and DNA cleavage in the presence of different radical scavengers further support the oxidative DNA cleavage by the zinc(II) complexes.Article Citation - WoS: 3Citation - Scopus: 5Spectroelectrochemical Studies of Nuclease-Active Zinc(ii) Coordination Compounds From the Ligands Hpyramol and Hpyrimol(Pergamon-elsevier Science Ltd, 2010) Ozalp-Yaman, Seniz; de Hoog, Paul; Maheswari, Palanisamy Uma; Casellas, Helene; Golobic, Amalija; Kozlevcar, Bojan; Reedijk, JanThe electrochemical oxidation of four zinc(II) coordination compounds from the ligands 4-methyl-2-(2-pyridylmethyl)aminophenol (Hpyramol()) and 4-methyl-2-(2-pyridylmethylene)aminophenol (Hpyrimol) with chloride or acetate as counter-ions has been studied by in situ spectroelectrochemistry in dimethylformamide (DMF) Low-temperature EPR studies of electrolyte solutions of all zinc compounds indicate the presence of a phenoxyl radical with a g-value in the range 2 070-2 099 which is illustrative for an electron delocalization over the metal centre The final product of this oxidative process is shown to be a benzoquinone methide derivative (C) 2010 Elsevier Ltd All rights reserved
