Canadian journal article (original) (raw)
AI-generated Abstract
This study explores the preparation and characterization of charge-transfer complexes formed between benzanthrone derivatives, acting as electron donors, and iodine, an electron acceptor. Techniques employed include spectrophotometry, infrared spectroscopy, and elemental analysis, focusing on azomethine-substituted benzanthrone dyes. The results indicate that the structural modifications in the dyes influence the stability of the resulting complexes, evidenced by changes in spectral properties.
Sign up for access to the world's latest research
checkGet notified about relevant papers
checkSave papers to use in your research
checkJoin the discussion with peers
checkTrack your impact
Sign up for access to the world's latest research
Related papers
2004
The Complex formation reaction between iodine with tetrabutylammonium halides (TBAX) has been studied spectrophotometrically in chloroform solution at 25oC. Various aspects of the spectra of iodine in the presence of various concentration of different tetrabutylammonium halides have been discussed in terms of electronic specifications of iodine and halides. In the case of tetrabutylammonium iodide and at high concentrations of iodine, both 1:1 (I3 ) and 2:1 (I5 ) complexes have been formed. Formation constants of charge transfer complexes were evaluated from the computer fitting of the absorbance-mole ratio data and found to vary in the order: TBAI>TBABr>TBACl>TBAF. Introduction Investigation of polyhalide complexes has a long background [1] and various aspects of these complexes have been studied extensively. Examples are molecular orbital study [2], [3], spectrophotometric study in different solvents such as acetonitrile and dichloroethane [4], conductometric study in non...
Polish Journal of Chemistry, 2004
The interactions between benzonitrile and iodine, bromine, iodine monochloride and iodine monobromide have been It is shown that benzonitrile forms 1 : 1 complexes with the halogens in carbon tetrachloride The following formation constants (K,) have been obtained at 20': 8.1 f 0.2, 2.0 =k 0.15, 0.8 f 0.1 and 0.2 rt Compared with No charge transfer studied spectroscopically. solution. 0.05 for the iodine monochloride, iodine monobromide, iodine and bromine complexes, respectively. data reported for the corresponding acetonitrile complexes, benzonitrile is a somewhat stronger donor. bands were observed for the present systems in the ultraviolet region above 250 mw. A large number of investigators have studied the charge transfer complexes between halogens and molecules with lone pair electrons.1 Formation constants and thermodynamic functions for such systems in solution frequently have been obtained from spectroscopic data.' The geometrical features of many such complexes in the crystalline state have been obtained by Hassel and co-workers2 from X-ray methods. These studies reveal that, e.g., nitrogen bases like the amines are strong donors3,* while oxygen-containing molecules like ethers6 or aldehydess form weak complexes with iodine. A4uch less information is available about the donor properties of nitriles. The addition compounds of nitriles to some metal halides7v8 have been investigated by infrared spectroscopic methods. Popov and Deskine studied the complexes between acetonitrile and halogens. In this Laboratory the infrared and ultraviolet spectra have been obtained for the complexes formed between different nitriles and halogens. The visible and ultraviolet spectroscopic data for the benzonitrile-halogen complexes in carbon tetrachloride are presented here. In forthcoming papers the corresponding infrared data, with special reference to changes in hybridization of the nitrile group upon complex formation, will be reported. Experimental Part Chemicals.-Benzoiiitrile, analytical grade from Fluka AG was shaken with hydrochloric acid, washed and drie:. The product was distilled in a Vigreux column, b.p. 191 , and only the middle fraction was used. Iodine, analytical grade, from Merck was sublimed with calcium oxide and resublimed under nitrogen atmosphere. Bromine, analytical grade, from Merck was used without further purification. The iodine monochloride and iodine monobromide, both from Merck, were purified by repeated fractional crystallization to constant melting points of 27.2''O and 4 2 O , " respectively. Carbon tetrachloride, analytical grade, hferck, (1) G.
Absorption spectra and formation constants of steroid-iodine complexes
Archives of Biochemistry and Biophysics, 1967
Studies have been made of the ultraviolet and visible absorption spectra of steroidiodine charge transfer complexes. Iodine complexes with keto-steroids in Freon solution have absorption maxima at 25&270 ml.c, and the complexes involving carbon double bonds as donors have maxima at 320-360 rnp. Equilibrium constants range from 0.4 to 12 liters/mole. At higher concentrations, dimer complex formation was observed for 5ol-cholestan-3-one with a formation constant of 350 liters/mole. Broad peaks at 280 and 390 rnp characterize the dimer spectrum. It is suggested the dimer rearranges to an "inner" complex involving an Ia-. The enthalpies of dimers formation are surprisingly high, about 15-20 kcal/mole. Conditions for the precipit,ation and crystallization of solid complexes were investigated. The spectra of several solid complexes are somewhat' similar to the dimer spectra.
International Journal of Electrochemical Science
A combined solution and solid state study was performed to describe the complexation chemistry of iodine with three highly fluorescent bis-1,8-naphthalimide dyes. The spectroscopic properties, photostability characteristics and the mechanism of interaction were investigated and discussed. The formed complexes were characterized stoichiometrically and structurally using ultraviolet-visible, midand far-infrared spectral techniques, as well as CHN elemental analyses. A remarkable change in the UV-Vis spectra was observed when the iodine acceptor was complexed with a 1:2 stoichiometry. Far-IR measurements confirmed the formation of triiodide (I 3-). The formation constant, molar extinction coefficient and other spectroscopic data were also determined and discussed. It has been found that the complexation with iodine increases the photostability of the reported dyes. Interestingly, a strong linear correlation (r = 0.991) between half-life of photostability and dissociation energy in solution is clearly evidenced for the first time.
The addition reaction of hydroxide or ethoxide ion with benzindolium heptamethine cyanine dyes
Dyes and Pigments, 2000
This paper pertains to a nucleophilic addition reaction at the C2 atom of a benz[c]indolium or 3,3-dimethyl-1Hbenz[e]indolium subunit of the corresponding near-infrared heptamethine cyanine that contains a chlorine atom at the central meso position of the chromophore. An important ®nding is that the ecient S RN 1 replacement of the chloro substituent in such dyes is completely suppressed in the reactions (i) of hydroxide and ethoxide ions, both of which are poor single electron donors and (ii) conducted in aqueous alcohol, a medium that does not promote single electron transfer. The adducts produced were isolated and characterized by elemental analysis, 1 H NMR, and 13 C NMR. The NIR-absorbing parent dye is regenerated quantitatively upon treatment of the corresponding adduct with a weak acid, including silica gel. #
Studies on the charge-transfer interaction between Tamoxifen citrate and chloranilic acid
Charge Transfer interaction between Adenosine and PF 190 7. Studies on charge transfer interaction between adenosine and proflavine hemisulphate: Mulliken's theory of charge transfer interactions between an electron donor and electron acceptor has been successfully applied to many interesting systems [1-3]. Charge transfer complexes are known to take part in many chemical reactions like addition, substitution and condensation [4-6]. These complexes have attracted great attention in non-linear optical materials [7-10]. Electron donor-acceptor interaction is also important in the field of drugreceptor binding mechanism, in solar energy storage and in surface chemistry as well as in biological fields [11-14]. On the other hand, the CT reactions of certain-acceptors have successfully been utilized in pharmaceutical analysis [15]. Due to these wide applications, extensive studies on CT complexes ofacceptors have been performed [16]. Molecular interactions between electron donors and acceptors are generally associated with the formation of intensely colored charge transfer complexes, which absorb radiation in the visible region [17]. However, the interaction of acridine derivatives with DNA has been the subject of note worthy research over the last two decades due to the antibacterial and mutagenic properties of these compounds. The nature of the binding of acridine derivatives with DNA has been explained by Peacocke et al. [18] and Ranstein et al. [19]. Georghiou found that proflavine (PF) forms molecular complexes with nucleotides in aqueous solutions and he reported the optical properties of these complexes [20]. The absorption spectrum of the dye with DNA was studied by Karmakar and Basu in various solvents [21]. Complex formation between PF and nucleosides was indicated by the absorption and fluorescence properties of the dye [22, 23]. The photophysical studies led us to the efficient fluorescence of proflavine hemisulphate (PF) with a quantum yield of 0.64 in aqueous solution. Therefore the interaction of PF with adenosine nucleoside, which is one of four bases in the basic materials of DNA, has been studied by absorption and Chapter-VII Charge Transfer interaction between Adenosine and PF 191 fluorescence spectroscopy in water-ethanol mixtures of varying composition and the formation constants of the complexes are calculated. Studies on photophysical properties of fluorescent organic materials in aqueous solution were performed. The materials such as 9-ANCA, perylene and PF were tested for photoabsorption and emission performance with a view to use as probe and develop analytical techniques for determination and also to understand the molecular interaction with components of DNA and RNA. 7.1 Spectrophotometric study of charge transfer complex: The electronic absoption spectra of the donor adenosine, acceptor proflavine hemisulphate (PF) and the resulting charge-transfer (CT) complex in pure water, ethanol and water-ethanol compositions were recorded in visible region using absorption spectroscopy. The absorption spectra were recorded in water ethanol mixtures by keeping concentration of PF constant at 3 x10-5 mol dm-3 and adenosine concentration was varied from 1.0 x10-2 mol dm-3 to 5.0 x10-2 mol dm-3. The details of these experiments are given in Table 7.1. Table 7.1: Experimental set for absorption studies of PF in absence and presence of varying concentrations of adenosine in different water-ethanol composition Sr. No. Vol. of 1.0 x 10-5 mol dm-3 PF in ml Vol. of 0.1 mol dm-3
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.
Related papers
Journal of Molecular Structure, 2011