Luminescent Study of the Binding Interaction on 1,4-Dihydroxy-2,3-Dimethyl-9,10-Anthraquinone with Titanium Dioxide Nanoparticles

Abstract

The photophysical properties of 1, in the absence and presence of titanium dioxide (TiO 2 ) nanoparticles have been studied using UV-visible absorption spectro scopy and steady-state fl uorescence spectroscopy. The fl uorescence intensity of the DHDMAQ decreases as the concentration of TiO 2 nanoparticles increases. The quenching is characterized by a Stern-Volmer plot, which dis plays a positive deviation from linearity. This could be explained by static quenching models. The Stern-Volmer quenching constant, association constant, and binding constant have been calculated. The distance between DHDMAQ and TiO 2 nanoparticles has also been evaluated using Forster's theory of non-radiative energy transfer. Introduction.Anthraquinone is an aromatic organic compound and an important quinone derivative of anthracence. Anthraquinone is chemically stable under normal condition. Anthraquinone naturally occurs in some plants like aloe, cascara, senna, buckthorn etc. They are used principally in photographic dye chemicals, in the paper industry as a catalyst, in the textile industry for coloring textile materials, and in medicine as an antioxidant. The hydroxyanthraquinone chromophore is the biologically active site in several antitumor anthracyclines. The stacking interaction between the chromophore of the drug and the base pair of DNA has been studied by means of several spectroscopic studies. Hydroxyanthraquinone glycosides are found in the leaves and fl ower of Cassia fi stula Linn [1]. It is also found in the leaves and bark of cassia podocarpa. Its commercialization is enhanced as a laxative due to its antimicrobial effect [2].The chemistry of anthraquinones [3] is based mainly on the concept of their exclusively 9,10-anthraquinoid structures. However, a growing amount of facts indicates a considerably greater role of tautomeric anthraquinones in chemical [4] and photochemical [5] processes. Since the majority of the applications of anthraquinones concern their color, spectrophotometry held a special position among the physicochemical methods used in their investigation. The information on absorption spectra [6] is very important for establishing the relation between the structure and properties. Titanium dioxide (TiO 2 ) is a material with applications in solar energy transfer and photocatalysis of poisonous compounds in the environment [7]. Further, the strong oxidizing power of the photogenerated holes, the chemical inertness, and the nontoxity of TiO 2 NPs has also made it a superior photocatalyst [8]. The use of TiO 2 NPs as a pigment in paints and the global oil crisis have inspired scientifi c and renewed interest in this material and the problem of using TiO 2 NPs for splitting of water, based on the principles of photoelectrochemistry [9]. This material is known to exist in several forms, among the most abundant being anatase, rutile, and brookite [10]. TiO 2 NPs are generally considered to be toxicologically inert, is manufactured in large quantities, and is extensively applied in consumer products such as s...

Understanding Interaction of Engineered Nanomaterials and Dissolved Organic Matters in River Sediments

“…Hence, static quenching was ascribed to the complexation of humic-like substances and nano-TiO 2 . Previous studies also approved that the interaction between nano-TiO 2 and anthraquinone substances could initiate static quenching (Pushpam et al, 2014). Phenolic group could cause the attachment of humic-acid substances, and smaller carboxyl groups also could set off complexation with nano-TiO 2 (Philippe and Schaumann, 2014).…”