Lithium-ion-conductive polyethylene oxide based polymer electrolytes containing tris(pentafluorophyenyl)borane

For enhancement of lithium-ion transference number, lithium-ion-conductive polymer electrolytes have been prepared from polyethylene oxide (PEO), lithium salt of LiCF₃SO₃ or LiF, plasticizer of polyethylene glycol dimethylether (PEGDME), and anion receptor of tris(pentafluorophenyl)borane (TPFB). Transport properties of the resultant polymer electrolytes have been studied by AC impedance spectroscopy. As a result, lithium-ion transference number increased with increasing TPFB due to the restriction of anion conduction by the interaction between anion and anion receptor. Effects of anion receptor on transport properties are discussed.     

Anion Recognition with Antimony(III) and Bismuth(III) Triaryl-Based Pnictogen Bonding Receptors

The synthesis and characterisation of a library of acyclic antimony(III) and bismuth(III) triaryl pnictogen bonding (PnB) receptor systems are reported. In the first-generation receptor series, quantitative ¹H NMR chloride titration experiments in THF solvent media reveal halide anion binding potency is intimately correlated with both the electronic-withdrawing nature of the aryl- substituent and the polarisability of the PnB donor. Further extensive anion binding investigations with the most potent Sb- and Bi-based PnB receptors: 1⋅Sb^2CF3 and 1⋅Bi^2CF3 , reveal novel selectivity profiles, both displaying Cl⁻ selectivity relative to the heavier halides and, impressively, to a range of highly basic oxoanions. The synthesis and preliminary chloride anion binding studies of a series of novel tripodal tris-proto-triazole triaryl Sb(III) and Bi(III) mixed PnB-HB receptor systems are also described. Whereas parent triphenyl Sb(III) and Bi(III) compounds are incapable of binding Cl⁻ in THF solvent media, the PnB-triazole HB host systems exhibit notable halide affinity.     

An electrochemical and optical anion chemosensor based on tripodal tris(ferrocenylurea)

A neutral tripodal tris(ferrocenylurea) anion receptor has been designed that can electrochemically and optically recognize sulfate and phosphate anions. The binding of the tetrahedral anion induced distinct cathodic shifts of the ferrocene/ferrocenium redox couple in chloroform, whereas the UV/Vis spectrum of the receptor showed an increase in the d–d transition band upon addition of sulfate ions. Furthermore, the anion complexes (TBA)₂ ? [SO₄?L] ? H₂O ( 1 ) and TBA[F?L] ( 2 ; TBA=tetrabutylammonium ion) were isolated. Crystal structural analyses showed that the receptor in the two 1:1 (host/guest) complexes encapsulated sulfate or fluoride ions in the tripodal cavity through multiple hydrogen bonds. ¹H NMR spectroscopic and ESI mass‐spectrometric analysis revealed strong sulfate and fluoride binding in solution.     

[Ru(phen)2(H2biim)](PF6)2配合物与阴离子的选择性作用

研究了[Ru(phen)₂(H₂biim)](PF₆)₂(1)与各种阴离子之间的选择性作用, 发现配合物1与Cl^-, Br^-, I^-, NO₃^-, HSO₄^-和H₂PO₄^-阴离子之间存在氢键作用. OAc^-阴离子与配合物1作用, 由于强的氢键作用使H₂biim上的一个H转移到OAc^-上, 使配合物1脱去一个质子, 形成{[Ru(phen)₂(H₂biim)](OAc)}结合体, 溶液颜色由黄色变为橙棕色. 由于F^-能形成非常稳定的HF₂^-, 配合物1逐步脱去2个质子, 溶液颜色由黄色变为紫色, 因此可作为裸眼检测阴离子的识别剂.     

Cobalt(III) Supramolecuar Complex: Synthesis,Crystal Structure and Anions Recognition Properties of 6,7-Dinitroquinoxaline-2,3-dione

A 3D supramolecular complex [Co(III)(Phen)₂Cl₂][DNQ]Cl·H₂O (DNQ = 6,7-dinitroquinoxaline-2,3-dione) has been synthesized and determined by single-crystal X-ray analysis. Anion binding studies carried out using ¹H NMR and UV-visible revealed that a genuine hydrogen bond interaction between anion receptor 2 and Cl^?  can be detected, but fluoride is deprotonating the anion receptor 2. X-ray analysis results show that it is not possible for the two amide nitrogen atoms of anion receptor to form hydrogen bonds to a chloride ion in the presence of small aliquots of water.     

Self-assembly architecture of bis(guanidiniums) receptors incorporated by sulfate anions in single crystals

A novel bis(guanidiniums)receptor for the catalytic cleavage of phosphosdiester was prepared and self-assembly architecture through hydrogen bonds and electrostatic interactions a-mong the bis(guanidiniums)receptor,the sulfate anion and water molecule was revealed by X-ray crystallographic analy-     

Acetate recognition by 2,6-bis(2-benzimidazolyl)pyridine

2,6-Bis(2-benzimidazolyl)pyridine, bbp, a simple tridentate ligand, is employed as a receptor for the recognition of anions. The binding of anionic guest species with bbp can be studied in short duration using UV/vis spectroscopy, fluorescence spectroscopy and (1)H NMR techniques at very low concentrations. The results obtained from the above spectroscopic techniques indicate that 2,6-bis(2-benzimidazolyl)pyridine is an efficient anion receptor providing chemical shift and optical modification based signals for the detection of acetate ions.     

A binary catalytic system based on mixed monolayers of a phospholipid and amphiphilic bis(Zn2+-cyclen)

Herein, we report on the study of the properties of mixed Langmuir monolayers composed of a synthetic amphiphilic receptor, alkylated bis-cyclic zinc complex of 1,4,7,10-tetraazacyclododecane, and a lipid, distearoyl phosphatidylcholine. The kinetics of a hydrolysis of a model substrate, bis(p-nitrophenyl) phosphate in individual and mixed monolayers of the amphiphilic receptor was studied by using fiber-optical absorption/reflection spectroscopy. The hydrolysis of the organic phosphate in these planar systems proceeded by a two-stage mechanism. This mechanism comprises substrate adsorption on the monolayer via a reaction of the zero order with respect to the adsorbate followed by the pseudo-second-order reaction of the hydrolytic decomposition of the substrate. Unlike the reaction in molecular and colloidal solutions, the process in the monolayer results in the complete decomposition of the model substrate into nitrophenol and phosphate anion. The amphiphilic receptor is directly involved in this reaction to yield a stable complex with the phosphate anion as a resulting product of hydrolysis. An increase in the receptor affinity for the phosphate anion is, most likely, due to the effect of the interface on the strength of the coordination bonds in an intermediate product and the receptor-phosphate complex. Immobilization of the receptor within the lipid matrix increases the rate of substrate decomposition in the monolayer by almost an order of magnitude. We suggested an explanation for the observed effect of the lipid matrix on the catalytic properties of the amphiphilic metallocomplex.     

Nitro-substituted 3,3'-bis(indolyl)methane derivatives as anion receptors: electron-withdrawing effect and tunability of anion binding properties

A series of nitro-substituted 3,3'-bis-indolyl phenylmethane derivatives were synthesized and their anion binding properties were investigated in detail. The introduction of the electron-withdrawing nitro group into indole unit and/or meso-phenyl ring, which leads to the increased acidity of indole NH and meso-position CH proton, has a positive effect on anion binding. The nitro-substituted bis(indolyl)methane receptors exhibited selective colorimetric sensing of F- anion, as revealed by the notable color and spectral changes, rationally due to the deprotonation of the indole NH of the receptor. Meanwhile, the additive introduction of the nitro substituents on the meso-phenyl ring of bis(indolyl)methane can lead to the deprotonation of the meso-position CH and further induce an irreversible oxidation process obtaining bis(indolyl)methene product in the F- anion sensing system.     

Diphenylmethane-based anion receptors bearing bis(p-toluenesulfonyl urea) groups

Diphenylmethane-based receptors (1) bearing urea units were prepared for anion recognition. Analogous anion receptors based on biphenyl (2), diphenylsulfide (3), cyclophane (4) and phenyl (5) were also synthesized as control compounds. Their anion recognition ability was evaluated by ¹H-NMR spectroscopy in CDCl₃ at 297 K. The association constants for the complexation between receptors and anions are strongly dependent on the framework of the receptors and the urea moiety substituent. The much stronger binding of a chloride anion by the diphenylmethane-based receptor (1a) having two p-toluenesulfonyl urea groups was observed. It is rationalized by the stronger hydrogen bond donor strength of the p-toluenesulfonyl urea group and the moderate flexibility of the diphenylmethane framework and is explained in terms of the complex geometry.     

OH(3) (-) and O(2)H(5) (-) double Rydberg anions: predictions and comparisons with NH(4) (-) and N(2)H(7) (-)

A low barrier in the reaction pathway between the double Rydberg isomer of OH(3) (-) and a hydride-water complex indicates that the former species is more difficult to isolate and characterize through anion photoelectron spectroscopy than the well known double Rydberg anion (DRA), tetrahedral NH(4) (-). Electron propagator calculations of vertical electron detachment energies (VEDEs) and isosurface plots of the electron localization function disclose that the transition state's electronic structure more closely resembles that of the DRA than that of the hydride-water complex. Possible stabilization of the OH(3) (-) DRA through hydrogen bonding or ion-dipole interactions is examined through calculations on O(2)H(5) (-) species. Three O(2)H(5) (-) minima with H(-)(H(2)O)(2), hydrogen-bridged, and DRA-molecule structures resemble previously discovered N(2)H(7) (-) species and have well separated VEDEs that may be observable in anion photoelectron spectra.     

胍盐化合物[C(NH_2)_3]_(6.3)K[Nb_(1.3)W_(10.7)O_(40)H_2]·H_2O的合成及性质

通过粉状白钨酸和可溶性铌酸钾水溶液的反应,合成了十二聚系列的钨铌杂多阴离子胍盐化合物[C(NH_2)_3]_(6.3)K[Nb_(1.3)W_(10.7)O_(40)H_2]·H_2O,研究了其水溶液的酸碱稳定性。根据红外、拉曼和紫外光谱、化学性质,认为该化合物可能具有十二聚偏钨酸根阴离子的结构骨架。     

Self-assembly of a chiral carbonate- and cytidine-containing dodecanuclear copper(II) complex: a multiarm-supplied globular capsule

A dodecanuclear copper(II) globular-shaped structure has been obtained with the cytidine nucleoside and the templating carbonate anion. It shows receptor properties through anion-cation and multiple anion-pi interactions toward ClO 4 (-) as well as an overall antiferromagnetic coupling.     

Tripodal nitro-imidazolium receptor for anion binding driven by (C-H)+- - -X- hydrogen bonds

[structure: see text] A positively charged tripodal receptor with nitro groups in the imidazolium rings was designed, synthesized, and characterized for its anion binding strength. The receptor shows strong affinity and high selectivity for Cl- through (C-H)+- - -X(-) hydrogen bonds wherein charge-charge and charge-dipole electrostatic interactions dominate. The association constant with chloride anion in a 9:1 mixture of acetonitrile-d3 and DMSO-d6 is measured to be 1.1 x 10(6) M(-1). The receptor also shows reasonably high affinity toward H2PO4-.     

Ab initio molecular orbital study of structures and energetics of Si(3)H(2), Si(3)H(2) (+), and Si(3)H(2) (-)

The geometric structures, isomeric stabilities, and potential energy profiles of various isomers and transition states in Si(3)H(2) neutral, cation and anion are investigated at the coupled-cluster singles, doubles (triples) level of theory. For the geometrical survey, the basis sets used are of the Dunning's correlation consistent basis sets of triple-zeta quality (cc-pVTZ) for the neutral and cation and the Dunning's correlation consistent basis sets of double-zeta quality with diffuse functions (aug-cc-pVDZ) for the anion. For the final energy calculations, the aug-cc-pVTZ: Dunning's correlation consistent basis sets of triple-zeta quality with diffuse functions and cc-pVQZ: Dunning's correlation consistent basis sets of quadruple-zeta quality basis sets are used for the neutral and the aug-cc-pVTZ ones for the cation and anion. The global minimum neutral (I-1: (1)A(1)) has the same framework as that (cyclopropenylidene) of the C(3)H(2) molecule. Other low-lying three isomers (I-2, I-3, and I-4) are also predicted to be within 20 kJ/mol. Five transition states are optimized and their energy relationships with the isomers are clarified. The geometric structure of the global minimum cation (C-1: (2)A(1)) has the same framework as that of the neutral, but that of the anion (A-1: (2)A(')) differs very much from those of the neutral and cation. The calculated vertical and adiabatic ionization potentials from the global minimum neutral (I-1) are 7.85 and 7.77 eV, respectively. The adiabatic electron affinity of the neutral I-1 and the electron detachment energy of the global minimum anion (A-1) are predicted to be 1.21 and 1.92 eV, respectively. The two-electron three-centered bond is widely observed in the present Si(3)H(2) neutral, cation, and anion. The contour plots of their localized molecular orbitals clearly show the existence of such nonclassical chemical bonds.     

A terpyridyl-imidazole (tpy-HImzPh3) based bifunctional receptor for multichannel detection of Fe2+ and F- ions

The X-ray crystal structures of the tridentate ligand, 4'-[4-(4,5-diphenyl-1H-imidazol-2-yl)-phenyl]-[2,2':6',2']terpyridine (tpy-HImzPh(3)) and its bis-homoleptic iron(ii) complex of composition [Fe(tpy-HImzPh(3))(2)](2+) have been determined, showing that the ligand crystallized in a monoclinic form with the space group P2(1)/c while its Fe(II) complex crystallizes in an orthorhombic form with space group Fddd. Both the anion and cation binding properties of the receptor were thoroughly investigated in dimethylformamide-acetonitrile (1?:?9) solution using absorption, emission, and (1)H NMR spectral studies which revealed that the receptor acts as a sensor for both F(-) and Fe(2+). In the presence of excess F(-) ion, deprotonation of the imidazole N-H fragment of the receptor occurs, an event which is signaled by the development of a yellow color visible with the naked eye. The estimated value of the equilibrium constant of the receptor with F(-) is 1.9 × 10(4) M(-1). Deprotonation is also observed in the presence of hydroxide. The receptor also shows colorimetric and fluorimetric sensing ability towards Fe(2+) ions. The binding site for the metal ion in the system has been unambiguously established by single-crystal X-ray diffraction studies of the Fe(II) complex of the receptor. The influence of solvents on the absorption and fluorescence spectra of the receptor has been investigated in detail. Cyclic voltammetric (CV) and square wave voltammetric (SWV) measurements carried out in dimethylformamide-acetonitrile (2?:?3) provided evidence in favor of cation (Fe(2+)) and anion (F(-)) concentration dependent electrochemical responses, enabling the ligand to act as a suitable electrochemical sensor for F(-) and Fe(2+) ions.     

Anion-selective interaction and colorimeter by an optical metalloreceptor based on ruthenium(II) 2,2'-biimidazole: hydrogen bonding and proton transfer

A new anion sensor [Ru(bpy)2(H2biim)](PF6)2 (1) (bpy = 2,2'-bipyridine and H2biim = 2,2'-biimidazole) has been developed, in which the Ru(II)-bpy moiety acts as a chromophore and the H2biim ligand as an anion receptor via hydrogen bonding. A systematic investigation shows that 1 is an eligible sensor for various anions. It donates protons for hydrogen bonding to Cl-, Br-, I-, NO3-, HSO4-, H2PO4-, and OAc- anions and further actualizes monoproton transfer to the OAc- anion, changing color from yellow to orange brown. The fluoride ion has a high affinity toward the N-H group of the H2biim ligand for proton transfer, rather than hydrogen bonding, because of the formation of the highly stable HF2- anion, resulting in stepwise deprotonation of the two N-H fragments. These processes are signaled by vivid color changes from yellow to orange brown and then to violet because of second-sphere donor-acceptor interactions between Ru(II)-H2biim and the anions. The significant color changes can be distinguished visually. The processes are not only determined by the basicity of anion but also by the strength of hydrogen bonding and the stability of the anion-receptor complexes. The design strategy and remarkable photophysical properties of sensor 1 help to extend the development of anion sensors.     

Ion Interactions with a New Ditopic Naphthalimide‐Based Receptor: A Photophysical,NMR and Theoretical (DFT) Study

A new multi‐component chemosensor system comprising a naphthalimide moiety as fluorophore is designed and developed to investigate receptor–analyte binding interactions in the presence of metal and non‐metal ions. A dimethylamino moiety is utilized as receptor for metal ions and a thiourea receptor, having acidic protons, for binding anions. The system is characterized by conventional analytical methods. The absorption and fluorescence spectra of the system consist of a broad band typical for an intramolecular charge transfer (ICT). The effects of various metal‐ion additives on the spectral behavior of the present sensor system are examined in acetonitrile. It is found that among the metal ions studied, alkali/alkaline earth‐metal ions and transition‐metal ions modulate the absorption and fluorescence spectra of the system. As an additional feature, the anion signaling behavior of the system in acetonitrile is studied. A decrease in fluorescence efficiency of the system is observed upon addition of fluoride and acetate anions. Fluorescence quenching is most effective in the case of fluoride ions. This is attributed to the enhancement of the photoinduced electron transfer from the anion receptor to the fluorophore moiety. Hydrogen‐bond interactions between the acidic NH protons of the thiourea moiety and the F^? anions are primarily attributed to the fluoride‐selective signaling behavior. Interestingly, a negative cooperativity for the binding event is observed when the interactions of the system are studied in the presence of both Zn²⁺ and F^? ions. NMR spectroscopy and theoretical calculations are also carried out to better understand the receptor–analyte binding.     

Protective layer with oligo(ethylene glycol) borate anion receptor for lithium metal electrode stabilization

The gel polymer electrolyte based on semi-IPN (interpenetrating polymer network) structure for the protection of lithium metal electrode was successfully developed by ultraviolet (UV) radiation-curing method. A curable mixed solution consists of linear polymer (Kynar 2801), crosslinking agent (1,6-hexanediol diacrylate), liquid electrolyte (ethylene carbonate (EC)/propylene carbonate (PC)/1 M LiClO₄), oligo(ethylene glycol) borate (OEGB) anion receptor, and photoinitiator (methyl benzoylformate). The OEGB was synthesized by the dehydrocoupling reaction of hydroxyl group in di(ethylene glycol) methyl ether with hydrogen in BH₃ and characterized by ¹H NMR. The presence of OEGB anion receptor in the protection layer could lead to an enhancement in the ionic conductivity, electrochemical stability, and the interfacial properties. The deposited lithium exhibited particle-like shape resulting from the introduction of the protection layer onto the lithium electrode surface. The unit cell based on the lithium anode protected with gel polymer electrolyte containing OEGB showed higher discharge capacity than that of the unit cell without OEGB after 100 cycles at C/2 rate (1.25 mA cm⁻²).     

The anion binding properties of neutral receptors bearing nitro group,phenanthroline or ruthenium(II) metal

A series of neutral cyclohexadiamine anion receptors containing nitro, phenanthroline or ruthenium(II) have been designed and synthesized. Their u.v.–vis spectroscopy investigations reveal that the receptor bearing nitro group displays the strongest affinities for F⁻, AcO⁻, H₂PO ₄ ⁻ and can be used as an efficient detection tool for the above anions. Results indicate that the anion affinities can be enhanced through appending nitro group and ruthenium(II) metal compared with phenanthroline moiety.