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Rajendran M.,Center for Research and Post Graduate studies in Chemistry
Photodiagnosis and Photodynamic Therapy | Year: 2015

Photodynamic therapy (PDT) is based on the dye-sensitized photooxidation of biological matter in the target tissue, and utilizes light activated drugs for the treatment of a wide variety of malignancies. Quinones and porphyrins moiety are available naturally and involved in the biological process. Quinone metabolites perform a variety of key functions in plants which includes pathogen protection, oxidative phosphorylation, and redox signaling. Quinones and porphyrin are biologically accessible and will not create any allergic effects. In the field of photodynamic therapy, porphyrin derivatives are widely used, because it absorb in the photodynamic therapy window region (600-900. nm). Hence, researchers synthesize drugs based on porphyrin structure. Benzoquinone and its simple polycyclic derivatives such as naphthaquinone and anthraquinones absorb at lower wavelength region (300-400. nm), which is lower than porphyrin. Hence they are not involved in PDT studies. However, higher polycyclic quinones absorb in the photodynamic therapy window region (600-900. nm), because of its conjugation and can be used as PDT agents. Redox cycling has been proposed as a possible mechanism of action for many quinone species. Quinones are involved in the photodynamic as well as enzymatic generation of reactive oxygen species (ROS). Generations of ROS may be measured by optical, phosphorescence and EPR methods. The photodynamically generated ROS are also involved in many biological events. The photo-induced DNA cleavage by quinones correlates with the ROS generating efficiencies of the quinones. In this review basic reactions involving photodynamic generation of ROS by quinones and their biological applications were discussed. © 2015 Elsevier B.V. Source


Subramanian T.,Madurai Kamaraj University | Kumarraja M.,Center for Research and Post Graduate studies in Chemistry | Pitchumani K.,Madurai Kamaraj University
Journal of Molecular Catalysis A: Chemical | Year: 2012

Mesoporous Al-MCM-41 catalyzes the chemoselective Michael addition reaction between indoles and α,β-unsaturated ketones to afford β-indolylketones at room temperature with excellent yields. The higher catalytic activity is attributed to Lewis acidic Al and the large surface area. The catalyst is readily recovered and reused more than six times without loss in its catalytic activity. The substitution at the indole nucleus occurs exclusively at the 3-position and N-alkylation products are not observed. © 2012 Elsevier B.V. Source


Kannan N.,Center for Research and Post Graduate studies in Chemistry | Veemaraj T.,Ayya Nadar Janaki Ammal College Autonomous
Electronic Journal of Environmental, Agricultural and Food Chemistry | Year: 2010

Batch adsorption dynamics and equilibrium studies for the removal of cadmium (II) ions from aqueous solution using indigenously prepared Eucalyptus globules bark carbon (EGBC), Bambusa glaucescens dust carbon (BGDC) and commercial activated carbon (CAC) have been carried out under various experimental conditions at 30 +1°C. Percentage removal of cadmium (II) ions increased with the decrease in initial concentration and increased with increase in contact time and dose of adsorbent. Amount of cadmium (II) ions adsorbed increases with the decrease in particle size of EGBC. Adsorption is highly pH sensitive. Adsorption data were modeled with isotherms and the first order kinetic equations. Kinetics of adsorption is observed to be first order with intraparticle diffusion as one of the rate determining steps. Removal of cadmium (II) ions by indigenously prepared activated carbons (IPACs) is found to be favourable and hence IPACs could be employed as an alternative adsorbent to commercial activated carbon (CAC) for effluent treatment, especially for the removal of cadmium (II) ions. Source


Senthilkumar S.,Center for Research and Post Graduate studies in Chemistry | Kumarraja M.,Center for Research and Post Graduate studies in Chemistry
Tetrahedron Letters | Year: 2014

A highly ordered nanoporous aluminosilicate (MMZY) is prepared and employed as a catalyst for the synthesis of benzimidazoles from 1,2-diaminobenzene and aromatic aldehydes. In all the cases, the reactions are highly chemoselective and afford 1,2-disubstituted benzimidazoles in excellent yield. The catalyst was characterized by electron microscopy and X-ray methods and its other advantages like functional tolerance, mildness of the reaction conditions, easy separation, and reusability are also highlighted. © 2014 Elsevier Ltd. All rights reserved. Source


Kannan N.,Center for Research and Post Graduate studies in Chemistry | Veemaraj T.,Center for Research and Post Graduate studies in Chemistry
Electronic Journal of Environmental, Agricultural and Food Chemistry | Year: 2010

Studies on batch adsorption dynamics and equilibrium for the removal of cadmium (II) ions from aqueous solution using indigenously prepared jack fruit seed (JFSC) and commercial activated carbons (CAC) have been carried out with an aim to obtain data for treating effluents from metal processing and metal finishing industries. Effect of various process parameters has been investigated by following the batch adsorption technique at 30 +1°C. Percentage removal of cadmium (II) ions increased with the decrease in initial concentration and increased with increase in contact time and dose of adsorbent. Amount of cadmium (II) ions adsorbed increases with the decrease in particle size of JFSC. As initial pH of the slurry increased, the percentage removal increased, reached a maximum and the final solution pH after adsorption decreases. Adsorption data were modeled with the Freundlich and Langmuir isotherms, the first order kinetic equations proposed by Natarajan - Khalaf, Lagergren and Bhattacharya and Venkobachar and intra- particle diffusion model and the models were found to be applicable. Kinetics of adsorption is observed to be first order with intraparticle diffusion as one of the rate determining steps. Removal of cadmium (II) ions by jack fruit seed carbon (JFSC) is found to be favourable and hence JFSC could be employed as an alternative adsorbent to commercial activated carbon (CAC) for effluent treatment, especially for the removal of cadmium (II) ions. Source

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