Cation Binding Ability Research Articles

Photoinduced control of cation binding ability of non-conjugated bichromophoric receptors

Several receptors based on nonconjugated bichromophores displaying phototunable cation binding properties have been designed and studied. Some of these systems undergo a reversible photocyclisation to produce a crown ether or a cryptand; the photoswitching induces significant changes on a long time scale (hours to months after illumination) of the complexing ability of the material. Other bitopic receptors display a sudden and transitory change of cation concentration only during the singlet excited state lifetime.

Intramolecular Sandwich Complexation of Light Lanthanoid Nitrates with Bis(benzo-12-crown-4)s: Enhanced Selectivity for Eu

Spectrophotometric titrations performed in anhydrous acetonitrile at 25°C give the complex stability constants (log Ks) and the Gibbs free energy changes (-ΔG° for the stoichiometric 1 : 1 intramolecular sandwich complexation of light lanthanoid (III) nitrates (La ∼ Gd) with the polymethylene-bridged bis(benzo-12-crown-4)s 1, the corresponding dioxo derivative 2 and its dihydroxy analogue 3. The complex stability sequence as a function of reciprocal ionic radius of lanthanoids showed similar profiles in stability constants (log Ks) and maximum stabilities were obtained at Eu3+ for the complexation of light lanthanoids with the three bis(benzo-12-crown-4)s 1–3. The cation binding abilities and relative selectivities for the trivalent lanthanoid ions of these structurally related bis(benzo-12-crown-4)s 1–3 are discussed according to the derivatization of the bridging.

Synthesis and cation binding ability of azacrown ethers with phosphine or phosphine oxide side chain

Synthesis and cation binding ability of azacrown ethers with phosphine or phosphine oxide side chain

Silver and Thallium Ion Complexation with Allyloxycalix[4]arenes

A series of six calix[4]arene derivatives bearing allyl groups and/or benzyl groups functionalized at the phenolic oxygen atoms were synthesized and their cation-binding abilities for silver(I) and thallium(I) ions were evaluated through solvent extraction experiments. The results showed that both silver(I) and thallium(I) picrates were readily extracted by the tetrasubstituted p-t-butylcalixarene derivatives, while no extraction of sodium or potassium picrates was observed. The high extractability of thallium(I) picrate by these ligands was independent of the functional groups present, but the extraction of silver picrate seemed to be dependent on the conformational rigidity of the calixarene; those locked into the cone conformation showed the highest extractability for silver picrate.

A new calix[4]arene-bis(crown ether) derivative displaying an improved caesium over sodium selectivity: molecular dynamics and experimental investigation of alkali-metal ion complexation

In the light of computational studies suggesting enhanced cation-binding abilities for various benzo derivatives of calix[4]arene-bis-crown-6 macrocycles, the synthesis and properties of one of these ligands, BC6B2, have been investigated. In this compound, di(1,2-phenylene)-annelated glycolic chains link the 1,3- and 2,4-phenyl rings of the calixarene, thereby forcing it into the 1,3-alternate conformation. The detailed structures of BC6B2·CH3NO2 1 and Cs2(NO3)2BC6B2·CHCl3·H2O 2 have been established by X-ray crystallography. Studies of coordination and solvent extraction of the alkali-metal ions have been used to compare this ligand with a number of related systems known previously.

ChemInform Abstract: N‐(9‐Anthryl) Aza‐18‐crown‐6: Palladium‐Catalyzed Synthesis, Photophysical Properties and Cation Binding Ability.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Competitive binding of divalent cations to poly(α-hydroxyacrylic acid)

The competitive binding of divalent cations (Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) on poly(α-hydroxyacrylic acid) (PHA) and poly(acrylic acid) (PAA) was investigated by equilibrium dialysis. In the Mg/Ca mixed system, binding selectivity for Ca2+ over Mg2+ was significantly higher in PHA than in PAA; this was attributed to coordination of α-OH groups on PHA to Ca2+. The binding ability and selectivity for the transition metal cations were almost the same for PHA and PAA at neutral pH, while PHA maintained appreciably higher degrees of binding than PAA in acidic solutions (pH about 3). This cation binding ability of PHA was ascribed to the lower pKa value in the relevant pH region. © 1998 SCI.

Competitive binding of divalent cations to poly(α-hydroxyacrylic acid)

The competitive binding of divalent cations (Mg2+, Ca2+, Mn2+, Co2+, Ni2+, Cu2+ and Zn2+) on poly(α-hydroxyacrylic acid) (PHA) and poly(acrylic acid) (PAA) was investigated by equilibrium dialysis. In the Mg/Ca mixed system, binding selectivity for Ca2+ over Mg2+ was significantly higher in PHA than in PAA; this was attributed to coordination of α-OH groups on PHA to Ca2+. The binding ability and selectivity for the transition metal cations were almost the same for PHA and PAA at neutral pH, while PHA maintained appreciably higher degrees of binding than PAA in acidic solutions (pH about 3). This cation binding ability of PHA was ascribed to the lower pKa value in the relevant pH region. © 1998 SCI.

N-(9-anthryl) aza-18-crown-6: Palladium-catalysed synthesis, photophysical properties and cation binding ability

N-(9-Anthryl) aza-18-crown-6 ( 3) was synthesised via the palladium-catalysed cross-coupling of 9-bromoanthracene ( 1) and aza-18-crown-6 ( 2). Its photophysical properties include an intramolecular charge-transfer absorption band ( λ max ≈ 425 nm) in polar and non-polar solvents, which disappears upon protonation or binding of K + (log K ass = 3.7 in acetonitrile).

Intelligent networks based on poly(oxyethylene)

AbstractFilms of PEO and PEO blends were efficiently crosslinked by exposure to ultraviolet radiation with high‐pressure mercury lamp. Photochemical crosslinking proceeded in the presence of photoinitiator such as benzophenone or pentaerythritol triacrylate. PEO networks obtained by UV irradiation in the presence of potassium salts (thiocyanate, perchlorate and triflate) as templates showed enhanced cation binding ability for Li+ and Na+ cations. Cationic networks were prepared from crosslinked PEO modified with ethyl methacrylate dimethyl dodecyl ammonium bromide. Stimuli‐sensitive hydrogels (pH and temperature) were prepared from combinations of PEO and poly‐N‐isopropyl acryl amide, polyvinyl methyl ether, polyvinyl acetate and poly‐2‐vinyl pyridine subjected to UV irradiation.

Primary hydroxy-modified cyclomaltoheptaose derivatives with two kinds of substituents. Preparation of 6I-(benzyloxycarbonylamino)-, 6I-(tert-butoxycarbonylamino)- and 6I-azido-6I-deoxy-6II,6III,6IV, 6V,6VI,6VII-hexa-O-tosylcyclomaltoheptaose and their conversion to the hexakis-(3,6-anhydro) derivatives

Three cyclomaltoheptaoses (1, 2 and 3) which possess a benzyloxycarbonylamino group, a tert-butoxycarbonylamino group or an azido group, and six tosyloxy groups, on their C-6 atoms have been prepared. These can be versatile intermediates for the synthesis of derivatives possessing an amino group as well as other functional groups. As an example of their derivatization, their conversion to compounds containing 3,6-anhydroglucoses, which possess cation-binding abilities, is also reported.

Cation binding acceleration of Diels–Alder reaction of quinocrown ethers with cyclopentadiene

Diels–Alder reactions of 15–21 membered quinocrown ethers 1a–c with cyclopentadiene have been accelerated by the addition of alkali, alkaline-earth, and scandium perchlorates, reflecting the selective cation-binding abilities of crown ethers.

Comparative study of the mixed monolayers of valinomycin with dioctadecyldimethylammonium bromide and dipalmitoylphosphatidylethanolamine

The surface pressure-molecular area and surface potential-molecular area isotherms for mixed monolayers of valinomycin and dipalmitoylphosphatidylethanolamine (DPPE) or dioctadecyldimethylammonium bromide (DOMA) at various aqueous salt subphases were measured. Specific interaction of valinomycin in the monolayers of both lipids with K + as compared to Na + from the aqueous subphase was found. The head groups, positively charged (DOMA) and zwitterionic (DPPE), respectively, of the lipids influence the cation binding ability of valinomycin at the interfaces.

Crowned polyacetylene: 3. Synthesis and cation-binding property of polyphenylacetylene with azacrown cavity by cyclopolymerization of α,ω-bis(4′-ethynylphenoxy)oligooxyethylene containing a pyridyl unit

The cyclopolymerizations of 2,6-bis[7′-(4″-ethynylphenoxy)-2′,5′-dioxaheptyl]pyridine ( 1a) and 2,6-bis[10′-(4″-ethynylphenoxy)-2′,5′,8′-trioxadecyl]pyridine ( 1b) were carried out using the (bicyclo[2.2.1]hepta-2,5-diene)rhodium(I) chloride dimer. The yellowish powdery, organic solvent-soluble polymers were obtained using an amine as a cocatalyst. The resulting polymers consisted of cyclic constitutional repeating units as the main structure along with pendant acetylenic groups, i.e. the extent of cyclization was from 0.89 to 0.99 for the polyphenylacetylenes with an azacrown cavity, 2a and 2b, obtained from monomers 1a and 1b, respectively. Polymer 2 exhibited cation-binding ability for alkaline earth metal, heavy metal, and transition metal ions and, in particular, for Ag +. The complex of 2 with Ag +, which was confirmed by the 1H n.m.r. spectrum, consisted of the azacrown cavity and Ag + with a ratio of 2.

Photochromic Dispironaphthoxazine Polyethers: Synthesis and Their Cation Binding Capability

Abstract Dispironaphthoxazines incorporating polyether chain were synthesized. Photochromic effects on cation binding capability of the molecules were investigated. Due to the photochromic spironaphthoxazine unit in these compounds, complexation with metal cations is easily identified by the conventional spectroscopic method. Cation binding ability of dispironaphthoxazine with tetraethylene glycol unit is enhanced under the UV light irradiation. This type of photochromic compound may work as a photoresponsive ionophore.

X-Ray crystallographic study of octakis(3,6-anhydro)-γ-cyclodextrin with a highly specific cation binding ability

Octakis(3-6-anhydro)-γ-cyclodextrin, which is composed of eight 3,6,-anhydroglucoses, is analysed by X-ray crystallography to determine its unique structure which contains a hydrophilic cavity enabling specific binding to Cs+.

Synthetic studies on development of a novel macrolide ionophore: Configurational requirement of 16-membered macrodiolide for binding ability

Twelve synthetic 16-membered macrodiolides were prepared from racemic homononactic acid. The compounds which have an anti-relationship between the ether linkage of THF and the adjacent methyl showed the cation-binding ability. Macrodiolide 12 exhibited the ion selectivity for Li +.

Synthesis and alkali metal ion binding of poly(3,6-anhydro)-α-cyclodextrins

Pentakis(3,6-anhydro)-α-cyclodextrin and three regioisomers of tetrakis(3,6-anhydro)-α-cyclodextrin were synthesized from the corresponding 6- O-sulfonates to investigate the relationship among the molecular geometry, hydrophobicity-hydrophilicity balance, and inclusion behavior of CD. Each of the CD derivatives exhibited charateristic cation binding ability reflecting the unique molecular structure.

Design of Photochromic Crown Compounds and Their Applications to Photoswttchable Ion-Conducting Materials

Abstract Crowned spirobenzopyran and spironaphthoxazine have been designed which are capable of modulating their cation-binding ability by photoisomerization. They have been successfully applied as a key compound for photoswitchable ion-conducting composite films.

Polyethyleneglycol-catalysed benzil-benzilic acid rearrangement: A reaction in soluble macromolecular cavities

Kinetics of benzil-benzilic acid rearrangement was investigated in the presence of polyethyleneglycols (PEG) at different concentrations. PEG of molecular weights 400 and 6000 were used for the studies. A set of solutions was prepared with varying PEG contents. The rearrangement was carried out in these systems and the rate constants were calculated. The rates surprisingly increased with PEG content instead of decreasing due to the reduced ionic movement in these viscous macromolecular solutions. In the presence of KOH and NaOH, PEG acts as a catalyst for the rearrangement. But in presence of LiOH, an inverse relation was observed between PEG content and the rate of reaction. These observations were explained on the basis of the cation-binding ability of polyethyleneglycols.