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Article Citation - WoS: 76Citation - Scopus: 81Unique 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, Jan; Özalp-Yaman, SenizThe 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: 8Citation - Scopus: 8Nanohydrotalcite Supported Ruthenium Nanoparticles: Highly Efficient Heterogeneous Catalyst for the Oxidative Valorization of Lignin Model Compounds(Wiley-v C H verlag Gmbh, 2017) Baguc, Ismail Burak; Celebi, Metin; Karakas, Kadir; Ertas, Ilknur Efecan; Keles, Muhammed Nuri; Kaya, Murat; Zahmakiran, MehmetThe catalytic transformation of lignocellulosic biomass derived chemicals into value-added chemicals under mild conditions remains a challenge in the fields of synthetic chemistry and catalysis. Herein, we describe a new heterogeneous catalyst system that efficiently works in the oxidative valorization of lignin model compounds. This new heterogeneous catalyst system comprised of nano-sized hydrotalcite (n-HT; Mg6Al2 (CO3)(OH)(16)) supported ruthenium(0) nanoparticles (Ru/ n-HT) was prepared by ion-exchange of [Ru(OH2)Cl-5](2-) anions with the extraframework CO32- anions of n-HT followed by their borohydride reduction (NaBH4) in water at room temperature. The characterization of Ru/n-HT was done by the combination of various spectroscopic and the sum of their results revealed that the formation of well-dispersed ruthenium(0) nanoparticles with a mean diameter of 3.2 +/- 0.9 nm on the surface of n-HT structure. The catalytic performance of Ru/n-HT in terms of activity, selectivity and stability was tested in the aerobic oxidation of cinnamyl, veratryl and vanillyl alcohols, which are important lignin model compounds used to mimic the propyl side chain, the phenolic and non-phenolic, respectively functional groups of lignin. We found that Ru/ n-HT nanocatalyst displays remarkable activity at high selectivity and almost complete conversion in these catalytic transformations under mild reaction conditions (at 373 K under 3 bar initial O-2 pressure).
