Solution Studies of Some Binary and Ternary Lanthanide Complexes

Tyagi, Shalu; Kumar, and Rajeev

doi:10.1021/je0400097

Cited by 5 publications

(4 citation statements)

References 16 publications

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“…Acidity is numerically estimated as p K a values and defines in what form uracil and its derivatives are presented under certain conditions. Currently, the experimental p K a values of uracils (See Supporting Information) have been obtained with potentiometric, − spectrophotometric, ,− and argentometric titration . A good agreement is observed for the results obtained by different techniques (with rare exceptions).…”

Section: Introductionmentioning

confidence: 99%

Theoretical Models for Quantitative Description of the Acid–Base Equilibria of the 5,6-Substituted Uracils

et al. 2017

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The acidities of 18 5,6-substituted uracils have been numerically estimated as pK values in terms of three theoretical models. The first scheme includes the calculation of the gas-phase acidity of uracil with the G3MP2B3 method and taking into account the solvent effect using the polarizable continuum approximation PCM(SMD)-TPSS/aug-cc-pVTZ. The second model is one step and implies calculation of the free Gibbs energies of the hydrate complex of uracil (and its anion) with 5 water molecules by the TPSS/aug-cc-pVTZ method. This model accounts for the solvent effect corresponding to both specific and nonspecific solvation. The third scheme required high time and computational resources and includes the strong features of the two previous schemes. Here, the theoretical estimation of pK is performed by the CBS-QB3 composite method. As in the second approach, both specific (as pentahydrate) and nonspecific solvent effects are determined. We have analyzed the advantages and model restrictions of the considered schemes for the pK calculations. All models have systematic errors, which have been corrected with the linear empirical regression relations. In the presented model, the absolute mean deviations of the pK values of uracils dissociating via the N1-H bonds diminish to 0.25, 0.28, and 0.23 pK units (respectively, for I, II, and III models), which corresponds to ∼0.3 kcal/mol on the energy scale. The applicability of our computational schemes to uracils dissociating via N3-H, O-H (orotic acids) and C-H bonds is discussed.

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Section: Introductionmentioning

confidence: 99%

Theoretical Models for Quantitative Description of the Acid–Base Equilibria of the 5,6-Substituted Uracils

et al. 2017

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“…Ternary interaction of naphthochrome green (NCG) with cetyltrimethylammonium bromide (CTAB) and rare earths (REs: Yb, Dy, Er and Eu) has been investigated with the microsurface adsorption-spectral correction technique (MSASC) 9 . The solution studies of ternary (1:1:1) complexes of Eu(III), Gd(III) and Tb(III) with benzoic acid/ its derivatives and uracil/ its halo derivatives in dioxane-water (30:70 v/v) medium (ionic strength I = 0.1 mol•dm -3 NaNO 3 ) have been performed 10 . Cationic surfactants, such as cetylpyridinium bromide (CPB) sensitize the color reaction of Nb(V) with 1-(2-benzothiazolylazo)-2-hydroxy-3-naphthoic acid (I a ), 5-(benzothiazolylazo)2,5-naphthalenediol (I b ), 5-(2-benzothiazolylazo)8-hydroxyquinoline (I c ) and 4-(2-benzothiazolylazo) 2,2 -biphenyldiol (I d ) reagents have also been reported 11 .…”

Section: Introductionmentioning

confidence: 99%

Spectrophotometric Study of Ternary Complex Forming Systems of Some Lanthanide Metal Ions with Eriochrome Cyanine R in Presence of Cetylpyridinium Bromide for Microdetermination

Dhepe¹,

Zade²

2010

Journal of Chemistry

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Study of coordination compounds of lanthanide elements has received a great attention due to growing applications in science and technology. Number of chromogenic reagents form water soluble colored complexes with lanthanides. Eriochrome cyanine R (ECR) a member of triphenylmethane type of dye has been reported to form green colored complexes with lanthanides and has been used for microdetermination of these metal ions. Addition of cationic surfactant, Cetylpyridinium bromide (CPB), a cationic surfactant sensitizes the color reactions of Gd(III), Tb(III), Dy(III), Ho(III) and Lu(III) with ECR. Formation of water soluble, highly colored ternary complexes with a considerable bathochromic shift of about 50 nm in presence of surfactant has been observed. Optimum reaction conditions and other analytical parameters were also evaluated. Stoichiometric ratio 1:3:3 of Ln: ECR: CPB are responsible for the observed rise in molar absorptivity and sensitivity. Beer’s law was obeyed between 0.50 to 13.00 ppm. Effective photometric range and molar absorptivity of these ternary complexes have been calculated. Effect of some common interfering ions on determination of these lanthanide metal ions was studied. A simple, rapid and highly sensitive spectrophotometeric method has been proposed for the determination of metal ions understudy.

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“…Among numerous materials and metal ions to be chosen, on one hand, lanthanum hydroxide nanowire (LNW) was selected as it possesses not only attractive properties of nanomaterials such as high surface area-to-volume ratio but also chemically special properties of La(III) ion such as electrochemical inertia and chemical coordination capability, especially with pyrimidine nucleobases (Reddy and Malleshwara 1986;Tyagi et al 2005). On the other hand, copper(II) ion was selected because both nontoxic copper(II) and copper(I) ions are known to possess low redox potential, and enable the coordination of uracil (Cummings and Elving 1978;.…”

Section: Introductionmentioning

confidence: 99%

Sensing System Integrating Lanthanum Hydroxide Nanowires with Copper(II) Ion for Uracil and its Application

Liu

Song

et al. 2007

Analytical Letters

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A sensing system for uracil was constituted by using lanthanum hydroxide nanowires (LNW) as a modifier to obtain LNW modified carbon paste electrode (LNW/CPE) and by introducing copper(II) ion into supporting electrolyte to transform electroinactive uracil to electroactive uracil-Cu(II) complex. The voltammetric behaviors of uracil in the presence of Cu(II) ion at LNW/CPE were investigated. A reduction peak of the uracil-Cu(II) complex at 20.18 V was the two-electron reduction of Cu(II) ion in the uracil-Cu(II) complex; while a new oxidation peak at 0.22 V was the one-electron oxidation of the uracil-Cu(I) complex. Additionally, the voltammetric responses of all the complexes at LNW/CPE were more sensitive than that at carbon and multiwall carbon nanotube paste electrodes, which resulted from both the large surface effect of LNW and the chemical coordination of uracil with La(III) ion in LNW. With the sensitive oxidation peak of the uracil-Cu(I) complex at LNW/CPE, a linear range of 4.0 Â 10 29 2 3.0 Â 10 28 mol/l for uracil was obtained along with a detection limit of 2.0 Â 10 210 mol/l. The proposed system was evaluated by the determination of uracil derivatives, anticancer drug 5-flurouracil, in pharmaceutical preparations.

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Solution Studies of Some Binary and Ternary Lanthanide Complexes

Cited by 5 publications

References 16 publications

Theoretical Models for Quantitative Description of the Acid–Base Equilibria of the 5,6-Substituted Uracils

Theoretical Models for Quantitative Description of the Acid–Base Equilibria of the 5,6-Substituted Uracils

Spectrophotometric Study of Ternary Complex Forming Systems of Some Lanthanide Metal Ions with Eriochrome Cyanine R in Presence of Cetylpyridinium Bromide for Microdetermination

Sensing System Integrating Lanthanum Hydroxide Nanowires with Copper(II) Ion for Uracil and its Application

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