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Adisorn Ratanaphan Tidarat Nhukeaw Pornvichai Temboot Kanidtha Hansongnern 《Transition Metal Chemistry》2012,37(2):207-214
A bidentate ligand, 5-chloro-2-(phenylazo)pyridine (Clazpy), and its two polypyridyl ruthenium(II) complexes, [Ru(Clazpy)2bpy]Cl2·7H2O (1) and [Ru(Clazpy)2phen]Cl2·8H2O (2), were synthesized and characterized. The DNA-binding properties of these complexes with DNA, the breast cancer susceptibility
gene 1 (BRCA1), and the pBIND plasmid DNA were probed by photocleavage, electronic absorption titration, ethidium bromide quenching, and
thermal denaturation. Both complexes were found to bind to the BRCA1 fragment through the intercalative mode into the base pairs of DNA, and the DNA-binding constants (Kb) for 1 and 2 were 7.0 × 104 M−1 and 5.1 × 105 M−1, respectively. In addition, both complexes enhanced the single-stranded cleavage of the plasmid DNA. Under comparable experimental
conditions, 2 cleaved DNA more effectively than 1, in a dose–response manner. The data indicated that the binding affinity of these two complexes to DNA was dependent on the
aromatic planarity and hydrophobicity of the intercalative polypyridyl ligand. 相似文献
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Tidarat Komolwanich Patomwat Tatijarern Sirirat Prasertwasu Darin Khumsupan Thanyalak Chaisuwan Apanee Luengnaruemitchai Sujitra Wongkasemjit 《Cellulose (London, England)》2014,21(3):1327-1340
Two-stage microwave (microwave/NaOH pretreatment followed by microwave/H2SO4 pretreatment) was used to release monomeric sugars from Kans grass (Saccharum spontaneum) and Giant reed (Arundo donax). The optimum pretreatment conditions were investigated, and the maximum monomeric sugar yields were compared. The microwave-assisted NaOH and H2SO4 pretreatments with a 15:1 liquid-to-solid ratio were studied by varying the chemical concentration, reaction temperature, and reaction time to optimize the amount of monomeric sugars. The maximum amounts of monomeric sugars released from microwave-assisted NaOH pretreatment were 6.8 g/100 g of biomass [at 80 °C/5 min, 5 % (w/v) NaOH for S. spontaneum and at 120 °C/5 min, 5 % (w/v) NaOH for A. donax]. Furthermore, the maximum amounts of monomeric sugars released from microwave-assisted H2SO4 pretreatment of S. spontaneum and A. donax were 33.8 [at 200 °C/10 min, 0.5 % (w/v) H2SO4] and 31.9 [at 180 °C/30 min, 0.5 % (w/v) H2SO4] g/100 g of biomass, respectively. The structural changes of S. spontaneum and A. donax were characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. 相似文献
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4‐Tolyldiphenylamine (TDPA) and N,N′‐diphenyl‐N,N′‐bis(4‐methylphenyl)‐1,1′‐biphenyl‐4,4′‐diamine (TPD), were reacted with benzaldehyde (BA) using p‐toluenesulfonic acid as a catalyst to yield linear polymers. The polymers were reacted with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) in tetrahydrofuran (THF) at room temperature. 1H‐NMR showed that all the methine protons in the residue of BA were completely removed at the mole ratio of repeating unit : DDQ, 2 : 1. The resulting polymers showed good solubility in chloroform or THF. The reacted TDPA‐BA and TPD‐BA polymers gave new UV absorption peaks at 697.0 and 722.5 nm and showed reversible redox potentials about 0.994 and 1.021 V, respectively. Direct current (d.c.) conductivity of the reacted polymers was in the range of 10?11 S/cm, which is more than two orders higher than the unreacted polymers. The polymer showed pentad split electron spin resonance (ESR) signal, whose concentration was one in 670 or 230 repeating unit for TDPA‐BA and TPD‐BA polymers, respectively. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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