Showing papers in "Journal of Inclusion Phenomena and Macrocyclic Chemistry in 2001"
TL;DR: In this article, the binding constants of host-guest chemistry have to be determined on many occasions, and the basic principle and the practical issue of determining binding constants is discussed, together with a practical experimental guideline, a representative method for the determination of stoichiometry and for the evaluation of a complex concentration, precautions to be taken on setting upconcentration conditions of the titration experiment, and a data-treatment method and estimation of statistical errors.
Abstract: When working in the field ofhost–guest chemistry, the binding constants have to bedetermined on many occasions Here is a detaileddocument of how to determine the binding constantswhich covers both the basic principle and thepractical issue: a practical experimental guideline,a representative method for the determination ofstoichiometry and for the evaluation of a complexconcentration, precautions to be taken on setting upconcentration conditions of the titration experiment,practical data-treatment methods and estimation ofstatistical errors This document is described indetail using the basic level of mathematics,statistics, and programs of spreadsheet softwareEspecially, the titration experiments by means ofUV-visible and NMR spectroscopy are carried out anddescribed
536 citations
TL;DR: In this paper, the authors present the results of their own study to demonstrate the potentials over the limits of the conventional calixarenes, putting emphasis on the indispensable role of the bridging sulfur.
Abstract: Heteroatom-bridged calixarenes have been confined intothe unexplored frontier of the vast realm of the calixarene chemistry because of their syntheticdifficulty. Since we found facile one-step synthesis of thiacalix[4]arene, in which four methylenebridges of calix[4]arene are replaced by four sulfides, we have been engaged in the study on thisnew molecular platform regarding the improvements for the synthetic procedures, structuralanalyses, chemical modifications, and functional developments. In this review are describedthe results of our own study to demonstrate the potentials over the limits of the conventionalcalixarenes, putting emphasis on the indispensable role of the bridging sulfur. Highlighted examples are(1) enlargement of the calix skeleton to provide larger cavity, (2) ready oxidizability to sulfoxideand sulfone for providing new members of S bridged calixarenes, and (3) coordination to specificmetal ions controlled by the oxidation state of S. These indicate a hopeful future for thethiacalixarene platform in the forthcoming applications to functional molecular devices.
169 citations
TL;DR: The analysis of the different compounds of the human sweat complexed by the cyclodextrins offers new possibilities in medical diagnostics and the formation of body odor is reduced by the complexes of the organic compounds of sweat.
Abstract: New areas of applications of cyclodextrins with textiles are possible The abilityof cyclodextrins to form inclusion complexes can be used, eg, to remove malodorfrom textile materials The permanent fixation of cyclodextrins offers new textileswith interesting properties Thus the formation of body odor is reduced by thecomplexation of the organic compounds of sweat The release of perfumes fromcyclodextrins is possible by the use of textiles with fixed cyclodextrins Pharmaceutical compounds are also set free in contact with the skin Last but not least the analysis of the different compounds of the human sweat complexed by the cyclodextrins offers new possibilities in medical diagnostics
137 citations
TL;DR: In this article, a host simultaneously binds both cationic and anionic guests, and the binding of one guest ion can induce electrostatic and conformational changes in the host, thereby enhancing the complexation of the counter ion.
Abstract: A small, but emerging field of topical interest in supramolecularchemistry is ion-pair recognition, in which a host simultaneously binds both cationicand anionic guests. Details of these receptors, which combine, for example, crownethers and calixarenes for cation complexation, with Lewis acid centers, pyrroles, amidesor urea groups for anion recognition, will be discussed. The predicate of this approach,successfully achieved in certain instances, is that the binding of one guest ion caninduce electrostatic and conformational changes in the host, thereby enhancing thecomplexation of the counter ion.
125 citations
TL;DR: In this article, a simple way to prepare cucurbit[5]uril is described, and the solubility of cucurbits in aqueous acids has been investigated by means of calorimetric titrations.
Abstract: A simple way to prepare cucurbit[5]uril is described. The macrocycles of the cucurbituril type are nearly insoluble in water. The solubilities of cucurbit[5]uril, decamethylcucurbit[5]uril and cucurbit[6]uril in hydrochloric acid, formic acid and acetic acid of different concentrations have been investigated. Due to the formation of complexes between cucurbit[n]urils and protons the solubility increases in aqueous acids. The macrocyclic ligands are able to form complexes with several organic compounds. Thus, the complex formation of the cucurbituril macrocycles with different amines has beenstudied by means of calorimetric titrations. The reaction enthalpy gives noevidence of the formation of inclusion or exclusion complexes. 1H-NMR measurements show that in the case of cucurbit[5]uril and cucurbit[6]uril the organic guest compound is included within the hydrophobic cavity. Decamethylcucurbit[5]uril forms only exclusion complexes with organicamines. This was confirmed by the crystal structure of the decamethylcucurbit[5]uril-1,6-diaminohexane complex.
91 citations
TL;DR: In this paper, some aspects of complexformation, liquid-liquid extraction, and transport through liquid membrane of various amine compounds like ammonium ion, amines, amino acids and peptides, withmacrocyclic receptors, such as crown ethers,cryptands, calixarenes, and cucurbituril are presented.
Abstract: Some aspects of complexformation, liquid–liquid extraction, and transportthrough liquid membrane of various amine compoundslike ammonium ion, amines, amino acids and peptides, withmacrocyclic receptors, such as crown ethers,cryptands, calixarenes, and cucurbituril arepresented. Log K, Δ H, andTΔ S data are reported for reaction of somerepresentative complexes of the amine compounds bymacrocyclic receptors obtained from differenttechniques such as calorimetric and potentiometrictitrations, or spectrophotometric methods in varioussolvents. Solvent extraction and transport of thesecomplexes through bulk liquid membranes are alsostudied. Based on these studies, the effect of somefactors that might influence the complex formation,the extraction, and the transport through liquidmembranes are discussed.
90 citations
TL;DR: In this paper, the authors examined the complex formation between cucurbit[5]uril, decamethylcucurbit [5]-uril and cucurbitsuril in aqueous solution and calculated the stability constants of the complexes formed without the knowledge of the exact solubility of the ligand.
Abstract: The complex formation between cucurbit[5]uril, decamethylcucurbit[5]uril and cucurbit[6]uril and alkali, alkaline earth and ammonium cations is examined. The solubility of these ligands is rather small in aqueous solution. In the presence of salts the solubility normally increases due to the formation of complexes. The total concentration of the ligands can be easily measured from the total organic carbon content of the salt solutions saturated with the ligand. From these results it is possible to calculate the stability constants of the complexes formed even without the knowledge of the exact solubility of the ligand.
72 citations
TL;DR: The minimum inhibitory concentration (MIC50) of the chlorhexidine : β-cyclodextrin inclusion compound against Streptococcus mutans, Eubacterium Lentum, Fusobacterium nucleatum, Bacteroides fragilis and Actinomices actinomycetemcomitans was determined.
Abstract: The 1 : 2 chlorhexidine : β-cyclodextrin(Cx : βCD) complex was prepared and characterised using X-ray crystallography, infrared spectroscopy, thermal analysis and nuclearmagnetic resonance. The minimum inhibitory concentration (MIC50) of the chlorhexidine : β-cyclodextrin inclusion compoundagainst Streptococcus mutans, Eubacterium Lentum, Fusobacterium nucleatum, Bacteroides fragilis andActinomices actinomycetemcomitans was determined. TheCx : βCD inclusion compound inhibited the bacterial growth at a low concentration.
69 citations
TL;DR: Molecular imprinting has gained increasing research interest during the past few years as mentioned in this paper, and the main focus will be on the present state of the art of molecular imprinting, as several breakthroughs have occurred since most reviews by us and other groups.
Abstract: Molecular imprinting has gained increasing research interest during the past few years. In this overview we would like to explain to the readers how a seemingly simple concept can eventually lead to useful applications in several areas. The main focus will be on the present state of the art of molecular imprinting, as several breakthroughs have occurred since most reviews by us and other groups have been written. In the last part of this article we would like to discuss future developments in the area of molecular imprinting.
63 citations
TL;DR: In this paper, a review of various synthetic routes to guanidiniums and a novel approach that allows the mild formation of multi-substituted derivatives is presented.
Abstract: The guanidinium group is found in many natural products and has been extensively incorporated into various drug designs as well as artificial receptor structures. In this paper we critically review the various synthetic routes to guanidiniums and describe a novel approach that allows the mild formation of multi-substituted derivatives.
56 citations
TL;DR: In this paper, the formation and structure of inclusion complexes of α- and β-cyclodextrins with 2-chlorophenol (2CP), 3-chlorophenol (3CP), 4-chloropharmol (4CP), 2,6-dichlorophenol(26DCP), and 3,4-diclorophenols (34DCP) were studied by UV-VIS and 1H NMR spectroscopy.
Abstract: The formation and structure of inclusion complexes of α- andβ-cyclodextrins with 2-chlorophenol (2CP), 3-chlorophenol (3CP),4-chlorophenol (4CP), 2,4-dichlorophenol (24DCP), 2,6-dichlorophenol(26DCP) and 3,4-dichlorophenol (34DCP) have been studied by UV-VIS and1H NMR spectroscopy. Both cyclodextrins were found to form 1:1inclusion complexes. Bindingconstants estimated from titration studies revealed that the stability of the complexes was highly dependent on the structure and polarity of the chlorophenol and on the cyclodextrin used. In general, weaker binding constants were observed for a given chlorophenol with α-cyclodextrin than withβ-cyclodextrin. The weakest binding constants (Kb < 200 M-1) were obtained for the ortho-substituted chlorophenols (2CP and 26DCP) and the largest binding constants were obtained between para-chlorophenols (4CP, 24DCP and 34DCP) andβ-cyclodextrin. 2D-TROESY studies of chlorophenol-cyclodextrincomplexes in D2O provided insight into the structure of the complexes.
TL;DR: In this paper, the authors performed PM3 calculations on the complexation of α-cyclodextrin (α-CD) with nitrobenzene, benzoic acid and 4-nitrophenolate anion.
Abstract: PM3 calculations were performed on the complexation of α-cyclodextrin (α-CD) with nitrobenzene, benzoic acid, benzoate anion, 4-nitrophenol, and 4-nitrophenolate anion. The results, in agreement with the experimental observations, indicated that the complex α-CD-benzoic acid was more stable than α-CD-nitrobenzene, and α-CD-4-nitrophenolate was more stable than α-CD-4-nitrophenol. Frontier orbital analysis suggested that charge-transfer interaction led to such behaviors, and hence constituted a nontrivial driving force in the molecular recognition of α-CD.
TL;DR: By copolymerizing acryloyl cyclodextrin (CD) and N,N'-methylenebisacrylamide with vinylated silica-gel in the presence of a template in water, a thin layer of molecularly imprinted CD polymer was immobilized on a porous silicagel support as mentioned in this paper.
Abstract: By copolymerizing acryloyl cyclodextrin (CD) andN,N'-methylenebisacrylamide with vinylated silica-gel in the presence of a template in water,a thin layer of molecularly imprinted CD polymer was immobilized on a porous silica-gel support. This mechanically weak polymer was reinforced by the silica-gel andsuccessfully used as a stationary phase in high-performance-liquid-chromatography (HPLC). When L-Phe-L-Phe was the template, the polymer/silica-gel conjugate retainedL-Phe-L-Phe in the aqueous eluent more strongly than D-Phe-D-Phe. As expected, the D-Phe-D-Phe-imprinted polymer retained D-Phe-D-Phe more strongly than L-Phe-L-Phe. Selective separation of antibiotics was also achieved by thepolymer/silica-gel conjugate. Molecularly imprinted CD polymer, immobilizedon silica-gel, is an eminent stationary phase for HPLC in water.
TL;DR: In this paper, a review of recent progress made in the field of molecular recognition involving multi-point selective binding processes, in which the establishment of a strong coordination bond is finely tuned by one or more weak interactions adequately introduced in the architecture of a functionalized zinc(II)-porphyrin, is presented.
Abstract: The tremendous efforts made in order to control the coordination chemistry of hemoprotein models have considerably enhanced the synthesis of functionalized porphyrins, whose carefully designed architectures allowed for selective bindings of exogenic substrates. The common use of zinc(II) in place of pentacoordinated iron(II) has induced the use of zinc(II) porphyrins as building blocks for selective receptors. These receptors offer a convenient combination of multi-point recognition of substrates, and monitoring of the complexation due to the chromophoric nature of the tetrapyrrolic unit. This review is dedicated to recent progress made in the field of molecular recognition involving multi-point selective binding processes, in whichthe establishment of a strong coordination bond is finely tuned by one or more weak interactions adequately introduced in the architecture of a functionalized zinc(II)-porphyrin.
TL;DR: Theresorcinarene-derived surfactants are highly effective at stabilizing metal nanoparticles of different sizes, creating opportunities tofabricate well-defined nanostructures with size-tunable materials properties as mentioned in this paper.
Abstract: Calix[4]resorcinarene-derived surfactants are highly effectiveat stabilizing metal nanoparticles of different sizes, creating opportunities tofabricate well-defined nanostructures with size-tunable materials properties. Theresorcinarenes have a critical role in the dispersion of nanoparticles under varioussolvent conditions and in the robustness of the protective surfactant layer.Magnetic cobalt particles stabilized by resorcinarenes self-assemble intonanostructured ``bracelets'' in toluene. Resorcinarene surfactants can also promote theself-organization of gold nanoparticles as large as 170 nm into two-dimensional arrays. Thesenanostructured films possess novel optoelectronic properties such as surface-enhancedRaman scattering (SERS), and are expected to have useful applications for chemical sensing.
TL;DR: In this article, the stability constants of host guest complexes of 4-sulphonic calix[n]arenes with testosterone in water and buffers (pH 5.8, 7.3 and 10.0) were determined from phase solubility curves.
Abstract: The complexation between water soluble calixarenes and testosterone has been studied. Stability constants of the host guest complexes of 4-sulphonic calix[n]arenes (n = 4, 6 and 8) with testosterone in water and buffers (pH 5.8, 7.3 and 10.0) were determined from phase solubility curves. These solubility curves indicated that the complexes were all of the AL type. The constants were in the range 26–341 M-1, dependent on the size of the calixarene and the pH of the solutions.
TL;DR: In this paper, the effect of the type of cyclodextrin (α-, β-, γ-, hydroxypropyl-β-CD) and of hydroxyacid (tartaric, citric, gluconic,malic, lactic) on the solubility enhancement by multicomponent complexation of econazole, a poorly water soluble base-type drug, was studied.
Abstract: The effect of the type of cyclodextrin (α-, β-, γ-,hydroxypropyl-β-CD) and of hydroxyacid (tartaric, citric, gluconic,malic, lactic) on the solubility enhancement by multicomponent complexationof econazole, a poorly water soluble base-type drug, was studied. A synergisticeffect was found in ternary systems, largely more effective than correspondingbinary complexes and salts. Moreover, the presence of a third component madeeffective the use of γ-CD, which had no solubilizing power in binarysystems. The solubilizing efficiency of multicomponent systems was not relatedto the solubilities of the corresponding salts or binary complexes. Phase-solubility analysis at different temperatures was also used to investigate the interaction of econazole with cyclodextrins, alone or in the presence of hydroxyacid. The best 1 : 1 : 1 molar ratio system was that with α-CD and malic acid which showed the best solubilizing power and the highest stability constant of the ternary complex.Ternary α-CD products, prepared by co-grinding, co-evaporation or colyophilization, were characterized by Differential Scanning Calorimetry and tested for dissolution properties. The higher solubilizing properties of multicomponent systems were reflected in better drug dissolution rates from their solid systems.
TL;DR: 6-CiO-α-CD formed intermolecular complexes to give supramolecular oligomers in the solid state as discussed by the authors, and 6-cinnamoyl β-cyclodextrin (6-HyCiOs-β-CD) formed insoluble supersampledes in the liquid state.
Abstract: 6-Hydrocinnamoyl α-cyclodextrin(6-HyCiO-α-CD), 6-hydrocinnamoyl β-cyclodextrin(6-HyCiO-β-CD), 6-cinnamoyl α-cyclodextrin(6-CiO-α-CD), and 6-cinnamoyl β-cyclodextrin (6-HyCiO-β-CD) have been prepared.6-HyCiO-β-CD formed an intramolecular complex in an aqueous solution. 6-HyCiO-α-CD formed weak intermolecular complexes.6-CiO-α-CD formed intermolecular complexes to give supramolecular oligomers. 6-CiO-β-CD formed insoluble supramolecular complexes in the solid state. The structures of these complexes are discussed.
TL;DR: In this paper, the effect of α-, β- and γ-cyclodextrin on the photochemical stability of 7-amino-4-methylcoumarin (C120) was studied.
Abstract: The effect of α-, β- and γ-cyclodextrin onthe photochemical stability of 7-amino-4-methylcoumarin (C120)was studied. Using spectroscopic techniques (UV/Vis absorption spectroscopy, fluorescence, fluorescence anisotropy and circular dichroism) combined with HPLC/MS and MS analysis it was demonstrated that addition of β-cyclodextrin to the aqueoussolution of C120 markedly inhibits the photodegradation of that dye. This results from theformation of an inclusion complex between C120 and β-cyclodextrin.
TL;DR: In this article, the complexation reactions of the electron rich, linear and bi-functional ligand, 9,10-bis(4-pyridyl)anthracene, with metal salts Cd(NO3)2, CdI2, CoI2 and CuI were studied.
Abstract: The complexation reactions of the electron rich, linear and bi-functional ligand, 9,10-bis(4-pyridyl)anthracene, with metal salts Cd(NO3)2, CdI2, CoI2 and CuI in the presence of guest molecules nitrobenzene, benzene and alkoxysilanes were studied. The single crystal analyses of the complexes reveal that an electron deficient guest molecule such as nitrobenzene consistently templated the open two-dimensional network with grid dimensions of ca. 15 × 15A. On the other hand the presence of benzene or alkoxysilane templated1D-zigzag chains and/or 2D-grid layers. The crystal structures revealthe importance of host–guest interactions in tailoring the network architectures ofcoordination polymers.
TL;DR: In this paper, a series of complexes of the type [Sn(TTP)L2] have been prepared by the condensation of [sn(tetratolylporphyrin) with a range of substituted phenols.
Abstract: A series of complexes of the type [Sn(TTP)L2] have been prepared by the condensation of [Sn(TTP)OH2] (TTP = meso-tetratolylporphyrin) with a range of substituted phenols. The resulting complexes were characterised using 1H NMR and single crystal X-ray diffraction techniques. In each case, the condensation of the phenols with the Sn(IV)porphyrin in CDCl3 solution is slow (h) but essentially quantitative. The slow kinetics of the formation of the diaxial phenolate complexes allows for the identification, by 1H NMR spectroscopy, of three independent complexes within this process, namely an outer-sphere (H-bonded) complex as well as two independent phenolate complexes. The rate of condensation is in the order phenol ≫ 4-methoxyphenol > 4-nitrophenol and suggests a steric rather than pKa dependency.
TL;DR: In this paper, a 2D coordination polymer was constructed from a hexaazamacrocyclic complex with methyl pendant arms and BTC3- layers, and the X-ray structure of 2 showed that the nickel(II) complex and BTC-3- formed a 2-dimensional coordination polymer.
Abstract: Inclusion studies for metal-organic open-frameworks, [Ni(C10H24N4)(H2O)2]3[BTC]2·24H2O (1) and [Ni(C10H26N6)]3 [BTC]2·18H2O(2) (BTC3- = 1,3,5-benzenetricarboxylate) with various organic andinorganic guest molecules have been carried out. 1 is the previously reportedmolecular floral lace with 1-D channels, where positively charged macrocyclic layersand negatively charged BTC3- layers are alternately packed by hydrogen bondinginteractions. 2 is assembled in this study from nickel(II) hexaazamacrocyclic complexcontaining methyl pendant arms and BTC3-. The X-ray structure of 2 shows thatthe nickel(II) complex and BTC3- form a 2-D coordination polymer. The XRPD patternsof 2 indicate that framework of 2 is slightly deformed upon removal of waterguest molecules but restored upon rebinding of water. The host solid 1 binds MeOHin toluene, and 1,3,5-trihydroxybenzene (THB) and 4-hydroxyacetophenone (HAP) in EtOH/toluene (v/v = 1/4) solutions. The binding constants (Kf) of 1 forMeOH, THB, and HAP are 66.4 M-1, 259 M-1, and 13.9 M-1,respectively. In the range of high concentration of the guest, however, the host showsvarious binding curves depending upon the types of guest. It binds PhOH in toluene,showing a sigmoid curve. It also binds transition metal complexes such as[Cu(NH3)4](ClO4)2, [Cu(ethylenediamine)2](ClO4)2,[Cu(histamine)2](ClO4)2, and[Cu(N,N'-bis(3-aminopropyl)ethylenediamine)](ClO4)2 in MeCN, with Kf values of 645 M-1, 9.52 M-1, 37.2 M-1, and 6.00 M-1,respectively. The host solid 2 binds selectively PhOH over PhCl and PhBr, showing that hydrogen bonding interaction between the host and guest plays an important role in the selectivity.
TL;DR: 1H NMR studies show that fatty acid protonation has a distinct effect on the chemical shift of CD protons, and the data demonstrate that the cyclodextrin cavity size exerts a greater influence on the association constant than the chain length of the acid for these compounds.
Abstract: This work evaluates the influence of the β- and γ-cyclodextrin (CD) cavity size on the association constant (KCDA) with decanoate (C10) and octanoate (C8) anions. The spectral displacement technique with phenolphthalein was used to obtain the 1:1 association constant (KCDA) in NaHCO3/NaOH buffer pH 10.5 at 25 °C. The KCDA value obtained were 2.6 (±0.2) × 103, 2.5 (±0.5) × 102, for beta;CD–C10 and γCD–C10 inclusion complexes, and 5.1 (±0.2) × 102 and 4.7 (±0.2) × 101 for βCD–C8 and γCD–C8 inclusion complexes, respectively. The KCDA values of either acid with βCD is approximately 10 times higher than for the same acid with γCD, where as for the same cyclodextrin, the KCDA value is 5 times higher for the C10 association than for the C8. The data demonstrate that the cyclodextrin cavity size exerts a greater influence on the association constant than the chain length of the acid for these compounds. 1H NMR studies show that fatty acid protonation has a distinct effect on the chemical shift of CD protons.
TL;DR: In this article, the number of molecules within a column of n-butanol columns was measured using the 'Sergeant and Soldiers' data, and the results showed a strikingly good match with data obtained from a theoretical model describing the self-assembly of the discotic molecules as a function of temperature and concentration.
Abstract: Strong amplification of chirality occurs in dynamic, but highly ordered, helical columns in n-butanol, for which one chiral seed molecule suffices to render a column of 400 molecules to become homochiral. The chiral columns are formed in a thermally dependent stepwise process. The transition from achiral stacks to helical columns is highly cooperative owing to well-defined intermolecular interactions. `Sergeant and Soldiers' measurements allow for the calculation of the association constant and cooperativity length of the homochiral segments. The `Sergeant and Soldiers' data on the number of molecules within a column show a strikingly good match with data obtained from a theoretical model describing the self-assembly of the discotic molecules as a function of temperature and concentration.
TL;DR: In this article, the extraction of Se(VI and Cr(VI) using a diammoniumcalix[4]arene was investigated and a study of parameters such as ligand concentration, pH or diluent was carried out and allowed to specify the stoichiometry of the extracted species.
Abstract: The extraction of Se(VI) and Cr(VI) using a diammoniumcalix[4]arene was investigated. A study of parameters such as ligand concentration, pH or diluent was carried out and allowed to specify the stoichiometry of the extracted species. It was shown that Se(VI) is extracted into CHCl3 as (LH22+, Cl-, HSeO4-) and ((LH22+)2, 2Cl-, SeO42-)species at pH 2.6. An increase of pH or an addition of 5% or 10% decanol in CHCl3 favors the extraction of SeO42- over HSeO4- but leads to a drastic decrease of seleniumextraction. Cr(VI) was shown to be extracted as(LH22+, Cl-, HCrO4-) at pH 2.6 and probably as (LH+, HCrO4-) for higher pH.
TL;DR: In this paper, the luminescent properties of 5-chloro-8-hydroxyquinoline (CHQ) free and appended to the amines in diaza-18-crown-6 (A218C6) were determined.
Abstract: Luminescent properties of 5-chloro-8-hydroxyquinoline (CHQ) free and appended tothe amines in diaza-18-crown-6 (A218C6) were determined. These propertieswere compared to those of bivalent alkaline earth and post-transition metal ioncomplexes of the appended macrocycle (CHQ-A218C6). The luminescent properties were foundto be pH dependent. In the pH range 3 to 7, CHQ-A218C6 forms luminescent complexes withonly Zn2+ and Cd2+. At higher pH values, luminescent complexes wereformed with Mg2+, Ca2+, Sr2+, and Ba2+. No luminescent complex was formed by Hg2+ over the pH range studied. This lariat macrocycle could findapplication as a chemosensor for several of the metal ions studied.
TL;DR: In this paper, a new class of ionophores exhibiting a very high efficiency and selectivity in the complexation of cesium ion and its removal from highly acidic (HNO3) radioactive waste having also high sodium nitrate concentration (NaNO3] = 2-4 M).
Abstract: Cesium possesses two long lived isotopes 135Cs and 137Cs and the first one has a very long (2.3 × 106 y) half life and is one of the most mobile nuclides in a repository.Calix[4]arene-crowns-6 in the 1,3-alternate conformation areemerging as a new class of ionophores exhibiting a very high efficiency and selectivity in the complexation of cesium ion and itsremoval from highly acidic ([HNO3] = 3–4 M) radioactive waste having also high sodium nitrate concentration ([NaNO3] = 2–4 M). In order to improve both efficiency and cesium selectivity we have synthesised the novel calix[4]arene dibenzo-crowns-6 1 and 2 and thecalix[4]arene-monobenzocrown-6 3 in 1,3-alternate conformationand evaluated their complexation properties towards alkali metal cations in homogeneous solution and in two phase systems, togetherwith their performance in radioactive waste treatment. All data confirm the higher Cs/Na selectivity of the 1,3-alternate calix[4]crown-6 1–3 containing aromatic rings in the polyether loop, in comparison to previously synthesised compounds of the same series.
TL;DR: In this paper, a laser-induced fluorescence investigation of the phenothiazine dyes Methylene Blue (MB+) and MG+ is reported, where the effect of environment, fluorescence spectra of these molecules in a variety of solvents with different polarity and various concentrations of an anionic surfactant were measured.
Abstract: A laser-induced fluorescence investigation of the phenothiazine dyes Methylene Blue (MB+) and Methylene Green (MG+) is reported. To study the effect of environment, fluorescence spectra of these molecules in a variety of solvents with different polarity and various concentrations of an anionic surfactant were measured. The polarization and anisotropy analysis showed that there is no abrupt behavior except at the surfactant concentrations corresponding to the critical micellar concentration.
TL;DR: In this article, a carbon paste electrode based on the new macrocyclic diamide was constructed for Ca 2+ determination, which has a fast response time of <10 s and can be used for at least 3 months without any considerable divergence in potentials.
Abstract: A synthetic procedure has been developed for the preparation of 1,4-diaza-2,3;8,9-dibenzo-7,10-dioxacyclododecane-5,12dione. A carbon paste electrode based on the new macrocyclic diamide was constructed for Ca 2+ determination. The calibration graph was linear over a wide concentration range (1.3 × 10 −6 –3.2 × 10 −3 M) with a near Nernstian slope of 32 mV decade −1 . The limit of detection is 7.9 × 10 −7 M (0.032 ppm). Selectivity coefficients were tabulated and the working pH range was determined. It has a fast response time of <10 s and can be used for at least 3 months without any considerable divergence in potentials. The electrode was successfully applied to the determination of Ca 2+ ions in a
TL;DR: In this article, the FT-Raman spectra of o-, m-, and p-nitrophenol included in α-cyclodextrin (CD), β-CD, hydroxypropyl (HP) β -CD, andsulfated β- CD were recorded.
Abstract: FT-Raman spectra of o-, m-, and p-nitrophenol included in α-cyclodextrin (CD), β-CD, hydroxypropyl (HP) β-CD, andsulfated β-CD were recorded The phenyl ν(C=C) band of o- and p-nitrophenol in the CD inclusion complexes was shifted to higher wavenumber thanthat of pure o- and p-nitrophenol,whereas the phenyl ν(C=C) band of m-nitrophenol in the CD inclusion complexes was shifted to lower wavenumber than that of pure m-nitrophenol The ring νCH peak of o-nitrophenol in the CD complexes was shifted to higher wavenumber than that of pure o-nitrophenol, whereas the ring νCH peak of m- and p-nitrophenol in the CD complexes was shifted to lower wavenumber than that of pure m- and p-nitrophenol